苯丙水溶胶的合成与性能研究(II) 水溶胶的转化及其流变性能

用一次投料法、半连续滴加法和单体预乳化法3种聚合工艺，合成了苯丙乳液聚合物，并加氨微细化，转化成水溶胶，研究了水溶胶的氨化反应对乳胶粒子大小及微观形成的影响。并考察了水溶胶的流变性能。     

室温交联型硅丙微胶乳的合成研究II.改性微胶乳的粒径控制及其微观形态表征

采用种子微乳液聚合法和单体预乳化法分别合成了室温交联型有机硅改性聚丙烯酸酯微胶乳,研究了硅烷单体的添加和氨化反应对改性微胶乳粒子大小及分布的影响。结果表明:采用种子微乳液聚合法得到的硅丙微胶乳粒子大小与硅烷单体的种类、用量和添加顺序无关,平均粒径约为40~60nm。TEM照片显示出,采用种子微乳液聚合法合成的硅丙微胶乳粒子由于内部存在交联结构而导致表面形状不规则,有“乳突”现象;而采用预乳化法合成的硅丙微胶乳粒径粗大,呈规则的球形,氨化后粒径从100nm以上减小到80nm左右,粒子表面出现“绒毛”现象,这是由于硅烷组分的水解反应受到抑制而使粒子内部的交联密度降低的缘故。     

核壳结构聚丙烯酸酯抗冲改性剂的合成及粒径控制

采用预乳化多步种子乳液聚合法合成聚丙烯酸酯类聚合物(ACR)胶乳,实验得出种子乳液用量与聚丙烯酸丁酯粒径之间的关系,实现对胶乳粒子粒径的控制;对反应中影响粒子粒径的因素做了分析,以此确定最佳反应条件为:温度为65℃;乳化剂:十二烷基硫酸钠和聚氧乙烯基醚硫酸钠摩尔比为4/3,乳化剂用量为0.9％,单体固含量30％～37％...     

功能单体α-烯烃磺酸钠用于无皂乳液共聚合

用工业原料α-烯烃磺酸钠(AOS)作为功能单体与甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)进行了乳液共聚合,通过测定AOS与MAA的竞聚率,确定了适宜的聚合方式为连续加料法.使用5%AOS制备了高固含量(>60%)的胶乳,并与用十二烷基硫酸钠(SDS)作乳化剂时该体系的乳液共聚合进行了比较.AOS是影响乳液稳定性和胶粒大小的主要因素,当AOS含量为单体总质量的1%时可以得到固含量大于40%粒径小于100 nm的乳液;当AOS含量为5%时可以得到固含量大于60%的乳液.两种情况下胶粒粒径分散性均较窄,明显优于同样条件下用SDS制备的胶乳.使用1%AOS制得的胶乳静置1年后粒径及其分布基本保持不变.     

可聚合乳化剂合成苯乙烯-丙烯酸丁酯-α-烯烃磺酸钠共聚物乳液

以工业原料α-烯烃磺酸钠(AOS)作为可聚合乳化剂,苯乙烯(St)和丙烯酸丁酯(BA)为单体,采用预乳化种子乳液聚合合成了St-BA-AOS共聚物乳液.通过测定AOS与两种单体的竞聚率确定了半连续加料法的聚合方式.探讨了单体的加料方式、反应温度、反应时间、AOS用量等工艺条件对胶乳的影响,获得了最佳聚合条件.IR,NMR和DSC测试结果分析表明:St,BA与AOS发生了自由基共聚反应,形成的P(St-BA-AOS)共聚物结构中含有磺酸基等亲水性基团有利于乳液的稳定.在此基础上考察了AOS用量对乳液的固含量及乳胶粒粒径等的影响.结果表明:随着AOS用量的增加,乳液的固含量增加、乳胶粒的平均粒径减少.当AOS含量为2%时乳液的固含量为45.01%,平均粒径为74 nm,粒径分布指数为0.08,玻璃化温度为23.17℃.TEM测试结果显示,用相同量的AOS代替十二烷基硫酸钠可得到粒径更小和粒径分布更为均匀的乳液体系.     

苯丙水溶胶的合成与性能研究(I) 聚合工艺和反应组分对聚合稳定性和胶体性能的影响

用一次投料法、半连续滴加法和单体预乳化法三种聚合工艺，合成了苯丙乳液聚合物，并加氨微细化，转化成水溶胶，考察了聚合工艺和反应组分（乳化剂，功能单体等）对苯丙乳液及其水溶胶反应稳定性和粒子大小及分布等胶体性能的影响。     

室温交联型硅丙微胶乳的合成研究Ⅲ.聚合工艺对聚合稳定性及胶膜性能的影响

采用两种聚合工艺(种子微乳液聚合法和单体预乳化法)分别合成了室温交联型有机硅改性丙烯酸酯聚合物微胶乳，研完了不同工艺条件对聚合稳定性、乳胶粒径和胶膜的结构性能的影响．     

有机颜料酞菁蓝微胶囊的原位微悬浮法制备及其表征

通过简单的超声分散及强力剪切将滤饼中的有机颜料颗粒以初级粒子形式均匀稳定地分散到单体分散液和微悬浮液中的单体小液滴内,经有机颜料单体分散液的预聚处理和原位微悬浮聚合制备得到一系列具有高颜料包裹率和窄粒径分布特点的微米级聚合物胶粒.实验观察和粒径分析DLS证明,预聚处理可明显提高微悬浮体系中单体液滴相的黏度,因而可有效改...     

高固含量低粘度P(MMA/BA/AA)乳液的制备及性能研究

先利用半连续种子乳液聚合法制备固含量为50%,粒径480nm的单分散甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)与丙烯酸(AA)的共聚物种子乳液;然后以上述种子乳液为介质,十二烷基硫酸钠为乳化剂,碳酸氢钠为缓冲剂,过硫酸铵为引发剂制备固含量72%,乳胶粒具有二元分布特征的高固含量、低粘度稳定乳液:其中大乳胶粒径500～600nm,小乳胶粒径约80nm.所得乳液中乳化剂总含量为聚合物质量的2.1%;粘度在剪切速率为21s-1时为400mPa·s.另外,相对于常规乳液,所制备高固含量乳液胶膜具有更好的光泽度.     

半连续和间歇式丙烯酸酯三元乳液共聚产物的形态及分子结构研究

研究了半连续和间歇式丙烯酸酯三元乳液共聚产物的形态和分子结构。结果表明,半连续式胶乳粒子呈“多核核壳结构”,其粒径和粒径分布随单体滴加速度减慢而变小。间歇式胶乳粒径较大,粒径分布亦更宽,呈硬相在外的“单核核壳结构”;共聚物分子链中VAc结构单元的序列较长。两种方法所获无规共聚物均存在微相分离结构,分离程度随单体滴加速度的加快而变大。     

A Facile Synthesis of Cu NPs and Ag NPs Coated by PS with Core–Shell Structure by Precipitation Polymerization

Copper nanoparticles (Cu NPs ) coated with polystyrene (PS ) (Cu NPs @PS ) were prepared by precipitation polymerization. First, Cu NPs were prepared by chemical reduction using cupric acetate as precursor, sodium polyacrylate (PAANa ) as stabilizer, and hydrazine hydrate as reducing agent. Then Cu NPs were coated by precipitation polymerization using styrene as monomer, 3‐(trimethoxysilyl) propyl acrylate as co‐monomer, and 2, 2‐azobisisobutyronitrile (AIBN ) as initiator. Ultraviolet–visible (UV –vis) spectroscopy and transmission electron microscopy (TEM ) results showed that stable composite particles could be synthesized by precipitation polymerization. The amount of PAANa had a significant effect on the size of Cu NPs . The addition of more PAANa resulted in smaller Cu NPs . The spherical Cu NPs became nanowires when increasing the stirring rate from 350 to 700 rpm during precipitation polymerization. Ag NPs @PS with core–shell structure were also prepared by this method, which appears to be universal.     

An emulsifier‐free core–shell polyacrylate/diacetone acrylamide emulsion with nano‐SiO2 for room temperature curable waterborne coatings

An emulsifier‐free core–shell polyacrylate emulsion, containing nano‐SiO₂ nanoparticles in the core and diacetone acrylamide (DAAM) in the shell, has been successfully prepared by emulsifier‐free seeded emulsion polymerization. The effects of reaction temperature, dropping time, nano‐SiO₂ and initiator contents, and variation of the composition of core monomers on the amount of coagulum, particle size, and monomer conversion have been investigated. The particle morphology and the distribution of emulsion particles have been measured by transmission electron microscopy (TEM) and dynamic light scattering. The keto‐carbonyl groups on the surface of the polyacrylate emulsion nanoparticles reacted with adipic dihydrazide (ADH) to form a film with a cross‐linked network structure at room temperature. Therefore, the emulsifier‐free core–shell emulsion could be used as a two‐component room temperature curable waterborne coating. It was also found that the properties of the coating were clearly superior after using the cross‐linker. Copyright © 2009 John Wiley & Sons, Ltd.     

离子液体中AM/AMPS/N8AM三元共聚物的合成及溶液性能

以丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为亲水单体, 以N-辛基丙烯酰胺(N8AM)为疏水单体, 在离子液体[bmim]BF4中实现了疏水缔合丙烯酰胺三元共聚物的合成.     

沉淀聚合制备聚(季戊四醇三丙烯酸酯-苯乙烯)单分散微球及其形成机理

以季戊四醇三丙烯酸酯(PETA)作交联剂,苯乙烯作共聚单体,偶氮二异丁腈作引发剂,在乙醇或其与水的混合溶剂中沉淀聚合制备了交联聚合物微球.研究了反应时间、交联剂用量以及溶剂中水含量对聚合过程及微球的影响.结果表明当PETA用量在单体质量的5%-35%之间且反应时间不低于6h时可制得单分散聚合物微球.当PETA用量低于20%时,所得微球的粒径随PETA用量的增加逐渐减小,粒径分布逐渐变窄;此后继续提高PETA用量,微球粒径又逐渐增大,粒径分布逐渐变宽.向反应介质中加入水,可明显提高微球产率及单体转化率,但其体积分数达30%时,所得微球分散性变宽.在此基础上对微球的形成机理也进行了讨论.     

Radiation-induced copolymerization of styrene/n-butyl acrylate in the presence of ultra-fine powdered styrene–butadiene rubber

Styrene (St)/n-butyl acrylate (BA) copolymers were prepared by two-stage polymerization: St/BA was pre-polymerized to a viscous state by bulk polymerization with initiation by benzoyl peroxide (BPO) followed by ⁶⁰Co γ-ray radiation curing. The resultant copolymers had higher molecular weight and narrower molecular weight distribution than conventional methods. After incorporation of ultra-fine powdered styrene–butadiene rubber (UFSBR) with a particle size of 100 nm in the monomer, the glass transition temperature (T_g) of St–BA copolymer increased at low rubber content. Both the St–BA copolymer and the St–BA copolymer/UFSBR composites had good transparency at BA content below 40%.     

On the copolymerization of acrylates in the modified microemulsion process

Copolymerization of methyl methacrylate, methyl acrylate, butyl methacrylate, and butyl acrylate in turn was performed in the modified microemulsion polymerization process, i.e., continuous addition of monomer to a preemulsified system. It was found that the particle size of the copolymer microlatex did not change distinctly with the monomer composition. The estimation of emulsifier coverage on the microlatex particles indicated that the process switched from a traditional microemulsion to a normal seeded emulsion polymerization very soon after monomer dropping began. Therefore, a longer dropping time is needed to produce a microlatex with narrow dispersed particle size. Besides, in the modified microemulsion polymerization less emulsifier is needed to produce a stable microlatex. This behavior is related to the mechanism of normal seeded emulsion polymerization during monomer dropping.     

Methyl Methacrylate–Ethyleneglycol Dimethacrylate–Acrylic Acid Surface as Stationary Phase for Stir Bar Sorptive Extraction

A novel poly(methyl methacrylate–ethyleneglycol dimethacrylate–acrylic acid) film has been introduced for coating on stir bars to sorptive extraction (SBSE). The effects of different contents of porogen, monomer, cross-linker, modifier and initiator during the solvent or bulk polymerization step on the mechanical property and solvent resistant of prepared sorptive stir bars were investigated. The evaluation of results were caused to obtain the four prepared sorptive stir bars with good mechanical stability and excellent resistance to organic solvents. The extraction efficiency of these prepared sorptive stir bars were investigated by liquid desorption-liquid chromatography-ultraviolet detection (LD-LC-UV) using N-Nitrosodiphenylamine as target analyte. SBSE assays showed the sorptive stir bar that prepared using solution polymerization method had the better recovery for N-Nitrosodiphenylamine in water samples. This sorptive stir bar showed good linearity and acceptable recoveries, as well as advantages such as sensitivity, simplicity, low cost and high feasibility. Based on atomic force microscopy (AFM) results, the average pore size of optimum prepared stir bar using solvent polymerization method was obtained ~9 nm. The thermal gravity (TG) and differential scanning calorimetric (DSC) results showed this polyacrylate film has high thermal stability.     

Synthesis and physicochemical properties of poly(perfluoro-2-trichloromethylisopropyl acrylate)

A new acrylic monomer derived from perfluoro-2-trichloromethylisopropanol was synthesized. Poly(perfluoro-2-trichloromethylisopropyl acrylate) was prepared by radical bulk polymerization, and its physicochemical properties were studied. It was found that the prepared polyacrylate can be used to manufacture optical waveguides.     

聚苯基硅氧烷/聚丙烯酸酯复合乳液的合成与性能

本文以二苯基二甲氧基硅烷(DPDMS)和γ-甲基丙烯酰氧基丙基三甲氧基硅烷(MAPTMS)合成了具有微交联结构的聚硅氧烷乳液,并以此为种子乳液再与丙烯酸酯类单体聚合,合成了稳定且性能优良的聚硅氧烷/聚丙烯酸酯复合乳液.用激光粒度分析仪、FTIR、DMA等进行了表征.结果表明,硅氧烷被有效的接枝到了聚丙烯酸酯分子链中;硅氧烷的加入,使聚合物的储能模量,损耗模量增大,玻璃化温度提高,加入量为10％时,Tg由50.5℃升高到57.2℃;加入20％的硅氧烷涂膜吸水率由13.8％降低到6.8％.     

Toughening of polyvinylchloride by core-shell rubber particles: Influence of the internal structure of core-shell particles

The work focused on the influence of the internal structure of MBS core-shell impact modifiers on the properties of PVC/MBS blends. MBS was synthesized by grafting styrene and methyl methacrylate onto PB seed latex by emulsion polymerization. Different monomer feeding manners and initiators were employed to control the internal structure of core-shell particles. The investigation of the morphology of MBS showed that when styrene monomer was fed in a semicontinuous feeding manner and redox initiator was used, core-shell particles with rarely sub-inclusions could be obtained. When preswollen manner of styrene monomer and redox initiator were employed, there were a large number of small sub-inclusions in the core of MBS. When AIBN was used as initiator, large sub-inclusions could be found in the core of MBS. The results of the Izod impact tests showed that PVC/MBS blend with MBS prepared by preswollen manner had the lowest brittle-ductile transition temperature. And TEM showed that the different internal structures of core-shell particles could lead to different deformation mechanisms. While the results of transparency tests showed that the presence of the sub-inclusions in the MBS impaired the transparency of the blends.