Study On Preparation Of Polyurethane Based On Eugenol By Olefin Metathesis Reaction

From the perspective of sustainable development,replacing fossil resources with abundant biomass resources can not only obtain stable and low-cost raw materials,but also conform to the theme of green chemistry.Eugenol derived from plant essential oils,is abundant in nature,green,safe,and low in cost.In this paper,eugenol and diisocyanate were used as raw materials,the structure of polymerization monomer was rationally designed by ammonia esterification reaction,and the bio-based monomer with amino ester bond and double bond at both ends was prepared.The monomers containing double bonds at both ends can be polymerized by olefin metathesis reaction to obtain bio-based polyurethane.It not only makes effective use of bio-based renewable resources,which is environmentally friendly,but also provides sufficient properties.for the preparation of bio-based materials with design properties.The main contents of this paper are as follows:(1)Syol was successfully synthesized from eugenol(Eug);Eug-HDI,Syol-HDI and Syol-MDI were synthesized by the reaction of Eug and Syol with diisocyanate.Their structures were characterized by FTIR and ~1H NMR.(2)The effects of catalyst type,solvent,reaction temperature,reaction time,molar ratio of catalyst dosage and metal salts on the redecomposition polymerization of Eug-HDI olefins were investigated.Under the optimal conditions,the yield reached 64.7%.It is worth noting that the addition of metal Ni salts can significantly promote the polymerization,in which Ni I2 can increase the yield to 86.6%.(3)Bio-based polyurethane P(Eug-HDI),P(Syol-HDI)and P(Syol-MDI)were obtained by olefin metathesis polymerization of three bio-based monomers.The thermal decomposition behavior of the polymer was studied.DSC test showed that P(Eug-HDI)was more prone to thermal decomposition by P(Syol-HDI)and P(Syol-MDI).The reversible behavior of thermal decomposition of polyurethane was tracked by variable temperature infrared spectroscopy.It was found that the characteristic absorption peak of NCO appeared with increasing temperature and increased with increasing heating time.In the cooling process,the characteristic absorption peak of NCO becomes weak,indicating that P(Eug-HDI)has reversible thermal decomposition properties.(4)Trifunctional monomer TEU was synthesized from eugenol and melamine,and was copolymerized respectively with Eug-HDI,Syol-HDI and Syol-MDI in proportion.The polymerization products were characterized by FTIR,~1H NMR and DSC.The results showed that the order of polymerization activity was Syol-MDI>Syol-HDI>Eug-HDI,and the Tg of copolymers with different proportions was significantly different.