Esterification of Condensed Tannins and Their Impact on the Properties of Poly(Lactic Acid)

Polymers

Warren J. Grigsby¹  James H. Bridson²  Cole Lomas² 

[1] Biopolymer Network Ltd and Manufacturing & Bioproduct Development, Scion, Rotorua, 3046, New Zealand;

关键词: condensed tannins;    polyphenolics;    esterification;    poly(lactic acid) (PLA);    plastic additives;   

DOI  :  10.3390/polym5020344

来源: mdpi

【 摘 要 】

Reported is a study evaluating the potential of esterified tannins as plastic additives in poly(lactic acid) (PLA). Tannin esterification using anhydrides was investigated as a route to synthesize tannin esters possessing varying ester chain length and degree of substitution (DS). Esterification decreased the tannin UV absorbance, predominately in the UVB region. However, tannin materials with longer ester chain lengths exhibited melt behaviors suitable for processing in plastics. On compounding into PLA, tannin hexanoate esters lowered the PLA glass transition by 5–6 °C. Shorter chain length tannin esters had a reduced effect on PLA polymer properties. The PLA flexural properties were significantly altered with stiffness decreases of up to 15% depending on ester chain length and loading. Artificial weathering of modified the PLA samples suggests the presence of tannin esters may confer a protection role to PLA on extended exposure. Overall, results suggest scope for the use of tannin esters possessing longer ester chain length as plastic additives.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.