Document 2jzzwOrdynZYvpOGBn1eM3dp5

POLYPHENYLENE RESINS A High Heat Resistant Resin System DATA SHEET - DEVELOPMENT PRODUCT AUGUST, 1968 Introduction A technique has been developed by Monsanto for the preparation of poly phenylenes - a thermo-oxidatively stable polymeric system that can be reinforced with fibres to yield useful composites. This data sheet gives information on the polyphenylene prepolymer 1711 which is the basic component for crosslinking or chain extension and leading to high molecular weight, infusible polyphenylene resin. The method of crosslinking using PP Curing Agent B1 is described along with information on the fabrication of composites from asbestos and high modulus carbon fibre. Properties of laminates made in the laboratory are given. The information contained in this bulletin is, to our best knowledge, true and accurate, but all recommendations or suggestions are made without guarantee, since the conditions of use are beyond our control. Monsanto Chemicals Limited disclaim any liability incurred in connection with the use of these data or suggestions. furthermore, nothing contained herein shall be construed as a recommendation to use any product in conflict with existing patents covering any material or its use. Monsanto 10-18 Victoria Street London SW1 01-222 5678 1 Place Madou Brussels 3 02-19.11.01 9 Rue d'Argenson Paris (8) 265.65.20 012092* TOWOLDMONOQ22732 PROPERTIES OF POLYPHENYLENE PREPOLYMER 1711 (Typical) Physical Description Form Colour Softening Range Boiling Point Specific Gravity 25C Solubility (gm/100 ml solvent) A mixture of low molecular weight polyphenylenes Solid (coarse powder) Dark Brown 133 - 1750C above 400OC 1. 17 Solvent Diphenyl Ether Toluene Chlorobenzene 1, 2 Dichloroethane Benzene Chloroform Dimethyl Formamide Water Ethanol Petroleum Ether At Reflux Temp. 150 140 130 100 85 85 20 ) ) Insoluble ) At 25C 30 40 50 45 35 50 5 Functional The propolymer crosslinks with PP Curing Agent B1 when heated to above 275C and this may be done in the presence of a fibre support to yield composite structures. Monsanto 0120925 2 TOWOLDMONOQ22733 POLYPHENYLENE/ASBESTOS LAMINATES The following procedure is recommended when using chrysotile asbestos felts: Impregnating Solution This is prepared from: Polyphenylene Prepolymer 1711 PP Curing Agent B1 PP Catalyst C30 Chlorinated aliphatic hydrocarbon solvent 260 gm 140 gm 0. 22 ml 2000 ml With chloroform as solvent, a 17. 5% w/v solution is obtained of density 1.45 gm/ml at 25C. Solution of the prepolymer is readily achieved if the powder is stirred slowly into the warmed solvent. Asbestos Composite Fabrication The asbestos felt contained in a suitable tray is completely saturated with impregnating solution. After lightly rolling, the felt is placed on a stainless steel mesh to dry either at room temperature under vacuum or at 50C. Pro-Pressing The felts are placed between two sheets of 5 thou aluminium foil that have already been sprayed with PTFE release agent. A pre-press treatment of 500 - 1000 p. s. i. at 130-140C for 5 minutes is optional but does assist the processing at the next stage. Pressing Stage Using a well ventilated press and with its platten temperature at 310C, the impregnated felts are inserted and kept under a slight positive pressure to ensure maximum heat transfer. This condition is maintained for 6 minutes in the case of a 12" x 12" x 1/8" board, during which time dry SO2 and HC1 gases are evolved. Then full pressure in the range of 500-1000 p. s. i. is applied. Pressure is released three times at 3 minute intervals. Pressing is complete after 4 hours and the laminate ejected when the temperature drops to 100C whilst maintaining pressure. Monsanto 0120926 3 TOWOLDMONOQ22734 Post- Cure The following schedule is recommended for post-curing the laminate 2750C............................................. 24 hours 300C.................... 24 hours 325C........................................... 24 hours Total loss due to cure volatiles estimated on the original weight of resin solids is approximately 25%. For other forms of asbestos, e. g. flock, woven fabric the same general procedure will be applicable but the solids level of the impregnating solution may need adjustment. Monsanto 012092 7 4 TOWOLDMONOQ22735 PROPERTIES OF THE P. P./ASBESTOS LAMINATE Using chrysotile asbestos the following laminate properties were obtained in the laboratory. The values quoted are typical. Resin content (w/w%) Specific Gravity Flexural Strength* (psi) Initial 25C 300C Flexural Modulus* (psi) Tensile Strength** (psi) Initial 25C 200C 300C 50 2 1.4 - 1.7 30 37,000 25 - 30,000 1. 8 - 2. 5 x 106 20 - 27,000 15 - 20,000 10 - 14,000 Ageing Life (Time taken for flex strength to fall below 5, 000 p s At 200C 240OC 300C 350C 400C 6-12 years (by extrapolation) 7000 - 15, 000 hours 1,000 - 1,500 hrs. 200 - 400 hrs. 30-150 hrs. Chemical Resistance Initial results have shown good hydrolytic and solvent resistance. (Further work is in progress on more resistant supports). * A STM D790-66 ** ASTM D638-64T Monsanto 0120928 5 TOWOLDMONOQ22736 POLYPHENYLENE/HIGH MODULUS CARBON FIBRE COMPOSITES For the preparation of carbon fibre composites a mould is used and the time in press before application of pressure is dependent on the size of the mould. The impregnating solution should be 20-25% w/v, but otherwise the procedure for fabrication is essentially that used for asbestos. Certain properties of the composite are affected by various surface treat ments of the fibre, as illustrated in the following table: PROPERTIES Resin Content (w/w%) Specific Gravity Flexural Strength* (psi) Initial 25C 240C Flexural Modulus** (psi) Ageing Life Untreated Fibre 30 - 50 1. 3 - 1.5 Treated Fibre 30 - 50 1.4 - 1.5 50 - 80, 000 40 - 55,000 80 - 116,000 12 - 13 x 106 12 - 17 x 106 (max. value found 23 x 106) Similar to asbestos * ASTM D7 90-66 ** ASTM D638-64T Monsanto 6 TOWOLDMONOQ22737 Chemical Resistance The following results on polyphenylene/carbon fibre (untreated) composites were obtained after 2, 000 hours unless otherwise stated. Knvironment 'best Temp. C Flexural Strength PS1 (Cold) Initial Final Weight Loss r/ Dimensional Change % llvSO^ (Cone. ) II2SO4 (50% w/w) UNO;; (Cone.) R. T. 90C K. T. 900 C 90 C UNO;; (50% w/w) 11 Cl (Cone.) HC1 (7.5% w/w) 1IF <-10% w/w) R. T. 90C 90C 90C K. T. NaOII (75% w/w) NaOH (SO';;, w/w) 90 C R. T. NaOH (20% w/w) NaCl ('O'iwAv) B0C It. T. NaOCl (15. 6% w/\v) R. T. Ho02 (100 vol. ) I). M. V. Pyridine R. T. 90C 90C 67, 500 59, 700 07,500 59, 700 5 9, 700 67,500 5 9, 700 59, 700 57, 800 67,500 57,800 67,500 57,800 67,500 67,500 67.300 57,800 57,800 70,300 Nil 60,900 Slight increase Nil Nil 63, 300 57,700 Nil Nil Nil Nil Nil After 696 hrs. sample swollen but had some strength. After 1784 hrs strength less than 3,000 psi. 62,200 24,500 t 12. 7 Swelling at ends < 2.6 58, 600 Nil Nil 64,800 Nil Nil 67,100 Nil Nil 64,200 Nil Nil 71,700 Nil Nil 67,500 Nil Nil 74,100 Nil Nil 65, 900 Nil Nil 72,700 Nil Nil 49, 100 Nil -1.0 17,000 After 288 hrs. No change after drying Very Swollen K fleet of Steam and Roiling Water Stea m Roiling Water 100C 100C 67,300 64,000 65,000 63, 100 Nil Nil Nil Nil The pure resin shows good resistance to cone. HC1, II2SO4 and pyridine after 2,000 hrs. at 90C. Klcmental analysis showed that the resin was essentially unchanged. Treat ment with cone. HNO3 however results in nitration of the resin. 7 Monsanto 0120930 TOWOLDMONOQ22738 Storage and Handling The impregnating solution made up of Polyphenylene Prepolymer 1171, PP Curing Agent B1 and Catalyst C30 is best stored in a cool place. Storage life can be increased by refrigerated storage. The Prepolymer 1171 is stable in the solid state and in solvent. Curing Agent B1 is stable in the solid state if kept dry, but in solution containing alcohol, it slowly releases HC1. Catalyst C30 contains alcohol solvent and is stable. All solutions should preferably be contained in glass lined vessels especially if long storage times are involved. When handling this resin system the normal precautions should be taken regarding the use of protective clothing, eye shields, etc. During the curing operation, volatile products are released, and these are dry SO2 and HC1 gases plus solvent. Mechanical exhaust ventilation should be associated with the press so as to vent these vapours to the external atmosphere. Patents Monsanto have British Patent No. 1, 037, 111 and other patents and patent applications covering the polyphenylene resins and their production in the United Kingdom and other countries. 0120931 Monsanto 8 TOWOLDMONOQ22739