Study On Copolymerization And Modification Of Poly(Butylene Succinate)

Biodegradable materials and composites of poly(butylene succinate) (PBS) were reviewed in this paper. These performance and properties of copolymers via copolymerization and modification of PBS by 1,4-cyclohexanedimethanol(CHDM) and 1,4-cyclohexyldiol (CHD) were analyzed. Stress self-oscillation which is a rare mechanical phenomenon of copolymer was observed during stretching, and its mechanism was studied and simulated.Poly(butylene succinate-co-cyclohexanedimethylene succinate) copolyesters (PBCMSs) and Poly(butylene succinate-co-cyclohexanediol succinate) copolyesters (PBCSs) from various amounts of cyclohexanedimethylene succinate (CMS) oligomer and cyclohexanediol succinate (CS) oligomer with butylene succinate (BS) oligomer were synthesized via polycondensation. Crystallization behaviors, morphologies and rheological properties of PBCMSs and PBCSs were investigated by a polarized optical microscopy (POM), a differential scanning calorimetry (DSC), a X-ray diffraction (XRD) and a parallel-plate rheometer (PPR). These tests revealed that the composition of PBCSs played an important role in controlling their properties. PBCMSs exhibited lower crystallinity and melting point than its homopolyesters either PBS or poly(cyclohexanedimethylene succinate) (PCMS). The spherulitic size gradually decreased with an increase of CMS content. When CMS content approached 50 wt%, the crystallinity of PBCMSs reached minimum value, while the viscosity approached the maximum value. Flow activation energy (En) systematically increased with increasing CMS content.Poly (butylene succinate-co-cyclohexanedimethylene succinate) (PBCMS-20) was synthesized from 20 wt% of cyclohexanedimethylene succinate (CMS) with 80 wt% of butylene succinate (BS) via esterification and polycondensation. Stress self-oscillation was observed in the necking portion, which resulted in a great enhancement in the strength and elongation simultaneously. Appearance of alternating opaque and transparent bands was perpendicular to the direction of neck propagation. X-ray-diffraction (XRD) studies revealed that stress oscillation induced orientation crystallization in (001) planes via a local deformation. A mathematical model was developed to describe stress self-oscillation using a new stress oscillation model, which was composed of a two element Maxwell model combined with oscillated cells. The parameters of the model were calculated and well fitted to the stress self-oscillation.Finally, these properties of Poly(butylene succinate-co-cyclohexanediol succinate) copolyesters (PBCSs) were analysed through these results of tests. By differential scanning calorimetry (DSC), melting endothermic peaks of the copolymers gradually shifted to the low temperature until it disappeared with CS content increased,and melting point decreased with the increase of CS. The toughness of PBCSs became higher with the 1,4-cyclohexanediol content increasing from mechanical data; Through the analysis of the mechanical properties of PBCSs, with increasing CS content the elastic modulus and yield stress decreased. But the elongation at break increased with CS content increased, it reached 376.9908% at 50 wt% of CS feeding fraction.Flexibilities of PBCSs reinforced after modified by adding 1,4-CHD, and these copolymers had better mechanical properties.