高固含量无皂丙醋乳液的制备

以P（VAc／AANa）两亲聚合物为乳化剂，对无皂聚丙烯酸丁酯／乙酸乙烯酯乳液的合成进行了研究，并对其性能进行了初步测试。得到的较佳合成工艺条件为：醋酸乙烯酯和丙烯酸丁酯的单体配比为70：30，引发剂为单体用量的0．5％，乳化剂为单体总质量的3％，反应温度为70℃，反应时间为3．5h，再保温1h。制得的无皂丙醋乳液各方面性能良好。     

水性涂料用醋丙乳液的研制

本采用种子乳液聚合方法合成了一种高性能醋酸乙烯-丙烯酸丁酯共聚乳液，讨论了聚合过程中单体的选择、聚合温度、乳化剂的配比及用量和引发剂等因素对产品性能的影响，确定了聚合配方和聚合工艺，经实验测试，乳液性能良好。     

丙烯酸酯无皂乳液的研究

在甲基丙烯酸甲酯和丙烯酸丁酯的无皂乳液体系中，加入适量的自制聚氨酯型反应性乳化剂(URE)，考察单体配比和有机溶剂对乳胶膜性能的影响，并研究了聚合物乳液的稳定性。结果表明：与传统乳液聚合体系相比，所合成的胶乳耐电解质、耐酸碱、耐有机溶剂的性能均好。     

无皂乳液聚合合成单分散纯丙乳液

研究了甲基丙烯酸甲酯、丙烯酸丁酯、甲基丙烯酸、丙烯酸羟乙酯的无皂乳液聚合,考察了单体浓度、引发剂用量、温度、单体配比等对无皂乳液聚合的影响,得到了单分散高固含量的纯丙乳液。     

丙烯酸酯无皂乳液的合成

以过硫酸铵( APS)为引发剂,甲基丙烯酸甲酯( MMA)为硬单体,丙烯酸丁酯(BA)为软单体,丙烯酸(AA)为功能单体,可聚合乳化剂(WE-9)为乳化剂,采用预乳化法合成了一种聚丙烯酸酯无皂乳液.讨论了聚合温度,预乳化液滴加时间,乳化剂用量对乳液性能的影响.结果表明,当温度80 ℃,WE-9质量分数为1 5％,滴加时...     

用AMPS合成高耐水性丙烯酸乳液压敏胶的研究

运用可聚合乳化剂AMPS和极少量低分子化剂CO－436相配合,采用特殊工艺的半连续无皂乳液聚合方法,研制出了一种耐水性较好的丙烯酸乳液压敏胶,并就其各种性能及影响因素进行了考查,结果表明,聚合工艺对AMPS乳液的聚合稳定性有较大影响,用可聚合乳化剂AMPS合成的丙烯酸乳液压敏胶具有较好的耐水性。     

含AMPS的丙烯酸酯无皂乳液的合成与性能研究

以少量2-丙烯酰胺基-2甲-基丙磺酸的钠盐(AMPS)作为功能性单体,成功制备了一种高稳定性,固含量达50%的甲基丙烯酸甲酯/丙烯酸丁酯[P(MMA/BA)]的无皂乳液。并且对不同单体配比乳液的性能进行研究,总结了单体配比与胶膜吸水性及Tg的关系;同时,讨论了功能性单体AMPS对乳液稳定性、粒子形态的影响。     

高性能无皂硅丙乳液合成的研究

本文在无乳化剂下合成了硅丙乳液。利用丙烯酸丁酯与甲基丙烯酸(钠)制备低聚物P(BA/MANa)代替乳化剂,由于低聚物P(BA/MANa)与合成的硅丙乳液P(BA/MMA)结构中都有PBA链段,有利于两者互容,因此,在硅丙乳液合成中虽不使用乳化剂,但乳化效果更好。研究了丙烯酸丁酯与甲基丙烯酸单体配比、pH值变化对低聚物性能的影响;研究了低聚物用量、软硬单体配比、有机硅单体种类与用量、有机硅单体(KH-570)加入方式等对合成硅丙乳液性能的影响,找出了合成无皂种子乳液与无皂硅丙乳液的最佳工艺参数,合成的无皂硅丙乳液的耐候性、耐水性等性能更加优良,硅丙乳液应用范围更加广泛。     

无皂硅丙乳液的制备

以丙烯酸酯类单体、苯乙烯、苯乙烯磺酸钠、有机硅类单体为原料，采用无皂乳液的聚合方法，使有机硅与丙烯酸树脂通过化学键连接，通过对不同单体的优化组合，合成了性能优良、稳定的无皂硅丙乳液。讨论了苯乙烯磺酸钠的用量、滴加速度、水性功能单体种类以及有机硅功能单体种类和用量对乳液性能的影响。结果表明：以丙烯酰胺为水性功能单体，当苯乙烯磺酸钠、乙烯基三异丙氧基硅烷用量分别为总量的0.086％和3％，原料滴加时间为5h时，产品的性能最佳。     

无皂苯丙乳液的合成及其性能研究

在少量甲基丙烯酸钠盐的存在下，成功合成了具有高稳定性、高透明性的聚（苯乙烯／丙烯酸丁酯）P（St/BA)无皂共聚乳液。同时，还对不同配方的乳液及其涂膜的综合性能进行了研究，总结了组成与性能之间的对应关系，并着重讨论了单体组成与乳液表面能、乳胶粒尺寸之间的关系。结果表明：随单体配比中St含量的增加，乳液接触角和乳胶粒粒径减小；乳胶粒具有均一的尺寸，并显示出明显的核壳结构。通过对苯丙无皂乳液组成与性能关系的研究，积累了一定量的理论数据，为无皂乳液产品的进一步研究开发提供了条件。     

Semi-continuous emulsion copolymerization of vinyl acetate and butyl acrylate in presence of AMPS

The emulsifier-free emulsion polymerization of vinyl acetate (VAc) and butyl acrylate (BA) in the presence of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) was carried out by a semi-continuous process. AMPS was a reactive surfactant in the aqueous emulsion, due to its amphiphilic structure and the unsaturated double bonds. Potassium persulfate (KPS) was used as initiator. The following factors were mainly examined: quantity of AMPS, BA and KPS concentrations, which could significantly affect the particle size and its distribution, conversion, gel content, minimum film-forming temperature, etc. The particle size and its distribution were characterized by dynamic laser particle size analyzer, and morphology of the latex particles was characterized by transmission electron microscopy (TEM). Fourier transform infrared spectroscopy was used to characterize chemical structure of copolymers. The results indicated that AMPS was successfully reacted onto the resulted copolymer of vinyl acetate and butyl acrylate. A hydrophilic sulfonic acid group in the molecular structure of AMPS tended to be distributed in particles surface after polymerization. As a result, an electrostatic repulsion between the particles was produced in order to maintain stability of the system. Thermogravimetric analysis curves suggested that as BA content increased, thermal stability of the polymer increased accordingly. The conversion-time plots with varying AMPS and initiator contents were obtained, which illustrated that the initiator concentration could greatly influence the polymerization rate and the final conversion. The TEM micrographs of the final emulsifier-free latex particles for P(VAc/BA/AMPS) system revealed small particle size in monodisperse polymer latex. The particles of the latex were measured as about 150 nm.     

无皂改性醋酸乙烯酯乳液的研究

研究了无皂改性醋酸乙烯酯乳液的合成工艺及条件,并采用小角激光散射仪,测得了粒子的粒径大小及分布;探讨了单体浓度、引发剂浓度、缓冲剂浓度等对粒径的大小、分布的影响及规律;用扫描电子显微镜,对粒子的形态进行了观测。用红外光谱仪,对聚合物的结构进行了表征。     

Semicontinuous heterophase copolymerization of vinyl acetate and butyl acrylate

Vinyl acetate (VAc) and butyl acrylate (BuA) were copolymerized in heterophase by a semicontinuous process (unseeded) and compared with the seeded semicontinuous microemulsion polymerization of the same monomers. A mixture of sodium dodecyl sulfate (SDS) and poly(ethylene oxide) dodecyl ether (Brij‐35®) were used as surfactants. The effects of monomer addition rate (R_a) and surfactants concentrations (4 or 1 wt % with respect to the initial mixture of reaction) on polymer and latex properties were studied. High copolymer content latexes (24–36 wt %) with average particle diameters (D_p) from 38 to 55 nm and relatively narrow particle size distributions, high polymerization rates, weight ratios of polymer to surfactant (P/S) from 13.3 to 32.8 were obtained. The number‐average molecular weights (M_n) were between 96,000 and 188,000 g/mol. Homogeneous copolymer compositions were obtained throughout the reaction for both, seeded and unseeded processes, which is not possible by the usual batch microemulsion process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Concentrated emulsion copolymerization of butyl acrylate and vinyl acetate initiated by a redox initiator at lower temperature

The concentrated emulsion copolymerization of butyl acrylate and vinyl acetate with an ammonium persulfate/sodium hydrogen sulfate mixture as a redox initiator, with a sodium dodecyl sulfate/cetyl alcohol mixture as a compound surfactant, and with poly(vinyl alcohol) as a liquid film reinforcer was carried out at lower temperature. In less than 3 h, the polymerization conversion was greater than 95%. The effects of the surfactant, the initiator, the volume fraction of the monomer, and the temperature on the stability of the concentrated emulsion, the kinetic process, and the average size of the latices were examined. The morphology of the polymer particles was observed by transmission electron microscopy, and the average size and distribution of the particle diameter were measured by photon correlation spectroscopy. The kinetic equation was R_p = k[M]^0.38[I]^0.89[E]^?0.80 at 30°C (where R_p is the polymerization rate, [I] is the initiator concentration, [M] is the monomer concentration, and [E] is the concentration of the compound surfactant), and the apparent activation energy was 22.69 kJ/mol. The thin‐layer polymerization of the concentrated emulsions, which enabled the removal of the heat of polymerization, was performed first. In comparison with test‐tube polymerization, thin‐layer polymerization provided a more regular morphology of the polymer particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 570–576, 2004     

高固含量丙烯酸酯无皂乳液的合成及性能研究

采用少量自制的可聚合乳化荆M-OP10,通过预乳化半连续滴加工艺成功合成了一种高稳定性、固含量达50%的甲基丙烯酸甲酯/丙烯酸丁酯/丙烯酸-2-乙基己酯[P(MMA/BA/EHA)]的无皂乳液.探讨了反应温度、反应时间、可聚合乳化荆用量等条件对合成的影响,并且对不同可聚合乳化剂用量的乳液及胶膜性能进行了研究.结果表明,当反应温度80℃、滴加时间1 h、保温时间1 h、可聚合乳化剂为单体质量分数0.4%时.制备的无皂乳液各项性能较好.     

丙烯酸(酯)改性聚醋酸乙烯酯乳液的研制

采用半连续种子乳液聚合法,使用丙烯酸(AA)功能性单体和丙烯酸丁酯(BA)软单体对醋酸乙烯酯(VAc)进行了共聚改性,制备出高固含量(50.2%)的聚醋酸乙烯酯(PVAc)改性乳液。该乳液适合用于喷雾干燥法制备可再分散聚合物粉末,并且其耐水性和耐碱性等都得到了明显地改善。对影响共聚物的诸多因素进行了较为全面地考察,得出最佳的工艺条件为:AA用量为主单体质量的3%～4%,BA用量为主单体质量的5%～10%,保护胶体用量为混合单体质量的7.5%～15%,引发剂用量为混合单体质量的0.4%～0.5%,阴/非离子型复合乳化剂的质量比为1∶2～1∶3、用量为混合单体质量的2%～3%,分散剂、消泡剂和酸碱缓冲剂等助剂均为适量,加料时间为3～4h,反应温度为70～75℃。     

Solvent effects in butyl acrylate and vinyl acetate homopolymerizations in toluene

A series of butyl acrylate (BA) and vinyl acetate (VAc) homopolymerizations in toluene was conducted to investigate the effect of solvent at different solvent and chain transfer agent (CTA) concentrations. Because the experimental determination of the individual propagation and termination rate constants for these systems is challenging, experimental observations were limited to the lumped rate constant (k_p/k). Differences in the lumped rate constant, at different solvent and CTA concentrations, were assumed to be attributed to the effect of solvent on the termination rate constant. Our hypothesis was that the termination rate constant k_t was affected by the presence of solvent. At higher solvent concentrations, chain transfer to solvent occurs more frequently and leads to the formation of shorter chains, which move more easily and are able to terminate more quickly compared to longer chains. Thus, k_t will increase, leading to a decrease in the lumped rate constant. The experimental results confirmed the presence of a solvent effect on the lumped rate constant. This effect was more pronounced in the case of VAc compared to BA solution homopolymerizations. Under the investigated conditions, increased CTA concentrations did not substantially affect the rate of BA homopolymerizations, whereas a slight synergistic effect between the CTA and solvent at higher CTA and solvent concentrations was apparent for VAc homopolymerizations. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 871–876, 2004     

Free radical copolymerization behavior of vinyl acetate with butyl acrylate in the presence of GeCl4 and BCl3

No alternating copolymers of vinyl acetate (VAc) and butyl acrylate (BA) were obtained by free radical copolymerization in the presence of GeCl₄ and BCl₃ (compared with the acrylic acid–vinyl acetate copolymerization system). By ultraviolet spectral analysis, it was concluded that both BCl₃ and GeCl₄ can form complexes with butyl acrylate. The BA–BCl₃ complex constants were determined by ¹H NMR; K_B=33·2 (25°C). The reason for the gel formation in the BA–Vac–BCl₃ copolymerization system was discussed. When vinyl acetate reacted with BCl₃, cationic polymerization probably occurred. A white gel product probably resulted from the polymerization of the BA–BCl₃ complex. © 1998 SCI.