【作者】 张文明；

【导师】 赵德丰； 张玉苍；

【作者基本信息】 大连理工大学 ， 精细化工， 2011， 博士

【摘要】 近年来,由于环境问题的日益严重及石油等化石资源的不可再生性,包括农业废弃物秸秆在内的生物质资源作为一种可再生资源的研究已日益引起人们重视。“液化”技术被认为是高效利用生物质资源最有效的方法之一已经引起国内外学者的高度关注。本文首先对四种生物质废弃物玉米秆、榛子壳、稻草和木粉的主要化学成分进行分析,对比研究了其在苯酚中的液化特性,并以玉米秆为研究对象,深入研究了反应时问、反应温度、苯酚与玉米秆的物料比(液比)对玉米秆在苯酚中液化反应的影响,通过GPC、HPLC、FTIR、NMR分析工具对玉米秆液化产物的分子量及其分布、结合酚、结构特征等进行了系统表征。结果表明,木粉的液化效果最好,榛子壳、玉米秆次之,稻草最差。液比为4：1,反应温度为150℃为佳,反应时间太长会出现“再凝聚的残渣”玉米秆苯酚液化前后化学结构变化很大,其在液化过程中发生了降解、酚化、缩聚等非常复杂的化学反应。玉米秆液化产物随着液化反应时间的延长,其分子量分布曲线逐渐变窄,液化物的高分子量和低分子量部分逐渐减少,液化物的组成物质分子量逐渐趋于均一化。以玉米秆液化物为原料,在碱性条件下与环氧氯丙烷反应合成出玉米秆基环氧树脂,并对树脂化过程中的影响因素和工艺进行了深入的研究。利用多种仪器分析方法：FTIR、13C-NMR、GPC对合成树脂的结构、分子量及其分布性能表征进行分析。以聚酰胺(PA-650)为固化剂进行固化,并利用TGA、DSC和剪切强度测试手段对固化物的热力学性能进行测试分析。结果发现,玉米秆基环氧树脂合成的最佳条件为：环氧氯丙烷与玉米秆液化物的结合酚摩尔比为20：1、氢氧化钠与玉米秆液化物的结合酚的摩尔比为4：1、反应时间4h和反应温度100℃,此时合成树脂的环氧值为0.292。以液化30mmin时液化物为基材合成的树脂分子量分布曲线最宽,而液化时间低于或者高于30min¨时,以其相对应的玉米秆液化物合成的环氧树胼分子量分们变窄。玉米秆基环氧树脂的必切强度段好,最高可达5.5MPa，且热稳定性较好,其固化物在热失重5%时对应的温度(Td)最高为264.5℃。采用AEO-9和SDS复配做乳化剂,通过相反转技术乳化玉米秆基环氧树脂,研究了复配乳化剂的HLB值、乳化剂用量、乳化温度、搅拌速度对相反转乳化过程中乳液临界含水量Rf值、乳液平均粒径及稳定性的变化规律,采用扫描电镜(SEM)对玉米秆基水性环氧树脂乳液粒子进行微观表征。研究表明,有利于乳化剂在油/水界面上的吸附并有利于增大乳化剂与水相之间作用力的因素将使环氧树脂从W/O型向O/W型的相反转容易发生,表现为Rf较小。在不利的情况下,通过增加水的相体积分数,相反转能够发生,但所得到的乳状液的稳定性较差。乳化剂的HLB值为17、浓度为8%、乳化温度为35°C、搅拌速度为800rmp时,玉米秆基水性环氧树脂乳液稳定性最好,其对应的乳液平均粒径最小为1.57μm。以玉米秆基水性环氧树脂乳液作为成膜基材,采用不同水性固化剂固化成膜,从双组份水性环氧树脂涂料的成膜机理研究了乳化剂对玉米秆基水性环氧树脂乳液成膜性能的影响,以及对比研究了固化剂种类和以水性聚酰胺(KINGCURE 525W60)为固化剂时固化剂与玉米秆基环氧树脂的当量比对涂膜性能变化规律。实验结果表明,乳化剂对涂膜的物理机械性能影响主要表现为高浓度乳化剂乳液成膜后残留于涂膜中的乳化剂起到增塑作用和低浓度乳化剂乳液粒子影响涂膜的固化成膜过程。以KINGCURE525W60为固化剂固化玉米秆基水性环氧树脂制得的涂膜的物理机械性能较好。且它与玉米秆基环氧树脂的当量比为1或者稍大于1时,其涂膜的各项性能可以达到相对较好的平衡。更多还原

【Abstract】 In recent years, environmental concern and restricted availability of petrochemical resource have attracted considerable attention, followed by the utilization of renewable biomass, including corn barn, because of its biodegradability, availability, and renewable nature. Liquefaction of biomass is considered to be an effective method for utilizing lignoellulosic materials.Four kinds of biomass waste (wood, hazelnut shell, rice straw and corn barn) were selected as materials. The main chemical components and liquefaction characteristics in phenol of them were firstly investigated. The factors influencing corn barn liquefaction, including reaction time, reaction temperature and the mass ratio of phenol to corn barn (liquid ratio), were analyzed. By means of GPC, HPLC, FTIR and NMR analysis, the molecular weight, bound phenol content and the structural characteristics of liquefied corn barn under different reaction conditions were investigated. The result shows that:Liquefaction efficiency of wood is better than hazelnut shell, rice straw and corn barn. The optimum condition of liquefied corn barn indicates that liquid ratio is 4:1, liquefaction temperature is 150℃and there will be recondensed residue when the liquefaction time is too long. The chemical structure of corn barn was changed greatly before and after liquefaction in phenol. Decomposition, phenolation and recondensation were all occured in liquefaction process. When increasing of the reaction time, the molecular weight distributions shift downward. Moreover, both low and high molecular weight parts are drastically diminished, and the molecular weight of liquefied product tends to homogenization.The liquefied corn barn-based epoxy resin (LCBER) was synthesized through the glycidyl etherification reaction from liquefied corn barn (LCB), which has groups of bound phenol, and epichlorohydrin under alkali conditions. The effective factors and technology of the resinification process has been studied. The structure and the molecular weight of LCBER has been analysed by many methods of instrumental analysis:FTIR,13C-NMR and GPC. The LCBER was cured with polyamide-650 (PA-650) and the thermal and mechanical properties were evaluated by TGA, DSC and lap shear strength measurement. The results showed that: the optimum conditions were obtained as molar ratio of epichlorohydrin to bound phenol of liquefaction product 20:1, molar ratio of sodium hydroxide to bound phenol of liquefaction product 4:1, reaction time 4h and reaction temperature 100℃. A highest epoxy index of 0.292 was obtained under these conditions. The distribution of retention volume of the synthesized resin (LCBER-30) from the corresponding LCB-30 is faster than the others. Before or after that, the distribution of retention volume of LCBER tends to narrow. The cured resins present good adhesive shear strength and have a highest value of 5.5 MPa. The cured resins have good thermal stability and the higher decomposition temperature at 5% weight loss (Td) is 264.5℃The waterborne dispersions of LCBER were prepared by the phase inversion emulsification technique using AEO-9 and SDS as compound emulsifier. The relationship among the critical water content of phase inversion (Rf) of LCBER, particle average size and the centrifugal stability of emulsion, and experiment condition such as HLB value of compound emulsifier, emulsifier content, emulsification temperature, stirring force was studied. The microtopography of emulsion was also observed. It shows that the factors for absorption of emulsifier and increasing its acting force with water will phase inversion from W/O to O/W easily, while under unfavourable conditions, phase inversion may occur through increasing volume fraction of water, but emulsion is very unstable. The optimum conditions were obtained as HLB value of compound emulsifier 17, emulsifier content 8%, emulsification temperature 35℃and stirring force 800rmp. The particle average size of emulsion was 1.57μm under these contions.The coating film has been prepared used home-made waterborne liquefied corn barn-based epoxy resin emulsion as base and different waterborne curing agent. The effect of emulsifier on film performance was discussed based on the film formation mechanism of double-pace waterborne epoxy resin coatings. The performance of waterborne liquefied corn barn-based epoxy resin film was further compared with different kinds of curing agent and the ratio of amine hydrogen with KINGCURE 525W60 as curing agent. The experiment results show that the emulsifier has a strong effect on physical mechanical properties of film: emulsifier residue in the film played plasticization using high concentration of emulsifier emulsion after the film formation. The curing process of film was affected by particle of low concentration of emulsifier emulsion. The physical mechanical properties of film was better than others with KINGCURE 525W60 as curing agent. The performance of waterborne liquefied corn barn-based epoxy resin film was satisfactory when the ratio of amine hydrogen with KINGCURE 525 W60 as curing agent was slightly greater than or equal to 1.更多还原