文献类型：期刊文献

英文题名：Cross-linking of technical lignin via esterification and thermally initiated free radical reaction

作者：Luo, Shupin[1,2] Cao, Jinzhen[1] McDonald, Armando G.[3]

第一作者：Luo, Shupin;罗书品

通信作者：Luo, SP[1];McDonald, AG[2]|[a000594b3b13a44a5476e]罗书品;

机构：[1]Beijing Forestry Univ, MOE Key Lab Wooden Mat Sci & Applicat, Qinghua East Rd 35, Beijing 100083, Peoples R China;[2]Chinese Acad Forestry, Res Inst Wood Ind, 1 Dongxiaofu, Beijing 100091, Peoples R China;[3]Univ Idaho, Dept Forest Rangeland & Fire Sci, Renewable Mat Program, 875 Perimeter Dr MS1132, Moscow, ID 83844 USA

年份：2018

卷号：121

起止页码：169-179

外文期刊名：INDUSTRIAL CROPS AND PRODUCTS

收录：;EI(收录号：20182005199602);Scopus(收录号：2-s2.0-85046780230);WOS:【SCI-EXPANDED(收录号:WOS:000437996900020)】；

基金：The authors acknowledge the sponsorship from (i) Fundamental Research Funds for the Central Universities in China (2015ZCQ-CL-01) and (ii) China Scholarship Council (No. 201506510031) to support travel to undertake research at the University of Idaho. The authors also like to acknowledge Mr. Eric Young for acquiring the ¹H NMR spectra.

语种：英文

外文关键词：Lignin; Esterification; Crotonate; Peroxide; Thermal; Cross-linking

摘要：A strategy of enhancing the reactivity of lignin molecule towards thermally initiated free radical polymerization was examined. Technical lignin samples were reacted with selected esterification agents (butyric and crotonic anhydrides) leading to extensive conversion of the available hydroxyl groups. The esterified lignins were then subjected to thermal processing in the presence or absence of dicumyl peroxide (DCP). The rheological and viscoelasticity behavior during this process were examined by in-situ rheology and dynamic mechanical analysis (DMA). The functionality and glass transition temperature (T-g) of samples before and after modification were assessed for evaluating the validity of modification. After crotonylation, the lignin derivatives were susceptible to thermally initiated free radical polymerization, especially in the presence of DCP. Upon heating, the lignin crotonate showed a significant increase in storage modulus (E') from around 200 degrees C to 260 degrees C. The T-g of lignin crotonate increased by about 20 degrees C after thermal treatment in the presence of DCP. Fourier transform infrared spectroscopy (FTIR) analysis of samples that were collected from rheological test confirmed the reaction of C=C took place. Vanillyl alcohol as a lignin model compound was subjected to the same modification procedure with lignin to uncover the mechanism by FTIR and nuclear magnetic resonance (NMR) analysis, indicating there are three potential reaction sites: C=C, C=O and -CH2-, among which C=C is likely to form a cross-linked network. The conclusions from this study may provide the foundations for a rational design of technical lignin based polymeric materials, by providing the double bonds to anchor the lignin molecules in the resin or copolymers.