苯丙乳液最低成膜温度的影响因素分析

采用复合乳化剂体系和预乳化法核壳乳液聚合工艺,制得苯乙烯-丙烯酸异辛酯共聚乳液.研究了乳胶粒粒径、形态、乳化剂和核壳结构组成对聚合物的最低成膜温度(MFT)和玻璃化温度(Tg)的影响.     

核壳型短链含氟丙烯酸酯乳液的合成及表征

该文研究了核壳型短链含氟丙烯酸酯乳液的合成与表征。以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)的共聚体为核,短氟碳链2-(全氟己基)乙基甲基丙烯酸酯(FMA6)和非氟烷基丙烯酸酯的共聚体为壳,采用多步乳液聚合法,合成系列具有核壳结构的含氟丙烯酸酯乳液,研究了壳相中氟单体用量和非氟烷基丙烯酸酯的烷基链长度n(链长n=4、8、12、16、18)对产物疏水疏油性能的影响,并对产物进行表征。结果表明:当采用氟单体用量为总单体质量的8.5%,甲基丙烯酸十六酯(CMA)的共聚体为壳层时,由合成乳液制得的乳胶膜的疏水疏油性最佳,对水接触角为124.67°,对二碘甲烷接触角为112.76°。FTIR、TEM和DSC/TGA表征表明,原料单体均参加了反应;乳液颗粒具有明显的核壳结构;聚合物存在两个玻璃化温度(-18.87℃和32.08℃),热分解温度比不含氟的聚合物提高了近20℃。由此说明,用合成的核壳型短链含氟丙烯酸酯乳液制得的涂膜具有优异的疏水疏油性和耐热性能。     

核-壳苯丙微乳液最低成膜温度的研究

通过核-壳微乳液聚合技术合成了具有较高玻璃化转变温度(Tg)的苯丙微乳液,研究了核-壳单体用量比、壳单体组成、交联剂、聚合物极性对乳液最低成膜温度(MFT)的影响;同时比较了三种成膜助剂对乳液MFT的作用。研究发现,成膜温度随核-壳比的增大而上升;交联剂羟甲基丙烯酰胺(NMA)能有效地降低成膜温度;醇酯—12是一种良好的成膜助剂,同一成膜助剂对极性不同的乳胶粒子MFT的降低效果明显不同。     

影响聚合物乳液最低成膜温度的因素

介绍了影响聚合物乳液最低成膜温度(MFT)的因素:聚合物化学结构、聚合物极性、乳液颗粒结构(核壳乳液聚合)及增塑剂、成膜助剂。     

聚合工艺和单体配比对醋苯丙乳液最低成膜温度的影响

分别以醋丙、苯丙种子乳液为基础，引入第3种单体，探讨了聚合工艺和单体配比对醋苯丙核壳乳液最低成膜温度(MFT)的影响，制得了MFT低、成本也低的硬核软壳的醋苯丙核壳乳液。     

乳化剂对醋苯丙核壳乳液性能的影响

简要叙述了乳化剂对聚合物乳液的影响。详细地讨论了AES、OP-10两种乳化剂对聚合物乳液最低成膜温度(MFT)、粘度、乳胶粒核壳结构等性能的影响。     

单组分核壳型苯丙乳液制备及其木材粘接性能研究

采用两阶段饥饿态种子乳液聚合法,制备了以PS(聚苯乙烯)基聚合物为核、以PA(聚丙烯酸酯)基聚合物为壳的核壳型苯丙复合乳液,研究了核单体组成对核壳型苯丙乳液乳胶膜热性能、吸水率、胶接性能等的影响。研究结果表明:不同试验条件都可以制得核壳型苯丙乳胶粒;随着核单体中BA(丙烯酸丁酯)含量的增加,苯丙乳胶膜吸水率显著降低;在构建核壳结构化乳胶粒后,苯丙乳液的胶接性能较苯丙无规共聚物乳液显著提高,其胶接强度大幅度增加且耐沸水开裂时间显著延长。     

核壳丙烯酸聚合物微粒子乳液的合成与解析

本文利用种子乳液聚合方法合成了丙烯酸聚合物乳液,核、壳聚合物的组成分别为：m(MMA)：m(BA)=76：24和m(MMA)：m(BA)：m(AA)=46：51：3;种子乳液和核壳乳液的MFT分别为66℃和28℃。说明最终的聚合物微粒子具有硬核软壳结构;通过SEM拍摄的照片可以清晰地观察到聚合物微粒子的大小,经计算,全部聚合物中的种子粒子数和最终粒子数基本相同,且未发现细小的粒子。说明壳单体的聚合完全是在种子粒子上进行的;本文还对影响聚合物微粒子核壳结构的主要因素进行了探讨。     

苯乙烯-甲基丙烯酸甲酯无皂核壳乳液合成及表征

采用溶液聚合法制得苯乙烯(St)与苯乙烯磺酸钠(NaSS)共聚物的种子乳液,将其用于甲基丙烯酸甲酯(MMA)的无皂种子乳液聚合,制得了一系列不同核壳单体配比的核壳乳液.通过对溶液聚合动力学、产物的结构与相对分子质量、种子粒径以及将其用于乳液聚合时所得产物的结构与粒子形态分析,结果表明:以溶液聚合法制得的苯乙烯型种子乳液能成功制备无皂核壳乳液,从而为制备无皂核壳乳液提供了新的途径.     

核/壳结构硅丙微乳液的合成与表征

以丙烯酸酯[如MAA(α-甲基丙烯酸)、n-BMA(甲基丙烯酸正丁酯)和MA(丙烯酸甲酯)等]和A-151(乙烯基三乙氧基硅烷)为共聚单体、OP-10(辛基酚聚氧乙烯醚)/JFC(聚醚渗透剂)为复合乳化剂、戊醇为助乳化剂和KPS(过硫酸钾)为引发剂,采用分段控温、补加引发剂等方法制得丙烯酸酯预聚乳液;然后采用核/壳接枝聚合反应和氨化反应,制得半透明核/壳型硅丙微乳液。研究结果表明:当分段聚合温度为75℃和65℃时,采用上述方法制成的硅丙微乳液中A-151含量高达12%左右(相对于微乳液总质量而言),乳胶粒具有明显的核/壳型结构,粒径为10⁶0 nm,并且微乳液体系聚合稳定性良好。     

Effect of morphology on mechanical and rheological properties of butyl acrylate–methyl methacrylate multiphase polymers

Polymers of butyl acrylate–methyl methacrylate with different morphologies were synthesized by emulsion polymerization. Four types of polymers were obtained: copolymer, core–shell, three layer, and a core–shell with a copolymer layer of variable composition (gradient). The effect of the morphologies on the mechanical and rheological properties of these polymers was studied. It was found that when the same overall composition was used the properties of the polymer can be varied from those of rigid plastic to those of an elastomeric material. It was found that increasing the content of butyl acrylate (BA) improves the mechanical properties and the presence of a copolymer zone improves the impact resistance of the material. © 1995 John Wiley & Sons, Inc.     

微交联丙烯酸酯纳米乳液的制备及应用

用半连续种子乳液聚合工艺,合成了微交联丙烯酸酯纳米乳液。讨论了乳化剂、官能性单体、聚合温度及交联改性剂等因素对丙烯酸类聚合物乳液性能的影响。研究结果表明,用本工艺当乳化剂质量分数为2%,N 羟甲基丙烯酰胺质量分数低于0 4%,聚合温度为75～85℃时,可得到平均粒径为49 6nm,多分散性指数为0 149的单峰宽分布丙烯酸酯共聚乳液,将其用于皮革的填充,可显著改善皮革的柔软性、弹性以及革面的手感。     

淀粉接枝共聚物瓦楞纸表面施胶增强剂的制备及其应用

利用无皂乳液聚合技术通过阳离子淀粉和苯乙烯(St)、丙烯酸丁酯(BA)等乙烯基单体进行接枝共聚反应,制备了一种淀粉接枝聚合物乳液,并对其表面施胶性能进行了研究。结果表明:当m(淀粉接枝乳液)∶m(氧化淀粉)=3∶100、w(硫酸铝)=0.4%和施胶液pH=4时,其应用效果好且性价比高;淀粉接枝乳液的施胶性能优于氧化淀粉和接枝单体共聚物。     

Synthesis of Bis(1H, 1H, 2H, 2H‐perfluoro‐octyl)methylenesuccinate copolymers and their application on cotton fabrics

Bis(1H, 1H, 2H, 2H‐perfluoro‐octyl)methylenesuccinate (FOM)/ethyl acrylate (EA)/methyl methacrylate (MMA) copolymer (FOME) latexes, FOM/butyl acrylate (BA)/MMA copolymer (FOMB) latexes, and FOM/octyl acrylate (OA)/MMA copolymer (FOMO) latexes were synthesized by continuous emulsion polymerization. Solution polymerization was also carried out to prepare FOMB. The influences of fluorine content and curing conditions on the surface properties of polymer films were discussed. The water and oil repellency of cotton fabrics treated with the FOM copolymers was better than that of conventional poly(fluoroalkyl acrylate)s containing the same fluorinated chain. The polymer films or the treated fabrics were characterized by Fourier transform infrared, scanning electron microscope, atomic force microscopy, thermogravimetric analysis, x‐ray photoelectron spectrometry, and wide angle x‐ray diffraction. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci, 2013     

Dynamic Mechanical Properties and Adhesive Joint Strengths of Emulsion Polymers Produced by Power Feed Technique. III. Adhesive Joint Strengths of Grafted Power Feed Copolymer

Power feed copolymers were synthesized using styrene and n-butyl acrylate through non-uniform feeding emulsion polymerization. Poly(vinyl alcohol) (PVA) was used as a protective colloid, onto which vinyl monomers were grafted. Power feed copolymer had a very broad glass transition temperature compared with random copolymer, even if grafting and/or crosslinking were introduced to the system. This tendency was almost the same as the non-grafted power feed copolymer where only low molecular weight surfactant was used.

Adhesive joint strengths of power feed copolymers were evaluated compared with random copolymers. In the case of usual linear power feed copolymer, the adhesive joint strengths were not higher than those of random copolymer, which was considered to be due to the lower film strengths of the power feed copolymer. Power feed copolymer having grafting showed slightly higher adhesive joint strengths over a wide range of temperatures than random copolymer. When crosslinking was introduced to the system, power feed copolymer showed much higher adhesive joint strengths over a wide temperature range.     

Dynamic Mechanical Properties and Adhesive Joint Strengths of Emulsion Polymers Produced by Power Feed Technique. III. Adhesive Joint Strengths of Grafted Power Feed Copolymer

Power feed copolymers were synthesized using styrene and n-butyl acrylate through non-uniform feeding emulsion polymerization. Poly(vinyl alcohol) (PVA) was used as a protective colloid, onto which vinyl monomers were grafted. Power feed copolymer had a very broad glass transition temperature compared with random copolymer, even if grafting and/or crosslinking were introduced to the system. This tendency was almost the same as the non-grafted power feed copolymer where only low molecular weight surfactant was used.

Adhesive joint strengths of power feed copolymers were evaluated compared with random copolymers. In the case of usual linear power feed copolymer, the adhesive joint strengths were not higher than those of random copolymer, which was considered to be due to the lower film strengths of the power feed copolymer. Power feed copolymer having grafting showed slightly higher adhesive joint strengths over a wide range of temperatures than random copolymer. When crosslinking was introduced to the system, power feed copolymer showed much higher adhesive joint strengths over a wide temperature range.     

Modification of polyvinyl chloride-vinyl acetate latex by seed emulsion polymerization of acrylic monomers

Fundamental studies were carried out to modify the thermal properties of polyvinyl chloride (PVC)-based latices. General features of composite PVC-vinyl acetate (VAc) copolymer latices synthesized from the seed emulsion polymerization of acrylic monomers are reported, in particular, the observation of particle morphology and the measurements of minimum film formation temperature (MFT) and DSC spectra. Acrylic monomers used as modifiers were methyl methacrylate (MMA), n-butyl methacrylate (BMA), methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (nBA), and MMA-nBA 75:25,50:50 and 25:75 wt%. Styrene whose polymer is incompatible with PVC-VAc was used as a counterpart of compatible PMMA. Compatibility between seed and modifier polymer and the mode of operation, either batch (flooded and pre-swollen) or semi-batch (starved and no swelling), induced morphology differences, and consequently variations of thermal properties.     

有机硅/丙烯酸酯共聚乳液的耐热性能

以八甲基环四硅氧烷、乙烯基三甲氧基硅烷、丙烯酸丁酯、甲基丙烯酸甲酯、丙烯酸等为原料，采用种子乳液聚合法合成了高有机硅含量的有机硅／丙烯酸酯接枝共聚物。利用红外光谱表征了有机硅丙烯酸酯共聚物的结构，利用热重分析测试了共聚物的热分解温度。结果表明，丙烯酸酯聚合物上成功地引入了有机硅链节，且耐热性能得到很大地提高。     

含氟丙烯酸酯四元共聚核壳乳液的合成与表征

采用半连续种子乳液聚合的方式,以十二烷基硫酸钠(SDS)和OP-10为复合乳化剂,甲基丙烯酸十二氟庚酯(Acty-flon-Go4)、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为原料制备了壳层含氟的核壳型丙烯酸酯共聚物乳液。研究了引发体系和聚合温度对聚合反应转化率的影响;通过透射电镜(TEM)、FTIR、示差扫描量热(DSC)对共聚物乳胶粒径、形态及结构进行了研究。     

Preparation of asymmetric film by blending two kinds of polymer emulsions having greatly different storage stabilities

Two kinds of anionic polymer emulsions with different particle sizes were blended and cast on a release-paper at 30°C. One was poly(butyl acrylate) emulsion, and the other was ethyl acrylate–methyl methacrylate (1 : 1, weight ratio) copolymer emulsion. They were produced by emulsifier-free emulsion polymerization. The blend films prepared in an appropriate range of the blend ratio had a great difference in tackiness between both surfaces: The air-side surface exhibited tackiness and the release-paper side showed nontackiness. The forming mechanism is discussed.