Preparation And Properties Of Bio-based Anti-ultraviolet Transparent Film

In this dissertation,three kinds of homogeneous and well-mixed biomass-based antiultraviolet transparent films were prepared by using the phoebe zhennan wood processing residues as materials.And their UV resistance,UV irradiation stability,functional group structure,thermal stability and mechanical properties were characterized.Starting with the chemical constituents of the extract of Phoebe zhennan,the anti-UV mechanism of the film was discussed.The main conclusions of the study are as follows:In 11 kinds of Phoebe zhennan wood extracts.The yield of methanol extract of Phoebe zhennan was the highest,being 8.16%,and the yield of chloroform extract of Phoebe zhennan was the lowest,being 2.75%.The color of the 1% Na OH extract is reddish,and the color of the methanol and other extracts is yellowish.The color of the hot water extract and the 1% Na OH extract was dark,and the color of the methanol extract,the acetone extract,the ether extract and the chloroform extract was bright.The above extract is mixed with PLA for film preparation,there are three kinds of extracts which are successfully formed into a film,which are ether extract,ethyl acetate extract and chloroform extract.The three films prepared are highly transparent.The color of the film is light yellow,and the higher the extract content,the darker the film color.The three extracts of Phoebe bournei wood have good miscibility with polylactic acid.The UV resistant film with 24% ether extract(PF+24% DE-EX)almost blocked all UV-B(280-315 nm)and over 90% UV-A(315-400 nm)compared to pure PLA film(PF).The UV resistant film with 24% ethyl acetate extract(PF+24% EA-EX)blocked almost all UV-B(280-315 nm)and 89% UV-A(315-400 nm).The UV resistant film with 24% chloroform extract(PF+24%TR-EX)almost blocked all UV-B(280-315 nm)and 88% UV-A(315-400 nm).The strong ultraviolet light irradiation test results show that the three prepared PF-EX are stable under ultraviolet light irradiation.Compared with the polylactic acid film,the intensity of the corresponding peak of the anti-ultraviolet film containing the extract is lowered.It may be because some of the components in the ether extract of Phoebe bournei react with polylactic acid.So that the ether extract of Phoebe zhennan wood is mixed with polylactic acid to form a uniform film.The thermal stability of the three biomass-based UV-resistant films is slightly lower than that of the blank polylactic acid film,but does not affect normal use.The tensile strength of the anti-ultraviolet film to which the ether extract and the ethyl acetate extract were added was slightly increased as compared with the blank polylactic acid film.Field degradation experiments on prepared films.There are significant differences in soil physical and chemical properties in different forest land.The microorganisms in the soil mainly include Proteobacteria,Acidobacteria and Chloroflexi.The texture of the biodegraded film is obviously brittle.The UV-resistant transparent film with added trichloromethane extract has the highest degradation rate.Indicates that its biodegradation rate after disposing is faster.There was a significant difference in the degradation rate of UV-resistant transparent film with added ethyl acetate extract between different forests.The rest of the film is not much different between the forest lands.Six identical substances were detected in the three extracts,accounting for 37.62-38.55% of all the tested substances.The main compounds in the extract are 3,7-Benz ofurandiol,2,3-dihydro-2,2-dimethyl-,2-Isopropyl-5-methyl-9-methylene[4.4.0]dec-1-ene,N-alpha-BOC-L-Lysine,b-Guaiene,Patchoulane(7CI),?-Maaliene and 2-Methyl-5-(2,6,6-tri methyl-cyclohex-1-enyl)-pentane-2,3-diol.The three extracts contain olefins,phenols,alc ohols,ethers,ketones and aromatic hydrocarbons,and the relative content of olefins,p henols and alcohols is relatively high.The compound in the wood extract of Phoebe bournei has a benzene ring structure,a C=C double bond and a C=O double bond,w hich can generate ???+ electronic transitions.The substituent causes the absorption b and generated by the ???+ electronic transition of the benzene ring to red-shift,and the lower energy is absorbed during the ???+ electronic transition.The benzene ring,C=C,and C=O have absorption peaks in the near-ultraviolet region(200-400 nm),so that the compound has ultraviolet absorption ability,and the biomass-based anti-ultrav iolet film can block ultraviolet rays.