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光交联型水性聚氨酯乳液的研究 总被引:13,自引:0,他引:13
以聚醚多元醇,TDI,丙烯酸-2-羟基乙酯及二羟烷基羧酸等为主要原料合成了光交联型水性聚氨酯乳液,讨论了光引发体系,光照时间以及nNCO/NOH和乙烯基质量分数对光交联模性能的影响,得到了合适的原料配比及光固化条件。 相似文献
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通过乳液聚合法成功合成了纳米SiO2/聚丙烯酸酯杂化乳液。首先将纳米SiO2经过表面官能团化处理,使其表面含有活性官能团,然后经过乳液聚合使丙烯酸酯单体在纳米SiO2表面引发聚合,合成了具有核壳结构的纳米杂化乳液。采用透射电子显微镜(TEM)对乳液的微观结构进行了表征,并对胶膜进行了机械力学性能测试和表面润湿性能测试。结果表明纳米SiO2的表面官能团化处理改善了纳米粒子在乳液中的稳定性,当纳米SiO2质量分数为0 2%时,杂化乳液胶膜的拉伸强度和断裂伸长率同时达到最大值。其表面润湿性与SiO2质量分数有关,SiO2质量分数为0 5%时其杂化乳胶膜的接触角最大,耐水性最好。 相似文献
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以甲苯二异氰酸酯(TDI)、聚丙二醇(PPG)、二羟甲基丙酸(DMPA)为原料,制备了阴离子型水性聚氨酯乳液。探讨了温度、DMPA用量、异氰酸基团和羟基的物质的量比、PPG的相对分子质量对其乳液合成的影响,从而得出制备阴离子型水性聚氨酯乳液的较佳配方。 相似文献
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本文采用改性蓖麻油合成了软段中含不饱和双键的阴离子聚氨酯水分散液(MCPU),将其作为可聚合乳化剂和种子成分同甲基丙烯酸甲酯(MMA)进行共聚,制得了MCPU-PMMA复合乳液。1HNMR谱图显示MCPU中含有双键结构,共聚后双键消失。通过考察单体转化率和复合乳液平均粒径、凝胶量及成膜耐水及甲苯性探讨了影响种子乳液聚合的多种因素:采用过硫酸钾作为引发剂,单体转化率高,乳液粒径小,成膜耐水及甲苯性好;反应的表观活化能Ea为164.86kJ/mol,反应温度控制在70℃较适宜;聚合反应速率Rp∝[I]1.0856,引发剂用量宜控制在聚合有效组份总质量的0.5%。 相似文献
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由种子乳液聚合法制备了聚苯乙烯-聚甲基丙烯酸甲酯核-壳粒子。以过硫酸钾(KPS)为引发剂,辛基酚聚氧乙烯醚(OP-10)为乳化剂,合成了聚苯乙烯(PS)种子核;连续滴加甲基丙烯酸甲酯(MMA),在核表面富集MMA,制备了粒径范围在0.16~0.67μm的核-壳粒子;当单体苯乙烯与甲基丙烯酸甲酯(St/MMA)的比为30∶70(质量比)时,所得粒径在0.18μm,粒径分布为0.012。差示扫描量热(DSC)研究显示,复合粒子的玻璃化转变温度(Tg)为97.2℃,峰形单一,表现出良好的热性能。 相似文献
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Heterogeneous latexes were prepared by a semicontinuous seeded emulsion polymerization process under monomer starved conditions at 80 °C using potassium persulfate as the initiator and sodium dodecyl sulfate as the emulsifier. Poly(butyl acrylate) latexes were used as seeds. The second‐stage polymer was poly(styrene‐co‐methyl methacrylate). By varying the amounts of methyl methacrylate (MMA) in the second‐stage copolymer, the polarity of the copolymer phase could be controlled. Phase separation towards the thermodynamic equilibrium morphology was accelerated either by ageing the composite latex at 80 °C or by adding a chain‐transfer agent during polymerization. The morphologies of the latex particles were examined by transmission electron microscopy (TEM). The morphology distributions of latex particles were described by a statistical method. It was found that the latex particles displayed different equilibrium morphologies depending on the composition of the second‐stage copolymers. This series of equilibrium morphologies of [poly(butyl acrylate)/poly(styrene‐co‐methyl methacrylate)] (PBA/P(St‐co‐MMA)) system provides experimental verification for quantitative simulation. Under limiting conditions, the equilibrium morphologies of PBA/P(St‐co‐MMA) were predicted according to the minimum surface free energy change principle. The particle morphology observed by TEM was in good agreement with the predictions of the thermodynamic model. Therefore, the morphology theory for homopolymer/homopolymer composite systems was extended to homopolymer/copolymer systems. © 2002 Society of Chemical Industry 相似文献
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Heterogeneous latexes were prepared by a two‐stage seeded emulsion polymerization process under monomer starved conditions at 80 °C using potassium persulfate as the initiator and sodium dodecyl sulfate as the emulsifier. Poly(butyl acrylate) latexes were used as seeds. The second‐stage polymer was poly(styrene‐co‐methyl methacrylate). By varying the amount of methyl methacrylate (MMA) in the second‐stage copolymer, the polarity of the copolymer phase could be controlled. It was found that the latex particles displayed different morphologies depending on the monomer ratio. The amount of MMA had a significant effect on the evolution of morphology. The morphologies were observed by transmission electron microscopy. In addition, the evolution of the particle morphology was predicted by the mathmatical model for cluster migration. The model gave the same trends as the experimental results. © 2002 Society of Chemical Industry 相似文献
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Polymer/Silica nanocomposite latex particles were prepared by emulsion polymerization of methyl methacrylate (MMA) with dimethylaminoethyl methacrylate (DM). The reaction was performed using a nonionic surfactant and in the presence of silica nanoparticles as the seed. The polymer‐coated silica nanoparticles with polymer content and number average particle sizes ranged from 32 to 93 wt % and 114–310 nm, respectively, were obtained depending on reaction conditions. Influences of some synthetic conditions such as MMA, DM, surfactant concentration, and the nature of initiator on the coating of the silica nanoparticles were studied. Electrostatic attraction between anionic surface of silica beads and cationic amino groups of DM is the main driving force for the formation of the nanocomposites. It was demonstrated that the ratio of DM/MMA is important factor in stability of the system. The particle size, polymer content, efficiency of the coating reaction, and morphology of resulted nanocomposite particles showed a dependence on the amount of the surfactant. Zeta potential measurements confirmed that the DM was located at the surface of the nanocomposites particles. Thermogravimeteric analysis indicated a relationship between the composition of polymer shell and polymer content of the nanocomposites. The nanocomposites were also characterized by FTIR and differential scanning calorimetry techniques. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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Emulsion polymerization of methyl methacrylate (MMA) in the presence of chitosan was studied and a reaction mechanism was proposed. It was proved in the companion article that potassium persulfate (KPS) free radicals can degrade chitosan chains into chain free radicals. Therefore, it is possible to produce a chitosan copolymer when the monomer and the KPS initiator are added into the chitosan solution. According to the proposed mechanism, concentrations of different species such as the initiator, total free radicals, and degraded chitosan chain were calculated with the reaction time. All the results agreed with the experimental observation. The results showed that the polymerization rate varied with 0.83‐ and 0.82‐order of the total free‐radical concentration and chitosan repeating unit concentration, respectively. It was also verified that chitosan played multiple roles in the reaction system. If the monomer was added into the chitosan solution before the addition of KPS, chitosan served mainly as a surfactant. Consequently, the polymer particle number was increased with the chitosan addition and so was the polymerization rate. However, if the monomer was added into the solution where the chitosan was already degraded by KPS, the polymerization rate was decreased with the predegradation time of chitosan. In both cases, the final polymer particles consisted of the poly(methyl methacrylate) (PMMA) homopolymer and the chitosan‐PMMA copolymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3047–3056, 2002 相似文献
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Different composition poly(methyl methacrylate-co-butyl methacrylate) copolymers through seeded semi-batch emulsion polymerization 总被引:1,自引:0,他引:1
Davide Silvestri Mariacristina Gagliardi Caterina Cristallini Niccoletta Barbani Paolo Giusti 《Polymer Bulletin》2009,63(3):423-439
In the present work the synthesis and the chemical and thermal characterization of poly(methyl methacrylate-co-butyl methacrylate)
copolymer, in three different macromolecular compositions, are reported. The aim of the present work was the identification
of a standard method to obtain copolymers with controlled macromolecular composition, molecular weights and particle size
distribution, together with the identification of the effect of the macromolecular composition on the material properties.
A monomer-starved seeded semi-batch emulsion reaction was carried out and optimized, monitoring the kinetic of the copolymerization
through the evaluation of residual monomer amounts. Then, an evaluation of the macromolecular composition was performed by
Fourier transform infrared spectroscopy analysis. Molecular weight, molecular weight distribution, latex characteristics and
thermal behaviour were also investigated. 相似文献