超顺磁性高分子微球的制备与表征

用化学共沉淀方法制备了Fe3O4纳米微粒,并用油酸(十八烯酸)和十二烷基苯磺酸钠为双层表面活性剂进行表面修饰,制备了稳定的水分散性纳米Fe3O4可聚合磁流体.在Fe3O4磁流体存在下,将苯乙烯与甲基丙烯酸通过乳液聚合方法制备了磁性高分子微球.透射电镜研究表明,Fe3O4微粒的平均粒径在10nm左右,乳液聚合形成的磁性高分子微球的粒径平均约为130nm;用超导量子干涉仪对微粒及高分子微球进行了磁性表征,结果表明,合成的Fe3O4纳米微粒以及磁性高分子微球均具有超顺磁性.同时,还用红外光谱及X射线衍射表征了磁性高分子微球的化学成分和晶体结构.用热失重方法测得磁性高分子微球中磁性物质的含量为23.6%.     

微米级PSt,P(St/MAA)磁性高分子微球的合成Ⅰ. 温度、引发剂、介质极性、稳定剂量的影响

以Fe3O4为核，采用分散聚合法，合成了粒径为0．5－2．0μm、单分散性好、磁含量可达10％的PSt、P（St/MAA)磁性高分子微球。讨论了温度、引发剂、分散介质、稳定剂等因素对反应结果的影响。对所得磁性微球的外观形态、磁响应性进行了表征。     

分散聚合法制备液相芯片聚苯乙烯磁性复合微球的研究

本文将丙烯酸基磁流体均匀分散到苯乙烯单体中,采用分散聚合法制备出了适于构建液相芯片微球载体的单分散性微米级磁性微球.考察了丙烯酸基磁流体预处理时间、加料顺序和单体量对微球形貌和粒径分布的影响及其条件优化.扫描电镜(SEM)显示磁性微球平均粒径为7.77 μm,具有良好的单分散性(多分散指数PDI为1.03),并且表面光滑致密;用超导量子干涉磁强计测量了Fe3O4纳米粒子的磁化曲线;用红外光谱(FT-IR)和热失重(TG)方法表征了磁性微球的化学结构及Fe3O4含量.     

磁性多孔γ-Fe_2O_3/P(St-DVB-MAA)聚合物微球的制备及其表征

以油酸包裹的γ-Fe2O3为磁性来源,选用苯乙烯(St)、二乙烯苯(DVB)和甲基丙烯酸(MAA)为共聚单体,通过改进的悬浮聚合法,制备了表面含有羧基的多孔磁性高分子微球.利用红外光谱(FTIR)、扫描电子显微镜(SEM)、光学显微镜以及热重分析仪(TG)等对聚合物进行了性能表征.FTIR和光学显微镜结果分析表明,苯乙烯、二乙烯苯和甲基丙烯酸在磁性粒子的表面发生了聚合反应,生成了聚合物包埋磁粉的磁性聚合物复合微球,且微球表面含有羧基;SEM和光学显微镜分析测试结果显示合成的磁性γ-Fe2O3/P(St-DVB-MAA)复合粒子呈球形,微球具有多孔结构,且微球之间不发生团聚,微球粒子粒径分布均匀,大多数粒子粒径分布在0.4~0.9mm之间;TG测试的结果表明,磁性γ-Fe2O3被包覆在聚合物微球之中,且磁性粒子在微球中的包覆率达到12.12%.     

高Fe_3O_4含量单分散P(St/AA)复合微球的合成与表征

在表面由十一烯酸和油酸共同修饰的Fe3O4磁流体存在下,以苯乙烯(St)和丙烯酸(AA)为共聚单体,用细乳液聚合法,制备了单分散,高Fe3O4含量,且表面带有羧基的超顺磁性高分子复合微球.采用透射电镜(TEM),热重分析(TGA),物性测量系统(PPMS),Zeta电位以及红外光谱等手段对磁性复合微球的各项性能进行表征.结果表明,Fe3O4粒子的表面改性是影响复合微球Fe3O4含量及形貌的关键因素.在优化的实验条件下,可以制得Fe3O4含量高达77wt%,平均粒径为137·9nm,表面羧基密度0·0894mmol/g,比饱和磁化强度为44·7emu/g的单分散超顺磁性高分子复合微球.     

无皂乳液聚合法合成阴离子PS微球及粒径控制

以苯乙烯(St)和丙烯酸(AA)为单体,过硫酸钾(KPS)为引发剂,采用无皂乳液聚合法合成了单分散阴离子聚苯乙烯(PS)微球,并对微球结构和影响单分散性的因素进行了研究。结果表明,AA单体也已共聚到聚合物链上,AA的加入使PS微球粒径减小,并赋予PS微球表面负电性;聚合反应的活化能为42.95kJ/mol,升高聚合温度提高了反应速率;随着KPS用量的增加,PS微球粒径减小,在用量为0.6%时呈现最好单分散性;随着反应介质中丙酮含量增加,聚合物在介质中溶解度增加,使PS微球粒径有所减小,但微球粒径分布有所变宽。     

硫化物-高分子复合微球表面形貌与模板组成关系的研究

以N-异丙基丙烯酰胺(NIPAM)和甲基丙烯酸(MAA)为单体, 通过反相悬浮聚合法制备了多种MAA含量不同的阴离子型P(NIPAM-co-MAA)共聚微凝胶. 以这些共聚微凝胶为模板, 在不同表面活性剂存在下, 合成了一系列CuS(CdS、ZnS)-P(NIPAM-co-MAA)无机-有机复合微球材料, 研究了表面活性剂种类, 模板组成等因素对上述硫化物-高分子复合微球表面形貌的影响. 结果表明, 实验条件下所得复合微球表面均具有图案化结构, 该结构明显依赖于表面活性剂的种类和模板微凝胶的组成. 就模型体系而言, 随表面活性剂Span-20、Span-80和Span-85的HLB(亲水亲油平衡)值降低, 微球表面形貌趋于粗糙, 但仍然十分规整; 就模板组成而言, 模板中MAA含量增加使得复合微球的表面形貌变得更加精细. 据此, 认为通过选用合适的表面活性剂和微凝胶模板可以在一定范围内调控这些无机-有机复合微球的表面形貌, 从而为后续应用研究奠定基础.     

两亲磁性高分子微球的合成与表征

在Fe3O4磁流体存在下 ,通过苯乙烯与聚氧乙烯大分子单体 (MPEO)分散共聚制备两亲磁性高分子微球 .研究了聚氧乙烯大分子单体对微球粒径的影响 .用扫描电子显微镜 (SEM)、原子力显微镜 (AFM)表征了磁性微球的粒径、表面形貌以及表面粗糙度 ,用傅立叶红外光谱 (FTIR)鉴定了共聚物的结构 .随着聚合物中聚氧乙烯大分子单体含量的增加 ,微球表面的粗糙度增加 ,通过改变共聚物中MPEO的含量 ,可以得到含有 0 4～ 3 5mg g羟值的两亲磁性高分子微球     

分散聚合制备聚苯乙烯/聚氧乙烯两亲磁性高分子微球

采用分散聚合法，以乙醇／水为介质，在Fe3O4磁流体存在下，通过苯乙烯与聚氧乙烯大分子单体共聚制备休磁性高分子微球。 研究了聚合条件对微球粒径的影响。通过改变聚合条件，可以得到平均粒径为5μm-100μm的两亲磁性高分子微球。     

醇/水介质对PEG大分子单体与BMA分散共聚反应的影响

通过端基反应法合成了苯乙烯单封端的聚乙二醇(St- PEG)大分子单体,使其与甲基丙烯酸丁酯(BMA)在乙醇 水混合介质中进行分散共聚,得到了聚乙二醇接枝的聚甲基丙烯酸丁酯(PBMA- g -PEG)高分子微球.PBMA- g -PEG共聚物的亲溶剂 疏溶剂平衡将影响微球的形成,反应结束时,体系随BMA浓度和介质中水含量的变化呈现出4种不同的状态,透明清液、乳液、伴有沉淀或凝胶的乳液和凝胶.用透射电子显微镜(TEM)和激光光散射(LLS)对乳液体系的粒径及其形态进行了表征,表明所得接枝高分子微球形态规整具有较好的单分散性.通过控制介质中水的含量和BMA的浓度可得粒径在4 0～5 0 0nm范围的PBMA -g -PEG微球.     

Effect of Polymerization Condition on Particle Size Distribution in St/BA/MAA Emulsion Polymerization Process

IntroductionIn the last decade of this century, the carboxylation of latexes has received more andmore attention because of their practical application[']. The application includes adhesives,coatings, etc.. Many studies on the theory of carboxylation emulsion polymerization havebeen carried out. Most of these studies have focused on ideal monomer and single emulsifier inorder to simplify the system['J. But in practicable application, mixed monomers and mixedemulsifiers are often usedL3j. The…     

超声无皂乳液聚合制备BA/St/AM三元共聚物乳胶粒及其聚合机理研究

将超声技术引入到无皂乳液聚合方法中,在不加入任何引发剂和乳化剂的情况下,制备了丙烯酸丁酯(BA)/苯乙烯(St)/丙烯酰胺(AM)三元共聚纳米乳胶粒.研究了不同超声时间对单体转化率、乳胶粒粒径以及乳液粘度的影响.同时还探讨了超声无皂乳液聚合机理,认为AM在聚合过程中起到了引发和稳定的作用.TEM照片表明,乳胶粒直径大约在80nm左右,FTIR及DSC分析表明产物为三元共聚物,而不是共混物.     

微米级单分散共聚物微球的制备

用分散聚合法制备了苯乙烯 甲基丙烯酸甲酯微米级单分散共聚物微球 ,粒径为 5 4 μm .将分散聚合体系与乳液聚合体系进行了比较 ,并对共聚物微球的形貌、粒径分布及共聚情况进行了表征研究 .     

Synthesis of iron oxide/poly(methyl methacrylate) composite latex particles: Nucleation mechanism and morphology

A magnetic poly(methyl methacrylate) (PMMA) composite latex was prepared by soapless emulsion polymerization in the presence of ferrofluid, and the ferrofluid was prepared by means of a coprecipitation method. The effects of various polymerization parameters, such as the monomer concentration, ferrofluid content, and initiator concentration, on the conversion curve and particle size of the magnetic composite latex particles were examined in detail. The results showed that two nucleation mechanisms were involved according to the polymerization conditions. In the monomer‐rich and less ferrofluid system, self‐nucleation of PMMA was dominant over the entire course of emulsion polymerization. In the ferrofluid‐rich system, seeded emulsion polymerization was the main course to form the magnetic composite latex particles. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5695–5705, 2004     

Preparation of sulphonate-containing core/shell latex particles via seeded emulsion copolymerization

<正>In this study,P(St-MAA) seed latex particles were first prepared via soap-free emulsion polymerization of styrene(St) and methacrylic acid(MAA),then the seed particles were allowed to swell with St at room temperature,and the P(St-MAA)/P(StNaSS) core/shell latex particles were then synthesized via seeded emulsion copolymerization of St and sodium styrene sulphonate (NaSS) using AIBN as initiator in the presence of N,N'-methylenebisacrylamide(BAA,water-soluble crosslinker).Results showed that the polymerization could be carried out smoothly when the ratio of BAA to total monomers was less than 3 mol%,the narrow dispersed P(St-MAA) seed particles with the diameter of 150 nm and the P(St-MAA)/P(St-NaSS) core/shell latexes with the particle size of about 200 nm were synthesized.When the 25/75 mole ratio of NaSS/(St + MAA) and 2 mol%of BAA were used in the seeded emulsion polymerization,the resulted P(St-MAA)/P(St-NaSS) latex product showed a low weight loss after water extraction,and the NaSS unit content in the whole particle and in the shell reached 11.7 mol%and 34.6 mol%,respectively.     

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.     

Synthesis and morphology of Fe3O4/polystyrene/poly(isopropylacrylamide‐co‐methyl acrylate acid) magnetic composite latex – 2,2′‐azobis (2‐methylpropionamidine) dihydrochloride as initiator

In this work, Fe₃O₄/polystyrene/poly(N‐isopropylacryl amide‐co‐methylacrylate acid) (Fe₃O₄/PS/P(NIPAAM‐co‐MAA)) magnetic composite latex was synthesized by the method of two stage emulsion polymerization. In this reaction system, 2,2′‐azobis(2‐methyl propionamidine) dihydrochloride (AIBA) was used as initiator to initiate the first stage reaction and second stage reaction. The Fe₃O₄ particles were prepared by a traditional coprecipitation method. Fe₃O₄ particles were surface treated by either PAA oligomer or lauric acid to form the stable ferrofluid. The first stage for the synthesis of magnetic composite latex was to synthesize PS in the presence of ferrofluid by soapless emulsion polymerization to form the Fe₃O₄/PS composite latex particles. Following the first stage of reaction, the second stage of polymerization was carried out by the method of soapless emulsion polymerization with NIPAAM and MAA as monomers and Fe₃O₄/PS latex as seeds. The magnetic composite particles, Fe₃O₄/PS/P(NIPAAM‐co‐MAA), were thus obtained. The mechanism of the first stage reaction and second stage reaction were investigated. Moreover, the effects of PAA and lauric acid on the reaction kinetics, morphology, and particle size distribution were studied. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3912–3921, 2007     

有机硅氧烷改性St/BA/AA三元共聚乳液的制备

采用核壳乳液聚合法,制备了乙烯基三乙氧基硅烷（VTES）改性的St/BA/AA三元共聚乳液,其结构经FT IR确证。研究了VTES用量、乳化剂用量及配比和引发剂用量对单体转化率和粒径的影响。结果表明：在最优条件［48%St, 48%BA, 4%AA, 1%N-MA, 4%VTES, 8%乳化剂（OP-10/SDS=1/3）, 0.8%引发剂］下,单体转化率为95.8%,平均粒径242 nm。并研究了改性St/BA/AA乳胶膜(1)的耐溶剂性和铅笔硬度。结果表明：1具有良好的耐溶剂性,铅笔硬度为2H。     

高固含量低粘度P(MMA/BA/AA)乳液的制备及性能研究

先利用半连续种子乳液聚合法制备固含量为50%,粒径480nm的单分散甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)与丙烯酸(AA)的共聚物种子乳液;然后以上述种子乳液为介质,十二烷基硫酸钠为乳化剂,碳酸氢钠为缓冲剂,过硫酸铵为引发剂制备固含量72%,乳胶粒具有二元分布特征的高固含量、低粘度稳定乳液:其中大乳胶粒径500～600nm,小乳胶粒径约80nm.所得乳液中乳化剂总含量为聚合物质量的2.1%;粘度在剪切速率为21s-1时为400mPa·s.另外,相对于常规乳液,所制备高固含量乳液胶膜具有更好的光泽度.     

Synthesis and morphology of an iron oxide/polystyrene/poly(isopropylacrylamide‐co‐methacrylic acid) thermosensitive magnetic composite latex with potassium persulfate as the initiator

In this work, an iron oxide (Fe₃O₄)/polystyrene (PS)/poly(N‐isopropylacryl amide‐co‐methacrylic acid) [P(NIPAAM–MAA)] thermosensitive magnetic composite latex was synthesized by the method of two‐stage emulsion polymerization. The Fe₃O₄ particles were prepared by a traditional coprecipitation method and then surface‐treated with either a PAA oligomer or lauric acid to form a stable ferrofluid. The first stage for the synthesis of the thermosensitive magnetic composite latex was to synthesize PS in the presence of a ferrofluid by emulsion polymerization to form Fe₃O₄/PS composite latex particles. Following the first stage of reaction, the second stage of polymerization was carried out with N‐isopropylacryl amide and methacrylic acid as monomers and with Fe₃O₄/PS latex as seeds. The Fe₃O₄/PS/[P(NIPAAM–MAA)] thermosensitive magnetic particles were thus obtained. The effects of the ferrofluids on the reaction kinetics, morphology, and particle size of the latex were discussed. A reaction mechanism was proposed in accordance with the morphology observation of the latex particles. The thermosensitive property of the thermosensitive magnetic composite latex was also studied. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3062–3072, 2007