PROCESS FOR OBTAINING THREE-COMPONENT POLYMERIC MATERIALS WITH ORIENTED VARIABLE COMPOSITION, SYNTHESISED THROUGH SEQUENTIAL COPOLIMERISATIONS IN A SEMI-BATCH REACTOR WITH FEED GRADIENT

摘要

Different ways have been used to optimise the contribution of each component in two-monomer systems to form copolymers, as the structures thereof strongly affect the composition of A-B type chains that may be formed during the reaction. For three components, the situation is further complicated if specific sequences are sought, since the number of possible growth reactions increases (9 for terpolymers, instead of 4 for copolymers). One way of constraining the relative content of the components in high-molecular-weight chains formed by traditional radical reactions is the use of a semi-batch process with feed gradient, wherein vinyl comonomers are sequentially fed in pairs (A-B and B-C), promoting the formation of A-rich chains, B-rich chains and C-rich chains, in addition to a certain amount of A-B and B-C copolymer chains which cover the spectrum of intermediate compositions. These act as compatibilisers. With this strategy, a synergistic combination of properties in the end material can be achieved.