Document NeV8y6EeNQVY6R6M7Q1vqZaV

126 Frank M. Noonan and Benjamin Linsky The asbestos samples were deposited onto both sides of a K RS-5 reflector plate appioximatcly SO x 20 x 2 mm with a 45 degree angle face that yielded approximately 25 reflections. Approximately one third to one half of the KRS-5 reflector plate surface area was covered with the asbestos sample supported in a Wilks MIR-2 steel holder. Pressure was applied to achieve efficient intimate contact of the ashestos with the reflector plate. Internal reflectance measurements were made by means of the Wilks Scientific Model 9 Single Beam Internal reflectance attachment, including a Wilks Model 2 sample holder, on a Perkins Elmer Model 137B. Infra-red Spectrophotometer with sodium chloride optics. A Wilks MIR-]] beam attenuator was used to attenuate the reference beam. The optica! efficiency of the Wilks Model 9 attachment with no sample present is about 50 per cent after reflection losses. Fine adjustments of the optical alignment were made without the reflectance unit to produce a recorder response of 98 per cent transmission at 2000 cm"1. The multiple internal reflection unit was inserted and produced a recorder response of 37 percent transmission at 2000 cm"1. The reference beam was then attenuated using a Wilks Model II beam attenuator such that the recorder pen response was 75 per ceiit transmission at 2000 cm *1 with no sample present. The infra-red interna) reflectance spectra obtained for the asbestos samples arc shown in Figs. 1-5. WOVElWigtK, Hm Tronmi>anc#, X FlC. I. Infrs-rtd imemI reflectance sreetrum uf Aniositc. 3. DISCUSSION No attempt was made to note band assignments since this part of the study has been directed only to detect instrumenlally measured differences between the various I'JCC standard referenoe asbestos samples, Br.lj.AMV (I4M) has noted the region of transmission absorption area between 11 (X> cm 1 and^JOOcni 1 tor silicate compounds. I.auni m (IV52) also shows a transmission spectrum of unthophyllitc that was obtained from thill hints of powder asbestos (liber length of less tliun 2 /mu deposited on a sodium chloride plate. Launer indicates that the nmphihols have a band near 7b9 cm "1 which is characteristic of the double-chain silicates. Tlirir is u strong similarity between llit- nbsmpliiiii spci tium ohi.nurd lot antin' phyllitr by direct transmission mensnremenls hy I,aimer and that winch was obtained P00U 0<M a l' PRODUCED BY FORD