Document jgonegOX3mwxG11bLaYJzZQaN

REFERfciw: autm iet To Be Taken Front library ,. ^JLaJAvv^ W, 2*j*. Niw 'fr ,vr--- 3 -G~4S s h It f A dLtruJ-'-' (jfouM-^>vJtf __ iit Company Organic Chemicals Division St. Louis Research Department ?-13th , jt*4- V 733, Jfu ) St. Louis Research Report No. P-1381 TENTATIVE PROCESS FOR PRODUCTION OF PLASTIMER III ETHYLENE/VINYL CHLORIDE COPOLYMER Job No. 2-02-760.01-4733 July 7, 1965 Written by: M. E. Gibbs R. W. Bucknell R. C. Gross B. Katlafsky W. M. Mees Work done by: *rs_ # r~' jf=x ** p Xr r s'" K 7- V'' ' fiv. . n "irw ] ' -\X ^ K- St !<*; ;! , ';;,!'f V. # R. W. Bucknell*^ A. Alt ^ B. Bhatia J. H. Brown A.W.M. Coaker*"" R. W. Flagg ^ M. E. Gibbs-' J . H Hahn J. D. Hinchen'*" ^ B. Katlafsky W. M. Mees ' RSV 0017463 MONSANTO COMPANY Organic Chemicals Division SC. Louis Research Department Date: MAY 4 1QR7 DISTRIBUTION R. w. Bucknell H. L. Hubbard M. E. Gibbs J. F. Quinn J. Neff T. H. Lafferre P. N. Biven - Interim Plant A. W. M. Coaker R. E. Bilger H. J. Hileraan Extras (5) (3) REJECTED APPROVED AMENDMENT TO THE TENTATIVE PROCESS FOR PRODUCTION OF PLASTIMER III ETHYLENE/VINYL CHLORIDE COPOLYMER Written by M. E. Gibbs etal; Dated July 7, 1965 Report No. P-1381; Job No. 2-02 760.01-4733 FINAL DISPOSITION Sub Title: Elimination of heat treatment prior to washing of polymer. f Cf tc ( iy t r f-w. t-L0 <- ^ c.t a--,-- 1' t.f,iX <; .x~Z<7&- 7 Signed: RSV 0017464 Date : / MONSANTO CCMPANY Organic Chemicals Division St. Louis Research Department November 9, 1965 DISTRIBUTION 1. File<*J*- 2. R. W. Bucknell' 3. H. L. Hubbard 4. Duplicate File 5. Technical Reports Library 6. M. E. Gibbs 7. J. F. Quinn 8. J. Neff - Org. Eng. 9. T. H. Lafferre - Org. Eng. SAFETY REVIEW COMMITTEE approved,^:; 10. Interim Plant - J. F. Queeny Plane 11. Interim Plant - J. F. Queeny Plant 12. Interim Plant - J. F. Queeny Plant 13. A. W. M. Coaker 14. R. E. Bilger 15. H. J. Hileraan - Cent. Res. 16. - 18. Safety Review Committee 19. - 35. Technical Information Group TENTATIVE AMENDMENT A to the TENTATIVE PROCESS FOR PRODUCTION OF PLASTIMER III ETHYLENE/VINYL CHLORIDE COPOLYMER Report No. P-1381; Job No. 2-02-760.01-4733 Objective: Elimination of heat treatment prior to washing of polymer. Present Practice: The Plastimer III copolymer slurry is agitated for 1 hour at 60-65C. with an equal weight of filtered tap water, the slurry is then cooled to 30C. or less and centrifuged. Proposed Change: The Plastimer III copolymer slurry is to be agitated at 30-35C. for 1 hour with an equal weight of water (227 pound/100 lbs. of polymer). Justification: Laboratory experiments indicate that a lower residual lauric acid content results when the heat treatment is eliminated. The expected lauric acid content will be in the range of 0.70-0.85% by weight. The heat stability of polymer will not be affected by cold washing. Precaution: No unusual hazards exist. Approved: / ' - /, if. Erl Hubbard /?., R. W. Bucknell ds Q R. W. Bucknell Date U-iUz Dace C. E. Butts R. D. Smith Dale Date' RSV 0017465 DISTRIBUTION OF REPORT NO. P-1381 1. File 2. R. W. Bucknell 3. H. L. Hubbard 4. Duplicate File 5. Central Reports Library 6. M. E. Gibbs 7. J. F, Quinn 8. J. Neff - Organic Engineering . 9. T. H. Lafferre - Organic Engineering 10. Interim Plant - J. F. Queeny Plant 11. ri it ti it ir m 12. ti u nn n m 13. A.W.M . Coaker 14. R. E. Bilger 15. H. J. Hileman - Central Research 16. Extra 17- n 18. n 19. t! This report contains confidential information which is the property of the Monsanto Company and which shall be disclosed only to duly authorized persons. Tne recipient is held accountable for the filing and safe custody of the report, which must be returned on demand. pgy Q017466 TABLE OF CONTENTS Page No. INTRODUCTION ................................................................................ 1 SYNOPSIS OF PROCESS ............... FLOW SHEETS ................................................................................... 1 5 MATERIAL BALANCE ............ 5 A. Bill of Materials for Plastlmer III made with Ammonium Laurate .......... B. Bill of Materials for Plastimer III made with ABS ............................ .............. * .. .. C. Yield ............... D. Material Balance Sheet ....................... 5 6 7 7 PROCESS IN DETAIL .................................................................. 10 A. Summary ....................................................................... B. Reaction ...................................................................... 1. Reactor Feeds ............ 2. Reactor System ............................................ C. Coagulation .............................................................. D. Washing ........................................................................ E. Drying ...................................... ................ F. Reactor Washout .................................................... 10 10 10 12 15 15 l8 18 DISCUSSION OF IMPORTANT VARIABLES .......................... l8 A. Reactor Charge ...................................................... 1. Persulfate Redox System and Surfactant ....................................................... 2. Oxygen a Retardant .................................. 5- Aqueous and Monomer Charge ............. 4. pH of Ammonium Persulfate Solution ............................................................ B. Control of Reaction .......................................... 1. Rate ................ ....................................-............... 2. Pressure Control ............... C. Reaction End Point ................. ......................... D. Formation of Solids in Reactor ...... 1. Solids Due to Shear ............. 2. Solids as Function of Extent of Reaction E. Pressure Letdown ................................................. l8 l8 19 19 25 25 25 25 25 25 25 27 27 RSV 0017467 i TABLE OF CONTENTS (Cont.) Page No. F. Coagulation of Latex . ............................. * G. Polymer Washing ................................................. H. Polymer Drying ............. ....................................... I. Coagulation Tube Washout .................. .. J. Materials of Construction .......................... K. Conversion ................................................................ 27 28 28 29 29 29 MATERIAL SPECIFICATIONS, ANALYTICAL METHODS . 29 A. Raw Materials ....................................................... 1- Vinyl Chloride ...........*............ ................ 2, Ethylene ................................. .................. 5- Persulfate Redox Catalyst System Materials ......................................................... 4. Surfactant ....................................................... 5* Water ................................................................... 6. Nitrogen ........................................................... B. Product ................................. 1. Reactor Latex Product .......................... 2. Specifications for Solid Polymer Product ............................ C. Analytical Methods ............................................ 1. Latex Solids ............................ 2 . pH . .................. 3. Determination of Alkyl Benzene Sulfonate in Plastimer ....................... 4. Determination of Water In Plastimer by Karl Fischer Reagent ........................................................... 5. Determination of Intrinsic Viscosity of Plastimer .......... 6. Infrared Determination of the Vinyl Chloride Content of Plastimer III ......................... 7. Determination of Te of Plastimer by D.T.A......................... 8. Melt Flow of Plastimer ....................... 9. Preparation and Molding of Plastimer Resin ...................................... 10. Thermal Stability of Plastimer .. 11. Buoyancy Method of Density Determination ............... 12. Shore "D" Hardness of Plastimer . 13. Determination o'f Tensile Strength, Elongation and Modulus of Plastimer - A Varient of ASTM D 638-6IT .................................................... .. . 29 29 50 50 51 52 52 52 52 55 55 55 5^ 54 35 58 4l 47 51 33 57 59 6l 63 RSV 0017468 TABLE OF CONTENTS (Cont.) Page No. 14. Plasticorder Fusion of Plastimer in S.V.T. .(Brabender) ...................................... 15* McBurney Hardness Test for Vinyl Floor Tile ............. ................... .................. 16. Armstrong Indentation Test for Vinyl Floor Tile ....................................... 17* Determination of Ethylene-Vinyl Chlorid_e Monomer Composition .... 66 70 73 76 TOXICITY AND HAZARDS ........................................................... 79 A. Vinyl Chloride ...................................................... B. Ethylene .......................................................... C. Ammonium Persulfate .......................................... 79 79 79 POLLUTION CONTROL ................................................................... 79 REFERENCES ..................................................................................... 80 ENGINEERING DATA ...................................................................... 80 ACKNOWLEDGEMENT ........................................................................ 80 APPENDIX .......................................................................................... 8l RSV 0017469 Page No. LIST OF -FIGURES 1. Plastimer III Material Balance Flow Sheet .......... 2. Vinyl Chloride Addition Versus Time ........... 3. Rate of Freezing of Latex ..................................... 4. Effect of Initial VC1 Concentration Upon Composition of Polymer ............................................ 3. Effect of Error in Aqueous and VC1 Charges Upon Initial Monomer Composition. *! v* 6. Total Reaction Time as a Function of AFS Feed Rate ................................................................... 7- Polymer Composition as a Function of Total Solids in Latex ............................................... 8. Plastimer III IR Spectra .................................... 9. Plastimer III IR Calibration ............................. 10. CaH-i-VCl Monomer Chromatogram .......................... 11. Heat Generation of Plastimer III Reaction As a Function of Batch Time ............................... 4 14 16 20 21 24 26 45 46 78 82 RSV 0017470 Page No. LIST OF TABLES I. Abbreviations and Molecular Weights ................ 2 II. Monomer Conversion ......................................... III. Plastimer III Material Balance for Ammonium Laurate ................................................................. 8 IV. Plastimer III Material Balance for ABS .. 9 V. Physical Constants Data for Ethylene .... 83 VI. Physical Constants Data for Vinyl Chloride ......................................................... .............. .. 84 7 APPENDIXES A. Laboratory Autoclave ..................................................... A-l. B. Preparation of Ammonium Laurate ......... A-2. RSV 0017471 1. INTRODUCTION Research studies on the ethylene/vinyl chloride reaction were initiated within the Central Research Department (CRD), and a recipe was developed for Plastlmer III, a copolymer high in vinyl chloride content. Plastimer III was prepared in quantity by CRD for application and evaluation in floor tile formulations at Armstrong Cork and Kentile. Preliminary results from these evaluations indicated favorable application properties. As a result, the responsibility of completing the process development was transferred to the Organic Division Research Department in March, 1965* Modifications of the recipe were made and a process developed. The purpose of this tentative process is to provide a basis for design and operation of manufacturing facilities to produce 1.0-1.5 million pounds per year of Plastimer III copolymer. SYNOPSIS OF PROCESS This process consists of reacting ethylene with vinyl chloride in the presence of a persulfate redox catalyst system. The reaction is carried out as a semi-batch type reaction in a single reactor at a pressure of 850 psig. and a temperature of 30C . The initial charge to the reactor includes an aqueous solution of the redox catalyst system, a surfactant and a buffer; and a mixture of ethylene and vinyl chloride monomers containing 68-69# vinyl chloride by weight. Ammonium persulfate (APS) which serves as an Initiator for the catalyst system is continuously added at a constant rate to the reaction mass. Vinyl chloride is added continuously and concurrently with the APS upon demand in order to main tain a constant pressure in the reactor. Ammonium persulfate is added to the reactor in such quantity that the reaction rate approaches zero when sufficient vinyl chloride has been added to give a product latex containing 45.5-47.5# total solids. When all of the vinyl chloride has been added, the VC1 feed stream is stopped and the unreacted monomers in the reactor are vented. When the reactor pressure reaches atmospheric pressure, the latex is drained, frozen in a cold stage at -15C. and subsequently thawed. The polymer slurry is diluted with water, heat-treated at 60-65C. batchwise and separated from the mother liquor by centrifugation. The polymer solid is washed on the centrifuge and dried at 35-45C. RSV 0017472 TABLE I Abbreviations and Molecular Weights Compound Formula Ammonium hydroxide NH-tOH Ammonium laurate CnHsaCOONH* Sodium dodecyl benzene sulfonate Ci2H2sCeH4S03Na Ammonium persulfate (NH4)aS20e Ethylene C2H4 Ferric ammonium sulfate Fe(NH4)(S04)a12HaO Soldum formaldehyde sulfoxylate NaHS02 *CH20 Sodium pyrophosphate Na4P207-10Ha0 Tetrasodium ethylenediamine tetraacetate Na4EDTA Vinyl chloride VC1 Water H20 Abbreviation NH4OH AL ABS APS c2h4 FAS SFS SPP Na4EDTA VC1 H20 Molecular Weight 35.05 217-34 349.49 228.20 28.05 484.21 154.12 446.11 380.2 62.50 18.02 ro 3. Simplified equations follow: Persulfate Redox System Fe(EDTA) + CH20H*S02-->Fe(EDTA) = + reduction products ...(1) Fe(EDTA)" + SsOeT-->Fe(EDTA)_ + S04 = + S04T ....................................(2) Polymerization Reaction 5HaC = CH + H2C - CHs I Cl S0+7 > ^HaC-CH-CHa-CH-CHa-CH-CHa-CH-CHa-CH-CHa-CHaVn. -(3; Cl Cl Cl Cl Cl FLOW SHEETS A schematic flow diagram is given in Figure 1. The material balances in Tables III and IV are keyed to this diagram and are based on 100 pounds of product produced (containing 98*6 pounds of E/VC1 polymer). RSV 0017474 r a <D<><D^ 1> o !l Q>S > * 1I <j K> Cj <2> 0<3> 0 <S>0<5> kl VJ ""J QQ ^4 't k $$ N <0 tel > \D k \ Vs. RSV 0017475 \2y I o o X UJ f o< G h- o Q-< 0 0 0 Uj VJ >4 00 -j sk ^ jy N |^ k N w vO X RSV 0017476 5. MATERIAL BALANCE A. Bill of Materials for Plastimer III made with Ammonium Laurate (Basis: 100 pounds of product (98.6 pounds E/VC1 polymer); total reactor volume 31.7 gallons.) Material Pounds Consumed Pounds Produced NH4OH (28#) APS AL SPP PAS Na^EDTA SPS C2H4 VC1 H20 Vent gas to flare Pot solids Mother liquor Wash liquor Off-gases Drier gases Product polymer 1.26 0.421 3.22 2-35 0.040 0.062 0.427 29.3 106. 3321. 33.9 0.420 340. 2968. 3.89 .17.9 100 Total 3464.080 3464.110 RSV 0017477 6. Bill of Materials for Plastimer III made with ABS (Basis: 100 pounds of product /98.6 pounds E/VC1 polymer/; total reactor volume 52.5 gallons.) Material Pounds Consumed Pounds Produced NH*0H (28#) APS ABS SPP PAS Na*EDTA SFS C2H4 VC1 Hs0 Vent gas to flare Pot solids Mother liquor Wash liquor Off-gases Drier gases Product polymer 1.27 0.424 5.21 2.36 0.040 0.062 0.429 29.8 105. 3338. 32.5 1.27 343. 2983. 5.18 17.8 100. Total 3482.595 3482.75 RSV 0017478 CnHaaCOONH^ 7- C. Yield Yield figures are given in Table II in terms of monomer conversion as pounds per 100 pounds of product polymer formed. TABI II Monomer Conversion Process Monomer VC1 C2H4 Total Monomer Pounds Charged 105-6 29-3 13^-9 Pounds Converted to Plastlmer III 87.3 11.3 98.6 Percent Conversion 82.6 38.7 73-0 Process VC1 C2H4 Total Monomer 105.3 29.8 133-1 86.7 11.3 98.0 82.2 37-9 72.6 D. Material Balance Sheet Detailed material balance sheets are given in Tables III (CnH23C00NH4 Process) and Table IV (ABS Process). Three significant figures to the right of the decimal point are carried throughout Tables III and IV to effect complete mathematical balances. The significant places in these two tables do not necessarily indicate required accuracy. Required accuracy is indicated in the remainder of this report. ABS RSV 0017479 TABlfi III ef III H3t`flal t'aUrctf for Ajmnonlum Uurau ' : U . O..X> 11 12 0.7)0 lu 17 18 15 22 ! 22 U 0.J2O o.o>6 21 25 26 21 2S 22 0.121 15.806 0,121 >.222 2.027 O.OlO 0.062 > .222 O.Br,) 0.166 0.17) >.222 0.>80 1 0.)80 1.777 0.115 1.000 1.000 0.708 3.222 1.319 "ja 17 .>17 1 .tflo 0.657 79B z.iod i }),860 >0 0.2> 1)3 0.127 2.350 o.oso 0.092 0.2 0.088 0.001 0.001 120.106 98.678 228.7*) 21.6 120.106 226.979 1.0)0 98.076 226.901 21.2 226.979 27.2 Q.699 7. 0.799 1.660 29-20 >16.620 29TJ.159 3.>76 98.o78 152.280 297>.159 51.>o >57-0 0.02a 0.118 6.20 535-971 2965.Bll \.8\9 1.521 >)9-567 2967.780 10.1 >56.J '* 18.266 98.678 U7-9H 17.667 0.077 17.911 >57 0.399 0.335 0.323 120.106 1.030 98.031 98.676 100.600 21.O* 1.06> 11.1 227.680 21.3 RSV 0017480 RSV 0017481 il 10. PROCESS IN DETAIL A. Suitunary This process for the manufacture of ethylene/vinyl chloride copolymer suitable for floor tile resin consists of four major steps: reaction, coagulation, washing and drying. The reaction is accomplished by an emulsion polymerization of ethylene and vinyl chloride under a pressure of 850 psig. at 30C. in a reactor with a volume of 31*7 gallons. The latex formed in the reaction is then frozen to coagulate the polymer solids. The polymer solids are recovered from the two-phase liquid-solid mixture after first under going a heat treatment to facilitate washing. After the catalysts and surfactant have been washed from the polymer, the polymer solids are dried under a vacuum of 15-30 mm. Hg at 40C. The reaction may be carried out with alternate surfactants. Complete material balances are given in Tables III and IV using both ammonium laurate and dodecyl benzene sulfonates (ABS) as surfactants. However, the Process in Detail Section is based only on the ammonium laurate process. The process for ABS is very similar except for small changes in material balance which can be obtained from Table IV and reaction volume (per 100 pounds product, 31*7 gallons for AL and 32.5 for ABS). B. Reaction 1. Reactor Feeds a. Iron-Versene Catalyst (Stream 8 in Material Balance) The ferric versene catalyst is made up batchwise from the following charge procedure: Tetrasodium ethylenediamlne tetraacetate Ferric ammonium sulfate hydrate Demineralized water 0.062 lbs. 0.040 1.63 Total 1.732 lbs. A nitrogen atmosphere is maintained above the solution while mixing to prevent the solution from being contacted with oxygen which acts as a reaction retarder. RSV 0017482 11. b. Aqueous Catalyst Charge (Stream 10 in Material Balance) The aqueous catalyst charge is made up batcnwise from the following charge procedure in the order given below: Demineralized water Ammonium hydroxide l28#) Sodium pyrophosphate Ammonium laurate Ferric versenate Sodium formaldehyde sulfoxylate 103. 1.25 2.35 16.8 1.73 0.427 lbs . Total 125*557 lbs. A method for the preparation of ammonium laurate is given in Appendix B. A nitrogen atmosphere is maintained above the solution while mixing to prevent the solution from being contacted with oxygen. c. Reactor Charge A 31.7-gallon reactor (based on 100 pounds of AL product polymer) is first evacuated, purged with ethylene and evacuated again. Then 126 pounds of aqueous catalyst solution is added, brought to 30C. + 0.2C., and 63.8 pounds of vinyl chloride is fed to the reactor without agitation resulting in a reactor pressure of 40 psig. at 30C. Ethylene is added batchwise to the reactor until the reactor pressure reaches 875 psig. At this point, the primary pressure sensing device is shut off from the reactor and agitation started. The pressure in the reactor will drop rapidly (to about 400 psig.) when agitation is begun and the contents in the reactor will begin to foam. At this point, reactor pressure is obtained by a gage in the ethylene charge line to the reactor. More ethylene is added with agitation until a reactor pressure of 850 psig. + 15 psi. at 30C. + 0.2C. is obtained, corresponding to the addition of 29.3 pounds of C2HH. After the addition of nearly all the ethylene, the primary sensing device can be opened to the reactor, allowing the trapped monomers at 875 psig. to blow back into the reactor at 850 psig. and thus avoiding deposition of foam in the pressure sensing line during charging. RSV 0017483 12. The temperature and pressure in the reactor are allowed to equilibrate. (Premixing and emulsifi cation were accomplished in the laboratory 1-gallon autoclave by utilizing an agitator speed of 400-600 rpm. A more complete description of the agitation system used in process development is given in Appendix A.) Before the reaction is started, the agitation is decreased to a point where complete emulsion is sustained but excessive shear of the reaction mass is eliminated. (This point corresponded to 400 rpm. in the laboratory autoclave.) d. Continuous Feeds The APS solution is added to the reaction continuously at the rate of 0.65-0.70 pounds per hour until 97-98# of the vinyl chloride which is to be fed during the reaction has been added (40.5-41.0 pounds). The reaction rate is controlled by APS feed rate, higher APS feed rates resulting in higher reaction rates. An APS feed rate of 0.65 pounds/hour results in an over-all reaction time of 5 hours. A discussion of the effect of APS feed rate upon reaction rate and, consequently, reaction time is given in Discussion of Important Variables, Section B. Vinyl chloride is added upon demand to maintain a constant pressure in the reactor. A typical vinyl chloride addition curve Is shown in Figure 2. The limiting factor governing the maximum VC1 addition rate is the heat removal capacity of the reactor cooling system. Typical reaction time is 5 hours, although reaction times shorter than 2 hours can be achieved and result in satisfactory product. The vinyl chloride feed stream is added subsurface. 2. Reactor System The reactor consists of a single, backmixed stage provided with heating (for start-up) and cooling media, and automatic temperature control. A pressure control system is also provided to maintain constant reactor pressure by regulation of vinyl chloride addition rate. An increase in vinyl chloride monomer RSV 0017484 13. concentration in the reactor causes the reactor pressure to increase, and a decrease in vinyl chloride monomer concentration causes pressure to decrease. The operating conditions are: Temperature 30C . controlled to + 0-5C. Pressure 850 psig. controlled to + 15 psi. Reactor volume 31*7 6al* Agitation sufficient to maintain adequate emulsion but not vigorous enough to cause excessive liquid shear is required. Reaction continues until the solids content of the latex reaches 45-5-^7*5^* The addition of 41.8 pounds of VC1`during reaction results in a solids content of 46.0#. To terminate the reaction at this point, the APS feed is stopped when 40.8 pounds has been added. The reaction rate will begin to decrease sharply. When 41.8 pounds of VC1 has been added, the VC1 feed line is closed and the unreacted monomers vented off the top of the reactor. Venting is started immediately after the reaction has stopped and agitation is used while venting. The gas phase is vented over a 30-60 minute period such that no latex is obtained from the vent. The agitator may be turned off at 50-150 psi. to facilitate venting without foaming. When the reactor pressure has reached atmospheric pressure, the latex is drained out of the reactor by gravity. The liquid composition after letdown is: Component Weight Percent Water Polymer solids Soap Dissolved VC1 Dissolved C2H4 Inorg. and Org. salts 52.5 43.1 1.4 0.3 0.9 1.8 Total 100.0 The reactor vent gas composition is: Component Weight Percent Ethylene Vinyl chloride Water 47.0 51.1 Total 100.0 RSV 0017485 aiai at* H a r j m r * . * ; * j h ( u c o i x u ^7 i.4. P0N : !* 1 :`i: 1; VCL Added D u rm a R e a , c f t d r \ ( R o u n d s ') 15- If provision is made for a hold tank prior to coagulation, degassing of dissolved monomers will occur. Degassing continues throughout the work-up steps until the final dried polymer is obtained. The average off-gas composition for a 4-hour period in the hold tank is: Ethylene . Vinyl chloride 66.8# 35*2# C. Coagulation The liquid latex Is coagulated by freezing in a cold stage tube at -15C. The volume of latex charged to the tube is such that 20# of the height of the tube is retained as freeboard for expansion and degassing. The tube is vented to a flame arrestor or suitable device to dispose of degassed monomers and ammonia. The amount of degassing that occurs upon charging and freezing is about 0.5# of the latex charge to the tube. The latex is charged to the tube such that free fall of latex down the tube is avoided (such as charging the latex into the bottom .of the tube). Free fall of latex when charging produce's appreciable foaming and causes the latex.to overflow the top of the tube. v Since the rate of freezing- of the latex affects -the particle size of the polymer, the latex Is frozen at a prescribed rate as shown in Figure 5* An over-all freezing cycle of 75 minutes Is obtained when a 1-1/2 inch OD, 1-3/8 inch ID tube is utilized as the cold stage. A thawing cycle of 15-20 minutes Is required to sufficiently melt the latex so that it may freely fall from the tube. The center core of the latex, however, is not sufficiently melted to form a free flowing slurry. Provision is made to break off the frozen latex into small sections as it drops. The temperature of the tube Jacket during the thaw cycle is 35-45C. The two phase mixture of polymer and other solids in water is subsequently washed. D. Washing The washing procedure consists of two steps: 1. Batch washing and heat treatment. 2. Continuous washing of centrifuge cake. RSV 0017488 3QOJ. JO StXV -bNOlW (JoJ 16. 17. In the first step, the polymer slurry is charged batchwise into a well-agitated vessel with an equal weight of filtered tap water (227 pounds). The mixture is heated to 60-65C. under agitation and maintained at 65C. for 1 hour. The vessel is vented to dispose of unreacted monomers and ammonia which degas during the heating period and total to 0,74# of the polymer slurry charged. The vessel is sized to retain all the foam created by the degassing of the dissolved monomers. A volume of foam approximately equal to the volume of diluted polymer slurry is formed. A greater amount of foam may be formed if the temperature of the slurry becomes greater than 65C. or if it Is heated too rapidly. The heat treatment off-gas composition is: Component Weight Percent Ammonia Ethylene Vinyl chloride Water 19.0 28.2 5.2 4?.6 Total 100.0 The polymer slurry is cooled to 30-35C. and subsequently dropped to a centrifuge. In the second step,, the polymer slurry is centrifuged to separate the solids from the mother liquor. Some degassing occurs during centrifugation; consequently, it is recommended that the centrifuge be closed and that it be purged with nitrogen during operation. The composition of the gases coming off the centrifuge are: Component Weight Percent Ammonia Ethylene Vinyl chloride Water 8.0 84.8 0.9 Total 100.0 The polymer cake is washed on the centrifuge with filtered tap water (2970 pounds) and wrung as dry as possible. RSV 0017491 18. E. Drying The washed polymer is dried at 35-^5C. and 30 mm. Hg pressure or less until a moisture content of less than 0.5$ Is obtained. Turnover of the solid as it is drying reduces drying time. A drying time of 6-8 hours is required at 40C. and 15 mm. Hg in a vacuum rotary drier to achieve a moisture content of 0.2-0.4$. F. Reactor Washout The reactor is washed out after each run with a solvent to remove reactor fouling. Polymer solids amounting to 0.2$ of the discharged latex adhere to the inside of the reactor and will accumulate in successive runs if the reactor is not cleaned. A solvent mixture of 50$ (by volume) benzene in acetone is charged to the reactor (after the latex has been drained) in sufficient quantity so that the reactor is 97"98$ full. The solvent is heated to 50C. with agitation for 1 hour, drained and stored for subsequent cleaning. The last traces of solvent are removed from the reactor by a water rinse. The solvent is reused until the dissolved polymer content reaches 3-0-3.5$, which normally requires 15-20 runs. The solvent may be recovered by charging it to a straight take over still and collecting 80-84$ of the charge as still overheads. The still is operated at atmospheric pressure and a still pot temperature of 6l-64C. The overhead vapor temperature rises to 57C. When 80-84$ of the charge has been distilled, the still is shut down and the still pot residue drained while hot. The still pot residue is a highly viscous, yellow-colored fluid which solidifies at room temperature. It is difficult to remove from the still pot if allowed to cool. The residue is disposed of as waste solvent. The condensed still over head is reused for reactor washout. DISCUSSION OF IMPORTANT VARIABLES A. Reactor Charge 1. Persulfate Redox System and Surfactant The chemical species serving to initiate monomer and partially reacted polymer thereby causing polymeri zation is the sulfate radical-ion (S04"). The sulfate RSV 0017492 19- radical-ion is formed from the following oxidationreduction system. Ferric versenate is reduced by SFS to ferrous versenate which serves to decompose persulfate forming a sulfate radical (SO*) and a sulfate radical-ion (S04T). The ferrous versenate is oxidized back to the ferric state, thereby being regenerated. The SFS activates the system; the iron acts as a catalyst; and the persulfate when decomposed serves as an initiator for polymerization. The formation of S04" from persulfate decomposition occurs only in a limited range of pH. For this reason, sodium pyrophosphate is used as a buffer to retain the pH of the reaction mass at 9`0-10-0` Ammonium laurate or sodium dodecylbenzene sulfonate is used as a surfactant or emulsifying agent. Reaction usually takes "place in the liquid phase and, since the ethylene and VC1 monomers are only slightly soluble in water, it is necessary to emulsify tne monomers in the liquid phase. 2. Oxygen a Retardant The presence, of a small amount of oxygen in the reactor will Inhibit the reaction and prevent it from starting. To prevent oxygen from getting into the reactor, the aqueous catalyst solution is made up in an atmosphere of nitrogen and charged into a reactor which has been evacuated, purged with ethylene, and evacuated again. Charge lines are also purged and evacuated. 5. Aqueous and Monomer Charge Since the aqueous charge and initial VC1 charge are charged by weight and the ethylene by difference (until a pressure of 850 psig. is reached), any error in water or VC1 charge will cause an error In ethylene charge and, consequently, an error in VCl/C2H4 ratio. Close tolerances must be maintained in the Initial reactor charges in order to achieve polymer compositions within specifications. The effect of the initial monomer composition upon final polymer composition is shown in Figure 4. At 4656 total solids in latex, by Figure 4, the initial VC1 composition must be 68.5# + 1.0# in order to obtain a final polymer composition of 88.5# VC1 + 0.4J6 VCl. Figure 5 shows the effect of error in aqueous and VCl charges upon initial monomer composition. If a RSV 0017493 3 e> * wd to c o ru t c tN tiw t't'i 4 ti I3 IG 2 u. fi-r.---------------------T It RSV 0017495 *$ 50 t a>4 $ <3- -S. s 21 7W O^ 6* sO QT a-u O %- 4 sbWHO noa 30 Nou\ffA3a Mvso&ad BSV 0017496 0 u W ff j: RSV 0017497 IO TOTHt CtNriMLIL" 46 1510 22. positive deviation in aqueous charge is followed by an appropriate negative deviation in VC1 charge (or vise versa), an initial monomer composition of 68.5# VC1 can still be obtained. However, since the type or amount of deviation would be unknown in any plant charge, the deviations having maximum effect must be assumed. Positive deviation in both water and VC1 charges have maximum effect. A positive deviation of +1.0? in both results in a monomer composition of 69.5# which in turn-will result in polymer just within specification at 88.9# VC1. Conclusions from this data indicate that both the aqueous and VC1 charges be within 1.0# of the specified amount. Because of the nonlinearity of the partial molal volume of vinyl chloride, the addition of vinyl chloride to ethylene or to a mixture of ethylene and vinyl chloride can cause the pressure of the mixture to raise or lower, depending on conditions. At a concentration of 68. b# VCT in a mixture of C2H4 and VC1 and a pressure of 850 psig., addition of more VC1 to the mixture causes the total pressure to increase. At low concentrations of VC1 (below 55)> the total pressure will decrease. Addition of all the C2H4 to the reactor in the Initial batch charge before any VC1 is added results in a total reactor pressure of greater than 1000 psig. To avoid exceeding a maximum pressure of 1000 psig., the initial batch charge of VC1 is added first, resulting in a pressure of 40 psig. The ethylene is then added (without agitation) until a reactor pressure of 875 psig. is reached. The line leading to the pressuresensing device is closed prior to start-up of agitation to prevent the foam caused by agitation to be forced into the pressure sensing line as more ethylene is added. In the presence of agitation, a significant amount of ethylene will dissolve in the VC1 causing the reactor pressure to decrease. As the remainder of the ethylene is added, the pressure will rise and, at temperature and pressure equilibration, a pressure of 850 psig. at 50C. is achieved. The pressure-sensing line can be opened during pressure equilibration allowing monomer to blow from the line back into the reactor leaving the line unplugged by dense foam. RSV 0017498 23. 4. pH of Ammonium Persulfate Solution The APS solution is made up as 20$ APS in water with enough NH4OH added to bring the pH to 7.0-8.0. An acidic solution such as an aqueous mixture of APS and water without NH40H will cause the reaction to stop by lowering the pH of the reaction mass. The appropriate sequence of reactions in the persulfate redox system only exists in a basic media. Addition of NH4OH to the APS solution also serves to prevent corrosion to the APS feed system. A 20$ APS-HaO mixture is quite corrosive to 316 stainless steel. B. Control of Reaction 1. Rate The SFS charged in the initial aqueous charge is present in slight excess of the amount needed. The ferric versenate is regenerated as it is used. Therefore, the limiting reagent in the catalyst system is the APS and the reaction rate is controlled by the amount of unreacted APS in the reactor. Total reaction time as a function of APS feed rate is shown in Figure 6. For an equivalent APS feed rate, the ammonium laurate process has a higher reaction rate. The over-all APS usage (or efficiency), however, is only slightly better when ammonium laurate is used as when D-94 is used. 2. Pressure Control The appropriate composition of VC1 in the reaction mass is controlled by reactor pressure. As reaction takes place and polymer is formed, the reactor pressure decreases since the product polymer is more dense than the reactant monomer. Reactor pressure is increased by addition of VC1 to the reactor. Since VC1 is used in a 5/1 weight ratio to ethylene in the reaction, the addition of pure VC1 to maintain reaction pressure is adequate to retain a sufficiently high concentration of VC1 in the reactor. The initial VC1 composition in the reactor is 68.5$ by weight; the final VC1 composition is 50$ by weight. Therefore, total pressure is a sufficiently good control media for control of reaction mass composition. RSV 0017499 w i dn . APS %ATE ('P- &PYAP$ PEE Hou&) Stiseg/ On /{?o fb Pohjmzjr Pr~&ducT. 25. C. Reaction End Point Sufficient reaction is achieved when the solids content of the latex reaches 45.5-47.5#. Reaction can proceed beyond this point, but latices with higher solids content are difficult to vent and result in higher deposits of solids in the reactor. Latices made with ammonium laurate are less stable than those made with ABS. Since the stability of a latex is also a function of polymer solid content, the total solids content of ammonium laurate latices are kept below 46.5# D-94 latices may be taken to 47-5# total solids or higher without becoming too unstable. At 49# total solids, the D-94 latices will become unstable enough to coagulate prematurely. To reach the desired end point, the appropriate amount of APS is added such that the reaction will cease when 41.8 pounds of VC1 has been added. The response of reaction rate to APS feed rate is very rapid causing the reaction rate to reach almost zero very shortly after the APS feed is stopped. If the APS feed is stopped when 97-98# of the total amount of VC1 has been added, the active amount of APS present in the reactor will reach zero when 41.8 pounds of VC1 has been added (this will take 8-10 minutes). The reaction end point has an effect upon final polymer composition as shown in Figure 7. D. Formation of Solids in Reactor 1. Solids Due to Shear Coagulated solids may be formed during the reaction or during pressure letdown. An Increased amount of coagulum is formed in the latex during the reaction If the reaction is carried out In the presence' of high shear agitation. Low shear agitation is desirable and minimizes formation of solids. A flat-bladed turbine-type impeller, turning at 350400 rpm., was found satisfactory in process develop ment work using a 1-gallon autoclave. An agitator speed of 600 rpm. was used to premix the initial batch charge but caused an increase In coagulum if used during polymerization. RSV 0017502 w-4< RSV 0017503 io io T H t c tH T iM irtn 4 6 1 5 1 0 27. 2. Solids as Function of Extent of Reaction The extent of completion of the reaction has an effect upon the amount of coagulated solids formed in the reactor. As the total solids content increases above 45#, the coagulated solids increase from O.3656 (based on product polymer obtained) to greater than 256 at 50# total latex solids. When ammonium laurate is used as the surfactant, a significantly smaller amount of solids is formed than when ABS is used. However, the stability of the ammonium laurate latex is less than that of the ABS latex at equal solids content and may form more coagulated solids after being drained from the reactor. E. Pressure Letdown The unreacted monomers are vented from the top of the reactor with agitation as soon as the reaction is completed. The monomers may be vented as rapidly as possible such that no foam or liquid is carried out the vent. The venting will occur rapidly (10-15 minutes) until the pressure in the reactor reaches 50-150 psig., when a great deal of foaming will occur in the reactor. At this point, the agitation is stopped and the venting rate decreased such that foam and latex are still prevented from being vented. To reach atmospheric pressure in the reactor from the point where the venting rate has been decreased takes 20-40 minutes. The reactor pressure must be decreased to atmospheric pressure before the latex can be drained. The latex will coagulate if subjected to even a small pressure gradient caused by dissolved monomers. To transfer the latex from one point to another, either gravity or 10-15 psig. nitrogen pressure should be used. F . Coagulation of Latex The rate of freezing has a pronounced effect upon particle size. Rapid freezing causes formation of small polymer crystals; slower freezing results in larger crystals. For this reason, the rate of freezing should be sufficiently fast to give a particle size such that 85# of the particles are smaller than 20 mesh and larger than 140 mesh. An adequate freezing time for coagulation in a 1.5 inch tube (OD) is 1-2 hours. Experiments in which latex was frozen in trays in 8-l6 hours resulted in particle sizes greater than 10 mesh. All of the latex must be frozen. A mixture of unfrozen latex and thawed coagulum presents a difficult material handling problem. RSV 0017504 28. The latex may coagulate prematurely If it is allowed to remain in the latex form too long. Ammonium laurate latlces will coagulate in 3 days at the 46# solids level. ABS latices will remain uncoagulated for several weeks. If a latex does coagulate before being frozen, it cannot satisfactorily be worked up as Plastimer III polymer. Subsequent freezing will not further coagulate it. G. Polymer Washing As the diluted polymer slurry is heated during the heat treatment step, foaming occurs. The volume of foam formed at 60-o5C., the maximum temperature in the heat treatment step, is approximately equal to the original volume of slurry. If the temperature is allowed to reach 8o-85C., an even greater volume of foam is formed and may cause overflowing from the heat treatment vessel. The temperature of the slurry appears to be much more sensitive to heat input at 55-6oC. than below 50C. Consequently, the same rate of heat input above a temperature of 30C. as below it may cause the temperature of the slurry to rapidly rise to QO-85C. Adequate control of slurry temperature must be maintained. The heat-treated polymer slurry is dropped to the centrifuge at 25-35C. If dropped above 50C., the polymer tends to cake in the centrifuge and cannot be adequately washed. Off-gas fumes also become a problem at a temperature of 50C. At a temperature of 25-35C., the slurry does not cake in the centrifuge and does not give off as much monomer and ammonia. However, even at a slurry temperature of 25-35C., the centrifuge should be closed and purged with nitrogen to keep objectionable gases away from operating personnel and to purge explosive mixtures of monomer from critical areas. H. Polymer Drying Much of the moisture to be dried from the wet polymer is actually in the pores of the solid particles. The surface moisture dries relatively quickly, but a much longer time is needed to remove the internal moisture. Large polymer particles take much longer to dry than smaller ones since they contain more internal moisture and the moisture must travel through longer capillaries to reach the particle surface. Tube frozen particles at an average size of 60 mesh dry in 6-8 hours at 40C. and 15 mm. Hg. Tray frozen particles at a size of about 10 mesh require 24-48 hours to dry at the same conditions. Turning over of the polymer particles during drying to expose new surface also aids in Increasing the drying rate. RSV 0017505 29. The polymer is heat sensitive and cannot be subjected to temperatures above 50C. for a very long period of time without discoloring. The drier temperature is maintained below 45C. I. Coagulation Tube Washout V. A small quantity of solids adhere to the coagulation tube, amounting to about 0.2# of a latex charge per run. The solids will build up in subsequent runs, especially near the top of the tube. A water washout is used every 20 runs and the polymer recovered. If the tube is not sufficiently clean after a water wash out, an acetone rinse may be used to thoroughly clean the tube. J. Materials of Construction 516 stainless steel is used for all surfaces exposed to reactants, product latex or polymer solids. No corrosion studies on other types of materials have been done. K. Conversion Vinyl chloride conversion is 82.6$. Conversion of both VC1 and C2H4 may be increased by increasing the aqueous charge to the reactor. Increasing the aqueous charge requires less 68.5$ VC1-31.5# C2H4 monomer mixture, as initial charge, to reach the required pressure of 850 psig. at 30C. To reach the same total solids content, a greater amount of VC1 is added during the continuous addition. The net result is a higher quantity of latex formed per unit volume of reactor and less off-gas to vent. An increase in aqueous charge by 10# results In an Increase of VC1 conversion to 88#. However, a fivefold increase in pot solids and a lower VC1 composition in the final product polymer makes such a conversion increase undesirable. MATERIAL SPECIFICATIONS. ANALYTICAL METHODS A. Raw Materials 1. Vinyl Chloride Uninhibited or polymerization grade vinyl chloride from the Texas City Plant (Monsanto) is used. It is passed through activated alumina (8-14 mesh) before use (maximum usage of 0.88 pounds of alumina per 100 pounds VC1). RSV 0017506 50. 2. Ethylene Monsanto Texas City ethylene, polymerization grade, is used. Polymerization grade ethylene from U. S. Industrial Chemical, Tuscola, Illinois is used as an alternate. The ethylene is passed through a charcoal and alumina absorber in series (0.01 pounds charcoal and 0.01 pounds alumina per 100 pounds Cam)- 5- Persulfate Redox Catalyst System Materials a. Ferric Ammonium Sulfate AR grade from Fisher Scientific Company. Typical analysis: Insoluble matter Chloride Copper Ferrous iron Nitrate Zinc 0.008# 0.001# 0.003# 0.001# P.T. 0.003# b . Tetrasodium Ethylenediamlne Tetraacetate Technical grade from Fisher Scientific Company. Powder form with 1 gram chelating 215 mg. of CaC03 at pH 11. c . Sodium Formaldehyde Sulfoxylate Technical grade from Fisher Scientific Company. d. Ammonium Hydroxide AR grade from Mallinckrodt Chemical Works. 15 N solution with typical analysis: Carbon dioxide Chloride Heavy metals Iron Phosphate Residue after- ignition Sulfur Assay Specific gravity 0.002# 0.00005# 0.00005# 0.00002# 0.002# 0.002# 0.0002# 28.0-30.0# 0.90 RSV 0017507 31. e. Ammonium Persulfate AR grade from Mallinckrodt Chemical Works, with following typical analysis: Acidity (as H2SO4) 0.20# Chloride and chlorate (as Cl) 0.001# Heavy metals (as Pb) 0.005# Insoluble matter 0.005# Iron 0.001# Manganese 0.00005# Residue after ignition 0.05# Assay (minimum) 98*0# f. Sodium Pyrophosphate AR grade from Mallinckrodt Chemical Works, with following typical analysis: Arsenic Chloride Heavy metals (as Pb) Insoluble matter Iron Nitrogen compounds Sulfate (S04) 0.0005# 0.002# 0.001# 0.010# 0.001# 0.001# 0.005# 4. Surfactant a. Ammonium Laurate See Appendix B. b. ABS (D-94-b) Slurry D-94-b (linear sodium dodecylbenzene sulfonate) is obtained from the Richardson Corporation, Chicago, Illinois. Local outlet is Krystall Chemical Company Plant at Lament, Illinois. D-94-b from Alkylate 215 has the following specifications: Total solids Active SDDBS Alcohol insolubles Unsulfonated oils pH of a 10# solution Iron 46-49# 44-47# 1.7# max. 2.5# max. 7.3-8.5 50 ppm. max. RSV 0017508 i\& 22. c. ABS (WW-b) Slurry WW-b (linear sodium dodecylbenzene sulfonate) is obtained from the Richardson Corporation, Chicago, Illinois. For the St. Louis area this is made by Richardson's Krystall Chemical Company Plant at Lamont, Illinois. WW-b slurry from Alkylate 215 has the following specifications: Total solids Active SDDBS Alcohol insolubles Unsulfonated oils pH _of a 10# solution Iron 45-46# 40-43# 1.7# max. 2.5# max. 7.3-80 50 ppm. max. 5. Water Demineralized water is used for all charges to the reactor. Filtered tap water is used in all washing steps. 6. Nitrogen Nitrogen used in process development work was obtained from the Air Reduction Company. It is prepurified nitrogen with a maximum oxygen limit of 5 ppm. A typical analysis is: B. Product Purity Dew point Oxygen 99`997% N2 -90F. 2 ppm. 1. Reactor Latex Product Latex from the reactor is obtained with the following typical analysis: # Total solids # Polymer solids Ratio of soap to polymer Latex viscosity 46.0 (46.5% for ABS latex) 43.1 0.0327 - with C11H23 C00NH* 0.0531 - with ABS 6-8 cs. RSV 0017509 33 2. Specifications for Solid Polymer Product Property Physical form and color. Contamination Min. Max. Method White, free- Visual comparison flowing powder, with standard. To be dBtermined ----- VC1 content by IR Molded density 88.1 1-3250 88.9 65-19 1.3330 TM-C-2d and Intrinsic viscosity 0.90 1.10 Moisture content 0.0 0.5 Karl Fischer Heat stability T by DTA 120 min. 39C. -- 49C . TM-H-2C Melt flow 1.0 3-5 TM-F-5b Equilibrium torque by Brabender 2000 2600 TM-P-5a Tensile properties TM-T-2b a. % elongation 210 b. Tensile strength at yield 5600 c. TEB 8750 -- Screen analysis % on 20 mesh % on 40 mesh % through 140 mesh Trace 20 15 C. Analytical Methods 1. Latex Solids A 10 ml. aliquot of latex is weighed into a tared aluminum foil dish, diluted with 10 ml. of ethanol to prevent foaming and spattering, and evaporated to dryness in a 105C. oven (about 16 hours). The net dry weight divided by the net latex weight equals the percent total solids in latex. RSV 0017510 34. 2. H The pH is determined directly on the latex with a standard Beckman expanded scale pH meter. 3. Determination of Alkyl Benzene Sulfonate in Plastimer Scope This method is intended for the determination of alkyl benzene sulfonate in concentrations up to 3-0$ in E/VC1 copolymer. The method can also be used for a variety of sulfated or sulfonated anionic surfactants. The estimated accuracy of the method is + 0.15# absolute. Equipment and Reagents a. Chloroform. b. Methylene blue. c. Methylene blue solution - dissolve 0.1 g. methylene blue, NF contained in a 100 ml. volumetric flask, in distilled water and dilute to 100 ml. Transfer 30 ml. of this solution to a 1 liter volumetric flask containing 500 ml. of distilled water, 6.8 ml. of concentrated sulfuric acid and 50 grams of monosodium phosphate monohydrate (NaHgPCU-HaO) AR grade. Shake until solution is complete and dilute to volume with distilled water. d. Toluene and ethanol solvent - 68# absolute ethanol/ 32# toluene by weight. e. Hellige Testing Outfit No. 367DO. f. Usual laboratory apparatus and reagents. Determination a. Accurately weight 1.000 grams of dried polymer into a 125 ml. iodine flask containing 100 ml. of solvent, stopper and swirl. Let stand with occasional swirling to extract the adsorbed ABS into the solvent (approximately 4 hours standing). b. Pipet 5 ml. of the above solvent layer into a 1 liter separatory funnel containing 750 ml. of distilled water and shake well (no real separation takes place, some toluene is seen on top of the water). RSV 0017511 35. c. Place 50 ml. (graduate) of the water taken from the bottom in a 125 ml. separatory funnel. To this add 15 ml. (graduate or pipet) of the methylene blue solution and 10 ml. (pipet) of chloroform. Shake well, allow to separate and filter the chloroform layer through a cotton pledget into the Hellige cell. Compare with standard and record ppm. ABS. Calculation PPm- ..read x 750 x 100 - ^ ABS in polymer or 106 0.05 ppm. read x 1.5 * # ABS in polymer. Discussion This method is an adaptation of the Hellige method (Hellige Instruments). The method depends on the forming of a complex between the methylene blue and ABS. This complex is then extracted from the water layer by the chloroform. The method can be applied to the water used in washing the copolymer. In this case, take 50 ml. of the wash water (1-2 ppm. range) and proceed as in Step 5* Cleaning of equipment is sometimes facilitated by the use of a 10$ HC1 solution which destroys the ABS. References Hellige, Inc., Garden City, N. Y., ABS Testing Outfit No. 567DO. Swisher, R. D., JAOCS 40, 648-656 (1965). 4. Determination of Water in Plastlmer by Karl Fischer Reagent Scope This method is Intended for the determination of water in dried polymer. It involves the solubilization of a sample to be analyzed in tetrahydrofuran and the titrimetric determination of the moisture present with Karl Fischer reagent. The end point may be detected colorimetrically or electrometrically. The estimated accuracy of the method is + 0.05# absolute. RSV 0017512 36 Equipment a. Tetrahydrofuran. b. Karl Fischer reagent. c. Usual laboratory apparatus and reagents. Determination a. Accurately weigh 10.0 grams of sample into a 100 ml. volumetric flask and dilute to volume with tetrahydrofuran. (Some difficulty will be encountered in dissolving the sample. When using volumetric flasks without a bulb, allowing some room to shake the contents will be helpful. This step can be accelerated if the contents can be freed from the sides of the flask shortly after the addition of the solvent. This step will usually require a minimum of 24 hours contact between the sample and solvent.) b. Blank about 25 ml. of methanol in 125 ml. Erlenmeyer flask. c. Zero the Karl Fischer burette. d. Weigh into the blanked methanol approximately 10.0 grams of the above copolymer solution. (On contact with the methanol, the copolymer will be precipitated, presenting some difficulty in the following titration.) e. Titrate the supernatant liquid back to the same end point. Calculation a ml. titre x KF factor x sample weight (copolymer soln.) 100 = % moisture contained in copolymer soln. HSV 0017513 yj b. (wt. of copolymer soln.)(# H2O copolymer soln.) = wt. H2O copolymer soln. ^wt. of copolymer soln.)(1.0 - wt. sample) = \ wt. soln. ) (wt. of solvent THF in copolymer soln.) ^wt. of solvent in copolymer soln.)x(# H2O in solvent THF) - wt. of H2O in solvent THF (wt. of copolymer soln.)(wt. sample) r (wt. soln. )" wt** 01 copolymer (wt. H2O copolymer soln. - wt. HgO in solvent) x 100 wt. of copolymer l)o moisture in copolymer Discussion No known interferences appear to be present in sufficient amounts to affect the accuracy of the analysis. Safety No unusual hazards are involved in this operation when cognizance is taken of the flammability and toxicity of the reagents and solvents. Reference Standard Procedure Method No. 78-A, B, John F. Queeny Plant. * NOTE: The moisture of the THF used as solvent can be determined by proceeding from Step 2 through calculation (a), substituting 10.0 grams of the solvent used for 10.0 of copolymer solution in Step 4. RSV 0017514 38. 5. DETERMINATION OF INTRINSIC VISCOSITY OF PLASTIMER (A VARIANT OF ASTM D 1245-60 AND D 1601-61) TM - None Organic Research I. Scope This method describes a test procedure for the determina tion of the dilute solution viscosity of Plastimer using tetrahydrofuran as a solvent at 30 C. Directions are given for the determination of relative viscosity, specific viscosity, reduced viscosity and intrinsic viscosity. II. Significance Dilute solution viscosity values for Plastimer are related to the average molecular size of that portion of polymer which dissolves in the solvent. This method is limited to samples which give clear uniform appearing solutions at the test dilution. Where a viscometer, solvent or tempera ture other than those specified are used, data may not be comparable to that obtained by this procedure. Ill. Outline of Procedure A sample of Plastimer is weighed accurately and dissolved in the solvent. Relative viscosity, specific viscosity, reduced viscosity, and intrinsic viscosity are calculated from the measured efflux times of the solvent alone versus a specified solution of the polymer in the solvent. IV. Apparatus and Materials 1. Cannon-Fenske Viscometer (ASTM D 445-64) No. 502. Constant temperature water bath, capable of maintain- ing 30 + 0.1b C. 3. Stop watch. 4. Thermometer, ASTM No. 91C having a range of 20 to 50 C with 0.1 C. subdivisions. 5- Mechanical shaker. 6. Transfer pipettes. 7. 125 ml. Erlenmeyer flasks with ground glass stopper. 8. 50 ml. volumetric flasks* 9. Funnel, coarse filter paper and cotton10. Tetrahydrofuran, THF, reagent grade. V. Test Specimens The test specimens should be washed and dried Plastimer. RSV 0017515 39- VI. Procedure Weigh 4 specimens of the following approximate weights to + 0.0002 into 125 ml. glass stoppered Erlenmeyer flasks. Specimen 1 Specimen 2 Specimen 3 Specimen 4 0.49 to 0.51 gm0.59 to 0.4l gm. 0.29 to 0.51 gm. 0.19 to 0.21 gm. .2 Add 50.00 ml. of filtered THF to the specimen flasks. Shake the flasks on the mechanical shaker until dissolved completely. When the solution is considered complete, examine visually to be certain that no undissolved par ticles, gel or particles of foreign matter are present. 3. Filter the solution through a coarse filter paper packed with cotton into a 50 ml- volumetric flask. Cover the funnel with a watch glass to reduce evapora tion. When filtration becomes slow, discontinue and immediately stopper the volumetric flask to avoid evaporation. It is not necessary to collect all the solution. 4. The -viscometer should be thoroughly cleaned with hot sulfuric acid and potassium dichromate solution followed by rinsing with distilled water and THF, and drying with vacuum. Traces of impurity in the viscometer may cause serious errors. 5 Pipette 10 ml. of the filtered THF into the viscometer and allow 10 minutes for the solvent to come to tempera ture equilibrium. Draw the liquid up above the upper gradation mark on the viscometer capillary by applying suction. By releasing the vacuum, allow the liquid to drain to the upper mark of the capillary. As the meniscus passes this point, start the timer and time the interval for the liquid to drain to the lower mark on the capillary. Measure the efflux time of the liquid at least 5 times. Three consecutive readings shall agree within 0.2 sec. 6. After each run, clean and dry the viscometer. If the viscometer is kept clean, the efflux time for the reference solvent, THF need not be redetermined on sub sequent determination; however, periodic checks should be run to monitor cleanliness. 7. Pipette 10 ml. of the filtered polymer solution into the viscometer and determine the efflux time as described above for the pure solvent. RSV 0017516 40. VII. Calculations The relative viscosity, specific viscosity and reduced viscosity are calculated as follows: Relative viscosity. Average efflux time of polymer solutio: Average efflux time of pure solvent ^sp rrSpecific viscosity Reduced viscosity 1 red = 9 -1 i SD *r-; C is in gm/100 ml. A plot of the 4 reduced viscosity numbers versus their respective concentrations on linear graph paper extrapolated to zero concentration gives the intrinsic viscosity. ZV= C ^ed) 0 = (IsR) - 0 VIII. Report The report shall include the following: 1. Complete identification of the material tested. 2. The intrinsic viscosity to 2 significant figures. RSV 0017517 41. METHOD WO. 65-19 6. INFRARED DETERMINATION OF THE VINYL CHLORIDE CONTENT OF PLASTIMER III SCOPE This method describes a solution procedure for the infrared determination of the vinyl chloride (VCl) content of Plastimer III, an ethylene-vinyl chloride copolymer (EVCl), in the range of 72 to 94# VCl. The estimated accuracy of the method is + 0.5# abso lute . PRINCIPLE The infrared absorbance ratio of the C-H bending vibration of vinyl chloride at 6.97 microns relative to the C-H bending vibration of ethylene at 6.85 microns is plotted as a function of the per cent vinyl chloride for a series of dilute solutions of Plastimer III standards in trichloroethylene. The infrared absorbance ratio for an unknown sample is determined in the same manner and its vinyl chloride content obtained from the empirical calibration curve. This method is a solution variation of previous cast film methods (1,2). APPARATUS AND REAGENTS Double beam recording infrared spectrophotometer, such as the Perkin-Elmer Model 221 or equivalent 5.0 mm. rocksalt cellVariable 0.8-5.0 mm. rocksalt wedge cell (Barnes Engineering Company W-2B wedge cell) or a suitable 3-0 mm. compensating cell 125 ml. iodine flashs. Water-cooled condenser. Magnetic stirrer hot plate. 1.5" teflon-coated magnets. 50 ml. volumetric pipette. Trichloroethylene - Fisher reagent grade. Methylene chloride - Fisher reagent grade* RSV 0017518 42. METHOD NO. 65-19 CALIBRATION Fill the sample and compensating cells with trichloroethylene. Place the cells in the spectrophotometer and adjust the compensating cell until the effects of the solvent absorbance in the 6.9 micron region are cancelled. Record the solvent blank for the region of 6.So to 7.00 microns using the following instrument parameters: slit program scan speed scale source intensity 100$ adjust 1 x 980 slow - 6 50 cm./micron 0.35 amps set to 98$ Weigh duplicate 600 + 3 mg. samples of each resin standard into 125 ml. iodine flasks. Pipette 50 ml. of trichloroethylene into each flask, add a magnetic stirrer bar, attach the condenser and place the assembly on the magnetic stirrer hot plate. Reflux the sample with stirring until complete solution is attained (usually 5 to 15 minutes) . Allow the solution to cool to about 35 C. Remove the solvent from the sample cell by aspiration. Fill the sample cell with the Plastimer III standard solution and record its infrared spectrum in the region of 6.80 to 7*00 microns using the instrument parameters above. Remove the sample solution from the cell by aspiration and clean the cel] by pumping methylene chloride back and forth with a pair of hypodermic syringes and removing the methylene chloride by aspiration. Record the infrared spectra of either the duplicate or new standard in the 6.80 to 7*00 micron region. Repeat the process until all the standards are run. Measure the absorbance difference between the sample spectrum and the solvent blank at 6.85 and 6.97 microns and calculate the absorbance ratio R by: R - (abs. of sample - abs. of blank) at 697ju tabs. of-sample - abs . of blank) at" 6.85 >u Plot the calculated absorbance ratio as a function of the vinyl chloride content of the standards to obtain the working calibra tion curve. The spectra of a typical solvent blank and sample are shown in Figure 8, and the working calibration curve for the method is shown in Figure 9. RSV 0017519 METHOD NO. 65-19 SAMPLE ANALYSIS Weigh 600 + 3 mg. of* sample into a 125 ml. iodine flask. Add 50 ml. of trichloroethylene and a magnetic stirrer bar to the flask, attach the condenser and reflux the stirred system on a heat plate until complete solution is attained. Cool the sample to about 35 C. Record the infrared spectra of the solvent blank and the sample solution in the 6.80 to 7.00 micron region under the conditions used in the calibration. Calculate the absorbance ratio of the vinyl chloride band at 6.97 microns relative to the ethvlene band at 6.85 and read the vinyl chloride content corresponding to this ratio from the calibration curve. ACCURACY Very good agreement was obtained in the calculated absorb ance ratio of the standards used in calibrating the method. The experimental data are: Sample Identification % VC1* Infrared Ratio ovc 637 P3-1-14U P3-1-20U P3-5-14U Ba #38u Ba #44U OVC 254 ovc 182 93.4 90.3 89.1 84.8 79.0 77.7 77-5 72.2 3.76 3.74 2.08 2.07 1.84 1.83 1.83 1.44 I.45 I.45 1.10 1.10 1.11 1.11 1.07 1.07 0.91 0.91 Based on chlorine data obtained by the J. P. Queeny Analytical Laboratory using the Schoniger combustion method. With these small variations, the vinyl chloride content of the samples can be read within +0.5% absolute. RSV 0017520 44. METHOD NO, 65-19 REFERENCES 1. Central Research Center infrared film method documented in memo to R. W. Bucknell from H. P. Holladay, October 5, 1964, 2. Organic Division Research Department, Analytical Method 64-45. Monsanto Company Organic Division Research Department St. Louis, Missouri - 6/65 - B. Katlafsky, R. E. Keller RSV 0017521