不饱和聚酯/苯乙烯无皂乳液共聚合与聚合物微凝胶

以羧基封端的不饱和聚酯（ＵＰ）和苯乙烯（Ｓｔ）为单体进行了无皂乳液共聚合,制备了聚合物微凝胶,提出了ＵＰ－Ｓｔ无皂乳液聚合的成核机理,讨论了ＰＨ值、ＵＰ／Ｓｔ等因素对体系稳定性和微凝胶产率的影响,该聚合物微凝胶能明显提高ＵＰ的冲击强度。     

淀粉与苯乙烯/甲基丙烯酸甲酯乳液共聚合

研究了淀粉与苯乙烯 (St)、甲基丙烯酸甲酯 (MMA)的接枝聚合反应。以焦磷酸锰 [Mn(H2 P2 O7) 3 ]3 -为引发剂 ,以十二烷基苯磺酸钠为乳化剂 ,考察引发剂浓度、反应温度、单体浓度对原位聚合反应中单体的转化率(X % )、接枝率 (G % )、接枝效率 (GE % )的影响。实验结果表明最高接枝率可达到 5 2 .4 % ,接枝效率可达 77.2 %。     

水溶性聚合物

水溶性聚合用途十分广泛，现已自成一类物质被人们研究，本文介绍它们的分类，合成方法及溶液的性质。     

用阳离子乳化剂的丙烯酸丁酯－苯乙烯共聚合

采用４种阳离子乳化剂，以过硫酸钾为引发剂合成了丙烯酸丁酯（ＢＡ）─苯乙烯（Ｓｔ）共聚物乳液。考察了乳化剂种类、聚合条件及加料方式对共聚合及乳液稳定性的影响，发现乳化剂十二烷基二甲基苄基氯化铵用量为２．０％时，ＢＡ─Ｓｔ共聚物的［η］和乳液粘度出现拐点现象。     

高固含量的苯乙烯/丙烯酸丁酯/丙烯酸共聚物乳液的制备

利用预乳化半连续乳液聚合方法,合成了固含量高达65%的苯乙烯/丙烯酸丁酯/丙烯酸(St/BA/AA)聚合物乳液,并系统研究了固含量、单体配比、乳化剂含量、引发剂浓度、聚合反应温度及功能单体浓度对聚合物乳液主要性能的影响,利用透射电子显微镜对乳胶粒子的微观形态进行了表征。     

非离子型可聚合聚氨酯/苯乙烯/甲基丙烯酸甲酯超浓乳液共聚合研究

用甲苯二异氰酸酯（TDI）、聚丙醚二醇（PPG）、丙烯酸-β-羟乙酯（β-HEA）、二羟基聚硅氧烷（PSi）分三步制得非离子型可聚合的聚氨酯（PUASi），然后将PUASi溶于苯乙烯、甲基丙烯酸甲酯混合单体中，以十二烷基硫酸钠（SDS）、平平加（OS15）、聚乙烯醇（PVA-7188）作乳化体系，以偶氮二异丁腈（AIBN）为引发剂，在55℃下引发聚合。研究了乳化剂质量浓度、不同种类的乳化剂、引发剂质量浓度、内相比、聚合温度、PUASi与St的比例等因素对聚合稳定性及转化率的影响。用红外光谱对PUASi进行了分析，用透射电子显微镜（TEM）观察粒子的形态、用光相关光谱（PCS）测得了粒子的大小及粒径分布。     

水溶性聚合物

水溶性聚合物又称水溶性高分子或水溶性树脂,它们是一类亲水性的高分子材料,在水中能溶解或溶胀而成溶液或凝胶状的分散液,这类的溶液或分散液一般是粘性液体,统统称液（Mucilage)。水溶性聚合物的亲水性,来自其结构中的羧基,羧基、酰胺基、胺基、醚基等亲水性基团。这些基团不但使高分子具有亲水性,而且使它们具有许多重要的特性和功能,如增稠、加溶、分散、润滑、缔合和絮凝等功能。水溶性聚合物已成为化妆品工业中的一类重要的功能性原料。     

苯乙烯/羟甲基丙烯酰胺无皂乳液共聚合的研究

以苯乙烯为主单体,N-羟甲基丙烯酰胺为功能性单体、K2S2O8为引发剂制备了固含量较高、稳定性较好的苯乙烯/N-羟甲基丙烯酰胺无皂共聚物乳液,探讨了固含量、单体配比、反应温度、引发剂用量等条件对乳液稳定性和粒径大小的影响。结果表明,合成最佳条件为固含量25%,功能性单体20%,引发剂1.7%,反应温度75℃。     

丙烯酸丁酯/VAE互穿聚合物乳液的研究

以互穿聚合物网络(IPN)方法合成丙烯酸丁酯与VAE共聚物乳液。研究了乳化剂、交联剂、溶胀时间、反应时间等条件对转化率的影响。以红外光谱、透射电子显微镜表征互穿共聚物乳胶膜的微观结构。通过吸水性及乳胶膜对水接触角的测定，证明其耐水性较VAE乳胶膜明显增强。。YEM照片表明互穿聚合物胶粒形态结构较VAE乳胶粒发生了明显变化。     

Emulsion copolymerization of styrene and butyl acrylate by reverse atom transfer radical polymerization

Reverse atom transfer radical copolymerization of styrene (St) and butyl acrylate was carried out in emulsion under normal emulsion conditions, using CuBr₂/bpy complex as catalyst. The effects of surfactant type, initiator type and concentration, and CuBr₂ addition on the system livingness, polymer molecular weight control, and latex stability were examined in detail. It was found that the Polysorbate 80 (Tween 80) and azodiisobutyronitrile gave the best exhibition in this system, polymer samples were got with narrow molecular‐weight dispersity (M_w/M_n = 1.1–1.2) and linear relationships of molecular weight versus monomer conversion, as well as a relatively low polydispersity index (<0.1). Through the GPC and SEM analysis, the polymerization processes under these conditions showed good living/control characteristics relative to the processes under normal emulsion polymerization, although the latex stability was susceptible to the CuBr₂ catalyst. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Molecular weight development in emulsion copolymerization of n‐butyl acrylate and styrene

The seeded emulsion copolymerization of n‐butyl acrylate and styrene in a weight ratio of 50/50 was investigated. The effect of the type of process (batch vs. semicontinuous) and the amounts of initiator and emulsifier charged into the reactor on the time evolution of the fractional conversion, number of polymer particles, and weight‐average molecular weight (M_w) was analyzed. It was found that the M_w depends to a slight extent on the type of process and the emulsifier concentration and to a larger extent on the initiator concentration. The molecular weight distributions (MWDs) and the gel content of the final latexes were also analyzed. In the absence of chain transfer agents (CTAs), the fraction of gel was higher in the semicontinuous processes. It was also found that the gel content increased with increasing initiator concentration in the recipe. The addition of 1 wt % CTA avoided gel formation and led to an important reduction of the M_w. Nevertheless, the MWDs presented a shoulder or even a second peak at high molecular weights that was due to reactions of chain transfer to the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1918–1926, 2003     

Stability and copolymerization of concentrated emulsion of styrene and butyl acrylate in the presence of polyurethane macromonomer

A study has been made of the stability and copolymerization of concentrated emulsion of styrene (St) and butyl acrylate (BA) in the presence of polyurethane macromonomer (DPUA), which contains C?C at one end. First, the DPUA macromonomer was synthesized from the appropriate amount of 2,4‐diisocyanate (TDI), polypropylene glycol (PPG), 2‐hydroxyethyl methylacrylate (HEMA), dimethylolpropionic acid (DMPA), and triethylamine (TEA) by four steps. Then, the DPUA was dissolved in St‐BA monomer mixtures. The DPUA/St‐BA concentrated emulsion copolymerization using sodium dodecyl sulfate/cetyl alcohol (SDS/CA) as composite surfactant and polyvinyl alcohol (PVA) as liquid film reinforcer, and ammonium persulfate/sodium hydrogen sulfate (APS/SHS) as redox initiator system was carried out at 30°C. The effect of NCO/OH molar ratio, surfactants' concentration, mass ratio of DPUA/St‐BA, initiators' concentration, volume fraction of the monomer phase (Φ), and temperature on the stability or the copolymerization of the concentrated emulsion of DPUA/St‐BA were investigated. The average size and distribution of the latex particles obtained under different conditions were also analyzed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1992–1999, 2007     

Core–shell emulsion polymerization of styrene and butyl acrylate in the presence of polymerizable emulsifier

A series of core–shell polymeric particles of styrene butyl acrylate were successfully prepared in the presence of polymerizable emulsifier. The compositions of the emulsions obtained were confirmed by Fourier transformed infrared spectrometry. Latexes and emulsion films were characterized by transmission electron microscopy and scanning electron microscopy, respectively. The thermostability of emulsion films was characterized by thermogravimetric analysis. The results showed that the existence of polymerizable emulsifier could enhance the solid content of the emulsion and the monomer conversion. The optimum mass ratio of polymerizable emulsifier to traditional emulsifier was 1:1, and the polymerizable emulsifier can participate in the emulsion polymerization perfectly. An emulsion with reverse core–shell particles exhibited better hydrophobic properties and thermostability than one with traditional core–shell particles. The film formed by the emulsion with reverse core–shell particles had lower water absorption, and it could be used in the fields of coatings, surface sizing agents, and spinning. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43091.     

A kinetic investigation of styrene/butyl acrylate copolymerization

An experimental investigation of the kinetics of the bulk free radical copolymerization of styrene/butyl acrylate initiated with 2,2′-azobisisobutyronitrile (AIBN) was conducted at 50°C using various initiator concentrations and initial monomer ratios including the azeotropic composition. Reactivity ratios were determined by analyzing composition data using the error-in-variables model. The experiments, designed using the Tidwell-Mortimer criterion, were conducted in sealed ampoules at 50°C to low conversion levels (< 7%). From the calculated reactivity ratios, the azeotropic composition was determined and further experiments were run at these conditions as well as at two other initial monomer feed compositions in order to collect composition, rate and molecular weight data. The experiments were run through the full conversion range at two different initiator concentrations.     

Agitation effects in the semicontinuous emulsion polymerization of styrene and butyl acrylate

The effect of agitation on the semicontinuous emulsion copolymerization of styrene and butyl acrylate was investigated. Both neat monomer addition and preemulsified feed were used. Experiments with and without a chain‐transfer agent were carried out. For neat monomer addition, a mild degree of agitation (≥ 0.1 kW/m³) was required to avoid monomer mass‐transfer limitations, but even a moderate degree of agitation (0.3 kW/m³) was not enough to overcome the CTA mass‐transfer limitations. Agitation was much less critical when preemulsified feeds were used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 841–851, 2001     

Emulsion copolymerization of styrene and n-butyl acrylate in presence of acrylic and methacrylic acids: Effect of pH on kinetics and carboxyl group distribution

The batch emulsion copolymerization of styrene with n-butyl acrylate in the presence of acrylic and methacrylic acids was investigated. Values of reaction rate and conversion observed at different pH values were examined. The effect of pH on the glass transition temperature of the polymers was also investigated and the results compared with model predictions. Its effect on the distribution of the carboxyl groups at different positions within the emulsion system (surface and core of particles, and in the aqueous phase) was also analyzed. Three methods were used to measure the number of carboxyl groups: conductimetry, organic phase potentiometry, and titration with a solution of sodium hydroxide in methanol. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2343–2355, 1997     

Preparation and characterization of monodisperse magnetic poly(styrene butyl acrylate methacrylic acid) microspheres in the presence of a polar solvent

Magnetic poly(styrene butyl acrylate methacrylic acid) [P(St–BA–MAA)] microspheres were prepared by emulsifier‐free emulsion polymerization in the presence of a polar solvent and a ferrofluid prepared by a coprecipitation method. The effects of some polymerization parameters, such as the medium polarity, reaction temperature, initiator content, and surfactant content in the ferrofluid, on the particle diameter and particle size distribution of magnetic P(St–BA–MAA) microspheres were examined in detail. The results showed that the electrostatic repulsion in the polymerization system significantly affected the monodispersity of the resulting magnetic polymer microspheres. The proper electrostatic repulsion, achieved through changes in the medium polarity and amount of surfactant in the polymerization system, improved the monodispersity, but a higher or lower repulsion led to a decrease in the monodispersity. Although the existence of surfactant and magnetite particles reduced the monodispersity more or less, the polymerization behavior of an emulsifier‐free emulsion polymerization in the presence of the ferrofluid was analogous to that of a conventional emulsifier‐free emulsion polymerization. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1733–1738, 2003     

Soap‐free cationic emulsion copolymerization of styrene and butyl acrylate with comonomer in the presence of alcohols

Preparation of a cationic polymer latex of styrene and butyl acrylate with comonomer N,N‐dimethyl, N‐butyl,N‐methacryloloxylethyl ammonium bromide (DBMEA) was carried out by soap‐free emulsion polymerization. The effect of reaction conditions such as the ratio of methanol to water, DBMEA concentration, AIBA concentration and ionic strength on properties of copolymer particles was studied. The results showed that the average diameter (D_w) decreased with increasing of AIBA and DBMEA concentration; D_w decreased first then increased with increasing of methanol content; variation of the ionic strength led to a variation in the particle number (N_p) and D_w because of the competition of two kinds of nucleation mechanisms. The same trend was found in the polymerization taking in pure water. The MWD was bimodal during the particle growth period. These results suggest that the particles can be generated through two particle‐formation mechanisms, micelle nucleation and homogeneous nucleation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2791–2797, 2003     

Emulsion polymerization and copolymerization in continuous reactor systems

Continuous reactors are important for commercial production of latex products and they can be useful tools for fundamental polymerization kinetics studies. Results are presented for four projects: (i) elimination of conversion oscillations in continuous stirred-tank reactors (CSTR) by use of a tubular prereactor; (ii) use of a seed-fed CSTR to measure free radical transport from monomer-swollen latex particles; (iii) development of a continuous process as an alternative to a commercial batch process; and (iv) determination of copolymerization kinetic parameters with a steady-state CSTR system.