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synopsisA method haa been developed for the determination of per cent ethylene incorporation in ethylene-propylene block copolymers by infrared spectroscopy. Standardization is done from mixtures of the homopolymers. Both standards and samplea are scanned at 180OC. in a spring-loaded demountable cell. The standardization waa confirmed by the analysis of copolymers of known ethylene content prepared with C14-labeled ethylene. By comparison of the infrared resuite from the analyses performed at 18oOC. and also at mom temperature, the p m n c e of ethylene homopolymer can be detected. An equation haa been derived for the quantitative estimation of per cent ethylene present as copolymer blocks.

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SynopsisA number of techniques have been used in the past for obtaining the infrared spectra of fine fibers. A new technique has been developed which overcomes many of the problems of previous methods. The present technique involves winding a single filament between two salt windows which are separated by a spacer which is the same or slightly greater in thickness than the fibers.Good-quality polarized infrared spectra were obtained on oriented poly(ethy1ene terephthalate) and oriented nylon 6 fibers with the new technique. The data demonstrate the high level of "A" conformation orientation present in highly drawn nylon 6 fibers and the existance of chain folds in drawn poly(ethy1ene terephthalate) fibers. The structural changes which occur during the shrinkage of nylon 6 fibers are also demonstrated.This results in a layer of adjacent parallel fibers.

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