Synthesis, Preparation Of All Bio-based Polyesters And Toughening Of Poly (Butylene Succinate)

Since the energy crisis and environmental problems intensifying,the development of biomass resources has received the widespread attention,research and development of high performance bio-based polymer materials has become the main trend.Poly(butylene succinate)(PBS)as a kind of biodegradable linear alipgatic polyester,compared to other biodegradable plastics,has good mechincal properties,processablity and themal stability.But some disadvantages,such as low melt strength and poor impact resistance,limit the applications of PBS,so we need to toughen the materical.Generally plastics can be toughened effectively by elastomers,but production of conventional elastomers is almost entirely dependent on fossil energy.In order to improve the impact properties of PBS and maintain the bio-based attribute,bio-based polyesters were synthesized by adopting several bio-based monomers with isosorbide,2,3-butanediol respectively.Finally,we use the polyester elastomers to toughen PBS.A series of whole bio-based polyesters PIBS were prepared by melt polycondensation reaction with isosorbide,succinic acid and 1,4-butanediol.With the increase dosage of isosorbide,the crystallinity and the molecular weight of PIBS polyesters gradually decreased.The tensile strenghth of polyesters decreased and the elongation at break increased with isosorbide content increasing,but the tensile strenghth and elongation at break rapidly decreased when the isosorbide content further increasing.Using 2,3-butanediol,succinic acid and 1,4-butanediol as reaction monomers,a series of bio-based polyesters PBBS with different 2,3-butanediol content were obtained by direct melt polycondensation.The number average molecular weight of PBBS is between 2.73 × 104 and 4.16×104 g/mol,the molecular weight distribution is between 1.7 and 2.2.With the increase of 2,3-butanediol content,the crystallinity of PBBS gradually decreased and the polyesters were transformed from crystalline plastics to amorphous elastomers.The whole bio-based PBS/PBBS blends were prepared by blending with PBS and different 2,3-butanediol content PBBS polyesters thourgh melting blending.The crystallization temperature and ctystallinity of PBS decreased after blending with PBBS.The results of DMTA and AFM show that blend systems changed from fully compatible to partially compatible with the increase content of 2,3-burtanediol.The tensile strength of blends decreased,and the impact resistance improved.Espcially PBBS-70/PBS blends,the notched impact strength increased from 4.68kJ/m2 of pure PBS to 41.32kJ/m,SEM images of impact fracture surfaces appeared obvious matrix deformation which proved to be ductile fracture.We made further research to study different filling amout of PBBS-70,and we found the materials blending with 15wt%PBBS-70 possessed excellent comprehensive properties.