Study On Synthesis And Photopolymerization Of Furan Acrylate Derivatives

The solid-state photodimerization reaction requires a high degree of regularity of the monomer structure,and fewer types of monomers that can realize the solid-state photodimerization reaction.Therefore,the study of solid-state photodimerization monomers has become a core issue in this field.Furfural is one of the most valuable renewable bio-based chemical materials.With the world's research on renewable biomass materials,the preparation of furan-based monomers from furfural has shown the importance.There are still few reports of polyester compounds containing furan ring prepared by photopolymerization.A bifunctional diethylene glycol difuran acrylate was synthesized from furfural.When the monomer molar ratio is 2.3:1,the reaction temperature is 100°C,the reaction time is 5 h,and the amount of catalyst is 3 wt%,the yield reached a maximum of 74.7.Infrared spectroscopy and ultraviolet spectroscopy were used to confirm the occurrence of solid-state light dimerization.After irradiation by ultraviolet,the C=C absorption peak at 1636 cm^-1 and the=C-H absorption peak at971 cm^-1 basically disappeared,and the UV absorbance decreased from 1.67 to 0.39,Which was mainly due to the[2+2]-cycloaddition reaction of crystal after UV irradiation,resulting in the decrease of C=C and trans furan acrylate group content.At the same time,the C=O peak at 1704 cm^-1 redshifted to 1729 cm^-1.and the maximum absorbance wavelength was also blue-shifted from 304 nm to 295 nm.This is mainly because the C=O and C=C on furan acrylate group changed from the conjugated structure before light to the non-conjugated structure.From the X-ray diffraction diagram,it can be seen that the diethylene glycol difuran acrylate is in a crystalline state,and the linear polyester is in an amorphous state.RT-FTIR was used to investigate the photopolymerization kinetics,and it was found that the free radical initiator not only did not promote the photodimerization reaction,but also played an inhibitory role to a certain extent.The double bond conversion rate increases with the increase of light intensity,the presence of the sensitizer 2,4-dinitroaniline increases the absorbance of the system,and the absorption edge is redshifted from 347 nm to429 nm.When the system contains no sensitizer,it take about 126s for the double bond conversion to reach 86%,and it takes about 64 s when the system contains 3%sensitizer,which indicates that proper amount of sensitizer can improve the reaction rate of photodimerization.The decomposition activation energy E of linear polyester calculated by Kissinger equation method and Flynn-Wall-Ozawa equation method are109.246 k J/mol and 113.984 k J/mol,respectively,indicating that linear polyester has good thermal and oxygen stability under air atmosphere.Tri-functional trimethylolpropane trifuran acrylate was synthesized from furfural.When the monomer molar ratio is 3.4:1,the reaction temperature is 120?,the reaction time is 6 h,and the amount of catalyst accounts for 3 wt%of the total monomer mass,the maximum yield is 67.5%.After irradiation by ultraviolet,the C=C absorption peak at 1637 cm^-1 and the=CH absorption peak at 969 cm^-1 basically disappeared,and the C=O at 1711 cm^-1 stretching vibration peak red shifted to 1734cm^-1.The UV transmittance increased from 1.25%to 67.4%,and the maximum transmittance wavelength was also blue shifted from 307 nm to 296 nm.It can be seen from the X-ray diffraction pattern that trimethylolpropane trifuran acrylate has high crystallinity and regular molecular structure.The body-shaped polyester synthesized after light is amorphous.The effect of light intensity and sensitizer on photodimerization was investigated by RT-FTIR.It was found that the conversion rate of double bond of furan acrylate group increased with the increase of light intensity.When the system did not contain sensitizer,it took about 270 s to achieve 77%conversion rate of double bond,and it takes about 90 s when the system contains 3%sensitizer.According to Kissinger equation method and Flynn wall Ozawa equation method,the E of bulk polyester is 165.37 k J/mol and 168.52 k J/mol,respectively,which is 56.12 k J/mol and 54.54 k J/mol higher than that of linear polyester.The results show that the network type polyester has better thermal oxygen stability than that of linear polyester.