| Abstract |
The dynamic-mechanical behaviour of several copolymers of ethylene and styrene, obtained with a heterogeneous catalyst, has been analysed and compared with that of the corresponding homopolymers. The copolymers show three relaxations alpha, beta and gamma. The alpha relaxation is associated with the crystalline content, the gamma relaxation with the movement of methylene groups in the main chain and the beta relaxation seems to be associated with the interfacial content. The alpha and beta relaxations overlap and their intensity depends on the styrene content. All the copolymer samples and their fractions, either soluble or insoluble in boiling toluene, show the beta relaxation at about -10 degrees C, indicating that they do not have a complete block structure. The microhardness values of the polymers studied have been related to the composition of the copolymers and the crystallinity of the samples. (C) 2000 Elsevier Science Ltd. All rights reserved. |
