Design, Synthesis And Performance Research Of Novel Polyesters Derived From10-Undecenoic Acid And Vanillic Acid

Aromatic thermolplastic polyesters were widely used in packing, electronic devices, constructive industry and auto industry due to their excellent properties. However, they are considered to be unfriendly compounds because of their great resistance to degradation by atmospheric and biological agents, and thus liable to cause white pollution. In addition, today’s polyester production relies almost exclusively on fossil feedstocks. Because of the rapid depletion and the rising prices of the fossil resources, the utilization of renewable resources for the production of biodegradable polymers via sustainable and environment-friendly pathways would be very appealing. During the past two decades, most research focus on plant oils, carbohydrates and furfural as renewable resourses for the production thermoplastic polyesters, however, there are more or less disadvantages for these polyester, lack of the mechanical strength necessary for broad applications, high prices and nondegradable. So far, few polyesters derive from renewable resources with excellent properties have been produced and further investigation should be taken. In this thesis, we have summarized the recent progress in designing and developmentment of monomers and novel polymers derived from renewable resources. Based on previous studies, several kinds of polyesters derived from10-undecenoic acid and vanillic acid were synthesized, and characterized using FTIR,’H-NMR, and SEC, and their thermo-mechanical properties were studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and their mechanical properties were evaluated using tensile test. Results indicated that these polyesters would have good application prospect due to their excellent properties.(1)10-Undecenoic acid, based on castor oil, was used as the raw materials for the synthesis of thermoplastic aliphatic polyesters (PEs). Thiol-ene click chemistry was used to afford renewable aliphatic diols and diester from10-undecen-l-ol and methyl10-undecenoate, respectively. A series of aliphatic polyesters with high number average molecular weight were synthesized in high vacuum and high temperatures. But these fully aliphatic polyesters lack the mechanical strength necessary for practical applications, in order to solve this disadvantage, we tried the incorporation of vanillic acid-based aromatic diesters to improve the mechanical stength, tensile test indicate that the mechanical strength indeed have been improved.(2) In the first part, it was concluded that the tensile modulus generally increased with the decreasing the number of the methylene units in the aliphatic diols. From this point, instead of the long renewable aliphatic diols derive from10-Undecenoic acid, a series of renewable diol, ethylene glycol,1,3-propanediol,1,4-butanediol and decamethylene glycol were used to copolymerize with the two vanillic acid-based aromatic diesters, a series of aromatic polyesters PEl-ms and PE2-ms were successfully synthesized via transesterification and polycondensation process. Tensile test indicated that the mechanical properties of PE1-ms and PE2-ms were remarkblely improved compared to those PEs1-7in the first part.(3) In order to further improve the mechanical properties of these polyesters, as well as bring down the prices of the resulting polyesters, the vanillic acid-based diesters were used as comonomers of dimethyl terephthalate in the melt with1,4-butanediol to produce a set of aromatic copolyesters PBIIVxTy, PBVxTy with vanillic acid diester contens ranging from10-90%. Tensile test indicated that the Young’s modulus of the obtained copolyesters were all relatively high, especially, the elongation at break for PBV70T30reaches as911%.