【作者】 黄先广；

【导师】 杨万泰；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2012， 硕士

【摘要】 本文主要研究了具有环状芳香半频哪醇结构的引发剂在聚合反应过程中的可逆断裂偶合机理，并依据此机理应用到各种聚合反应体系中。主要研究内容如下：1.双氧杂蒽二醇引发剂分解生成的半频哪醇自由基与聚马来酸酐/异戊二烯（MAH/IP）交联微球表面的乙烯基双键加成反应，制得微球表面带有引发剂片段的聚合物MAH/IP-XTOH，以MAH/IP-XTOH为大分子引发剂釆用溶液聚合法引发不同单体（MMA、St、BA）聚合反应，合成核壳微球。探讨反应过程中转化率、时间、粒径之间的关系。结果表明，聚合过程中单体转化率和微球粒径都随反应时间增加而增加，微球体积随转化率增加而近似线性增加，得到微球粒径均匀性和单分散性较好，变异系数小。2.双氧杂蒽二醇分解生成的半频哪醇自由基与聚丁二烯橡胶（PB）侧链乙烯基双键发生加成反应，得到PB侧链上带有引发剂片段的聚合物PB-XTOH。以PB-XTOH为大分子引发剂釆用溶液聚合法引发MMA单体聚合反应，合成PB-g-PMMA聚合物。3.采用还原偶合羰基化合物的方法把ITX合成频哪醇结构的双异丙基硫杂蒽酮BITX。在加热和光照条件下，BITX裂解生成半频哪醇自由基引发单体聚合，研究了自然光引发本体聚合、可见光引发本体聚合、热引发本体聚合和热引发溶液聚合等不同聚合体系的自由基聚合特征。得到不同反应体系聚合特征为：在单体转化率40%以前，单体转化率随反应时间增加而增加，分子量随转化率增加而近似线性增加，从1万增长到6万左右，但分布指数也随转化率增加而增加。4.利用ITX在可见光和热作用下合成高分子量PMMA。ITX在低温14度可见光引发MMA本体聚合，分子量在280万左右。ITX在高温80度热引发MMA本体聚合，分子量随ITX浓度的增加而减少，从ITX浓度0.2%时的1600万下降到ITX浓度4%时的750万。更多还原

【Abstract】 In this paper, the reversible breaking and coupling mechanism ofsemipinacol radicals to initiate living radical polymerization was explored.Anthracene diols initiator was applied to a variety of the polymerizationsystem based on this mechanism. The main contents were listed as followed:1. MAH/IP-XTOH microspheres containing initiator fragments on itssurface was prepared by the addition reaction between semipinacol radicalsgenerated from the homolytic cleavage of9,9’-bixanthydrol (BXAN) initiatorand double bond on the surface of the cross-linked microspheres ofpolymaleic anhydride/isoprene. Analysis of IR and UV spectroscopyconfirmed the presence of the initiator fragments on the surface ofcross-linked microspheres. Using the MAH/IP cross-linked microspherecontaining BXAN fragment as a macroinitiator, the solution polymerization ofdifferent monomer (MMA, St, BA) was carried out, and core-shellmicrosphere was obtained. The relationship between the conversion, reactiontime, particle size was explored. In the polymerization process, the monomerconversion and the core-shell microsphere size both increased with reaction time, the volume of the core-shell microspheres increased linearly with theconversion. SEM measurements indicated that the core-shell microsphereshad good uniformity, monodisperse and coefficient of variation.2. PB-XTOH polymer containing initiator fragments in its side chain wasprepared by the double bond addition reaction between semipinacol radicalsgenerated from the homolytic cleavage of9,9’-bixanthydrol initiator andpolybutadiene rubber. Using the PB-XTOH polymer containing BXANfragment as a macroinitiator, the solution polymerization of MMA was carriedout, and a PB-g-PMMA copolymer was obtained.3.9,9’-biisopropylthioxanthene-9,9’-diol(BITX) was synthesized byreductive coupling of two isopropyl thioxanthone(ITX) molecules.Semipinacol radicals generated from the homolytic cleavage of BITX initiatorin the heating and lighting conditions initiated polymerization of monomer.Radical polymerization characteristics of the different polymerization systemwhich contains MMA bulk polymerization with natural light, MMA bulkpolymerization with visible light, MMA bulk polymerization with heat andMMA solution polymerization with heat has been studied. The mainpolymerization characteristics of the different polymerization system werelisted as followed: The monomer conversion increased with reaction time, themolecular weight increased linearly with the conversion from10000to60000,the molecular weight distribution was in the range1.3to3.4. The high molecular weight of PMMA was synthesized by isopropyl thioxanthone(ITX) in the visible light or heat. ITX initiated bulkpolymerization of MMA with visible light at14℃, the molecular weight ofPMMA was about2.8million. ITX initiated bulk polymerization of MMAwith avoid light at80℃. The molecular weight is reduced with the increase ofthe concentration of ITX, the molecular weight decline to7.5million in theITX concentration of4%from16million in the ITX concentration of0.2%.更多还原