【作者】 刘玉鹏；

【导师】 储富祥；

【作者基本信息】 中国林业科学研究院 ， 木基复合材料科学与工程， 2014， 博士

【摘要】 从传统石化原料到合成树脂、化纤、橡胶等高分子材料都可以以木质纤维素、淀粉、非食用油脂等可再生资源为原料，通过各种技术路线实现石油基产品的有效替代。设计、合成来自可再生资源的新型“绿色”聚合物，使其物理、化学性质类似或优于石油基同类聚合物是当前生物基高分子材料研究的主要方向。本论文以纤维素、蓖麻油等可再生资源为原料，将甲基丙烯酸羟乙酯等石油基单体以及来源于可再生资源的松香基单体、油脂基单体以多种形式分别接枝到纤维素、蓖麻油骨干上，合成了具有刷状结构的纤维素基聚合物以及类似星状（三臂状）结构蓖麻油基聚合物，可制备出全生物基的新型高分子材料。通过FT-IR、1H-NMR、13C-NMR、GPC、TEM、TGA、AFM、力学性能测试等分析手段对纤维素、蓖麻油基引发剂的合成与聚合反应过程进行了研究，讨论了共聚物组成结构与热力学、力学等性能之间的关系。相关研究为利用可再生资源为原料，设计合成新型全生物基聚合物材料提供了理论依据和技术基础。1．采用LiCl/二甲基乙酰胺均相溶剂系统制备了用于纤维素修饰的纤维素基ATRP大分子引发剂，纤维素单元/2-溴代异丁酰溴的摩尔比投料为1：5时，溴含量（引发点）为4.17mmol/g，引发剂可溶于DMF、THF等多种有机溶剂中。在此基础上，使用CuBr/PMDETA催化体系，控制单体/引发剂/催化剂/配体的摩尔比，反应温度40-60℃下通过ATRP聚合反应将2-HEMA接枝到纤维素骨干上，制备的聚合物水化球形胶束半径约为80nm。TGA分析显示，纤维素引发剂及Cell-g-PHEMA聚合物与纤维素相比热稳定性降低。2．使用CuBr/PMDETA催化体系，通过控制单体/引发剂/催化剂/配体的摩尔比将两种不同结构的树脂酸基单体（DAEMA、DAEA）接枝到纤维素骨架上，调整单体进料比可合成不同分子量的聚合物，Cell-g-PDAEMA（或PDAEA）接枝聚合物的动力学曲线中，ln([M]0/[M])均和时间呈线性关系，显示聚合反应基本可控，DAEMA的聚合活性强于DAEA。接枝共聚物Cell-g-PDAEMA（或PDAEA）玻璃化转变温度为83.2℃（PDAEA，51.8℃），树脂酸单体的引入提高了纤维素材料的疏水性能，聚合物具有紫外吸收性能。TGA显示，纤维素接枝树脂酸单体聚合物的热稳定性较纤维素有明显的提高。3．合成了两个系列的刷状接枝共聚物纤维素-g-聚〔丙烯酸正丁酯-co-脱氢枞酸（β-甲基丙烯酰氧基乙基）酯〕〔Cell-g-P（BA-co-DAEMA）〕和纤维素-g-聚〔甲基丙烯酸月桂醇酯-co-脱氢枞酸（β-甲基丙烯酰氧基乙基）酯〕〔Cell-g-P（LMA-co-DAEMA）〕，通过控制单体摩尔比来调整P(BA-co-DAEMA)和P(LMA-co-DAEMA)侧链长度，制得的接枝聚合物有不同的玻璃化转变温度（-60-50℃），拉伸应力-应变和蠕变柔量测试显示了接枝共聚物具有良好的力学性能。当单体：引发剂投料摩尔比为1000：1时，接枝聚合物样品屈服应力在0-2.5MPa之间，杨氏模量最高为99MPa，测试的6个接枝共聚物样品显示弹性应变之间恢复值在50%至85%，断裂时都有大的应力形变（500%或以上），具有弹性体材料特征。通过AFM、SAXS显示聚合物没有相分离，同时聚合物显示出了很好的疏水性和热稳定性。4．通过2-溴代异丁酰溴与蓖麻油中的羟基进行酯化反应，制备了蓖麻油基ATRP引发剂，使用FT-IR、1H-NMR、13C-NMR等分析方法确定了引发剂的结构。通过蓖麻油ATRP接枝聚合影响因素的初步考察，结果表明在蓖麻油基的ATRP聚合接枝聚甲基丙烯酸甲酯反应体系中，溴化亚铜的催化效果要比氯化亚铜好，且溴化亚铜用量低时，ATRP聚合过程控制效果更好，溶剂用量体积百分比在70%以上可以使ATRP聚合顺利进行，其中使用极性高的溶剂有助于聚合的进行。5．通过合成的蓖麻油基ATRP引发剂（Cas-BiB），利用蓖麻油三官能团羟基结构合成了类似星状（三臂状）蓖麻油基接枝丙烯酸酯聚合物，聚合反应过程可控。TGA分析显示聚合物的起始分解温度和最大降解温度分别为350℃和450℃，在聚合过程当中可以调整单体MMA、BA的不同摩尔投料比来制备具有不同Tg值的共聚物。力学性能测试结果表明，在MMA单体投料摩尔含量在40%-60%之间时，当MMA含量为50%时，聚合物膜的断裂伸长率接近300%，当MMA含量为60%时屈服应力为20MPa，可以看出当MMA的含量增加时，断裂伸长变小，断裂应力增大。更多还原

【Abstract】 The feedstock used for preparation of synthetic resin, chemical fibre, rubber and otherpolymer materials is shifting from petroleum resource to renewable resources such as woodcellulose, starch, non edible oils and fats, etc, by various technical approach, which eventuallyexpect to achieve an effective replacementof petroleum based products. Currently, the mainpurpose of the research on renewable biomass based polymer materials is to obtain a novel"green" polymers whose physical and chemical properties is similar or better than those ofpetroleum based similar polymers by concise design and synthesis strategy. In this paper, thebackbones of cellulose, castor oil or other renewable resources used as starting material, weregrafted by petroleum based monomers like hydroxyethyl methacrylate (2-HEMA), as well asby renewable monomers such as rosin based monomers and oil based monomers by atomtransfer radical polymerization (ATRP), respectively, in order to obtain cellulose basedpolymer with brush structure, and castor oil based polymer with star shaped (three arms)structure. FT-IR,1H-NMR, solubility, GPC, TEM, TGA, AFM, mechanical property test etc,were then used to characterize the structure and initiating activity of cellulose or castor oilbased initiators and as well as counterpart polymers.The relationship of the structure ofcopolymer composition and thermodynamic, dynamics, etc, were also discussed. Theseresearchs will provide a good theoretical basis for the design synthesis and application of novelbiomass based polymers by using the renewable resources as a feedstock.1. By using LiCl/dimethyl amine solvent system, cellulose based macroinitiators used forthe ATRP were prepared. In this case, a macroinitiators with bromide content (initiating point)of4.17nmol/g, which can dissolve in DMF, THF and others solventss, was synthesized withfeeding molar ratio of cellulose unit and2-bromo isobutyryl bromine feeding of1:5, and usedto prepare the cellulose-g-poly(2-hydroxyethyl methacrylate)(Cell-g-PHEMA) applyingCuBr/Pentamethyldiethylenetriamine (PMDETA) as catalytic system. By controlling the molarratio of monomer, initiator, catalyst and ligand, as well as the reaction temperature rangingfrom40℃to60℃, poly(2-HEMA) was grafted on the cellulose backbone by ATRPpolymerization. The radius of hydration spherical micelles of prepared polymer was about80nm. The TGA analysis showed that the thermal stability of cellulose initiator andCell-g-PHEMA polymer and decreased, while compared raw material cellulose. 2. By using the CuBr/PMDETA catalyst system and controlling the molar ratio ofmonomer, initiator, catalyst and ligand, two kinds of resin acid monomers（DAEMA、DAEA）with different structures wereapplied to conduct the "graft from" ATRP on the cellulosebackbone. Varying the monomer feed ratio could lead to the polymers with different molecularweight. In the kinetics curve of Cell-g-PDAEMA（or PDAEA）graft polymer, the linearrelation of ln([M]0/[M]) with the timeshowed that polymerization was basically controllable,and the polymerization activity of DAEMA was higher than that of DAEA. The glass transitiontemperature of the graft copolymer Cell-g-PDAEMA（or PDAEA）was83.2℃（PDAEA，51.8℃）. It was found that hydrophobic properties, as well asUV absorption properties of theresulting cellulose polymers increased after the introduction of resin monomers. TheTGAanalysis indicated that the thermal stability of the resin acid monomer graft cellulosepolymers were obviously higher than that of cellulose.3. Two series of brush graft copolymers cellulose-g-poly (n-butyl acrylate-co-dehydroabietic acid ethyl methacrylate)(Cell-g-P (BA-co-DAEMA)) and biological basis ofcellulose-g-poly (methacrylic acid ethyl Laurate alcohol ester-co-dehydroabietic acid methylacrylic acid)(Cell-g-P (LMA-co-DAEMA)) were synthesizedby “grafting from” atom transferradicalpolymerization (ATRP). By manipulating the molar ratios in the P(BA-co-DAEMA)andP(LMA-co-DAEMA) side chains, graft copolymers with varying glass transition temperatures（-60-50℃) were obtained.. Tensile stress-strain and creep testing showed that the graftcopolymers had good mechanical properties. When the molar ratio of monomer and initiatorwas1000:1, the yield stress of the grafted polymer samples was0~2.5MPa, and the maximumof Young’s modulus was99MPa. All graft copolymers showed elastic strain recovery valuesbetween50%and85%, and manifested remarkable elasticity at strain deformation (500%ormore) beforeexperiencing failure, which were indicative of rubber-like elasticity. AFM andSAXS analysis confirmed that copolymers had no phase separation and wasdisordered.Meanwhile,all copolymers also showed a good hydrophobicity and thermal stability.4. Castor oil based ATRP initiator was prepared by the fast and efficientesterificationreaction between2-bromoisobutyryl bromideandhydroxyl group in castor oil. The structure ofthe initiator was then confirmed by FT-IR,1H-NMR, and13C-NMR. Sequently, theinfluencing factors on ATRP graft polymerization of castor oil were investigated. In these cases,poly(methyl methacrylate)(PMMA) was used to graft castor oil by ATRP. It was found that thecatalytic effect of copper bromide was better than that of CuCl, and when the dosage of copperbromide was low, ATRP polymerization process achieve a good control. The amount of solvent percentage which was at more than70%could make the polymerization of ATRP runsmoothly.Additionally, the use of high polar solvent could be helpful to polymerization.5. Based on the previous work, castor oil based star shape (three arms) copolymers withunique structure were synthesized by "graft from " ATRP of methyl methacrylate (MMA) andbutyl acrylate (BA). These polymerizations were indicative of well-controlled. TGA analysisshowed that the onset decomposition and maximum decomposition occurred in the temperatureranging from350oC to450oC. By varying the molar ratio of MMA and BuA, the copolymerswith different glass transition temperature were obtained. The mechanical analysis showed thatthe optimum usage of MMA was ranging from40%to60%. When the content of MMA was50%, the copolymer showed a elongation of approximate300%and a maximum stress. Inaddition, when the content of MMA increased, the fracture strain decreased and fracture stressincreased.更多还原