聚氯甲基苯乙烯纳米乳胶粒子的制备

聚氯甲基苯乙烯纳米乳胶粒子的制备;聚氯甲基苯乙烯;纳米乳胶粒子;乳液聚合     

聚合物纳米粒子乳液的制备及性能研究——添加组分对乳胶粒子形态及胶膜吸水率的影响

本文采用种子微乳液聚合方法,经后期氨化反应,合成了聚丙烯酸酯纳米粒子乳液,讨论了乳化剂、缓冲剂和水溶性丙烯酸单体等添加组分对乳粒子形态和胶膜吸水率的影响,并探讨了微乳液聚合的反应机理。     

甲基丙烯酸对聚合物乳胶粉再分散性影响机理

采用半连续种子乳液聚合法,以甲基丙烯酸(MAA)为壳层亲水功能单体,合成了丙烯酸酯原乳液,并通过喷雾干燥法制得具有可再分散性的聚合物乳胶粉.讨论了原乳液粒子粒径随pH值和MAA量的变化关系;重点研究了MAA量对乳胶粉水分散液稳定性、再分散乳液zeta电位、乳胶粒粒径分布及乳胶粉内部微观形貌的影响,并分析其作用机理.研究结果表明:原乳液粒子粒径随pH值的增大逐渐增大,且MAA含量越高,粒径增幅越大;随MAA量增加,再分散液稳定性增强,zeta电位绝对值增大,平均粒径逐渐变小,乳胶粉再分散性显著改善.透射电子显微镜(TEM)结果显示:当MAA含量较高时,乳胶粉内部出现较大孔径的中空微孔结构.中空微孔结构提供水分向乳胶粉内部扩散通道,因而优化其水分散性,再分散乳液的"绒毛结构"与较高的zeta电位赋予其优异的分散稳定性.     

核壳型聚丙烯酸酯乳胶粒子及其乳液的研究进展

综述了目前制备核壳型聚丙烯酸酯乳胶粒子的常用方法,如种子乳液聚合法、无皂乳液聚合法、反相乳液聚合法、细乳液聚合法以及种子分散聚合法;分析了聚合工艺、单体种类、温度、乳化剂和引发剂种类及用量等因素对聚丙烯酸酯核壳乳液合成及性能的影响;并对聚丙烯酸酯核壳乳液的研究现状进行了归纳;最后,展望了聚丙烯酸酯核壳乳液的发展方向。     

PMMA/P(AN-MMA)纳米复合粒子的制备与形貌表征

采用种子乳液聚合的方法制备PMMA／P(AN-MMA)纳米复合粒子,在第二阶段聚合过程中分别采用水溶性引发剂、油溶性引发剂以及氧化还原引发体系,通过透射电子显微镜(TEM)来观察复合乳胶粒子的形态结构,得到的PMMA／P(AN-MMA)纳米复合粒子为半球形结构,与热力学理论预测结果一致。     

中空结构聚合物微粒的制备方法

对国内外有关中空结构聚合物微粒(包括微球和乳液粒子)的制备方法进行了综述，包括自组装法，模板法以及乳液法等。参考了国内外最新的40余篇论文和专利文献。     

聚苯乙烯乳胶球三维有序体的制备及其显微形貌表征

A three-dimensional (3D) ordered structure was achieved by self-organization of monodisperse polystyrene latex about 250nm in diameter after being ambient dried. The stacked morphology was investigated by scanning electron microscopy(SEM) observation. It is shown that the face-centered cubic(FCC) phase dominantly exists. This finding presents a potential template for preparing an inverse FCC structure as a photonic crystal of full band gap if the index contrast is higher than 2.8.     

无机中空球壳材料的制备方法

中空球壳材料具有低密度、高比表面积、高的稳定性和表面渗透性的特点,使其在化学、生物技术、材料科学领域具有极其广泛的应用前景,如用作微胶囊的缓释。还可用于药物疏运、轻质填料、形状选择吸收剂和催化剂等。本文就近几年来无机中空球壳材料的制备方法进行了综述。     

核壳型聚（丙烯酸丁酯/甲基丙烯酸十二酯）乳液的制备及表征

丙烯酸丁酯;甲基丙烯酸十二酯;核壳结构;制备     

中空纤维担载氧化硅膜的制备及结构研究

采用SXRD,HRTEM,FTIR,SEM和氮气吸附等测试手段对膜结构、形貌、孔径及其分布进行了表征.SXRD和HRTEM结果显示,所制备的膜具有短程有序结构.SEM分析发现膜表面完整.气体渗透实验表明,担载膜具有一定的气体选择性,在0.1MPa下对H₂/N₂和CH₄/N₂的分离因子分别为2.25和1.56,气体透过膜孔的扩散由努森机制所控制.等温氮气吸附实验显示,经500℃热处理后氧化硅膜的最可几孔径小于3.34nm,非担载膜的比表面积为919.8m²/g,孔容为0.43mL/g.     

微波辐照制备多孔乳胶粒

在微波辐照的条件下，通过间歇无皂种子乳液聚合，制得聚[苯乙烯－甲基丙烯酸甲酯－丙烯酸]复合乳液。将所得复合胶乳进行碱／酸分段处理，得到具有多孔结构的乳胶粒。用透射电镜对胶粒形态进行了表征，研究了不饱和酸用量、碱处理初始pH值及碱处理时间对胶粒成孔的影响。     

P(St-EAE-MAA)共聚物多孔微球的合成

利用无皂种子乳液聚合法合成了以聚苯乙烯(St)为骨架、丙烯酸乙酯(EA)和甲基丙烯酸(MAA)为共聚单体的P(St-EA-MAA)共聚物乳液;乳液经碱酸分步处理法制得共聚物多孔微球.考查了MAA用量和碱酸处理温度对微球形态的影响.     

含丙烯酸的苯丙共聚乳液乳胶粒形态的电镜研究

采用透射电镜观测了苯乙烯-丙烯酸丁酯-丙烯酸乳液共聚体系的乳胶粒形态,讨论了组分含量、共聚物链柔性和乳液pH值等因素对乳胶粒形态、乳液粘度及成膜性的影响.结果表明:软单体的加入和体系pH值的提高将促进乳胶粒的粘连成膜和溶涨及部分聚合物的溶解.羧基主要富集于乳胶粒表面.     

Preparation and Characterization of Polymer Core Shell Latex Particles

Stable core‐shell latex was synthesized by semicontinuous seeded emulsion polymerization with core monomers consisting of styrene (St), butyl acrylate (BA), and shell monomers consisting of methyl methacrylate (MMA), eutyl acrylate (EA), and methacrylic acid (MAA). The effects of compound emulsifier amount, mass ratio of anionic/nonionic emulsifier, and initiator amount on latex performance were investigated. By particle size analysis and transmission electron microscopy (TEM) observation, results suggest that final latex particles have clearly core shell structures.     

镶嵌型乳胶粒子的合成

以苯乙烯、甲基丙烯酸甲酯、丙烯腈等单体或它们的混合物为硬单体,天然胶乳为弹性组分,经多步种子乳液聚合法制得了在天然胶乳的粒子上镶嵌硬聚合物相的互穿网络型乳胶粒子.考察了十二烷基硫酸钠、十二烷基苯磺酸钠、壬基酚聚氧乙烯醚、油酸等乳化体系,过硫酸钾、过氧化苯甲酰热引发体系及异丙苯过氧化氢-四乙烯五胺、叔丁基过氧化氢-四乙烯五胺等氧化还原引发体系对聚合反应的影响.研究了交联剂用量对互穿结合率、溶胶含量的影响及溶胀时间、硬单体组成、乳化剂种类对乳胶粒子形态的影响,确定了适宜的聚合配方和工艺条件.透射电镜观察乳粒形态结果表明,单一使用极性或非极性单体,仅得到核-壳结构乳液,而采用不同极性单体复合、溶胀、互穿,得到的是镶嵌硬聚合物型乳粒结构.     

多孔结构聚合物乳胶粒

介绍了多孔结构乳胶粒的制备方法、表征手段以及成孔机理。着重阐述了“碱酸分段处理法”中不饱和酸与交联剂的种类与用量、以及碱酸处理条件等因素对乳胶粒成孔的影响。     

微波种子乳液聚合制备多孔乳胶粒

微波辐照下，通过间歇无皂种子乳液聚合制得聚(苯乙烯-甲基丙烯酸甲酯-丙烯酸)复合乳液，将所得复合乳液进行碱／酸分段处理，得到具有多孔结构的乳胶粒。用透射电镜对胶粒形态进行了表征。研究了酸处理初始pH值及酸处理时间对胶粒成孔的影响。     

氯丁胶乳-聚甲基丙烯酸甲酯复合乳胶粒结构形态

以氯丁胶乳（Pa）为种子乳液,甲基丙烯酸甲酯（Pb）为第二单体,采用种子乳液聚合法,制备了氯丁胶乳-聚甲基丙烯酸甲酯复合乳胶粒。 热力学分析表明,当Pb的体积分数Φb＜0.69时,可同时形成Pa-Pb型正核-壳和（Pa＋Pb）分离型乳胶粒,当Φb＞0.69时,形成Pb-Pa型翻转型核壳结构乳胶粒,并伴有Pa-Pb型正核-壳结构乳胶粒的形成。 动力学分析表明,引发剂类型、第二单体的加入方式、种子乳胶粒的交联、单体/聚合物质量比是影响乳胶粒形态的主要因素。 采用水溶性引发剂过二硫酸钾（KPS）,以饥饿态方式加入单体,氯丁胶乳 聚甲基丙烯酸甲酯(PCR-PMMA)复合乳胶粒呈现正核-壳结构,以充溢态方式加入单体则不能形成明显的核-壳结构;而以油溶性偶氮二异丁腈（AIBN）为引发剂时,单体无论以充溢态方式加入还是饥饿态加入均倾向于形成翻转核-壳型粒子。 在种子乳胶粒中加入一定量交联剂二缩三乙二醇二甲基丙烯酸酯,有利于形成明显的正核壳结构。 以饥饿态进料,KPS为引发剂时,随着单体用量增加,壳层变厚,仍呈正核-壳结构,与热力学分析结果相吻合;以AIBN为引发剂时,随着单体用量增加,PCR-PMMA复合乳胶粒逐渐由翻转核壳型结构变为互穿结构。     

Preparation of block copolymers of polystyrene and poly (t‐butyl acrylate) of various molecular weights and architectures by atom transfer radical polymerization

Block copolymers of polystyrene and poly(t‐butyl acrylate) were prepared using atom transfer radical polymerization techniques. These polymers were synthesized with a CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine catalyst system and had predictable molecular weights based on the degree of polymerization, as calculated from the initial ratio of monomer to initiator. The final polydispersities were low (1.10 < M_w /M_n < 1.3) for all the homopolymers and block copolymers. Polymers of various chain architectures were prepared, ranging from linear AB diblocks to three‐armed stars composed of AB diblocks on each arm. The key to controlled synthesis with this catalyst system was the choice of the solvent, temperature, and concentrations of catalyst and deactivator. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2274–2283, 2000     

Synthesis of Well‐Defined Amphiphilic Core–Shell Particles Containing Amine‐Rich Shells

A new route to synthesize amphiphilic core–shell particles that consist of well‐defined hydrophobic polymer cores and poly(vinylamine) (PVAm) shells has been developed. The PVAm was treated with a small amount of tert‐butyl hydroperoxide to generate free radicals that subsequently initiated both graft‐ and homo‐polymerization of vinyl monomer such as n‐butyl acrylate, methyl methacrylate, and styrene. Stable particles in the range from 100 to 250 nm in diameter with very narrow size distributions (polydispersity index between 1.08 and 1.15) were produced in high yields. TEM images of the particles revealed that they had well‐defined core–shell nanostructures with thick and hairy PVAm shells. The structures of the vinyl monomer and water‐soluble polymer were found to strongly influence the formation of particles and their sizes.