无皂乳液聚合法制备非球形聚苯乙烯粒子研究

采用苯乙烯(St)、二乙烯基苯(DVB)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为单体,在乙醇和水混合介质中通过无皂乳液聚合法制备了非球形聚苯乙烯(PS)粒子。通过FT-IR、TEM和激光粒度及电位分析仪对粒子的结构、形貌、粒径以及Zeta电位进行了表征。结果表明,所合成PS粒子均含三种单体结构单元,且形貌上均为非球形;随着DVB用量的增加,PS粒子形貌更趋于球形,粒径和单分散系数均逐渐增加;随DMC用量增加,PS粒子粒径随之增加,单分散系数逐渐减小,表面Zeta电位也逐渐增加;KHCO3用量的增加能使PS粒子粒径和单分散系数均增加;随着醇水比的减小,PS粒子粒径逐渐减小,而单分散系数则逐渐增加。     

单分散交联聚（4—乙烯吡啶／丙烯酸丁酯）无皂正电性共聚乳胶

以偶氮二异丙基脒盐酸盐（V50)为引发剂,采用4－乙烯吡啶（4－VP）／丙烯酸丁酯（BA）为混合单体,分别以二乙烯苯（DVB）或双甲基丙烯酸乙二醇酯（EGDMA）为交联剂,用无皂乳液聚合的方法合成了一系列正电性共聚乳液,并用扫描电镜（SEM）、Zeta电位测定仪详细研究了单体配比、交联剂种类和交联度对粒径大小及其分布、粒子形态和乳液电性能的影响,并探讨了该三元无皂乳液聚合的成核机理。结果表明：4VP／BA的无皂乳液聚合遵循均相成核机理。当BA含量低或者微球交联度较小时,高分子亲水性强,临界链长度大,生成粒子数目少,所以粒径大;随着BA含量的增加或者交联度的增大,高分子疏水性增强,临界链长度沽小,生成粒子数目增多,粒径变小,当BA／4VP＝1／4（g/g)时,得到单分散共聚乳胶,少量BA与4VP共聚可以明显提高乳液的稳定性。     

纳米醋丙乳液的合成与性能表征

以醋酸乙烯酯(VAc)为原料,丙烯酸丁酯(BA)和丙烯酸(AA)为改性单体,过硫酸钾(KPS)为引发剂,OP-10,SDS和可聚合乳化剂丙烯氧基壬基酚聚氧乙烯(10)醚硫酸铵为乳化剂体系,采用半连续种子乳液聚合法制备了纳米粒径的醋丙乳液.对得到的乳液进行了分子量,热性能,红外光谱,乳液稳定性等测试,用激光散射粒度仪和透...     

苯乙烯-丙烯酸酯微乳液的合成研究

目前国内外许多专家学者积极研发低污染、低能耗、高性能的胶粘剂,以代替传统的毒性大、成本高、稳定性差的溶剂型胶粘剂[1]。苯乙烯-丙烯酸酯微乳液(苯-丙微乳液)是重要的胶粘剂之一。与常规乳液胶粘剂相比,它具有以下几个特点[2]:(1)是热力学稳定体系,可以自发形成;(2)分子粒     

单分散聚丙烯酸丁酯-二氧化硅核壳粒子的制备

近年来,有机-无机核壳材料因其具有可调的光、电、磁等特性而备受关注．无机物外壳可以增强粒子的热力学稳定性、机械强度和抗拉性能．高分子乳胶粒内核具有弹性,且易成膜,外部包覆无机物的乳胶粒可结合两者特性并产生协同效应．     

苯乙烯和甲基丙烯酸环氧丙酯共聚物单分散粒子的合成

分散聚合;苯乙烯和甲基丙烯酸环氧丙酯共聚物单分散粒子的合成     

甲基丙烯酸环氧丙酯共聚物乳液的研究

研究了以甲基丙烯酸环氧丙酯作为活性单体，采用种子乳液聚合制备四元体系的核—壳结构共聚物乳液，用透射电子显微镜观察了乳胶粒的微观形态，并对其稳定性、流变性等进行了测试，考察了甲基丙烯酸环氧丙酯及其含量对乳液性能的影响．     

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...     

单分散聚苯乙烯乳液高温成膜过程的形态观察

单分散乳液指微粒具有相同化学组成、粒径及界面性质等特征的分散体系 ,因其颗粒均一 ,结构可调 ,赋予了其很多独特性质 ,广泛应用于计量、电子、生物、分析、医学、化工和信息等领域 .同时 ,单分散微粒体系作为研究原子或分子结晶过程的模型物 [1] ,在凝聚态物理中具有重要作用 .单分散乳液在一些条件下能排列成最大密堆积规整结构 ,从而赋予乳胶膜更优异的性能 [2 ] .因此 ,研究单分散乳液的成膜过程 ,在基础理论和实际应用中具有重要意义 .软的乳胶微粒玻璃化温度在室温附近 ,它们在常温下就可形变融合成膜 ,此时水蒸发速度较慢 ,乳液中…     

阳离子高分子絮凝剂的合成与其表面电性的测定

以三乙烯四胺对聚氯乙烯(PVC)进行改性,合成一系列胺化产物,并经硫酸二甲酯季铵化,得到阳离子高分子絮凝剂.采用元素分析、红外光谱对产物进行结构表征,并通过电荷密度、特性粘度和Zeta电位等测定,研究了该高分子絮凝剂的结构与相关性质间的关系.结果表明:通过控制合成条件,可以改变阳离子高分子絮凝剂的分子量和电荷密度,以适应各种应用条件的需求.     

Synthesis and characterization of a novel fluorine-containing polymer emulsion with core/shell structure

A novel fluorine-containing polymer emulsion 4 with core/shell structure was synthesized in water phase by a two-stage emulsion polymerization technique using monomer 3 (i.e., 2-methacryloyloxyethyl perfluorooctanoate (MAEF)) reacting with the monomers such as butyl acrylate (BA), acrylic acid (AA) and styrene (ST). The monomer 3 was synthesized from the intermediate 2 (pentadecafluoro-octanoyl chloride) reacting with β-hydroxyethyl methacrylate (HEMA). Polymer film were prepared by coating emulsion 4 directly on a cleaned glass plate and allowed to dry at room temperature. Moreover, the characteristics of polymer film such as hydrophobicity, chemical resistance, surface composition, thermal stability, emulsion particle morphology, as well as the film-forming property were also studied.     

Synthesis of a novel series of polymerizable surfactants and application in emulsion polymerization

A series of polymerization surfactants (surfmers) was synthesized, whose structures combined the characteristics of polyoxyethylene as nonionic group and quaternary ammonium a as cationic group. The structures of the product were confirmed by MS, and the content of cationic‐activity matter was determined by two‐phase titration. The surfmers were then used with constant addition profiles in semicontinuous polymerization of vinyl acetate–butyl acrylate–Veova 10–hexafluorobutyl methacrylate, and the polydispersity indexes (PDI) were lower than 0.1. The particle size, amount of coagulum, and stability against electrolyte and freeze/thaw were evaluated. As a reference, an unreactive surfactant cetyl trimethyl ammonium bromide (CTAB) was also used for the polymerization. Compared to CTAB, the surfmers behaved much better. Not only stabilities to electrolyte and water resistance were improved, but also freeze/thaw stability got a superior performance. Copyright © 2008 John Wiley & Sons, Ltd.     

Nanostructured latexes made by a sequential multistage emulsion polymerization

A series of linear and lightly crosslinked nanostructured latices was prepared by a sequential multistage semicontinuous emulsion polymerization process alternating styrene (S) and n‐butyl acrylate (BA) monomer feeds five times, that is ten stages, and vice versa, along with several control latices. Transmission electron micrographs of the RuO₄‐stained cross sections of nanostructured and copolymer latex particles and films showed that their particle morphologies were not very different from each other, but the nanostructured latex particles were transformed into a nanocomposite film containing both polystyrene (PS) and poly(n‐butyl acrylate) (PBA) nanodomains interconnected by their diffuse polymer mixtures (i.e. interlayers). The thermal mechanical behaviors of the nanostructured latex films showed broad but single T_gs slightly higher than those of their counterpart copolymer films. These single T_gs indicated that their major component phases were the diffuse interlayers and that they behaved like pseudopolymer alloys. The minimum film formation temperatures of nanostructured latices capped with PBA and PS, respectively, were 15 °C lower than and equal to those of their counterpart copolymer latices, but their T_gs were about 10 °C higher. Consequently, nanostructured latices enabled us to combine good film formation with high strengths for adhesives and coatings applications. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2826–2836, 2006     

“水包水”型阳离子聚丙烯酰胺乳液的合成

The emulsion of cationic polyacrylamide was prepared by a soap-free polymerization,using water as media,the oligomer that prepared by myself as emulsifier and stabilizer,(NH_4)_2S_2O_8 as initiator.The effect of the amount of isopropanol,oligomer and the ratio of DMC/AM on the molecular weight of cationic polyacrylamide were all studied.The best amount of isopropanol,oligomer are 25%,20% of the total monomer and the ratio of DMC/AM is 3/7.     

Theory of colloid stability and particle nucleation kinetics in emulsion polymerization

The DLVO theory of colloid stability is applied to the uncatalyzed and catalyzed agglomeration of small primary particles formed in the earliest stages of emulsion polymerization in the manufacture of a carboxylic styrene/butadiene latex. The inverse 6th-power relationship between the stability ratio and the cation concentration revealed experimentally in an earlier work can be confirmed theoretically using variable Stern potentials. The Stern potential changes as parabolic function of log cation concentration. From the viewpoint of DLVO and Stern theory it is suggested that a spacer effect is crucial for the activity of the catalyst used.Presented at the 5th European and Interface Society Conference together with the 35th meeting of the Deutsche Kolloidgesellschaft on Trends in Colloid and Interface Science September 25–28, 1991, Maiz, FRG     

pH值对硅油乳液Zeta电位及其制备的影响

1994年,T．M．Obey和V．Brian采用二甲基二乙氧基硅烷在氨水催化剂下进行乳液聚合,获得了具有较好单分散性的聚二甲硅油乳液。本文研究了pH值对二甲基二乙氧基硅乳液Zeta电位的影响,比较了有相同单体浓度的单相体系在低pH值(酸性)和高pH值(碱性)条件下乳液聚合的规律,以期对硅烷乳液制备做更进一步的研究。     

聚丙烯酸-b-聚丙烯酸甲酯的制备及其在乳液聚合中的应用

采用三硫代碳酸S-1-十二烷基-S'-(a,a'-二甲基-a"-乙酸)酯(MTTCD)作为链转移剂,偶氮二异丁腈(AIBN)为引发剂,丙烯酸(AA)为第一单体,通过可逆加成-断裂链转移(RAFT)自由基聚合合成大分子链转移剂PAA-MTTCD,以丙烯酸甲酯(MA)为第二单体,合成5种不同嵌段比的两亲性嵌段共聚物聚丙烯酸-b-聚丙烯酸甲酯(PAA-b-PMA).采用FT IR和1H NMR确定了PAA-MTTCD和PAA-b-PMA的结构,用GPC测定了PAA-MTTCD和PAA-b-PMA的分子量及分子量分布.分析了聚合反应动力学,发现该聚合具有活性可控聚合的特征,聚合动力学呈一级线性关系.测定了PAA-b-PMA的乳化性能,并将其作为乳化剂用于丙烯酸丁酯(BA)的乳液聚合中,同时考察了不同嵌段长度共聚物对乳液聚合的影响.结果表明,具有21个AA单元和18个MA单元的两亲性嵌段共聚物具有较好的乳化性能,其作为乳化剂时乳液聚合效果相对最好.     

Synthesis of submicron-sized peanut-shaped poly(methyl methacrylate)/polystyrene particles by seeded soap-free emulsion polymerization

Submicron-sized peanut-shaped poly(methyl methacrylate)/polystyrene(PMMA/PS) particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles.The obtained peanut-shaped particles showed a novel internal morphology:PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.