【作者】 胡丽华；

【导师】 施文芳；

【作者基本信息】 中国科学技术大学 ， 高分子化学与物理， 2011， 博士

【摘要】 本论文通过分子设计合成了一系列新型混杂型光引发剂,进行了其结构表征及光引发聚合行为的研究,并以此引发制备了聚氨酯丙烯酸酯/LDH纳米复合材料、聚氨酯丙烯酸酯/SiO₂纳米杂化材料以及聚环氧丙烯酸酯/SiO₂纳米杂化材料,对于它们的微观结构、热稳定性能、热机械性能及力学性能进行了重点研究,并取得了初步结果,具体内容如下:1.二苯甲酮基复合型超支化大分子光引发剂的合成及其紫外光引发聚合活性研究在超支化多元醇(Boltorn^TM P1000)分子外围引入不同比例的二苯甲酮（BP）、哌啶叔胺基团和丙烯酸双键,成功合成了一系列二苯甲酮基复合型超支化大分子光引发剂（HPPIs）。采用1H NMR和FTIR光谱对分子结构进行了表征。HPPIs具有与BP相似的紫外-可见吸收光谱。采用Photo-DSC方法研究了HPPIs引发三官能度单体三羟甲基丙烷三丙烯酸酯（TMPTA）的聚合反应动力学。结果表明,与BP相比,在相同引发色团含量情况下,采用HPPIs引发的最大聚合速率及最终双键转化率均较低,这是由于大分子自由基迁移受阻所致。当HPPI的分子末端叔胺与BP基团的摩尔比为2:1时,其引发活性最高。另外,采用HPPIs和BP分别引发双酚A环氧丙烯酸酯EB605的聚合反应,经动态机械热分析（DMTA）研究表明,前者所得固化膜的玻璃化转变温度高于后者。2.层状双氢氧化物-光引发剂复合物的合成及其聚合物纳米复合材料的制备与性能研究采用4-羟基-4’-（2-羟乙氧基）-2-甲基苯丙酮（Irgacure 2959）改性的层状双氢氧化物（LDH）前躯体作为光引发剂复合物,引发丙烯酸酯低聚物聚合交联,制备了层离型聚合物/LDH纳米复合材料。将Irgacure 2959依次与巯基乙酸,3-（2,3-环氧丙氧）丙基三甲氧基硅烷（KH-560）反应,得到三甲基硅基团改性的大分子光引发剂（TMS-2959）,再通过硅氧烷基和羟基之间的反应,将TMS-2959插入十二烷基硫酸钠（SDS）改性的LDH（LDH-DS）层间,得到了光引发剂复合物LDH-2959,采用1H NMR和FTIR对其结构进行了表征。为了比较,采用LDH-2959单独及其与Irgacure 2959共同引发丙烯酸酯聚合,分别得到了层离型和插层型的聚合物/LDH纳米复合材料。依据XRD测试及HR-TEM观察结果分析,在使用5 wt%的LDH-2959引发制备的纳米复合材料中LDH失去了原来的有序堆积结构,且均匀地分散于聚合物基体。而在LDH-2959和Irgacure 2959共同引发的形貌结构中发现了多片层的团聚体。与纯聚合物相比,该层离型的纳米复合材料的玻璃化转变温度从55°C升高到了64°C,拉伸强度从10.1 MPa提高到25.2 MPa,硬度也从2 H提高到4 H,而断裂伸长率略有下降。而插层型的纳米复合材料的性能改善有限。3.三甲氧基硅基光引发剂的合成及其有机/无机纳米杂化材料的制备与性能研究采用三甲氧基硅修饰的Irgacure 2959光引发剂（TMS-2959）引发丙烯酸酯聚合,制备了光固化有机/无机纳米杂化材料（Nano-TMS）。巯基乙酸与Irgacure 2959进行酯化反应后,再与KH-560进行加成反应,制得TMS-2959。化合物的结构由1H NMR和FTIR表征。将TEOS在乙醇和水中经盐酸催化水解缩合而得到正硅酸四乙酯的预聚物（oligo-TEOS）。TMS-2959与Irgacure 2959具有相似的吸光性能,但由于前者光引发基团含量低,其摩尔吸光系数也较低。采用Photo-DSC研究比较了TMS-2959与Irgacure 2959的光引发活性,结果表明,采用TMS-2959引发的体系的最大聚合速率及最终双键转化率略低。从扫描电子显微镜观察结果发现,在采用TMS-2959引发的Nano-TMS固化膜中SiO₂纳米粒子均匀分散于聚合物基体;而在Irgacure 2959引发的Nano-Irg固化膜中观察到了SiO₂纳米粒子的聚集及相分离现象。与采用4 wt%的Irgacure 2959引发的不含oligo-TEOS的纯丙烯酸酯固化膜相比,采用6 wt%的TMS-2959引发的Nano-TMS6固化膜的玻璃化转变温度从55.3°C升高到了66.1°C,橡胶态储能模量从36.4 MPa提高到54.3 MPa,采用6 wt%的Irgacure 2959引发的Nano-Irg6固化膜则为40.5 MPa。Nano-TMS6的拉伸强度也从纯聚合物膜的7.5 MPa提高到17.5 MPa, Nano-Irg6则为9.7 MPa。另外,Nano-TMSs固化膜的硬度也得到了大大提高,而断裂伸长率却略有下降。4.乙氧基硅基多官能团大分子光引发剂的合成及其有机/无机纳米杂化材料的制备与性能研究采用乙氧基硅修饰的多官能团大分子光引发剂（Si-m-PI）引发丙烯酸酯聚合,制备了紫外光固化有机无机纳米杂化材料（Nano-Si-m-PI）。将Irgacure 2959与巯基乙酸进行酯化反应,再与双季戊四醇六丙烯酸酯（EM265）和3-氨基丙基三乙氧基硅烷（KH-550）进行加成反应合成了Si-m-PI,采用1H NMR,FTIR证实化合物的结构。通过TEOS的水解缩合制得了TEOS预聚物（oligo-TEOS）,以形成无机交联网络。Si-m-PI与Irgacure 2959具有接近的摩尔吸光系数。Photo-DSC测试结果表明,6 wt% Si-m-PI引发的固化膜Nano-Si-m-PI具有较高的最大聚合速率和最终双键转化率,分别为6.8 J g^-1s^-1和78.4%,而采用Irgacure 2959引发的固化膜Nano-Irg6分别为5.5 J g^-1s^-1和67.9%。经扫描电子显微镜观察发现,在Nano-Si-m-PI杂化膜中SiO₂纳米粒子均匀分散于聚合物基体,而在Nano-Irg杂化膜中却存在纳米粒子的聚集。Nano-Si-m-PI膜的热稳定性较高,当失重率为10%时,其分解温度比纯固化膜提高22 oC,而Nano-Irg杂化膜提高12 oC。与Nano-Irg膜相比,Nano-Si-m-PI膜的储能模量提高16 MPa,玻璃化转变温度（Tg）提高10 oC。与采用4 wt%的Irgacure 2959引发的光固化纯聚合物膜相比,Nano-Si-m-PI膜的拉伸强度从32.6 MPa提高到了45.8 MPa。更多还原

【Abstract】 The present thesis was aimed on the synthesis, characterization and photoinitiating behavior of benzophenone （BP）-based polymeric photoinitiators, as well 2-hydroxy-4’-（2-hydroxyethoxy）-2-methylpropiophenone （Irgacure 2959）-based hybrid photoinitiators. The hybrid photoinitiators were used to prepare the polyurethane/LDH nanocomposites, polyurethane/SiO₂ hybrid nanocomposites and polyepoxyacrylate SiO₂ hybrid nanocomposites. The morphology, thermal behavior and mechanical properties of the UV-cured nanacomposites were studied in detail. The outline is elaborated as the follows:1. Synthesis and photoinitiating behaviors of benzophenone-based hybrid hyperbranched polymeric photoinitiatorsA series of benzophenone （BP）-terminated hyperbranched polymeric photoinitiators （HPPIs） based on hyperbranched polyester/polyether （BoltornTM P1000） bearing amine moiety, which was obtained by reacting with piperidine, were synthesized. For comparison, the polymerizable hyperbranched photoinitiators were also prepared by introducing acrylate group at the terminals. The chemical structures were characterized by FTIR and 1H NMR spectroscopy. HPPIs exhibited the similar UV-Vis absorption as BP. The photoinitiating behavior of HPPIs with trimethylolpropane triacrylate （TMPTA） as a trifunctional monomer was investigated by using photo-DSC analysis. The results indicated that the maximum photopolymerization rate and unsaturation conversion of in the cured TMPTA film initiated by HPPIs were both lower than that by BP. Among them, the HPPI with twice tertiary amine moiety of BP moiety was found to be the most efficient in initiating reaction. Additionally, the cured bisphenol A epoxy acrylate （EB605） films initiated by HPPIs showed the uniform microstructures and high Tg from DMTA due to their better compatibility and incorporation of hyperbranched structure.2. Preparation, and properties of polymer/LDH nanocomposite by UV-initiated photopolymerization of acrylate through LDH/photoinitiator hybrid complex The exfoliated polymer/layered double hydroxide （LDH） nanocomposite by UV-initiated photopolymerization of acrylate system through 2-hydroxy-4’-（2-hydroxyethoxy）-2-methylpropiophenone （Irgacure 2959）-modified LDH precursor （LDH-2959） as a polymeric photoinitiator complex was prepared. The LDH-2959 was obtained by the esterification of Irgacure 2959 with thioglycolic acid, following by the addition reaction with 3-（2, 3-epoxypropoxy）propyltrimethoxysilane （KH-560）, finally intercalation into the sodium dodecyl sulfate-modified LDH. Moreover the intercalated polymer/LDH nanocomposite was obtained by using additive Irgacure 2959 except for LDH-2959. From the X-ray diffraction （XRD） measurement and HR-TEM observation for the UV-cured exfoliated nanocomposite film with 5 wt% LDH-2959 loading, the LDH lost the ordered stacking-structure and well dispersed in the polymer matrix. But for the nanocomposite with Irgacure 2959 addition the LDH was not completely exfoliated and shows the partly intercalation into the thin tactoids. Compared with the pure polymer without LDH addition the UV-cured exfoliated nanocomposite showed the increased Tg of 64°C from 55°C; the tensile strength of 25.2 MPa from 10.1 MPa; as well the greatly enhanced Persoz hardness, while an acceptable level of the elongation at break.3. Preparation, and properties of UV-cured organic-inorganic hybrid nanocomposite initiated by trimethoxysilane-modified fragmental photoinitiatorAn effective approach is proposed to prepare the UV-cured organic-inorganic hybrid nanocomposite （Nano-TMS） through the photopolymerization of acrylic resin initiated by trimethoxysilane-modified Irgacure 2959 （TMS-2959）. The TMS-2959 as a hybrid photoinitiator was obtained by the esterification of 2-hydroxy-4’-（2-hydroxyethoxy）-2-methylpropiophenone （Irgacure 2959） with thioglycolic acid, following by the addition reaction with 3-（2, 3-epoxypropoxy）propyltrimethoxysilane （KH-560）. The chemical structure was characterized by FTIR and 1H NMR spectroscopy. The oligomeric tetraethylorthosilicate （oligo-TEOS） was prepared by a sol-gel process. The TMS-2959 exhibits the similar UV-vis absorption as Irgacure 2959 except for a lower molar extinction coefficient. The photoinitiating activity of TMS-2959 was investigated through photo-DSC analysis in comparison with Irgacure 2959. The results showed that the lower photopolymerization rate at the peak maximum and final unsaturation conversion in the cured film were obtained with the TMS-2959 initiating system but at an acceptable level compared with Irgacure 2959. From the SEM observation, the SiO₂ nanoparticles dispersed uniformly in the Nano-TMS film, whereas the aggregation of nanoparticals occurred in the UV-cured hybrid nanocomposite （Nano-Irg） initiated by Irgacure 2959. Compared with the UV-cured pure polymer initiated by 4 wt% Irgacure 2959 without oligo-TEOS addition, for the cured Nano-TMS6 film obtained with 6 wt% TMS-2959, the Tg increased to 66.1°C from 55.3°C; the rubbery storage modulus increased to 54.3 MPa from 36.4 MPa, which is higher than 40.5 MPa of Nano-Irg6 initiated with 6 wt% Irgacure 2959; the tensile strength was greatly improved to 17.5 MPa from 7.5 MPa, which was also higher than 9.7 MPa of Nano-Irg6. Moreover, the Persoz hardness enhanced greatly, while the elongation at break remained at an acceptable level.4. Preparation, and properties of UV-cured organic-inorganic hybrid nanocomposite initiated by ethoxysilane-modified multifunctional polymeric photoinitiatorThe UV-cured organic-inorganic hybrid nanocomposite （nano-Si-m-PI） was prepared through the photopolymerization of acrylic resin initiated by ethoxysilane-modified multifunctional oligomeric photoinitiator （Si-m-PI）. The esterification reaction of 2-hydroxy-4’-（2-hydroxyethoxy）-2-methylpropiophenone （Irgacure 2959） with thioglycolic acid, and the following addition reactions with dipentaerythritol hexaacrylate and then 3-aminpropyltriethoxysilan were carried out for preparing the Si-m-PI. An oligomeric tetraethylorthosilicate was prepared by the hydrolysis of TEOS through a sol-gel process, and used as an inorganic component for forming the crosslinked organic-inorganic network. The Si-m-PI exhibits the similar UV-vis absorption and a molar extinction coefficient as Irgacure 2959. The photoinitiating activity study by photo-DSC analysis showed that the Si-m-PI possesses high photopolymerization rate at the peak maximum and final unsaturation conversion （Pf） in the cured hybrid films, reaching to 6.8 J g^-1s^-1 and 78.4%, respectively, compared with 5.5 J g^-1s^-1 and 67.9% of the UV-cured hybrid nanocomposite （Nano-Irg） initiated by Irgacure 2959 both with 6 wt% chromophoric moiety loading. From the SEM observation, the SiO₂ nanoparticles dispersed uniformly in the formed Nano-Si-m-PI, whereas the aggregation of nanoparticals occurred in Nano-Irg. Moreover, compared with the UV-cured pure polymer and Nano-Irg, the Nano-Si-m-PI showed remarkably enhanced thermal stability. The increase in decomposition temperature of over 22 oC for Nano-Si-m-PI with 6 wt% Irgacure 2959 moiety loading was obtained at 10% weight loss, compared with only 12 oC increase for Nano-Irg than the pure polymer. The enhancements of around 16 MPa in storage modulus and 10 oC in Tg for Nano-Si-m-PI than that for Nano-Irg were observed. The tensile strength for Nano-Si-m-PI increased to 45.8 MPa from 32.6 MPa of pure polymer with 4 wt% Irgacure 2959 moiety loading.更多还原