Synthesis And Study Of Syringaldehyde-Biobased Polymers

Due to the advantages of sustainable development,little pollution to environment,biological compatibility,easy degradation and so on,bio?based polymers have attracted ever-increasing attention in the last decades and lead to a new wave of research.Lignin is a kind of resource-rich biomass with aromatic structure in nature.As the products refined from lignin,syringaldehyde and vanillin are a kind of biomass that contains multisubstituted benzene ring structure providing steric effect and functionally active aldehyde group.With the special structure,syringaldehyde and vanillin have great potential in biological structure materials and function materials.At present,the poor heat resistance of bio-based materials greatly limits their application.Therefore,it is valuable to prepare heat resistant bio-based materials at molecular design leval.In this research,four(meth)acrylate monomers are synthesized fully taking advantage of the structural features of syringaldehyde and vanillin,then undergo free radical polymerization to prepare noval heat resistant polymers.This kind of polymers are expected to be applied to bio-based heat-resistant materials.Subsequently,the syringaldehyde-containing monomer is copolymerized with lauryl methacrylate(LMA)through reversible addition-fragmentation chain transfer radical polymerization(RAFT)to obtain block copolymers.In the block copolymer chains,the LMA-containing polymer works as soft segment and syringaldehyde-containing polymer works as hard segment.This kind of block copolymers are expected to be used in aldehyde biobased function materials or thermoplastic elastomers.The main research contents are shown as follows:1.Four novel bio-based monomers,namely syringaldehyde methacrylate(SMA),syringaldehyde acrylate(SA),vanillin methacrylate(VMA)and vanillin acrylate(VA),are obtained via the condensation reaction between syringaldehyde(vanillin)and(meth)acryloyl chloride.Then the corresponding homopolymers(PSMA,PSA,PVMA and PVA)are obtained via free radical polymerization.FTIR,NMR,and elemental analysis measurements are conducted to manifest the structure of the four novel bio-based monomers,while GPC,DSC and TGA measurements are conducted to study the properties of the four corresponding polymers.A comparison was further made between the present polymers with two typical petroleum-based polymers(PS and PMMA)and a typical commercialized bio-based polyester(PLA)reported in literatures.2.The controllable polymerization capability of SMA is studied through RAFT polymerization by using two suitable chain transfer agents.And on this basis bi-block copolymers are obtained through RAFT polymerization by using SMA and LMA as monomers.Further,a di-functional RAFT agent is synthesized and used to prepare tri-block copolymers.The structures and properties of the block copolymers are determined by GPC,NMR,DSC,TGA,TEM and AFM measurements.