含二十二烷基聚氧乙烯醚甲基丙烯酸酯功能单体的缔合型乳液增稠剂的制备及表征

以甲基丙烯酸、丙烯酸乙酯、邻苯二甲酸二烯丙酯和不同量的功能单体二十二烷基聚氧乙烯醚甲基丙烯酸酯(BEM)为原料,采用半连续乳液聚合方法合成了疏水改性碱溶性缔合型增稠剂乳液.测定了增稠剂乳液的粘度、透光率、乳胶粒粒径及其分布等性能,考察了不同固含量下乳液粘度和透光率随pH的变化情况.结果表明随着BEM用量的增加,乳胶粒粒径逐渐增大.随着pH值的增加,乳液的粘度首先迅速升高,然后缓慢下降.与不含BEM的增稠剂乳液相比,当乳液固含量大于0.5%,BEM含量占单体量低于5.0wt%时,该缔合型增稠剂的增稠效果和抗剪切性有显著提高,BEM含量较高(8.0wt%或更高)时反而使增稠效果和抗剪切性变差.在此基础上研究了增稠剂对苯丙乳液的增稠效应,结果显示BEM含量占单体量的2.5wt%时,对苯丙乳液的增稠作用最好.与使用功能单体三苯乙基苯酚聚氧乙烯醚甲基丙烯酸酯改性的增稠剂相比,含BEM的增稠剂在BEM用量较少的情况下就能起到明显的增稠效果.     

交联剂含量对憎水改性缔合型增稠剂性能的影响

以甲基丙烯酸、丙烯酸乙酯和功能单体二十二烷基聚氧乙烯醚甲基丙烯酸酯为原料,过硫酸铵为引发剂,变化交联剂邻苯二甲酸二烯丙酯(DAP)的量,采用半连续乳液聚合方法合成了DAP含量不同的憎水改性缔合型增稠剂乳液.测定了乳液的黏度和乳胶粒粒径及其分布等性能.考察了乳液运动黏度和透光率随pH的变化.随着pH值的增加,乳液的透光率...     

改性苯丙乳液的合成及用于浸渍滤纸的研究

油品中的微量水分是降低油品质量,威胁发动机安全寿命的主要因素。为了制备优良的油水分离滤纸,本研究首先采用半连续乳液聚合法合成改性苯丙乳液,研究了乳化剂用量及比例、引发剂用量等对乳液稳定性的影响。结果显示,复合乳化剂用量为0.8-1.0 wt%,引发剂用量为0.8 wt%,交联单体用量为3 wt%,反应温度为80℃时,制备的改性苯丙乳液具有良好的稳定性,乳液粒径分布均匀。在上胶量为20±0.5 wt%时,此乳液浸渍的滤纸耐破度为304 kPa,拉伸强度为4.18 kN.m~(-1),耐水时间为24.0 h。水滴在浸渍滤纸表面上的接触角为110.2°,而煤油的接触角为25.6°。本研究为改性苯丙乳液在发动机滤纸上的应用提供了基础数据。     

基于氧化淀粉的新型Pickering苯丙乳液表面施胶剂的合成

以苯乙烯、丙烯酸丁酯为单体,过硫酸铵为引发剂,氧化淀粉作固体粒子乳化剂,采用无皂乳液聚合的方法来制备Pickering苯丙聚合物乳液,考察了不同含量的氧化淀粉对乳液固含量、转化率、卡伯值以及稳定性的影响,并对制备的Pickering苯丙聚合物乳液进行了粒径、红外光谱表征,当氧化淀粉的含量为2%时,制备的Pickering苯丙聚合物乳液转化率为96%,粒径为264.4nm,卡伯值为71.4g/m~2,抗水性和稳定性较好.     

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.     

(丙烯酰胺-丙烯酸十六酯)共聚物的合成及其增稠性能研究

采用沉淀聚合法合成丙烯酰胺 -丙烯酸十六酯共聚物。重点讨论了合成条件如单体配比、引发剂用量、温度等对共聚反应的影响以及共聚物对苯丙乳胶的增稠性能的影响。并用DMTA和凯达尔定氮法表征了共聚物组成 ,结果表明 :所合成的共聚物可以作为疏水缔合型增稠剂使用     

软段含羧基的水性聚氨酯物性研究

合成了单官能团小分子物质封端的软硬段皆含羧基的脂环族水性聚氨酯(PU),研究了反离子种类、固含量、外加小分子盐/酸、pH值对水性PU的粘度、粒径、CMC和电导率的影响,同时,比较了不同软段分子量水性PU分散液pH临界值和CMC的差异.实验结果表明,随固含量升高,PU分散液体系粘度增大,当固含量为30wt%时,粘度比固含量20wt%的体系粘度增大约20倍;随小分子盐NaCl的加入,PU分散液电粘滞效应逐渐消失,电导率呈现先减小后增大的趋势,随NaCl的加入/软段分子量提高,PU分散体系的CMC值减小,钙离子对PU粒子扩散双电层的破坏作用更加明显.随pH值的增大,PU分散液体系粒径减小,电导率则升高,随软段分子量提高,pH临界值增大,PU分散体对外加小分子酸存在缓冲作用.     

新型可聚合蒽醌染料单体及其共聚物乳液的制备及性能

通过多步有机反应合成了新型蒽醌染料单体1-(间(2-(2-(丙烯酰氧基)乙氧基)乙基砜基)苯胺基)蒽醌(AVSAQ),对其化学结构进行了表征;然后将其与苯乙烯(St)、丙烯酸丁酯(BA)和甲基丙烯酸(MAA)进行半连续乳液共聚合,制备出了共价键合型P(St-BA-MAA-AVSAQ)橙红色聚合物乳液,并对乳液以及乳胶膜的性能进行了表征,系统考察了AVSAQ和过硫酸铵(APS)用量对单体总转化率以及乳液胶体性质的影响.结果表明,当AVSAQ用量不高于单体总量的4.0 wt%、APS用量不低于单体总量的0.5 wt%时,聚合反应可以平稳进行,所得乳胶粒水合粒径均在60 nm左右.总单体转化率和AVSAQ转化率随着AVSAQ用量的增加而降低,当AVSAQ用量达到4.0 wt%时,二者分别为95.0%和93.6%.P(St-BA-MAA-AVSAQ)的UV-Vis吸收光谱特性与AVSAQ完全一致,最大吸收波长均为486.8 nm.与相应非共价键合型橙红色聚合物乳液相比,P(StBA-MAA-AVSAQ)聚合物乳液具有良好的储存稳定性和保色性,乳胶膜的光色牢度和耐溶剂牢度也显著提高.     

含丙烯酸的苯丙共聚乳液乳胶粒形态的电镜研究

采用透射电镜观测了苯乙烯-丙烯酸丁酯-丙烯酸乳液共聚体系的乳胶粒形态,讨论了组分含量、共聚物链柔性和乳液pH值等因素对乳胶粒形态、乳液粘度及成膜性的影响.结果表明:软单体的加入和体系pH值的提高将促进乳胶粒的粘连成膜和溶涨及部分聚合物的溶解.羧基主要富集于乳胶粒表面.     

聚丙烯酸增稠剂的反相乳液聚合及其增稠性能

采用具有增稠和抗电解质作用的丙烯酸聚氧乙烯酯活性单体和具有聚合稳定作用的高分子表面活性剂,通过反相乳液聚合法合成了涂料印花用丙烯酸系增稠剂.研究了活性单体、交联剂、反应时间等因素对产物性能的影响.得出活性单体用量占共聚单体摩尔数的0.5%,交联剂占共聚单体质量的0.3%,反应时间为1.5h时,增稠剂的综合效果最好.     

A novel associative latex thickener using ethoxylated behenyl methacrylate as functional monomer

<正>Alkali-soluble associative latex thickeners modified with hydrophobic long chain alkyl groups were prepared using common acrylics and varying amount of a functional monomer,ethoxylated behenyl methacrylate(BEM),through emulsion polymerization.It was found that the size of the emulsion particle became larger with addition of BEM.The light transmittance of the thickener latex sharply increased with pH varied from 6 to 7.The associative latex thickener manifested a higher viscosity when solids in the latex thickeners were kept at 0.5 wt%or higher,and the optimal amount of BEM was found to be around 2.5 wt%,or 0.16 mol%.All thickener latexes modified with BEM have better shearing resistance than the BEM-free thickener.     

Surfactant and Electrolyte Effects on Latex Depletion Flocculation by Thickeners

Summary: Polymer thickeners can induce good dispersion, bridging, or depletion flocculation of latexes depending on the polymer structure and concentration. Unlike non-associative polymers, associative polymers have the ability to create a good latex dispersion. However, when the associative interactions are destroyed, depletion flocculation of the latex can result. This happens when an excess of ionic surfactant is added to the system. In addition, the surfactant may associate with the thickener backbone, thus modifying the molecular volume of the polymer thickener. This paper explores the effect of anionic surfactant and electrolyte on the molecular volume of both associative and non-associative thickeners. Both HEUR and HASE structures are included. For HEUR thickeners, formation of a pseudo-polyelectrolyte through the association of anionic surfactant with the polyethylene oxide backbone is confirmed. Further, the ability of the thickener to depletion flocculate latexes as a function of surfactant and electrolyte is explored. Experimental critical flocculation concentrations (CFC) are compared to values expected based on molecular volume and potential energy calculations. A good correlation is found between molecular volume and CFC for a wide range of thickener compositions.     

Viscoelastic behaviour of butyl acrylate/styrene/2-hydroxyethyl methacrylate/acrylic acid latices thickened with associative thickeners

The rheological behaviour of butyl acrylate/styrene/acrylic acid latices thickened with a hydrophobically modified ethoxylated polyurethane (HEUR) or hydrophobically modified alkali-soluble polyacrylate emulsion (HASE) was investigated. While the pseudoplastic character of frequency dependence of complex viscosity was similar for both thickeners, viscoelastic behaviour, expressed as the ratio of loss and storage moduli, significantly differed, indicating that the HEUR molecules, unlike swollen HASE particles, create a viscoelastic space structure. The increase in hydrophilicity of the particle surface, achieved by incorporation of 2-hydroxyethyl methacrylate (HEMA) monomer into the latex copolymer reduced the viscoelasticity of latices thickened with HEUR, but not of those thickened with HASE. This confirms that adsorption of hydrophobic end-groups on particle surface is important for thickening of latices with HEUR and that a physical network of latex particles interconnected by the thickener macromolecules is formed. To cite this article: O. Quadrat et al., C. R. Chimie 6 (2003).     

Preaparation of cationic latexes of poly(styrene-CO-butyl acrylate) and their properties evolution in latex dilution

Cationic latexes were prepared through emulsion copolymerization of styrene(St) and butyl acrylate(BA) with a cationic surfactant,cetyl trimethyl ammonium bromide(CTAB).Latex properties,including particle size,size distribution,ζpotential,surface tension and monomer conversion,were determined for latexes prepared with different CTAB amounts. Evolution of these properties during emulsion polymerization was followed in order to understand the mechanism of the particles formation.Results showed that both particle size andζpotential were function of polymerization time and latex solids.Parallel emulsion polymerizations with cationic,anionic charged initiator and charge-free initiators were also carried out,the latex properties were determined at different polymerization time.All these results were attentively interpreted based on the mechanisms of emulsion polymerization,surfactant adsorption and latex particle stabilization.     

Influence of Emulsifiers on Acrylate Latex Blends

The poly(methyl methacrylate/butyl acrylate/acrylic acid) [P(MMA/BA/AA)] and poly (styrene/butyl acrylate/acrylic acid) [P(St/BA/AA)] latexes were synthesized using the emulsifier octylphenol polyoxyethylene(10) ether (OP-10) and ammonium sulfate allyloxy nonylphenoxy poly(ethyleneoxy)(10) ether(DNS-86). The optimum amount of OP-10 and DNS-86 was 1.5% and 2.5% respectively. The P(MMA/BA/AA) and P(St/BA/AA) latex containing 1.5% OP-10 or 2.5% DNS-86 were blended pairwise. The performances of latex blends and parent latexes as a function of emulsifiers content in parent latexes were determined. The results indicated that the stability of latex blends is favorable, and particle size distribution was more uniform and thermal stability was improved after blending.     

High solids content latexes with low viscosity

The effect of particle size distribution (PSD) on the solids content and viscosity of the multi-sized latex was investigated by blending mono-sized latexes and measuring their rheological properties. The results showed that the maximum packing (highest solids content) was observed at a weight fraction 80% of large particles with respect to total solids content for both bi-modal and tri-modal latexes, and the lowest viscosity was obtained when the ratio of large to medium to small particles was approximately 80/10/10 (by weight). A two-stage technique to prepare high solids multi-sized polymer latex was developed by using a polymer latex previously made as seed and by adding small amount of additional surfactants and/or second group of polymer particles. The PSD of the latex was optimized by varying the amount of the seed, the additional surfactants, and the second group of particles. Film forming latexes with high solids (>65%) and low viscosity were obtained. Received: 18 February 2000 Accepted: 30 September 2000     

Effect of different surfactants on colloidal and polymer properties of fluorinated acrylate latex

Fluorinated acrylate latex was successfully prepared by semi-continuous seeded emulsion polymerization of dodecafluoroheptyl methacrylate (DFMA) with butyl acrylate (BA), methyl methacrylate (MMA) initiated by potassium persulfate in the water. The resultant latexes and their films are characterized with Fourier transform infrared (FTIR) spectrometry, contact angle determinator, dynamic light scattering detector and surface tension determinator. Effect of different surfactants on colloidal and polymer properties of fluorinated acrylate latex was studied. Results show that the latex prepared with sodium dodecyl benzene sulfonate surfactant has the smallest particle size and contact angle but the moderate surface tension. The latex prepared with perfluorooctanesulfonic acid potassium surfactant has the smallest surface tension, moderate particle size but the biggest contact angle. The latex prepared with sodium 2-hydroxy-3-(methacryloyloxy) prop- ane-1-sulfonate surfactant has the biggest particle size and surface tension but moderate contact angle. In addition, the latex prepared with sodium 2-hydroxy-3-(methacryloyloxy) prop- ane-1-sulfonate has higher electrolyte stability.     

Convenient synthesis of novel fluorinated polyurethane hybrid latexes and core-shell structures via emulsion polymerization process with self-emulsification of polyurethane

Novel fluorinated polyurethane hybrid latexes in the size range of 40–50 nm, fluoroalkyl acrylate as fluorinated monomers, with various fluorine content (F% = 9∼26 wt%) were successfully prepared via emulsion polymerization process without traditional emulsifier. The waterborne polyurethane, which was synthesized by using isophronediisocyanate, dimethylol propionic acid, polyethylene glycols, etc., served not only as copolymerizable macromonomer but also as polymeric high molecular weight emulsifier. The structures of polyurethane macromonomer and fluorinated polyurethane were characterized by Fourier transform infrared and H¹-NMR. Particle size, zeta potential, micromorphology of the latex par.ticles, and surface properties were investigated by dynamic light scattering, potential particle size analyzer, transmission electron microscopy, and contact angle measurement, respectively. Results illustrated that the advantage of this process is that the size of fluorinated polyurethane hybrid particle is less sensitive to the composition. Furthermore, it was showed that fluorinated polyurethane latex particles had core-shell structures, especially when the content of fluorine was 26.08 wt%. Moreover, there was an obvious migration of fluorinated groups to the surface during the formation of fluorinated polymer films, although fluorinated groups were covered by polyurethane in latex particles.