Interfacial Regulation And Properties Of Graphene Oxide/Polylactide Nanocomposites

The shortage of fossil energy reserves and the increasing environmental problems have promoted the development of biodegradable materials.Alternative materials of petroleum-based polymers are the basis for sustainable development in the 21st century,biodegradable polylactic acid has attracted wide attention as one of the research hotspots.However,poor barrier and thermal stability limit its application.Adding nano filler is one of the most important solutions.Graphene oxide(GO)has ultra-high specific surface area and vertical and horizontal ratio,making it an ideal NF,which can improve the mechanical properties,barrier properties and thermal stability of nanocomposites.Chemical structure on the surface of GO is very important for achieving homogeneous mixing of GO and polymer.However,the extremely easy aggregation of GO severely limits its use.In order to improve the mechanical properties and oxygen barrier properties of the polymer by grafting different length molecular chains(DLMC)and different structural molecular chains(DSMC)on the surface of the GO,the dispersion of GO in the matrix and the interfacial bonding properties between the polymer and matrix are improved.DLMC consists of ethylenediamine(EDA),dodecylamine(DA)and octadecylamine(ODA),DSMC includes polyethylenimine(PEI)and PLA.Specific steps:in this paper,DLMC and DSMC were grafted onto GO surface to prepare functionalized graphene oxide(FGO).GO,DLMC-g-GO and DSMC-g-GO were used as NF,and FGO was dispersed uniformly in PLA matrix by ultrasonic melting blending,and then GO/PLA,DLMC-g-GO/PLA and DSMC-g-GO/PLA composite films were prepared.The results show that the thermal stability and mechanical properties of the DLMC-g-GO/PLA and DSMC-g-GO/PLA composite films increase with the increase of the molecular chain and the compatibility of the molecular chain,which is mainly attributed to the effective interfacial regulation to enhance the dispersion of FGO in the matrix,increase the boundary area of the interaction and enhance the interfacial bonding.In DLMC,with the increase of the grafting molecular chain,the melting temperature(Tm)increased from 168.40?to 169.10?,and the tensile strength increased to 58.00MPa,58.16MPa,58.38MPa,and the oxygen permeability coefficient reached the lowest value in GO-g-DA/PLA,which was 1.17×10-4cm3cm/(cm2·s·Pa).In DSMC,from PEI to PLA,Tm increased from 168.00? to 169.40?,and the tensile strength increased from 33.53MPa to 60.22MPa;oxygen permeability coefficient was reduced from 1.62×10-13cm3cm/(cm2·s·Pa)to 3.06×10-14cm3cm/(cm2·s·Pa).In this paper,the preparation methods of DLMC-g-GO and DSMC-g-GO are discussed,compare the two groups of materials respectively.The influence of different interface controls produced by the addition of FGO on the thermal stability,mechanical properties,and oxygen barrier properties of composites were investigated.Studying the law of change provides a reliable direction and theoretical basis for follow-up research.