有机硅氧烷对乘用车专用阻尼材料的性能影响

将乙烯基有机硅氧烷、苯乙烯、丙烯酸丁酯及甲基丙烯酸等单体共聚,制备了不同配比的丙烯酸酯共聚乳液,并在乳液中加入无机填料,在多种助剂配合下制备出了性能优良的复合阻尼材料。采用傅里叶红外光谱仪和动态力学分析仪研究了共聚乳液中有机硅氧烷组分对乳胶膜的结构、阻尼性能和复合材料的损耗因子的影响,通过扫描电子显微镜对比研究了经有机硅氧烷改性前后的乳胶粒的变化以及改性前后丙烯酸酯乳液与填料的界面相容性,并研究了有机硅氧烷对阻尼材料的力学性能的影响。结果表明,当共聚乳液组成中含有一定量的有机硅氧烷进行改性后,乳胶膜的阻尼性能、丙烯酸酯乳液与填料的相容性以及阻尼材料的力学性能均得到明显的改善。     

有机硅改性丙烯酸酯共聚乳液的合成及表征

采用间歇和种子半连续乳液聚合方法合成有机硅改性丙烯酸酯(硅丙)共聚乳液,用激光粒度仪、透射电子显微镜、差示扫描量热仪、表面张力仪等分析了硅丙共聚乳液和涂层的性能。采用种子半连续乳液聚合和间歇乳液聚合均可得到具有核-壳结构的硅丙共聚乳液。半连续乳液聚合得到的硅丙共聚乳液的粒径较小,粒径分布窄;采用半连续滴加纯丙烯酸酯单体和滴加单体预乳液对共聚乳胶粒子的平均粒径及粒径分布、形态影响不大。采用间歇乳液聚合可使有机硅单体的开环聚合和丙烯酸酯单体的自由基聚合同时进行,获得的硅丙乳液稳定性好,但聚合转化率偏低,乳胶粒子粒径较大,粒径分布较宽。硅丙共聚乳液胶膜的吸水率小于纯丙烯酸酯聚合物乳液胶膜,并随有机硅共聚率的增加而降低;硅丙乳液胶膜的接触角接近有机硅接触角。硅丙共聚乳液涂层整理的织物手感优异,但涂层牢度小于纯丙乳液整理剂。     

苯乙烯磺酸钠用于硅丙无皂乳液聚合研究

以离子型共聚单体苯乙烯磺酸钠与非离子型共聚单体甲基丙烯酸β-羟乙酯为功能单体,以K2S2O8-NaHSO3为氧化-还原体系,进行MMA-BA无皂乳液聚合研究.详细讨论了乳化剂用量、配比、反应温度、引发剂配比等条件对乳液聚合及共聚物性能的影响.并在纯丙无皂乳液聚合的研究基础上进行有机硅改性丙烯酸酯无皂乳液聚合研究,研究了有机硅的加入及加入顺序对乳液聚合及其性能的影响.结果表明:有机硅的加入使共聚物的耐水性提高,而且有机硅后加的聚合稳定性优于先加的.透射电镜表明有机硅先加得到的乳胶粒子为均匀的球形核壳结构,而有机硅后加得到的乳胶粒子形状不规则,且有机硅的加入使乳胶粒径减小.     

柔性硅丙外墙乳胶涂料的制备及性能研究

通过合理的乳胶粒子结构设计,采用有机硅单体对乳胶粒子的壳层进行改性,合成出核壳型柔性硅丙乳液。研究了乳胶粒子结构,有机硅单体含量对乳液制备过程,乳胶膜及其配制涂料性能的影响。研究结果表明：乳胶粒子设计成硬核软壳型,有机硅用量占单体总量5%,所得乳液制备的柔性硅丙外墙乳胶涂料各项性能良好。     

有机硅改性丙烯酸酯乳液

复旦大学的游波等通过乳液聚合制备出有机硅改性丙烯酸酯乳液。乳液中的有机硅分子在催化剂作用下与基材表面的羟基脱水交联 ,使粘接力大大提高。研究了有机硅单体用量及丙烯酸交联单体对乳液性能的影响 ,结果表明 :有机硅单体质量分数为 8%时 ,乳液的综合性能最好 ,其耐水性、抗粘性、附着力、拉伸强度等均得到提高 ;加入丙烯酸单体Ａ ,可起催化剂作用 ,使共聚乳液交联度增加、粘接性提高 ,以苯乙烯代替部分甲基丙烯酸甲酯 ,不会影响乳液稳定性和质量 ,可降低成本。有机硅改性丙烯酸酯乳液     

工艺条件对丙烯酸酯-苯胺共聚乳胶涂层防腐性能的影响

在丙烯酸酯乳液中引入苯胺单体,采用原位乳液聚合法制备了丙烯酸酯-苯胺共聚乳液,分析了共聚机理,详细研究了反应温度、反应时间、共聚乳液中乳化剂种类、乳化剂用量、引发剂与苯胺的物质的量比[n(APS)∶n(An)]等条件对共聚乳液性能及乳胶涂层防腐性能的影响。对制备的共聚乳胶涂层进行了电化学阻抗谱(EIS)、塔菲尔曲线(Tafel)、开路电位(OCP)等测试,通过扫描电子显微镜(SEM)和X射线能谱(EDS)对腐蚀表面进行了分析。结果表明:丙烯酸酯-苯胺共聚乳胶涂层可以使金属基材表面形成钝化膜,且当反应温度为10℃,反应时间为5 h,乳化剂十二烷基苯磺酸钠(SDBS)用量占乳液总质量的2%,引发剂与苯胺的物质的量比为1.5∶1时,共聚乳液的性能及其乳胶涂层防腐蚀性能最佳。     

有机硅改性丙烯酸酯乳液的合成及性能研究

采用有机硅氧烷与丙烯酸酯单体共聚制备有机硅改性丙烯酸酯乳液,研究了有机硅单体用量、乳化剂配比和温度等因素对乳液的影响,并对涂膜性能进行了测试。研究结果表明,有机硅与丙烯酸酯单体能很好地聚合,且制备出的乳液性能优异,可以作为高性能外墙涂料的基体树脂。     

D_4改性丙烯酸酯乳液的合成研究

以甲基丙烯酸甲酯、丙烯酸丁酯为主要单体,加入八甲基环四硅氧烷(D4)进行共聚改性,制备出有机硅改性丙烯酸酯乳液。探讨了D4用量、反应温度、预乳化工艺等条件对乳液性能的影响。红外光谱和DSC分析表明D4与其它单体发生了共聚。     

核壳结构聚硅氧烷/丙烯酸酯复合乳液(Ⅰ)乳化剂对乳液聚合过程及粒径分布和粒子形态的影响

采用种子乳液半连续法合成了具有高有机硅含量的聚硅氧烷/丙烯酸酯核壳结构复合乳液,研究乳化剂的种类、复配比例及质量浓度对有机硅／丙烯酸酯壳核乳液性能与乳胶粒径、分布和结构的影响.结果表明：阴离子乳化剂十二烷基硫酸钠(SDS)、十二烷基磺酸钠(SDS-2)、十二烷基苯磺酸钠(SDBS)所合成的乳胶粒子粒径依次增大,SDS与非离子型乳化剂OP-10复配使用时,随OP-10质量分数的增加,聚合速率和转化率降低,化学稳定性增加,乳胶粒子粒径增大,分布变宽,确定了复合乳化剂的最佳配比.随复合乳化剂浓度的增加,聚合速率加快、转化率增加,乳胶粒子粒径减小而分布加宽.通过改变乳化剂加入方式可减小乳胶粒子的粒径分布.为减少壳层聚合物新粒子的产生,需严格控制乳化剂的浓度,使加入的壳层单体处于“饥饿”状态,在乳胶粒子表面富集、引发聚合,形成表层“过渡层”,最终形成核壳结构复合粒子.     

叔碳酸乙烯酯/有机硅改性丙烯酸酯乳液的制备与性能研究

采用预乳化半连续种子乳液聚合法,以反应型阴离子乳化剂(DNS-86)和非离子型乳化剂(OP-10)复配,引入叔碳酸乙烯酯(V-10)和乙烯基三甲氧基硅烷(A-171)为改性单体合成了叔碳酸乙烯酯/有机硅改性丙烯酸酯乳液.通过红外光谱(FT-IR)、透射电镜(TEM)、粒径分布分析(PSD)、差示扫描量热法(DSC)和热重分析(TG)对乳液结构、粒子形态和乳胶膜性能进行了分析和表征.结果表明:叔碳酸乙烯酯、有机硅氧烷与丙烯酸酯发生了共聚反应,生成的乳胶粒子为核壳型结构,粒子大小比较均一,粒径较小.通过与丙烯酸酯、叔碳酸乙烯酯改性丙烯酸酯、有机硅改性丙烯酸酯的乳液对比可知,核壳型叔碳酸乙烯酯/有机硅改性丙烯酸酯乳液的性能较佳.其涂膜吸水率仅为2.19％;接触角为109.5°,达到了对乳液改性的目的.     

乳液聚合法制备全氟碳涂料及性能的研究

以自制的全氟丙烯酸酯单体 ,经乳液聚合的全氟丙烯酸酯乳液共聚物配制的全氟碳乳液涂料 ,其耐水性、耐碱性等均优于传统的丙烯酸酯乳液涂料     

Structure and mechanical properties of the hybrid films of well dispersed SiO2 nanoparticle in polyimide (PI/SiO2) prepared by sol–gel process

Methyl methacrylate-butyl acrylate structural latexes were synthesized by two-stage seeded emulsion polymerization using 1,1-diphenylethylene (DPE) as a control reagent. In the first stage, the seed latex particles with the precursor poly (methyl methacrylate-DPE) (P(MMA-DPE)) were prepared, and then the second monomer n-butyl acrylate (nBA) was swollen into the seed latex particles under stirring at room temperature. In the second stage, the polymerization of nBA was thermally initiated at 80 °C, and the latex particles composed of block copolymer were synthesized. The size and morphology of the latex particles were investigated by light scattering and TEM. The contact angles of different latex films were also measured. The block copolymer was characterized by size exclusion chromatography, nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. Microphase separation of the block copolymer was examined using atomic force microscopy.     

有机硅改性醋丙乳液的制备与表征

采用半连续种子乳液聚合技术,以丙烯酸丁酯、醋酸乙烯酯和有机硅单体合成了有机硅改性醋丙乳液,并研究了有机硅含量、复合乳化剂配比、种子单体含量等对乳液聚合稳定性及乳液性能的影响。制备出的乳液稳定性良好,随着种子乳液单体含量的增加,乳胶粒粒径变小。     

Batch and Continuous Emulsion Copolymerization of Ethyl Acrylate and Methacrylic Acid

Emulsion copolymerization of a moderately water-soluble monomer (ethyl acrylate) with a completely water-soluble monomer (methacrylic acid) was initially examined in a batch reaction system. The reaction rates, copolymer composition, and physical properties of the latex product were characterized. Batch reactions were run with various monomer ratios. The latex stability was strongly dependent on both the temperature and the overall fractional conversion. Several continuous processes involving a tubular reactor and/or a continuous stirred-tank reactor were designed and utilized so as to produce a latex product with properties similar to the batch product.     

Synthesis and properties of branched organosilicon-acrylate copolymer latexes

Summary Stable organosilicon-acrylate copolymer latexes with high silicon content were prepared by seeded semibatch emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA) with a novel branched organosilicon monomer 3-methacryloxypropyl tris(trimethylsiloxy) silane (MPTS). Monomer conversion, evolution of the particle size and its distribution were monitored by dynamic light scattering. The effects of MPTS on the polymerization kinetics, the nucleation mechanism and properties of latex were investigated. The results indicated that, in addition to micellar nucleation, a coagulative nucleation step was also observed as a result of the addition of the organosilicon monomer, accordingly, the particle number of the silicon-acrylate latexes increased, the average particle diameter decreased and the polymerization rate accordingly increased compared to those of the acrylate latexes without organosilicon monomer. Moreover, the particle size distribution presented bimodal curves, which indicated that there were large particles formed at an early stage. However, the particle size distribution curves became monomodal at the later stage, and the final latex shows a narrow particle size distribution. It was found that the properties of latex and latex film were obviously influenced by MPTS content. With increasing MPTS content, latex film glass transition temperature and water absorption ratio decreased, the degradation temperature and water contact angle were increased. Hence, the resulting latex films containing MPTS showed lower glass transition temperature and excellent water-resistance, which probably due to the incorporation of the bulky branched hydrophobic group of MPTS into the copolymer chains.     

Nanostructured latex particles synthesized by nitroxide-mediated controlled/living free-radical polymerization in emulsion

Suspensions of diblock and triblock copolymer particles comprising a poly(n-butyl acrylate) first/central block and polystyrene or poly(methyl methacrylate) second/outer blocks were synthesized by nitroxide-mediated controlled/living free-radical emulsion polymerization. Monofunctional and difunctional alkoxyamines based on the nitroxide SG1 were used as initiators. For the sake of simplicity, sequential monomer additions were performed without any removal of unreacted monomer. Self-assembly of the obtained block copolymers was investigated both under the latex form as well as after different thermal treatments. AFM and TEM analyses revealed the occurrence of “onion-like” lamellar microphases directly inside latex particles for high enough copolymer molar masses and irrespective of molar mass distribution. This particular organization evolved towards more classical block copolymer morphologies upon solvent casting and/or thermal annealing of latex films.     

丙烯酸十二酯共聚物稠化能力的试验研究

聚(甲基)丙烯酸酯或丙烯酸高级酯与其它一些单体的共聚物是一类优良的油品增粘-降凝双效剂。丙烯酸十二酯与第二单体A的共聚物对润滑油有较好的降凝效果。丙烯酸十二酯与第二单体A的共聚物对润滑油也应有较好的增粘作用(即稠化能力)。用四种溶剂分别采用溶液聚合方法,用正交试验法对丙烯酸十二酯与第二单体A进行共聚试验,共聚物以1%的添加量加入到润滑油基础油中,做调合油的粘度测定,以增比粘度、粘温指数Q和粘度指数VI为考察目标,探讨丙烯酸十二酯与第二单体A共聚物对润滑油基础油的稠化能力,并找出较好的共聚条件。试验结果表明:丙烯酸十二酯与第二单体A共聚物对润滑油确有较好的增粘和改变油品粘温性能的作用,是一种增粘-降凝双效添加剂。     

偏二氯乙烯-丙烯酸酯共聚乳液的制备与性能研究

采用软单体丙烯酸异辛酯对聚偏二氯乙烯乳液进行增韧改性,得到了韧性、附着力、耐中性盐雾等综合性能优良的偏二氯乙烯-丙烯酸酯共聚乳液。研究了偏二氯乙烯、丙烯酸异辛酯、功能单体丙烯酸、引发剂的用量以及乳化剂用量与配比等因素对乳液性能的影响。结果表明:偏二氯乙烯用量为单体总量80%,丙烯酸异辛酯和丙烯酸用量分别为单体总量12%和3%,引发剂用量为单体总量0.5%,乳化剂十二烷基硫酸钠与KL-100用量为单体总量1.2%且质量比为1∶5时得到的共聚乳液具有优良的综合性能。     

Synthesis of well‐defined,functionalized polymer latex particles through semicontinuous emulsion polymerization processes

The design of a semicontinuous emulsion polymerization process, primarily based on theoretical calculations, has been carried out with the objective of achieving overall independent control over the latex particle size, the monodispersity in the particle size distribution, the homogeneous copolymer composition, the concentration of functional groups (e.g., carboxyl groups), and the glass‐transition temperature with n‐butyl methacrylate/n‐butyl acrylate/methacrylic acid as a model system. The surfactant coverage on the latex particles is very important for maintaining a constant particle number throughout the feed process, and this results in the formation of monodisperse latex particles. A model has been set up to calculate the surfactant coverage from the monomer feed rate, surfactant feed rate, desired solid content, and particle size. This model also leads to an equation correlating the polymerization rate to the instantaneous conversion of the monomer or comonomer mixture. This equation can be used to determine the maximum polymerization rate, only below or at which monomer‐starved conditions can be achieved. The maximum polymerization rate provides guidance for selecting the monomer feed rate in the semicontinuous emulsion polymerization process. The glass‐transition temperature of the resulting carboxylated poly(n‐butyl methacrylate‐co‐n‐butyl acrylate) copolymer can be adjusted through variations in the compositions of the copolymers with the linear Pochan equation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 30–41, 2003     

一种钻井液用有机高分子絮凝剂的反相乳液法制备

用环己烷作为连续相,Span80/OP10作为复合乳化剂,KPS-TMEDA作氧化还原引发剂,在室温通过反相乳液聚合法制备了黏均相对分子质量大于700万的丙烯酰胺(AM)与丙烯酸钾(AA-K)的稳定共聚物胶乳,并研究了聚合温度、引发剂浓度、单体浓度及配比对聚合物黏均相对分子质量的影响。反应条件:c(KPS)=1 7×10-3mol/L,c(monomer)=3 5～5 5mol/L,n(AA-K)/n(AM)=0 1,温度20～30℃较适宜。对聚合物胶乳的絮凝及泥浆的应用效果进行了评价,发现效果明显,应用方便。