核／壳结构聚丙烯酸酯增韧剂改性PVC的研究

用核／壳结构聚丙烯酸酯增韧剂对ＰＶＣ进行了抗冲击改性，研究了增韧剂的组成结构与增韧效果之间的关系，通过实验发现在本工作所考察的范围内，增韧剂粒径越大，其增韧效果越好．电镜观察证实共混体系的形态为弹性体粒子均匀地分散在ＰＶＣ基体中．     

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％...     

核壳结构对聚苯乙烯／聚丙烯酸酯LIPN力学性能的影响

本文系统研究了核壳结构对聚苯乙烯/聚丙烯酸酯(PS/PA)LIPN力学性能的影响.通过改变加料顺序、溶胀时间及双相互穿等多步聚合方法,考察了动态力学和力学性能变化的规律.结果表明,核壳结构随加料顺序的变化,导致力学性能相差十分悬殊.增加溶胀时间及采用多步聚合的双相互穿,能明显地提高互穿程度,使玻璃化温度发生内移,力学性能得到改善.     

聚丙烯酸酯改性水性聚氨酯的制备

在回顾聚丙烯酸酯改性水性聚氨酯的研究历史基础上，系统地介绍了聚丙烯酸酯改性水性聚氨酯乳液（PUA）的制备方法，其中包括聚氨酯（PU）和聚丙烯酯（PA）的直接掺混法、PU和PA的乳液共聚法，接枝法，互穿网络法，核壳聚合法，对这些方法做了简单的评述，对其应用范围及前景进行了初步探讨。     

纳米SiO_2/聚丙烯酸酯复合乳液的制备与表征

根据核壳乳液聚合理论,以经过硅烷偶联剂表面改性的纳米SiO2为种子,采用适当的乳液聚合工艺,制备了纳米SiO2/聚丙烯酸酯复合乳液,并表征了其性能.结果表明,纳米SiO2经过改性后,硅烷偶联剂接枝在其表面;以其为种子制备的复合乳液具有核壳结构,其热稳定性有所提高.     

一种新型塑料增韧剂——核壳结构聚合物

本文综述了核－壳结构聚合物用于通用塑料和工程塑料增韧的最新进展，并对该领域的研究进行了模型。     

核／壳结构增韧剂对环氧树脂的抗冲改性

核／壳结构增韧剂对环氧树脂的抗冲改性张明耀，张会轩，杨海东，冯之榴（吉林工学院化学工程系长春１３００１２）（中国科学院长春应用化学研究所长春）关键词核／壳结构，增韧剂，环氧树脂，共混核／壳结构增韧剂是用分步乳液聚合技术制造的一种复合乳胶粒子，其核为橡...     

聚丙烯酸酯-LiNi铁氧体纳米复合物的制备和磁性研究

用流变相法制备了LiNi铁氧体纳米粒子, 通过硅烷偶联剂对纳米LiNi铁氧体表面改性, 用乳液聚合法制备了纳米LiNi铁氧体-聚丙烯酸酯复合物. 用X射线衍射(XRD)、红外光谱(IR)、透射电镜(TEM)、热重分析(TGA)、振动样品磁强计(VSM)以及阻抗-材料分析仪等表征了样品的结构、形貌和磁性能. 结果表明, 引入的纳米铁氧体被聚丙烯酸酯分子链所包覆, 明显提高了复合物的热稳定性. 在外加磁场下, 复合物表现出了较弱的亚铁磁性, 并具有一定的磁滞损耗特性.     

无皂乳液聚合制备单分散核-壳聚丙烯酸微粒

核壳微粒;丙烯酸聚合物;无皂乳液聚合制备单分散核-壳聚丙烯酸微粒     

氟聚合物改性聚丙烯酸酯乳液的制备

氟聚合物改性聚丙烯酸酯乳液的制备;氟改性;聚四氟乙烯;聚丙烯酸酯乳液     

Synthesis of Poly(n‐butyl acrylate/methyl methacrylate)/CNC Latex Nanocomposites via In Situ Emulsion Polymerization

Cellulose nanocrystals (CNCs) are renewable, nontoxic and naturally available organic nanoparticles derived from cellulosic resources such as cotton and wood pulp. Poly(n‐butyl acrylate‐co‐methyl methacrylate)/CNC latexes are successfully synthesized via in situ emulsion polymerization. The effect of CNC loading on overall conversion, polymer particle size, glass transition temperature (T_g), gel content, latex viscosity, and storage and loss moduli of dried latex are studied. While the effect of CNC content on overall conversion, polymer particle size, and T_g of the resulting latexes is negligible, significant increase in gel content, latex viscosity, and storage and loss moduli are observed.

     

Viscoelastic and damping characteristics of poly(n‐butyl acrylate)‐poly(n‐butyl methacrylate) semi‐IPN latex films

This article reports the synthesis, characterization, and damping characteristics of semi‐interpenetrating (semi‐IPN) latex systems composed of poly n‐butyl acrylate (PBA) core and poly n‐butyl methacrylate (PBMA) shell. The IPN's were prepared by seeded emulsion polymerization using crosslinked PBA seeds with varying crosslinker (m‐diisopropenyl benzene) concentration. The polymer weight ratio in the first and second stage polymerization is maintained at 1:1 in all the cases. The particle size determined by dynamic light scattering shows a decrease in the shell thickness with increasing crosslinker concentration of the seed. The mechanical properties, like Shore A hardness of the films, increased from 18 to 65 when the crosslinker concentration is increased from 0 to 4.8 mol%. The dynamic mechanical studies show that the modulus value of the IPN's is below that of non‐crosslinked films, and the value depends upon the crosslink density of the seed. Mechanical models, such as the Kerner's model and the Takayanagi's model, were used to explain the variation in the dynamic mechanical properties with the degree of seed crosslinking. The study indicates lower bound (rubbery) behavior for the films with lightly crosslinked cores. The study also shows that, at lower crosslinker concentration enhanced phase separation and better damping properties are achieved but at higher cross linker concentration (>2 mol%) greater interpenetration of the shell monomer to the cores takes place and tough films, with reduced damping properties are formed. Copyright © 2007 John Wiley & Sons, Ltd.     

Emulsion terpolymerization of butyl acrylate/methyl methacrylate/vinyl acetate: Experimental results

A systematic study of the terpolymerization of butyl acrylate/methyl methacrylate/vinyl acetate (BA/MMA/VAc) was conducted. In this stage of the study, batch emulsion terpolymerizations were performed in a 5 L stainless steel pilot plant reactor. The experiments were designed using a Bayesian (optimal) technique. The polymers produced were characterized for conversion, composition, molecular weight, and particle size. Conversion, terpolymer composition, number- and weight-average molecular weight, and average particle size results are discussed in light of the influence of seven factors and the interaction of these factors. The factors studied include monomer feed composition, initiator concentration, chain transfer agent concentration, impurity concentration, initiator type, emulsifier concentration, and temperature. A “two-stage rate” phenomenon, similar to that occurring in bulk co- and terpolymerization and emulsion copolymerization of acrylic/vinyl acetate systems was observed in the conversion, composition and molecular weight data. Furthermore, an interesting yet often ignored effect of impurities on emulsion polymerization kinetics was explained. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1659–1672, 1997     

聚甲基丙烯酸甲酯-氯化银复合纳米微球的制备及其摩擦学性能

采用原位种子乳液聚合法合成了聚甲基丙烯酸甲酯 氯化银(PMMA AgCl)核壳结构复合纳米微球,通过透射电镜(TEM),红外光谱(IR),热分析(TG DTA)和X射线粉末衍射(XRD)等测试手段对其结构及性能进行了表征.在四球试验机上对其摩擦学行为进行了考察,研究结果表明,PMMA AgCl核壳结构复合纳米微球用作润滑油添加剂具有良好的抗磨性能,能显著提高基础油的失效负荷.     

Kinetics of the seeded semicontinuous emulsion copolymerization of methyl methacrylate and butyl acrylate

The effect of a chain‐transfer agent (CTA) on the kinetics and molecular weight distribution of the methyl methacrylate/butyl acrylate semicontinuous emulsion polymerization was investigated. The dodecanethiol had a slight effect on the reaction rate but significantly affected the secondary nucleation. The effect of the CTA concentration on the gel formation and the effect of the reaction conditions on the mass‐transfer limitations of the CTA are discussed. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 367–375, 2000     

Stabilization and kinetics in the emulsion copolymerization of butyl acrylate and methyl methacrylate

We carried out emulsion homopolymerizations and copolymerizations of butyl acrylate (BuA) and methyl methacrylate (MMA) with different types and concentrations of surfactants to determine the influence of these parameters on the particle size and particle size distribution and to elucidate the mechanism of particle formation. As expected, the mechanisms of nucleation above and below the critical micelle concentration were very different; however, it was also found that the presence of partially soluble monomers such as MMA in the water phase had a significant influence on the critical micelle concentration of Triton X‐405 (>50%). In addition, the nucleation mechanism during copolymerization seemed to be dominated by BuA, with the number of particles per liter being very similar to the number nucleated during its homopolymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2832–2846, 2001     

Butyl acrylate/methyl methacrylate latexes: adhesive properties

In this study, butyl acrylate/methyl methacrylate (BA/MMA) latexes of bimodal molecular weight and particle size distribution were prepared in a multi-step process by seeded conventional emulsion and seeded miniemulsion polymerization. For the conventional emulsion case, a BA/MMA batch copolymerization was conducted as a first step (seed generation) and was followed by a monomer addition step to ensure particle growth. In a third step, a BA/MMA pre-emulsified mixture was added to generate a second particle population. For the miniemulsion case, a BA/MMA copolymerization was carried out as a first step (seed generation) and was followed by a monomer addition step. The addition of a BA/MMA miniemulsion served to generate a bimodal particle size and molecular weight distribution. The final latexes were coated onto a polyethylene terephthalate carrier, dried and their performance as pressure-sensitive adhesives was evaluated using tack, peel and shear adhesion measurements. Structure-property relationships between the adhesive properties and the weight-average molecular weight and average particle size were examined. Even though the polymers obtained by miniemulsion showed better shear resistance, their shear resistance was low. There was no statistically significant difference in peel resistance of the polymers obtained by the two reactions. While a significant difference in tackiness between the two emulsion procedures was found when the adhesives were tested using the less sensitive, rolling ball test, no differences were found when they were tested using a loop tack test.     

Preparation and characterization of poly(methyl methacrylate)/titanium oxide composite particles

Before polymerization, the introduction of double bonds onto the surface of the TiO₂ particles was achieved by the treatment of the TiO₂ particles with the silane-coupling agent. Via in-situ emulsion polymerization, the poly(methyl methacrylate) (PMMA)/titanium oxide (TiO₂) composite particles were prepared by graft polymerization of MMA from the surface of the modified TiO₂ particles. The structure of the obtained PMMA/TiO₂ composite particles was characterized using fourier transform infrared spectra (FT-IR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and size excluding chromatography (SEC). The morphology of the obtained PMMA/TiO₂ composite particles was observed by transmission electron microscope (TEM). The results of FT-IR and TGA measurements show that PMMA is successfully grafted from the surface of the TiO₂ particles and that the percentage of grafting and the grafting efficiency can reach 208.3% and 96.6%, respectively. At the same time, the TGA and DSC measurements indicate an enhancement of thermal stability. TEM images demonstrate a better dispersion of the TiO₂ particles in the composite latex. In addition, UV-visible absorption measurements show that the PMMA/TiO₂ composite particles can absorb over 95% UV light at 210–400 nm wavelength.     

TiO2/聚丙烯酸丁酯纳米复合薄膜的制备及结构表征

利用微乳液原位聚合法在普通玻璃表面上制备了TiO2/聚丙烯酸丁酯纳米复合膜.采用傅立叶变换红外光谱、高分辨透射电子显微镜和X射线光电子能谱对膜的结构进行了表征.结果表明， TiO2以纳米线的形式弥散在聚丙烯酸丁酯的高分子网络中，并且所制备的TiO2纳米线具有板钛矿相结构.