Preparation of random poly(butylene alkylate-co-terephthalate)s with different methylene group contents: crystallization and degradation kinetics

摘要: Random copolyesters having 1,4-butanediol units were synthesized from a transesterification process between homopolymers constituted by aliphatic dicarboxylates (i.e. succinate, adipate or sebacate) and the aromatic therephthalate derivative, as verified NMR spectroscopy. Biodegradability of resulting was studied via enzymatic hydrolysis using Pseudomonas cepacia lipase at pH = 7.2 37 °C. Kinetics degradation showed that in all cases rate decreased after 19 days exposure. The observed glass transition temperatures, T g, random non-linear dependence on composition, feature explained terms internal stiffening effect butylene terephthalate units. Copolymers with higher 50 70 mol-%) methylene sebacate units) contents double melting peaks DSC thermograms. These resulted two different crystalline rich phases melt-crystallization subsequent cooling. ratio these logically depended predominant dicarboxylate content. copolymers initially crystallized through heterogeneous nucleation spherulitic growth. presence hindered beginning crystallization process, but overall growth kinetic constant similar for samples. secondary constants determined values samples contents.