The Extraction And Epoxy Modification Of Eucommia Ulmoid Gum

This article mainly consisted of two parts:the extraction and epoxy modification of eucommia ulmoide gum(EUG).We have obtained eucommia ulmoide gum(EUG)by using the ultrasonic method,supercritical fluid CO2 method to extract and separate the enzyme-treated eucommia bark,leaves,seeds shell of eucommia ulmoides.We studied the effect of different pre-processing methods and extraction methods on the extraction rate of glue,and made a research of EUG.The results showed that the EUG extracted from enzyme-treated materials had high molecular weight(3 × 105～4.5 × 105);whereas EUG extracted with the mechanical crushing method had low m,olecular weight(4 × 104).When enzyme-treatment was used,the destruction of EUG could be avoided and the initial degree of polymerization could be maintained.The ultrasonic method and supercritical fluid CO2 method contributed to the great increase of the extraction yield of EUG.The result from the characterization showed that the content of trans-1,4-polyisoprene in the extracted EUG was 99%.Solution method and emulsion method had been employed in the article for the epoxy modification of EUG.For the solution method,the synthesis conditions of epoxidized eucommia ulmoide gum(EEUG)synthesized with peracetic acid was studied in this paper,including the characterization of EEUG.The results showed that epoxy content could be controlled by the mole ratio of peracetic acid and double bonds of EUG.When the ratio increased,epoxy content and side reaction would increase correspondingly.Epoxy content was highest and side reaction was the minimum,when the ratio was 0.4,the reaction time was 1h,and the concentration of peracetic acid was 2～3mol/L.The rigid and polarity of EEUG molecular chains,Tg,density of EEUG increased,but crystallinity and Tm of EEUG decreased,the hardness increased then decreased while the epoxy content of EEUG increased.The A1250/A1383 in IR spectrum of EEUG had a good linear relation with the epoxy content tested by 1H-NMR,and calibration curve was made.The structure information and epoxy content of EEUG could be both obtained from IR spectrum.For emulsion method,the synthesis conditions of epoxidized eucommia ulmoide gum(EEUG)synthesized with formic acid was studied in this paper,including the characterization of EEUG.The results showed that the appropriate synthesis conditions of EEUG was as following:the temperature was 40 ℃,the mole ratio of formic acid,hydrogen peroxide and EUG was 1:2:1,reaction time was 1hr.Then epoxy content of EEUG was about 25%.Compared with the solution method,reaction conditions of emulsion method was simple and epoxy reagent could be prepared anytime.Though epoxy content with emulsion method was relatively lower,the side reaction was smaller and epoxy content was more stable.Meanwhile,epoxy group was sensitive to formic acid,but not to sodium carbonate.Moreover,EEUG could be kept for a long time at room temperature,but EEUG would age quickly at high temperature.Therefore,the control of residual acids in the reaction system was the dominant method to improve the ageing-resistant performance.