高官能度植物油基不饱和酯的分子设计及共聚固化机理研究

Polymer materials derived from natural resources have gained increased attention in recent years due to the threats of uncertain petroleum supply in the future and environmental pollution. As one of the most widely applied renewable resources, plant oils are suitable starting materials for polymers because of their low cost, the rich chemistry that their triglyceride structure provides, and their potential biodegradability. In this project, in order to meet the requirement for sustainable development, several unsaturated ester (UE) macromonomers will be synthesized from plant oils which can be applied in structural plastics - a relatively new area. First, a series of high-functionality UE macromonomers from plant oils are designed based on the advance in this new area and the principle of molecule design. Second, these UE macromonomers will be synthesized by chemical modification of various plant oils, eg. tung oil (TO), castor oil (CO) or epoxidized soybean oil (ESO). The chemical modification mainly includes alcoholysis, esterification, and ring opening of epoxy groups. These macromonomers will be characterized by Fourier transform infrared (FT-IR) spectrum, hydrogen nuclear magnetic resonance (1HNMR), mass spectrum (MS), and gel permeation chromatography (GPC). After that differential scanning calorimetry (DSC) and IR techniques will be employed to study the curing behaviour of these macromonomers with styrene monomers under different curing conditions. The correlation of the curing behavior and the material properties will also be discussed. Finally, the structure-property relationships of these plant-oil-based thermosetting polymers will be investigated. Specially, the two effects of phase separation and crosslink density are used to correlate the microstructure factors with the thermo-mechanical and mechanical properties of the resulting polymers. The present study will not only provide several high-performance unsaturated ester resins, but also give perspectives for both fundamental studies and applications of the biobased UE materials.

基于石油原料的枯竭和保护环境的需要，利用可再生资源-植物油，合成优良的不饱和酯大分子单体，具有十分重要的意义。结合国际前沿并依据分子设计原理，本项目创新地引入丙烯酸羟乙酯或丙烯酸羟乙酯化马来酸半酯等对植物油进行协同改性，设计了系列高官能度的植物油基不饱和酯大分子单体。进而拟通过醇解、酯化或环氧开环等反应，合成该系列植物油基不饱和酯单体，并利用红外、核磁、质谱和凝胶色谱等对其进行结构表征。随后，利用差热扫描量热和红外等技术对该单体与苯乙烯共聚时的固化机理进行深入表征，探讨不同固化条件下的固化机理及其对最终性能的影响。最后，对该系列不饱和酯树脂的结构与性能关系进行研究。该项目不但可以获得高性能的不饱和酯树脂，满足可持续发展的要求，亦可为新型生物基不饱和酯材料的应用提供一定的理论基础。

利用可再生的植物油资源合成优良的不饱和酯（Unsaturated Ester，简称UE）类大分子预聚体，对于石油基不饱和树脂产业的可持续发展以及环境保护来说具有非常重要的意义。本项目以桐油、环氧化大豆油、蓖麻油等为起始原料，采用不同的改性方法，合成了三种高官能度的植物油基UE大分子预聚体（含单体），并表征了其结构及性能。例如，利用桐油，通过马来酸酐、丙烯酸羟乙酯等先后协同改性，获得了桐油基不饱和共酯（由于含有两种以上不同的C=C结构，故称为不饱和共酯），其官能度达2.08每脂肪酸链，固化后拉伸强度与模量分别可达36.3MPa和1.70GPa，玻璃化转变温度（Tg）可达140.3℃；利用环氧化大豆油，通过预合成的丙烯酸羟乙酯化马来酸半酯、马来酸酐等先后协同改性，获得了豆油基不饱和共酯，其官能度达8.15每甘油三酯，固化后拉伸强度与模量分别可达33.1MPa和2.11GPa，Tg可达114.1℃。所得结果处于植物油基热固性不饱和树脂研究的前列，证明了合成高官能度的植物油基UE大分子预聚体有利于获得高性能（如刚性强、耐热性好等）的植物油基不饱和树脂材料。其次，研究了树脂的结构性能关系，发现基体树脂的刚性随稀释单体含量的变化取决于交联密度与相分离的协同作用；并根据自由基共聚的恒分共聚理论，推导了适用于新型不饱和共酯的最佳共聚配比。最后，利用差热扫描量热技术，研究了所得植物油基不饱和共酯树脂的固化动力学，计算了固化活化能、最佳固化温度、后处理温度、反应级数等多种参数。本项目所得的植物油基不饱和树脂有望用于结构性塑料，如模塑料、纤维增强材料等，其结构性能、固化动力学等研究亦可为该类材料的应用提供较好的理论基础。