Amorphous Polyolefins: The Relations between Molecular Structure, Submolecular Motion and Mechanical Behavior

摘要

The thermomechanical spectra of two series of amorphous polyolefins represented by ((CH2)m-C(CH3)2)n and ((CH2)m-C(CH3)(C2H5))n where m = 1, 2, and 3, are presented from -180C to a point above the glass transition temperature. The polymers were obtained by cationic polymerization of alpha-olefins. The mechanical spectra show a maximum in glass transition temperature and secondary transition temperature for the second member of each series. This maximum is interpreted in terms of a proposed intermolecular interlocking considered to be at a maximum for the second member of the series, and serving to restrict the submolecular motions associated with the transitions. The proposal is discussed in terms of its consequences upon free volume, density, cohesive energy density, and chain flexibility. (Author)