超临界二氧化碳中的分散聚合

在介绍以超临界二氧化碳(Sc-CO2)为介质的分散聚合的成粒机理的基础上,阐明分散剂在分散聚合中的稳定作用,着重综述分散剂的结构组成及用量对分散聚合树脂颗粒特性、聚合速率、产物分子量及分布等的影响,并展望Sc-CO2中分散聚合的研发和应用。     

原位分散聚合法聚合物微球PMMA包覆尿嘧啶的合成及表征研究

本课题采用分散聚合法对抗肿瘤药物进行了原位包覆,研究了其合成工艺以及聚合的机理,并探究了分散剂和反应介质对微球的粒径、粒度分布和包药率的影响。实验结果表明:当无水乙醇取40 g,蒸馏水取60 g所组成的反应介质时,能够制得理想粒径的的聚合物微球,且聚合物微球的粒度分布较为均匀。当单体质量为15 g时,取分散剂3 g可得到理想粒径的微球。当分散剂占单体质量15%～20%时,会取得较高的包覆率。单体聚合的转化率随着引发剂用量的增加而增加,且单体聚合的"高发期"在反应开始后1 h内。     

盐水介质中CPAM分散聚合的分散介质与分散剂选择研究

考察了CPAM分散聚合中,两种不同硫酸盐作为分散介质的可行性,并详细讨论了不同类型的分散剂对盐水介质中CPAM分散聚合的影响。通过研究发现,由于硫酸钠在水中的溶解度随温度波动较大,不适合作为CPAM分散聚合的分散介质。另外实验表明,由于非离子型分散剂在盐水介质中溶解性不佳,不适合作为CPAM分散聚合的分散剂。故选择硫酸铵与PDMDAAC分别作为盐水介质中CPAM分散聚合的分散介质与分散剂,并确定了硫酸铵最佳用量为聚合体系质量的27%~29%,PDMDAAC最佳用量为单体质量的10%~18%,该条件下制得的产品具有较好的流动性。     

一种大分子量抗盐耐温性二元聚合物驱油剂及其制备方法

一种大分子量抗盐耐温性二元聚合物驱油剂的制备方法,以丙烯酰胺和功能单体为聚合单体,以醇水混合液为反应溶剂,在引发剂和分散剂的存在下,通过分散聚合的方式     

分散聚合法合成疏水缔合聚丙烯酰胺衍生物

首次采用分散聚合方法合成疏水缔合聚丙烯酰胺衍生物。在聚合前期(溶液聚合)得到高相对分子质量的聚合物,聚合后期(乳液聚合)生成的聚合物分散成胶束进行乳液聚合,进一步提高相对分子质量,得到稳定的微凝胶体系,且体系有很好的水溶性和成丝性。实验中研究了不同的单体物质的量配比、引发体系的用量和配比及分散剂的用量对聚合的影响。     

单分散亚微米级聚合物微球的研究进展

本文综述了单分散亚微米级聚合物微球的自由基聚合主要制备方法,包括分散聚合、RAFT分散聚合、乳液聚合和无皂乳液聚合,讨论了溶剂、引发剂、单体、分散剂、乳化剂、搅拌和温度的选择及其对聚合物微球粒径和单分散性的影响以及粒径控制机理.     

超临界CO_2中RAFT聚合制备含氟嵌段聚合物

在超临界CO_2中,以亲CO_2的含氟聚合物PDFMA-CDB作为大分子链转移剂和分散剂,通过RAFT分散聚合制备聚甲基丙烯酸十二氟庚酯-b-聚(苯乙烯-CO-马来酸酐)(PDFMA-b-PSMA)含氟嵌段聚合物,并对聚合产物进行FTIR、1H NMR、GPC等表征。结果表明,制备的聚合物结构明确,分子量分布窄,符合RAFT聚合。     

异丙醇-水介质中微米级单分散聚(苯乙烯-甲基丙烯酸)微球的制备

以苯乙烯和甲基丙烯酸为单体、PVP为分散剂,AIBN为引发剂,在异丙醇-水介质中,用分散聚合方法制备了微米级单分散的聚(苯乙烯-甲基丙烯酸)[P(St-MAA)]微球。结果表明,采用反应初期低温、中后期升温的聚合工艺可制得单分散的聚合物微球,并提高聚合反应的速率和转化率。P(St-MAA)微球的粒径及其分布可通过改变介质组成来控制。分散介质中异丙醇质量分数降低,聚合反应速率增大,转化率升高,微球的粒径减小。当分散介质中异丙醇的质量分数降低到60％时,聚合反应中有凝胶生成,粒径分布呈多分散性。     

分散聚合研究进展及单分散聚合物微球的应用

分散聚合是一种能得到很好单分散聚合物微球的新型聚合方法,该方法已广泛应用于医学、涂料工业、生物工程、化学工业等方面。大粒径单分散聚合物微球在许多领域里有着广阔的应用前景,越来越受到人们的关注。笔者对分散聚合中的反应机理、粒径的控制以及稳定剂和分散介质的研究进展进行了概述,并简要介绍了单分散聚合物微球的应用。     

亲水性单体甲基丙烯酸—2—羟丙酯分散聚合动力学研究

本工作采用梳状分散剂，以偶氮二异丁腈为引发剂，１２０＾＃汽油／昆合物为分散介质，进行了亲水性单体甲基丙烯酸－２－羟丙酯的分散聚合研究，讨论了分散剂种类，结构及浓度，反应温度等反应条件对反应及聚合物微球形态的影响，提出了两种机理：均相成核机理和反相微悬浮机理，总结出了ＨＰＭＡ分散聚合的动力学规律。     

Dispersion polymerization of styrene in aqueous alcohol solution: Effects of reaction parameters on the polymer particle formation

Dispersion polymerization of styrene in an aqueous alcohol solution using poly(2-ethyl-2-oxazoline) as a polymeric stabilizer was performed to prepare micron-size monodisperse polystyrene particles. As the water content of the solvent increased, the polymerization rate and the molecular weight of the polymer particles increased and the particle size decreased. Effects of concentrations of stabilizer and initiator upon the polymerization and the size of the resulting polystyrene particles have been examined in the solvent containing different water contents.     

超临界二氧化碳乳液聚合技术的研究进展

采用超临界二氧化碳(ScCO2)作为反应介质进行乳液聚合是高分子材料合成与加工的一种绿色技术,具有无毒无害,聚合反应速率快,产物易分离和高选择性等特点。介绍了ScCO2乳液聚合技术的发展状况及其国外最新进展,指出ScCO2技术与乳液聚合相结合制备高分子合成材料,可避免使用有毒或挥发性有机溶剂、减少环境污染、提高材料性能和简化加工生产工艺,具有广阔的应用前景。     

应用正交试验法对醌胺聚合物合成的研究

应用溶液聚合法合成醌胺聚合物,采用正交试验法研究原料配比、氧化剂用量、溶剂用量、反应温度和时间对反应产率和聚合物特性粘度的影响,获得优化的聚合工艺条件。     

Synthesis of PCL/clay masterbatches in supercritical carbon dioxide

Pre-exfoliated nanoclays were prepared through a masterbatch process using supercritical carbon dioxide as solvent and poly(?-caprolactone) as organic matrix. In situ polymerization of ?-caprolactone in the presence of large amount of clay was conducted to obtain these easily dispersible nanoclays, collected as a dry and fine powder after reaction. Dispersion of these pre-exfoliated nanoclays in chlorinated polyethylene was also investigated. All the results confirm the specific advantages of supercritical CO₂ towards conventional solvents for filler modification.     

Polymerization of allyl methacrylate with nylon 6 using benzoyl peroxide as initiator

Polymerization of allyl methacrylate with nylon 6 using benzoyl peroxide as initiator was carried out under different conditions. The polymer add-on was dependent upon allyl methacrylate and benzoyl peroxide concentrations, polymerization time and temperature as well as addition of metallic salts or organic solvents. The polymer add-on increased by increasing benzoyl peroxide concentration up to 0.5 mmol/l then decreased by further increase in peroxide concentration, whereas it increased as the allyl methacrylate concentration increased from 80 – 300 mmol/l. A polymerization temperature of 85°C constituted the optimal temperature, below or above this temperature resulted in lower polymer add-on. The effect of polymerization time was related to the polymerization temperature, no induction period occured at 95°C in contrast to 15 and 30 minutes at 85°C and 75°C, respectively. The incorporation of Cu^{+ +}ions in the polymerization system improved the magnitude of polymer add-on. A similar situation was encountered with Fe^{+ + +} and Li⁺ ions. Using a water/organic solvent mixture as a polymerization medium was advantageous in enhancing polymer add-on provided that the organic solvent did not exceed 1% in case of ethanol and isopropanol and 4% in case of methanol.     

Polymer particles with a pomegranate-like internal structure via micro-dispersive polymerization in a geometrically confined reaction space I. Experimental study

The synthesis of micron-sized polymer particles with a core-shell pomegranate-like morphology is presented. The proposed polymerization technique takes advantage of a reaction-induced micro-phase separation within a suspended organic liquid droplet containing monomer, a chemical initiator, a steric stabilizer, and a poor solvent for the polymer. With an increase in monomer conversion, the monomer droplet suspended in a continuous aqueous medium is transformed first into a micro-capsule with a thick pericellular membrane, and eventually into a polymer particle packed with 300-500 nm polymer sub-particles. The experimentally observed evolution of particle morphology indicates that the reaction pathway is strongly influenced by micro-phase separation and transport phenomena. In the first stage of polymerization, a pseudo-homogeneous polymerization takes place at the droplet surface, followed by a starved macro-dispersive polymerization in the inner region where polymer precipitates out from the solvent phase as nano-sized sub-particles.     

微胶囊相变材料制备技术的研究进展

微胶囊相变材料（Microencapsulated Phase Change Material,MEPCM）是应用微胶囊技术在固液相变材料表面包覆一层性能稳定的高分子膜,而构成的具有核壳结构的复合材料。系统地讲述了相变材料的分类,微胶囊相变材料的工作原理,并重点介绍了几种微胶囊的制备方法,包括界面聚合法、原位聚合法、复凝聚法、溶剂挥发法、凝聚相分离法等,并提出了微胶囊技术今后的发展方向。     

高分子聚合物包覆无机纳米粒子的研究进展

简单介绍了非液滴内成核法、液滴内成核法包覆无机纳米粒子的原理,重点讨论了乳液聚合法、无皂乳液聚合法、分散聚合法、悬浮聚合法、细乳液聚合法包覆无机纳米粒子的优缺点。针对包覆过程中产生的独立聚合物粒子、独立无机粒子,提出采用引发剂吸附在无机颗粒表面、采用反应性乳化剂和偶联剂处理无机粒子并控制单体用量;针对包覆多个无机粒子,提出采用聚合前超声空化技术。     

Synthesis of photo- and pH-responsive composite nanoparticles using a two-step controlled radical polymerization method

We present a versatile synthetic method for photo- and pH-sensitive composite nanoparticles using a combined use of reversible addition-fragmentation chain transfer (RAFT) and atom transfer radical polymerization (ATRP). Crosslinked nanoparticles of a random copolymer composed of methyl methacrylate (MMA), 4-vinylbenzyl chloride (VBC) and divinylbenzene (DVB) were first synthesized using RAFT miniemulsion polymerization in aqueous solution. This was followed by solvent exchange through extraction and dialysis that allowed the nanoparticles to be transferred to and highly swollen in an organic solvent (anisole or THF). By dissolving a monomer of a stimuli-responsive polymer in the solution, subsequent ATRP grafting polymerization could be initiated by halide groups on the swollen nanoparticle, resulting in larger composite nanoparticles. Photosensitive poly(1-pyrenylmethyl methacrylate) (PPyMA) and pH-sensitive poly(dimethylaminoethyl methacrylate) (PDMAEMA) were incorporated in the composite nanoparticles, and their photo- and pH-responsive behaviors were investigated. With this method, monomers soluble in organic solvents can be used in conjunction with emulsion polymerization in aqueous solution to design functional composite nanoparticles.