In this study, we developed a new type of cross-linked polyvinyl alcohol (PVA)-lignin i.e., esterified PVA-CA-lignin resin by using citric acid (CA) cross-linker. Firstly, hydrogen bonded PVA-CA-lignin resin was prepared by the mixing of PVA, lignin and CA and then esterification of hydrogen bonded PVA-CA-lignin resin was carried out at 180oC. Subsequently, the esterification of PVA-CA-lignin resin was confirmed by FTIR and the morphology of the esterified PVA-CA-lignin resin was examined with the help of scanning electron microscopy.Finally, the effects of CA cross-linker on the properties of esterified PVA-CA-lignin resin, especially the tensile strength and thermal stability were evaluated and analyzed. The results demonstrated that CA was cross-linked in PVA-lignin resin matrix and the content of CAenhances the performance of esterified PVA-CA-lignin resin significantly. The esterified PVA-CA-lignin resin is applicable for the natural fibre reinforced composites.
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