Kinetics study of Ti[O(CH2)4OCHCH2]4 initiated ring‐opening polymerization of ε‐caprolactone by differential scanning calorimetry

Chemical shrinkage was used for the in situ measurement of the progressing chemical stabilization reactions and the influence of ozone during the stabilization of polyacrylonitrile. A method for evaluating the activation energy through the sensitivity temperature is presented. The calculated results show that the activation energies were 161.57 kJ/mol in air and 181.23 kJ/mol in ozone-enriched air. Therefore, the chemical reactions were postponed during stabilization in ozone-enriched air. Ozone seemed to act in three ways: first, ozone promoted the formation of the serious skin–core structure. Second, ozone accelerated the chemical reactions and shortened the stabilization time at lower heating rates. Third, ozone postponed the chemical reactions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Maghnite‐H+, a solid catalyst for the cationic polymerization of α‐methylstyrene

The polymerization of α‐methylstyrene (AMS) catalyzed by Maghnite‐H⁺ (Mag‐H) was investigated. Mag‐H is a montmorillonite sheet silicate clay, exchanged with protons. It was found that the cationic polymerization of AMS is initiated by Mag‐H at ambient temperature in bulk and in solution. The effect of the amount of Mag‐H, the temperature, and the solvent was studied. The polymerization rate increased with increase in the temperature and the proportion of catalyst, and it was larger in nonpolar solvents. These results indicated the cationic nature of the polymerization. It may be suggested that the polymerization is initiated by proton addition to monomer from Mag‐H. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polymerization strategies to overcome limiting monomer conversion in silicone-acrylic miniemulsion polymerization

The limiting conversion phenomenon observed in high solid content silicone-modified acrylic miniemulsion polymerizations was investigated. It was found that the limiting conversion was mainly due to the formation of inactive radicals upon propagation of butyl acrylate radicals with the vinyl end groups of the polydimethylsiloxane. Polymerization strategies that allowed overcoming this problem and achieving high monomer conversion were implemented.     

间歇式液相本体聚丙烯装置计算机控制与管理系统

介绍一种间歇式液相本体聚丙烯装置计算机先进控制与管理系统。它是由“基本控制层”和“上位控制层”构成的经济适用型集散控制装置。该装置采用了多屏显示技术、网络通讯技术、PLC程控技术、ActiveX控件技术和面向对象程序设计方法、数据库技术以及闭环辩识、预测控制、反应优化、底层PID控制与上层先进控制无扰动自动切换等多种技术和控制方式，因而可以灵活有效地实现聚合反应的全过程自动化生产和安全保护。     

DMDAAC/AM絮凝剂的合成与性能评价

以二甲基二烯丙基氯化馆（DMDAAC）和丙烯酰胺（AM）为原料，采用反相悬浮聚合法合成了DMDAAC/AM絮凝剂（JHT絮凝剂），讨论其对聚合物驱产出污水的絮凝和破乳效果。结果表明，JHT有机絮凝剂具有良好的絮凝除浊，破乳除油和去除产出污水中有机污染物的能力。明显优于聚丙烯酰胺有机絮凝剂。     

甲基丙烯酸乙酯的"活性"/可控阴离子聚合

采用空间位阻大的引发剂1,1-二苯基己基锂(DPHLi),添加新型络合剂LiClO4,在-5℃,实现了活性阴离子聚合反应,获得分子量分布为1.05的单分散聚甲基丙烯酸乙酯(PEMA)。     

Polymerization behavior and polymer properties of eosin-mediated surface modification reactions

Surface modification by surface-mediated polymerization necessitates control of the grafted polymer film thicknesses to achieve the desired property changes. Here, a microarray format is used to assess a range of reaction conditions and formulations rapidly in regards to the film thicknesses achieved and the polymerization behavior. Monomer formulations initiated by eosin conjugates with varying concentrations of poly(ethylene glycol) diacrylate (PEGDA), N-methyldiethanolamine (MDEA), and 1-vinyl-2-pyrrolidone (VP) were evaluated. Acrylamide with MDEA or ascorbic acid as a coinitiator was also investigated. The best formulation was found to be 40 wt% acrylamide with MDEA which yielded four to eightfold thicker films (maximum polymer thickness increased from 180 nm to 1420 nm) and generated visible films from fivefold lower eosin surface densities (2.8 versus 14 eosins/μm²) compared to a corresponding PEGDA formulation. Using a microarray format to assess multiple initiator surface densities enabled facile identification of a monomer formulation that yields the desired polymer properties and polymerization behavior across the requisite range of initiator surface densities.     

CpTi(dbm)Cl_2催化烯烃聚合及其聚合物性质

开发了一种新型非茂聚烯烃催化剂———CpTi(dbm)Cl2,考察了催化剂在均相及负载条件下对乙烯及乙烯-1-己烯共聚的催化行为。催化剂在均相条件下对乙烯聚合的催化活性较低,但用MgCl2和MgCl2/SiO2复合双载体对催化剂进行负载后,催化乙烯聚合具有非常好的催化活性。催化剂还具有良好的共聚能力及良好的氢调敏感性。     

新型聚丙烯酸(934P、980)树脂的制备

详细研究了以乙酸乙酯和环己烷为溶剂，丙烯酸为单体，BPO，LPO，AIBN为引发剂，聚烯基多醚为交联剂，合成增稠能力强、透明度高的聚丙烯酸树脂。于混和溶剂存在下制得的聚合物，消除了以往由二氯甲烷为溶剂的反应介质中所得产品的毒性，可广泛应用于医药及日用化工等行业。     

水溶性聚偶氮酯的研究

用Ｐｉｎｎｅｒ合成方法制备了用ＰＥＧ４００封端的水溶性聚偶氮酯，并表征了其结构；研究了热分解反应动力学及用于乳液聚合的动力学。结果表明，该种引发剂具有引发速度快、热分解机理简单和具有辅助乳化作用等优点。