有机硅改性丙烯酸酯乳液的合成

乳液聚合;涂料;有机硅改性丙烯酸酯乳液的合成     

有机硅改性磺酸型聚氨酯/丙烯酸酯复合乳液的制备

将磺酸型聚酯多元醇、异佛尔酮二异氰酸酯（IPDI)和三羟甲基丙烷(TMP)在无有机溶剂参与的情况下进行预缩聚,以硅烷偶联剂γ-氨丙基三乙氧基硅烷（KH550）作为改性剂,加入双官能团单体甲基丙烯酸-β-羟乙酯(HEMA),得到含乙烯基和有机硅封端的聚氨酯作为种子乳液,然后与甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)混合单体共聚,合成了有机硅改性磺酸型聚氨酯/丙烯酸酯复合乳液。 红外光谱的表征确定了有机硅改性磺酸型聚氨酯/丙烯酸酯复合乳液的化学结构;透射电子显微镜观察证实了此复合乳液具有明显的核壳结构;热重分析表明,经有机硅和丙烯酸酯改性后,胶膜的最大热失重温度提高了20 ℃,X射线衍射分析表明胶膜的结晶度降低,有利于提高膜的韧性。 力学性能测试及吸水率测试结果表明,当有机硅含量为1.9%时,胶膜的拉伸强度最高达到25.03 MPa,断裂伸长率为328%,此时膜的吸水率最低。     

有机硅改性丙烯酸酯共聚乳液合成方法及胶膜性能的研究

用一次投料法、单体乳液滴加法和引发剂滴加法有机硅改性丙烯酸酯共聚乳液，聚合过程、胶粒形态及乳液稳定性的观测结果表明：单体乳液滴加法是合成该类乳液的最佳方法，研究了单体乳液滴加法中有机硅含量与聚合反及胶膜性能的关系，结果表明：有机硅含量在１５％以下时，聚合反应可以顺利进行，胶膜性能不仅依赖于聚合时有机硅单体的总量，而且还依赖于有机硅单体中活性硅氧烷所占的比例。     

有机硅改性聚氨酯丙烯酸酯光-潮气双固化体系

有机硅改性聚氨酯丙烯酸酯光-潮气双固化体系;潮气固化     

有机硅改性丙烯酸酯乳液的流变性

聚合物乳液;流变性能;反应性乳液;有机硅改性丙烯酸酯乳液的流变性     

有机硅-丙烯酸酯微乳液的合成与表征

采用高温乳化种子单体滴加法制备了有机硅-丙烯酸酯共聚微乳液。对合成条件及微乳液的性能进行了研究。用红外光谱(FT-IR)、透射电镜(TEM)、动态激光粒度仪(PCS)对微乳液的结构和粒子形态进行了表征。结果表明:有机硅氧烷与丙烯酸酯发生了共聚反应,生成的微乳液粒子大致为球形结构,粒子大小比较均一,粒径较小。     

UV固化丙烯酸酯化有机硅及杂化材料的研究与应用

丙烯酸酯化有机硅及杂化材料因兼具有机硅材料的优异性能和光固化的高效、节能及环保等特点而得到广泛的应用。文章综述了光敏性丙烯酸酯化有机硅单体的种类、结构特点及其制备方法,分析了紫外光（UV）固化后聚合物及其杂化材料的性能,介绍了它们的研究与应用现状及其发展前景。     

有机硅-丙烯酸酯聚合物乳液合成及粒径分析

通过种子乳液半连续法合成了有机硅改性丙烯酸酯聚合物乳液,并对其粒子形态及分布进行分析。结果表明:通过种子乳液半连续聚合工艺可制备出固含量42wt%,乳化剂含量4wt%(基于单体量)、窄分布纳米粒子的有机硅改性丙烯酸酯聚合物乳液。随反应进行,粒径分布变窄,平均粒径逐渐增大。随乳化剂中SDS与OP-10的摩尔比减少,粒径增大。     

荧光探针法研究核壳结构有机硅-丙烯酸酯乳液的聚合行为

以芘为荧光探针,探讨了有机硅-丙烯酸酯核壳乳液聚合过程中,芘的第一振动峰(373 nm处)与第三振动峰(384 nm处)荧光强度的比值I1/I3与乳化剂、有机硅单体(D4)和引发剂(KPS)用量之间的关系,并结合聚合过程中探针芘的I1/I3峰值与单体转化率及乳胶粒形态演变之间的关系,研究了核壳结构有机硅-丙烯酸酯乳液的聚合行为.研究结果表明,探针芘的I1/I3峰值随乳化剂用量,D4用量,KPS用量不同发生相应的变化,随单体转化率的增加而增大.当乳化剂用量、D4用量、KPS与总单体的质量比依次为2 g、8 g、0.7%时,得到的乳液具有优良的综合性能.聚合反应过程中,当种子乳胶粒转变为核壳乳胶粒时,芘的I1/I3峰值仍呈现出明显的转变,说明有机硅-丙烯酸酯核壳乳液具有互穿聚合物网络结构.因此,荧光探针可用于研究有机硅-丙烯酸酯核壳乳液聚合反应进程.     

有机硅改性聚氨酯丙烯酸酯细乳液的制备及性能

将自制的聚氨酯大单体与含乙烯基有机硅单体、丙烯酸酯进行共聚反应,通过合适的工艺条件,制备了一系列性能稳定的细乳液。研究了聚合方法、有机硅含量对共聚细乳液及胶膜性能的影响。结果表明,种子细乳液法制得的聚合物结构明确,细乳液粒径均在150 nm左右,分布指数约为0.07,有机硅的引入使乳液胶膜耐水性及耐高温性得到了明显提高。     

A novel method for preparing monodispersed polystyrene nanoparticles

A preparation manner for monodispersed polystyrene (PS) nanoparticles polymerized by using a novel addition procedure of a monomer is suggested. In systems containing a smaller amount of surfactant compared with conventional microemulsion polymerization, the polymerization processes consists of three stages: adding dropwise the first part of the monomer for a few minutes at 80°C and polymerizing for 1 h; adding collectively the residual part of the monomer and polymerizing at the same temperature for another 1 h; and then polymerizing at 85°C for another 1 h. Based on discussions on the nucleation mechanism of particles in the polymerization system, the influences of monomer weight added dropwise, and amounts of initiator and emulsifier on the size and distribution of PS particles were investigated. PS nanoparticles with smaller diameter such as a number-average diameter of 18.7 nm and better monodispersity were obtained since the dropped styrene amount was suitable under 20wt-% emulsifier amount and 3wt-% initiator amount based on the monomer. Translated from Journal of Nanjing University (Natural Science), 2006, 2 (in Chinese)     

丙磺舒药物键合两亲共聚物的制备

丙磺舒药物键合两亲共聚物的制备;丙磺舒; 两亲共聚物; 高分子药物     

含氨基、羟基丙烯酸乳液聚合的稳定性

采用间歇及半连续乳液聚合方式,以过硫酸铵/亚硫酸钠为引发体系,合成了甲基丙烯酸甲酯/丙烯酸丁酯/甲基丙烯酸羟乙酯/甲基丙烯酸二氨基乙酯四元共聚物胶乳.系统研究了乳化剂种类和浓度、聚合温度、乳化单体进料方式及进料速率对聚合过程稳定性的影响.聚合温度降低,乳化单体进料速度减慢有利于聚合过程的稳定,采用种子半连续聚合方式比间歇聚合过程更稳定,乳化剂浓度的增加有利于聚合稳定性的提高和乳胶粒子的均匀化.     

胶乳型互穿聚合物网络研究 Ⅰ.环氧树脂／聚丙烯酸酯半LIPN的制备

采用复合乳液聚合技术,合成了环氧树脂/聚(丙烯酸丁酯—苯乙烯—甲基丙烯酸甲酯)[EP/P(BA—St—MMA)]半胶乳型互穿聚合物网络(semi—LIPN),并探讨了反应温度、乳化剂用量、引发剂用量、不同单体配比、体系 pH 值、搅拌速度、EP 含量、交联剂种类及用量对聚合反应转化率及聚合稳定性的影响。     

硅丙乳液的合成工艺研究

采用半连续种子乳液聚合工艺,以乙烯基三乙氧基硅烷(VTS)为改性剂、十二烷基硫酸钠(SDS)和烷基酚聚氧乙烯醚(OP-1O)为复合乳化体系,在引发剂过硫酸铵(APS)的作用下合成稳定的硅丙乳液.利用红外光谱(FTIR)和扫描电镜(SEM)对涂膜进行了表征.结果表明:单体转化率随乳化剂用量、引发剂用量、有机硅用量、聚合温...     

Suspended Emulsion Copolymerization of Acrylonitrile with Methyl Acrylate: Effects of Reaction Parameters on the Polymerization

Acrylonitrile/methyl acrylate copolymers were synthesized by suspended emulsion polymerization with water as dispersed phase and monomers as continuous phase, potassium peroxydisulphate (KPS) as initiator, Span-80 as emulsifier, and poly(vinyl alcohol) (PVA) as suspending agent. Effects of reaction parameters such as water/monomer mass ratio, concentration of initiator, polymerization temperature and agitation rate on polymerization conversion and the particle size distribution of acrylonitrile/methyl acrylate copolymers were studied. It was found that polymerization conversion increased with an increase of water/monomer mass ratio, concentration of initiator and polymerization temperature, while the agitation rate had no significant effect on the polymerization conversion. Particle size distribution became narrower with an increase of water/monomer mass ratio and agitation rate. Under the same initiator concentration and polymerization temperature, particle size distribution became wider along with polymerization time. The differential scanning calorimetry (DSC) results indicated that the peak temperature of the copolymers decreased with increasing MA content.     

氯丁胶乳乳液接枝甲基丙烯酸甲酯的反应动力学

采用乳液聚合法将甲基丙烯酸甲酯(MMA)接枝到氯丁胶乳上,红外光谱和核磁共振氢谱证实了接枝产物的生成。 研究了反应温度、乳化剂浓度、引发剂浓度和单体浓度对表观聚合速率的影响。 结果表明,当反应温度为50 ℃,引发剂叔丁基过氧化氢 四乙烯五胺（t-BHP/TEPA）用量为氯丁胶乳干重的0.5%,单体/聚合物质量比m(M)∶m(P)=3∶5,乳化剂十二烷基连苯醚二磺酸钠（DSB）用量为单体总质量1%时,单体转化率和接枝效率分别为99.1%和54.9%。 聚合反应动力学关系式为：Rp=Kc(E)0.15c(I)0.30c(MMA)1.41,式中,K为常数,在40~55 ℃范围内,聚合反应的表观活化能Ea＝60.2 kJ/mol。 接枝聚合基本符合自由基反应机理。     

Kinetic and particle size studies of emulsion polymerization of methyl methacrylate and styrene with using polyamidoamine dendrimer as seed

The emulsion polymerization of methyl methacrylate (MMA) and styrene (St) were investigated with using polyamidoamine (PAMAM) dendrimer as seed, potassium persulfate as initiator and sodium dodecyl sulfate as emulsifier. The effects of 4.0GPAMAM dendrimer concentration, initiator concentration, emulsifier concentration, monomer concentration, and polymerization temperature on the monomer conversion and polymerization rate were investigated. At the same time, the influence of the generation of PAMAM dendrimer on latex particle size was studied also. The results showed that the monomer conversion and polymerization rate increased with increasing initiator concentration, emulsifier concentration, monomer concentration, and polymerization temperature. But polymerization rate increased firstly with an increase in the 4.0GPAMAM dendrimer from 0.03 g to 0.09 g and then decreased with further increase to 0.12 g. When the concentration of 4.0GPAMAM dendrimer less than 1.449 × 10^?4 mol/L, the kinetic equation can be expressed by Rp∝[4.0GPAMAM]^0.772[SDS]^0.562[KPS]^0.589[M]^0.697, and the activation energy (Ea) of emulsion polymerization is 62.56kJ/mol. In additional, the copolymer latex particle size decreased and possessed monodispersity with increasing the generation of PAMAM dendrimer. According to FT-IR spectrum analysis, PAMAM dendrimer is successfully incorporated into the poly(PAMAM-St–MMA) latex particles.     

反相乳液共聚合制备两性丙烯酰胺共聚物的研究

采用Span80-Tween80复合乳化剂和AIBA引发剂,进行丙烯酸钠(NaAA)/丙烯酰胺(AM)/丙烯酰氧基乙基三甲基氯化铵(DAC)反相乳液共聚合.研究了聚合温度、引发剂用量、单体浓度、共聚单体中DAC和AM含量、乳化剂用量及其HLB值、水/油比和水相pH值等聚合反应工艺条件或参数对聚合反应单体转化率和聚合物特性粘度的影响,聚合物特性粘度随引发剂用量和单体浓度的增大而增大的实验结果证实了该两性丙烯酰胺共聚物反相乳液制备过程中凝胶效应的存在.傅立叶红外光谱组成分析表明了两性丙烯酰胺共聚物的成功合成,扫描电镜观测乳胶粒粒径范围在0.6~8.0μm.     

Unseeded semibatch emulsion polymerization of butyl acrylate: Bimodal particle size distribution

Unseeded semibatch emulsion polymerization of butyl acrylate (BA) using sodium lauryl sulfate as emulsifier and potassium persulfate as initiator was carried out at the conditions where secondary nucleation was probable. This was achieved by using no emulsifier in the initial reactor charge. The effects of changes in monomer emulsion feed rate, initiator concentration and distribution, emulsifier concentration in the feed, and temperature on the evolution of particle size averages and distribution were investigated. Bimodal particle size distributions (PSD) were obtained for most of the latexes. Inhibition effects were found to be important in the development of PSD. Primary particle formation occurred through micellar nucleation, whereas secondary nucleation probably occurred through homogenous nucleation. The polydispersity index (PDI) of the latexes increased with the decreasing monomer emulsion feed rate. The application of a larger amount of initiator to the reactor charge or using a higher temperature, reduced the formation of secondary particles and resulted in a formation of an unimodal PSD. The overall steady‐state rate of polymerization was found to approach the rate of monomer addition (R_p ≈ R_a ), if the emulsifier concentration in the aqueous phase was appreciable. This is different from the correlation 1/R_p = 1/K + 1/R_a obtained for the BA semibatch process with neat monomer feed. This suggests that different rate expressions can be used for BA semibatch emulsion polymerization at different conditions. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 528–545, 2000