Synthesis and Characterization of PLA-Based Aliphatic-Aromatic Copolyesters: Effect of Diols

Abstract

AcknowledgementI wish to express my deepest and sincere gratitude to my supervisor, Asst. Prof. Dr. Pakorn Opaprakasit for his supervision, valuable instructions, excellent suggestions, kindness and assistance on the preparation of this thesis. This accomplishment would not be possible without his help.Moreover, I feel very thankful and grateful to Dr. Atitsa Petchsuk, Dr. Mantana Opaprakasit for their kindness and valuable discussion and comments on this thesis.My appreciation is also extended to the staff of the School of Bio-Chemical Engineering and Technology and the department of Common and Graduate Studies, Sirindhorn International Institute of Technology (SIIT), Thammasat University.Unforgettably, this work was made possible by a financial support from the SIIT-NSTDA scholarship and partial support from the teaching assistant program.I would like to thank all of my colleagues for great cooperation and the best wonderful relationship. Finally, thank you my lovely family for their love and encouragement.Montree Namkajorn ii Abstract PLA-based aliphatic aromatic copolyesters have been synthesized and characterized in order to incorporate the degradability of PLA and good mechanical property of aromatic species. Synthesis of the copolymer was conducted by polycondensation of lactic acid with dimethyl terephthalate (DMT) and diols using Stannous(II)octoate as a catalyst. Four types of diols with different methylene length were employed, i.e., ethylene glycol (EG), propylene glycol (PG), 1, 4-butanediol (BD), 1,3-propanediol (PD). Effects of diols and comonomer ratio on the polycondensation and the molecular weight of resulting copolymers were investigated. Diacids and diol ratios of L-lactic acid (LLA), dimethyl terephthalate (DMT) and diol of 1/1/2, 1/2/4, and 2/1/2 were employed, respectively. Characterization of chemical property, molecular weight, thermal property and degradability of the resulting copolymers were conducted by FTIR, UV, NMR, TGA, and DSC experiments.

Polyester-based polyurethanes derived from alcoholysis of polylactide as toughening agents for blends with shape-memory properties

“…22,23 Its undesired properties, especially low toughness, can be enhanced by plasticizing, blending, or copolymerizing with other polymers or elastomers. [24][25][26][27][28] Elastomers commonly used in PLA blend systems include natural rubber and derivatives, polyurethanes, polyamides, poly(butylene succinate), and starshaped PDLA. [24][25][26][29][30][31][32] This leads to desirable or balance properties of modulus, toughness, and high elasticity.…”