Bio-Based Poly(lactic acid)/Poly(butylene sebacate) Blends with Improved Toughness

• Published in: Polymers Vol. 14; no. 19; p. 3998
• Main Authors: Frone, Adriana Nicoleta, Popa, Marius Stelian, Uşurelu, Cătălina Diana, Panaitescu, Denis Mihaela, Gabor, Augusta Raluca, Nicolae, Cristian Andi, Raduly, Monica Florentina, Zaharia, Anamaria, Alexandrescu, Elvira
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 24-09-2022; MDPI
• Subjects: Bioplastics; biopolymer blends; Butanediol; Ductility; dynamic mechanical analysis; Elongation; Flexibility; Glass transition temperature; Glycerol; Impact strength; Melt flow index; Mixtures; Modulus of elasticity; Monomers; poly(butylene sebacate); Polyester resins; Polylactic acid; Polymerization; Polymers; Sebacic acid; Synthesis; Tensile strength; Tensile tests; thermal analysis; Thermogravimetric analysis; Toughness; Vegetable oils
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym14193998

A series of poly(butylene sebacate) (PBSe) aliphatic polyesters were successfully synthesized by the melt polycondensation of sebacic acid (Se) and 1,4-butanediol (BDO), two monomers manufactured on an industrial scale from biomass. The number average molecular weight (Mn) in the range from 6116 to 10,779 g/mol and the glass transition temperature (Tg) of the PBSe polyesters were tuned by adjusting the feed ratio between the two monomers. Polylactic acid (PLA)/PBSe blends with PBSe concentrations between 2.5 to 20 wt% were obtained by melt compounding. For the first time, PBSe’s effect on the flexibility and toughness of PLA was studied. As shown by the torque and melt flow index (MFI) values, the addition of PBSe endowed PLA with both enhanced melt processability and flexibility. The tensile tests and thermogravimetric analysis showed that PLA/PBSe blends containing 20 wt% PBSe obtained using a BDO molar excess of 50% reached an increase in elongation at break from 2.9 to 108%, with a negligible decrease in Young’s modulus from 2186 MPa to 1843 MPa, and a slight decrease in thermal performances. These results demonstrated the plasticizing efficiency of the synthesized bio-derived polyesters in overcoming PLA’s brittleness. Moreover, the tunable properties of the resulting PBSe can be of great industrial interest in the context of circular bioeconomy.