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Order in amorphous polystyrenes as revealed by electron diffraction and diffraction microscopy

1972; Taylor & Francis; Volume: 6; Issue: 3 Linguagem: Inglês

10.1080/00222347208219127

1525-609X

G. S. Y. Yeh,

Advanced Physical and Chemical Molecular Interactions

Abstract Ordered regions ranging in size between 15 and 45 A have been established in several atactic polystyrenes of various molecular weights (4800; 51,000; and 1,800,000) as well as in an amorphous isotactic polystyrene by means of electron diffraction and high-resolution diffraction microscopy. The order is due to long-chain polymer molecules which tend to align more-or-less parallel to one another with a constant average spacing. The orderly chain packing can be disturbed upon cross-linking by electron irradiation, the disturbance being manifested in the irreversible changes in the d spacing and broadening of one of the diffuse rings which is inter-molecular in origin. From the results obtained, the high-resolution diffraction microscopy technique appears to have the potential for resolving the question regarding the presence of order in unoriented amorphous polymers. The technique can also differentiate between a broadened diffuse ring due to small crystallites and another due to paracrystals contai...