液体杜仲胶的制备  

Preparation of Liquid Eucommia Ulmozdes Gum

作　　者：杨凤 胡世睿[1] 魏佳煜 李东翰 康海澜 方庆红[1,2] Feng Yang;Shirui Hu;Jiayu Wei;Donghan Li;Hailan Kang;Qinghong Fang(School of Materials Science and Engineering,Shenyang University of Chemical Technology;Key Laboratory for Rubber Elastomer of Liaoning Province,Shenyang University of Chemical Technology,Shenyang 110142,China)

机构地区：[1]沈阳化工大学材料科学与工程学院 [2]沈阳化工大学辽宁省橡胶弹性体重点实验室,辽宁沈阳110142

出　　处：《高分子材料科学与工程》2020年第9期32-39,45,共9页Polymer Materials Science & Engineering

基　　金：国家重点研发计划(2017YFB0306902);中科院合成橡胶重点实验室开放课题(KLSR201702);沈阳市中青年科技创新人才支持计划(RC180154)。

摘　　要：采用间接氧化法降解杜仲胶(EUG),制备室温下可流动杜仲胶。首先采用乳液法对杜仲胶进行环氧化改性制备了环氧化杜仲胶(EEUG),进而用强氧化剂高碘酸实现氧化降解,制备了数均相对分子质量Mn≤10000、端基为醛基和酮基的液体杜仲胶(LEEUG)。利用红外光谱(IR)、核磁共振(^1H-NMR和^13C-NMR)、凝胶渗透色谱、差示扫描量热分析、热重分析及旋转流变仪等研究了环氧度、降解反应时间和高碘酸用量对产物相对分子质量及其分布的影响以及降解产物的结构和性能。结果表明,降解反应温度30℃,降解时间6 h,nH5IO6∶nC=C=0.03条件下可得到数均相对分子质量8000~10000的LEEUG。IR、^1H-NMR和^13C-NMR结果表明高碘酸通过进攻环氧基团,而非碳碳双键,使其开环断链,生成端基为醛基与酮基的LEEUG。环氧基团的含量对LEEUG的相对分子质量几乎没有影响,但可通过调控环氧度调控LEEUG的结晶性。与EUG和EEUG相比,LEEUG的热降解温度提高了56℃。液体杜仲胶相对分子质量及其分布对其流变行为影响明显,数均相对分子质量越高,相对分子质量分布越窄,LEEUG的复数黏度越大。Flowable Eucommia ulmoides gums(EUG)with aldehyde and ketone end group were prepared by indirect oxidation method.First,Epoxidized Eucommia ulmoides gums(EEUG)were prepared via emulsion process,and then EEUG was oxidized and degraded with periodic acid.The effects of the degree of epoxidation,reaction time and amount of periodic acid on the molecular weight and its distribution of LEEUG were studied by^1H-NMR and GPC.Also,the structure and properties of LEEUG were measured by IR,^13C-NMR,DSC and TG.The results show that the number average molecular weight of the obtained liquid Eucommia ulmoides gum ranges form 8000 to 10000 under the optimal experimental conditions of oxidative degradation.Periodic acid breaks the chains by attacking epoxy group rather than carbon carbon double bond.The degree of epoxidation shows little effect on the molecular weight of LEEUG,but the crystallinity of LEEUG can be controlled by regulating the degree of epoxidation.Compared with EUG and EEUG,the thermal degradation temperature of LEEUG is increased by 56℃.The molecular weight and molecular weight distribution of liquid Eucommia ulmoides gums have a significant effect on the rheological behavior.The higher the number average molecular weight and the narrower the molecular weight distribution,the greater the complex viscosity of LEEUG.

关 键 词：杜仲胶 液体杜仲胶 高碘酸 氧化降解 间接氧化法 

分 类 号：TQ332.2[化学工程—橡胶工业]