Production of multi-hollow polymer particles by the stepwise acid/alkali method

 Recently, we reported that multi-hollow polymer particles can be prepared from carboxylated polymer particles by the stepwise alkali/acid method. In this article, an attempt was made to prepare similar particles from acid-swellable polymer particles by the stepwise treatment with acid and alkali, which was named the stepwise acid/alkali method. The acid-swellable particles were produced by emulsion terpolymerization of styrene, butyl acrylate, and dimethyl 2-amino ethyl methacrylate. The effects of initial pH value, temperature, and time in the acid and alkali treatment processes on the multi-hollow structure were examined. Received: 18 December 1996 Accepted: 11 March 1997     

High solids content emulsion terpolymerization of vinyl acetate,methyl methacrylate and butyl acrylate. II. Open loop composition control

A method for the calculation of the optimal monomer addition policies for polymer composition control in emulsion terpolymerization is developed. The method is applied to reactors with and without limited heat removal capacity. A mathematical model that incorporates the main features of the vinyl acetate/methyl methacrylate/butyl acrylate high solids content emulsion terpolymerization system allows the calculation of the composition of the initial charge of the reactor and the time-dependent monomer addition rates required. © 1994 John Wiley & Sons, Inc.     

Preparation and properties of polymer and quantum dot composites

Quantum dots (QDs) were prepared in an organic system through a simple and low-cost wet chemistry method. Polymer beads with a diameter of 60–70 nm and specific functional groups were synthesized by a particular seeded emulsion polymerization technique. QDs were embedded in the polymer beads with the specific functional groups through dissolving and swelling method, which provided the condition for the conjunction of biomolecules and QDs as fluorescent probes. The prepared composites were characterized with UV-Vis, PL, TEM, FTIR, CLSM and conductance titration etc. The results show that QDs are successfully embedded in polymer beads, which breaks the limitation that the conjunction of biomolecules and QDs can be achieved only for those synthesized in aqueous system. __________ Translated from Journal of Shanghai Jiaotong University, 2005, 39(1) (in Chinese)     

乙烯基聚硅氧烷共聚反应竞聚率的测定及其对复合粒子形态的影响

用Ｆｉｍｅｍａｎ－Ｒｏｓｓ法处理数据，测定了乙烯基聚硅氧烷（ＳＶ）与苯乙烯（ＳＴ）、甲基丙烯酸甲酯（ＭＭＡ）和甲基丙烯酸正丁酯（ｎ－ＢＭＡ）的共聚反应的竞聚率，结果为ｒＳＴ＝１．４５和ｒＳＶ＝１．０８，ｒＭＭＡ＝０．７８和ｒＳＶ＝２．０１，ｒｎ－ＢＭＡ＝０．４６和ｒＳＶ＝３．４９．以含ＳＶ的乳液作为种子进行烯类单体的乳液聚合，单体和ＳＶ共聚反应对复合粒子的形态有很大影响。     

Nondestructive Monitoring of Sucrose Diffusion in Oil-in-Water Emulsions by Ultrasonic Velocity Profiling

The diffusion of sucrose through an optically opaque oil-in-water emulsion was monitored nondestructively by measuring the ultrasonic velocity as a function of height. Initially, a corn oil-in-water emulsion (0, 5, 10, 15, or 20 wt% oil) stabilized by Tween 20 (1 wt%) and xanthan (1 wt%) was placed in a measurement cell at 30°C. A 20 wt% sucrose solution containing the same concentration of Tween 20 and xanthan as the aqueous phase in the emulsion was placed on top of the emulsion. The ultrasonic velocity of this two-layer system was measured as a function of sample height and time and then converted into sucrose and oil concentration–distance profiles using empirical calibration curves. The translational diffusion coefficient of the sucrose in the upper and lower layers was determined by fitting the experimental data to a Fickian diffusion model. The measured diffusion coefficients of the sucrose molecules decreased as the droplet concentration in the emulsion increased, indicating retardation of the sugar molecule movement. Ultrasonic profiling was also used to monitor the compression of the emulsion due to movement of water molecules into the upper layer.     

Production of submicron-sized multihollow polymer particles by alkali/cooling method

Submicron-sized styrene-methacrylic acid copolymer particles, which were produced by emulsion copolymerization, were changed to those having multihollow structure by treating stepwise the emulsion as follows. First alkali treatment was carried out at higher temperature than the glass transition temperature and subsequently the emulsion was cooled by keeping it at room temperature. This was named alkali/cooling method. The effects of methacrylic acid content, pH, time and temperature in the alkali treatment on the formation of multihollow structure were clarified.Part CLV of the series Studies on suspension and emulsion     

单体极性对甲基丙烯酸甲酯/丙烯酸丁酯/甲基丙烯酸钠无皂乳液共聚合的影响

研究了少量甲基丙烯酸钠（ＮａＭＡ）存在下单体极性对甲基丙烯酸甲酯（ＭＭＡ）／丙烯酸丁酯（ＢＡ）无皂乳液共聚合的影响．单体极性降低，使粒径减小、聚合速率提高、乳液表面张力和粘度降低、粒子表面电荷密度增大、聚合物分子量提高．ＭＭＡ／ＮａＭＡ无皂乳液聚合物只呈现一个玻璃化温度Ｔｇ，ＢＡ／ＮａＭＡ无皂乳液聚合物呈现两个Ｔｇ，ＭＭＡ／ＢＡ比为２∶１～１∶２的ＭＭＡ／ＢＡ／ＮａＭＡ无皂乳液聚合物呈现四个Ｔｇ，这是由于粒子外面相对富含ＯＳＯ－３和ＣＯＯ－基聚合物的亚层溶解了较多的水，使ＢＡ向粒子中心扩散，ＭＭＡ向外扩散，造成组成差异和相分离而引起的．     

配糖蛋白B肠溶微胶囊的研究

采用双乳液法研制配糖蛋白Ｂ的肠溶微胶囊，考察了微胶囊的形态、粒径及其分布，在摸拟肠液的缓冲液中进行溶解释放试验。配制了两种口服微胶囊混悬制剂，并考察了它的稳定性。     

乳状液膜法提取L—谷氨酸的研究

乳状液膜法提取Ｌ－谷氨酸的研究徐占林（四平师范学院化学系四平１３６０００）严忠张河哲（东北师范大学化学系长春１３００２４）关键词Ｌ－谷氨酸乳状液膜载体萃取中图分类号Ｏ６２３．７３６氨基酸作为重要的生化产品，广泛应用于食品、饲料、医药、化工等许多领域，...     

烷基硫酸钠对MMA种子乳液聚合的影响

研究了烷基硫酸钠纯度，烷基碳链分布对甲基丙烯酸甲酯种子乳液聚合反应的影响。结果表明，烷基硫酸钠中乙醇不溶物含量的增加，可提高ＭＭＡ乳液聚合反应速度，在采用Ｋ２Ｓ２Ｏ８－ＮａＨＳＯ３－Ｃｕ＾２＋三元氧化－还原引发体系的ＭＭＡ乳液聚合中，Ｆｅ＾２＋降低反应速率，而Ｆｅ＾３＋则提高聚合反应速率；