Functionalization of Graphene Oxide with Low Molecular Weight Poly (Lactic Acid).

Mingwei Yuan,Minglong Yuan,Xiansong Xia,Hongli Li,Chengdong Xiong,Yike Chen

doi:10.3390/polym10020177

Abstract

In this paper, the hydroxyl groups on the surface of graphene oxide (GO) were used to initiate the ring-opening polymerization of a lactic acid O-carboxyanhydride. GO grafted with poly (l-lactic acid) molecular chains (GO-g-PLLA) was prepared. Lactic acid O-carboxyanhydride has a higher polymerization activity under mild polymerization conditions. Thus, the functionalization of the polymer chains and obtaining poly (lactic acid) (PLLA) was easily achieved by ring-opening polymerization with 4-dimethylaminopyridine (DMAP) as the catalyst. The results showed that with this method, PLLA can be rapidly grafted to the surface of GO in one step. As a result, the chemical structure of the GO surface was altered, improving its dispersion in organic solvents and in a PLLA matrix, as well as its bonding strength with the PLLA interface. We then prepared GO/PLLA and PLLA/GO-g-PLLA composite materials and investigated the differences in their interfacial properties and mechanical properties. GO-g-PLLA exhibited excellent dispersion in the PLLA matrix and formed excellent interfacial bonds with PLLA through mechanical interlocking, demonstrating a significant enhancement effect compared to PLLA. The water vapor and oxygen permeabilities of the GO-g-PLLA/PLLA composite decreased by 19% and 29%, respectively.

Highlights

(lactic acid) (PLLA) is receiving considerable attention for conventional uses, such as a packaging material, for the production of agricultural film, and more recently, as composites for technical applications [1]
This study provides a new thought process and method to solve the key problem of nanomaterial-poly L-lactide (PLLA) composite materials, and to lay a theoretical foundation for next-generation green food packaging materials
Polymerization of lactide monomers, initiated by the grafted OH groups on graphene oxide (GO) and under the Chaobin and Inoue reported the synthesis of GO-g-PLLA through the ring-opening catalysis of Sn(Oct

Summary

Introduction

(lactic acid) (PLLA) is receiving considerable attention for conventional uses, such as a packaging material, for the production of agricultural film, and more recently, as composites for technical applications [1]. Its wider application has been limited by its relatively slow crystallization rate, poor gas barrier performance, and poor flexibility [1]. To overcome these challenges, various methods (such as Copolymerization and blending) have been used to enhance the comprehensive performance of poly L-lactide (PLLA). The degree of crystallinity and mechanical properties can be changed by blending. Copolymerization can change the performance of many aspects, mainly based on the properties of the graft molecules. Feng et al developed a versatile method by grafting polymers on GO to enhance the properties of nanocomposites [8,9].

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