吸附树脂AB－8对甜菊甙的吸附性能及在其提取纯化中的应用

考察了大孔吸附树脂ＡＢ－８对甜菊甙的吸附性能，和溶液的ｐＨ值、洗脱剂的种类及流速对树脂吸附，脱附性能的影响；结果表明，ＡＢ－８树脂对甜菊甙吸附量高，循环使用性能好且易于洗脱。     

酸处理对制备中空乳胶粒子的影响

聚苯乙烯;酸处理对制备中空乳胶粒子的影响;形态;丙烯酸丁酯;中空结构乳胶粒子;甲基丙烯酸;共聚物     

Butyl acrylate and vinyl acetate semicontinuous emulsion copolymerizations: study of stabilization performance

The use of small amounts of carboxylic monomers in industrial recipes with high solids content enhances colloidal stability due to the presence of carboxylic groups on the outer surface of the polymer particles. Understanding the relationship between several different but interdependent phenomena, including particle nucleation, kinetics, particle aggregation, monomer type, solids content, the role of the carboxylic monomer and the influence of reaction temperature may improve the control over particle size and latex stability. In this work, the kinetics and stabilization performance of semicontinuous vinyl acetate (VA) and butyl acrylate (BA) emulsion copolymerization reactions are studied under different reaction temperatures, acrylic acid (AA) concentrations, solids contents and monomer feed compositions. Results show that choosing optimal AA concentrations and reaction temperatures are key factors in order to enhance the stabilization performance in semicontinuous VA/BA emulsion copolymerization.     

聚合工艺及m(MMA)/m(EA)对MMA-Ea-AA三元无皂乳液聚合及乳胶粒性质的影响

聚合工艺及m(MMA)/m(EA)对MMA-Ea-AA三元无皂乳液聚合及乳胶粒性质的影响;甲基丙烯酸甲酯;丙烯酸乙酯     

Interpenetrating Polymer Networks of Uralkyd Resin Based on Hydrogenated Castor Oil and Poly(Butyl Acrylate)

Abstract

Semi‐ and full‐interpenetrating polymer networks (IPNs) of uralkyd (UA) resin based on hydrogenated castor oil and poly(butyl acrylate) (PBA) were prepared by the sequential mode of synthesis. These IPNs were characterized for their resistance to thermal behavior, swelling (%), and mechanical properties. The morphology of the IPNs was studied by scanning electron microscopy (SEM). The effect of the variations of the blend ratios on the above‐mentioned properties was examined. The mechanical properties significantly enhanced by increasing UA component in the blend. Full‐IPNs exhibited higher apparent densities, mechanical properties, and thermal stability than the corresponding semi‐IPNs.     

磷钨酸催化合成丙烯酸丁酯

用磷钨酸为催化剂 ,由丙烯酸和丁醇直接酯化合成了丙烯酸丁酯。研究了醇 /酸比、酯化时间、催化剂用量、带水剂用量对酯化率的影响 ;选择了最佳反应条件 ,重复反应酯化率达到 95 %以上。     

自交联型丙烯酸酯共聚物乳液的研究

以羟甲基丙烯酰胺、丙烯酸作为活性单体，采用种子乳液聚合法制得四元体系自交联型丙烯酸酯共聚物乳液。用透射电镜观察了乳胶粒的微观形态，并对共聚物乳液的流变性，稳定性等进行了测试，考察了羟甲基丙烯酰胺和丙烯酸的含量、聚合方式对共聚物乳液性能的影响。     

Low‐Temperature,Rapid Copolymerization of Acrylic Acid and Sodium Acrylate in Water

Regulating the aqueous polymerization of acrylic acid (AA) is a major opportunity for future materials design, requiring the development of scalable, industry‐oriented procedures that afford modest molar mass and dispersity control without long reaction times and environmentally demanding conditions. To address these challenges, this report presents the rapid copolymerization of aqueous mixtures of AA and sodium acrylate using an inexpensive and scalable protocol based on alkyl iodides/sodium iodide as mediators in water. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1414–1419     

分光光度法测定丙烯酸及丙烯酸酯中阻聚剂的含量

采用乙醇作溶剂,亚硝酸钠作显色剂,用分光光度法于400 nm处对丙烯酸及丙烯酸酯中阻聚剂含量进行测定。阻聚剂含量y在0~120μg/(25 mL)范围内与吸光度x呈线性关系,线性方程为y=1 768.5x-15.123,r=0.999 5。方法检出限为0.1μg/mL,测定结果的相对偏差为2.26%~2.91%(n=5)。加标回收率为96.5%~100.7%。     

Effect of Cellulose Suspension Agent Structure on the Particle Morphology of PVC. Part II. Interfacial Properties

The particle structure of polyvinyl chloride is controlled by the shear field imposed on the monomer droplet and the interfacial behavior of the vinyl chloride/water phases during polymerization. The inter facial tension in the presence of hydroxypropyl methylcellulose (HPMC) was measured as a function of concentration and temperature. The molecular weight distribution of HPMC was determined by coupled GPC-LALLS (low angel laser light scattering) technique. By monitoring the concentration of HPMC in the aqueous phase during polymerization, the coverage powers of HPMC were calculated and compared with the theoretical value based on Langmuir layer consideration. The effects of agitation on resin porosity were also examined. These results are discussed with respect to the particle structure.