纳米TiO2/P(MMA-BA-MAA)复合粒子的制备及聚合动力学

用乳液聚合法制备了纳米TiO₂/甲基丙烯酸甲酯-丙烯酸丁酯-甲基丙烯酸共聚物［TiO₂/P(MMA-BA-MAA)］复合粒子。考察了乳化剂的浓度、单体的用量比对复合粒子形貌的影响。系统研究了乳化剂浓度、引发剂用量、单体用量比、共乳化剂浓度、反应温度对TiO₂/P(MMA-BA-MAA)复合粒子包覆反应动力学影响。用TEM、FTIR及TG分析等证实P(MMA-BA-MAA)包覆在TiO₂表面形成表面光滑、分散性好的球形核 壳复合粒子。根据动力学实验结果,求出整个乳液聚合包覆反应的反应速率方程,反应的表观活化能为163.0 kJ.mol^-1。推测可能的包覆反应机理应为无机纳米TiO₂表面吸附乳化剂分子形成所谓的TiO₂/surfactant胶束成核或均相凝聚成核。TG结果显示,复合粒子的热稳定性高于相同条件下得到的共聚物的稳定性。ζ电位、接触角实验表明,与纳米TiO₂相比,复合粒子亲水性能下降、亲油性能提高。     

纳米TiO2/P(MMA-BA-MAA)复合粒子的制备及聚合动力学

用乳液聚合法制备了纳米TiO₂/甲基丙烯酸甲酯-丙烯酸丁酯-甲基丙烯酸共聚物［TiO₂/P(MMA-BA-MAA)］复合粒子。考察了乳化剂的浓度、单体的用量比对复合粒子形貌的影响。系统研究了乳化剂浓度、引发剂用量、单体用量比、共乳化剂浓度、反应温度对TiO₂/P(MMA-BA-MAA)复合粒子包覆反应动力学影响。用TEM、FTIR及TG分析等证实P(MMA-BA-MAA)包覆在TiO₂表面形成表面光滑、分散性好的球形核 壳复合粒子。根据动力学实验结果,求出整个乳液聚合包覆反应的反应速率方程,反应的表观活化能为163.0 kJ.mol^-1。推测可能的包覆反应机理应为无机纳米TiO₂表面吸附乳化剂分子形成所谓的TiO₂/surfactant胶束成核或均相凝聚成核。TG结果显示,复合粒子的热稳定性高于相同条件下得到的共聚物的稳定性。ζ电位、接触角实验表明,与纳米TiO₂相比,复合粒子亲水性能下降、亲油性能提高。     

原位乳液聚合制备丙烯腈聚合物/纳米氧化硅复合粒子

利用2,2'-偶氮(2-脒基丙烷)二氯化氢(AIBA)引发剂与纳米氧化硅粒子的静电作用而使AIBA吸附在纳米氧化硅表面,进而引发丙烯腈-甲基丙烯酸甲酯(AN-MMA)原位乳液聚合.考察了AIBA浓度和反应温度对AN-MMA原位乳液聚合动力学的影响以及氧化硅含量对AN-MMA共聚物/纳米氧化硅复合乳胶粒径分布和形态的影响.结果表明:聚合速率随AIBA浓度和聚合温度的升高而增大; AIBA浓度相同时,原位乳液聚合速率小于普通乳液聚合;AN-MMA共聚物/纳米氧化硅复合粒子粒径随纳米氧化硅含量增加而增大;原位乳液聚合得到的复合胶粒表面粗糙,当纳米氧化硅质量分数为10%时,纳米氧化硅与聚合物乳胶粒子复合良好;当纳米氧化硅质量分数为20%和30%时,有部分纳米氧化硅粒子与乳胶粒子分离而分散在连续相中.     

细乳液聚合法TiO_2/PMMA纳米复合粒子的制备及其性能

采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯(TiO2/PMMA)纳米复合粒子,研究了引发剂、助乳化剂、乳化剂、单体结构对TiO2/PMMA纳米复合粒子性能的影响。结果表明,十六烷(HD)比十二醇和十六醇更能有效抑制甲基丙烯酸甲酯(MMA)液滴在水相中的Ostwald熟化效应,当MMA占TiO2质量的60%,HD占单体质量的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵(DNS-86)占整个体系质量的2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185 nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备喷墨印花用白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。     

纳米TiO2/SiO2复合食品抗菌材料

以水玻璃和Ti(SO4)2为原料,制备出了多孔的纳米TiO2/SiO2复合粒子,在后处理过程中,利用无机包覆剂溶解度随温度的变化,在复合粒子表面包覆了一层无机结晶膜,经热处理除去包覆剂后,得到了以单分散纳米复合粒子组成的复合微粉.对复合微粉进行比表面和孔容测试,并运用XRD和TEM进行了表征,发现TiO2以12.6nm的纳米晶粒的形式被多孔的SiO2包覆,所形成的复合粒子则约为20nm.为了了解复合微粒的灭菌效果,运用纳米TiO2和复合粉末对4种保健食品进行对照灭菌实验,两个月以后,测得含复合微粒的样品中的菌落总数为50～120个/g,是相应保健食品企业标准许可菌落数的0.25%～0.7%,为相应空白样和纳米TiO2粉样品菌落数的0.52%～0.97%和33.3%～83.3%.     

纳米TiO_2/SiO_2复合食品抗菌材料

以水玻璃和Ti(SO4) 2 为原料 ,制备出了多孔的纳米TiO2 /SiO2 复合粒子 ,在后处理过程中 ,利用无机包覆剂溶解度随温度的变化 ,在复合粒子表面包覆了一层无机结晶膜 ,经热处理除去包覆剂后 ,得到了以单分散纳米复合粒子组成的复合微粉。对复合微粉进行比表面和孔容测试 ,并运用XRD和TEM进行了表征 ,发现TiO2 以 12 .6nm的纳米晶粒的形式被多孔的SiO2 包覆 ,所形成的复合粒子则约为 2 0nm。为了了解复合微粒的灭菌效果 ,运用纳米TiO2 和复合粉末对 4种保健食品进行对照灭菌实验 ,两个月以后 ,测得含复合微粒的样品中的菌落总数为 5 0～12 0个 /g ,是相应保健食品企业标准许可菌落数的 0 .2 5 %～ 0 .7% ,为相应空白样和纳米TiO2 粉样品菌落数的 0 .5 2 %～ 0 .97%和 3 3 .3 %～ 83 .3 %。     

原位乳液聚合制备的聚丙烯酸丁酯/纳米SiO2复合粒子的形貌和形成机理

通过吸附于水相分散纳米SiO2粒子表面的2,2'-偶氮(2-脒基丙烷)二氢氯化物(AIBA)的引发作用,进行丙烯酸丁酯(BA)的原位乳液聚合,制备聚丙烯酸丁酯(PBA)/纳米SiO2复合乳胶粒.分别采用透射电镜观察复合粒子的形貌,高速离心分离/超声分散和氢氟酸腐蚀表征复合胶乳中PBA乳胶粒与纳米SiO2粒子的结合程度.发现有纳米SiO2粒子聚集于复合乳胶粒表面,复合粒子表面粗糙,呈"草莓形"结构;当复合粒子中SiO2质量分率为14.6%～22.6%时,60%左右的纳米SiO2富集于复合粒子表面,30%左右被包覆在复合粒子内部,另有少量游离于水相.采用原位乳液聚合得到的复合粒子中纳米SiO2与聚合物的结合牢度远大于以AIBA为引发剂合成的PBA乳液与纳米SiO2分散液直接混合所能达到的结合牢度.认为在原位乳液聚合过程中,由于纳米SiO2粒子表面锚固的PBA量的不同,引起SiO2粒子的亲水/亲油性和与PBA的相容性也不相同,导致出现以上的SiO2的分布特性和复合粒子形貌.     

基于细乳液聚合法TiO2/PMMA纳米复合粒子的制备及其性能

采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯（TiO2/PMMA）纳米复合粒子,考察了引发剂、助乳化剂、乳化剂、单体结构和种类对TiO2/PMMA纳米复合粒子性能的影响。结果表明与十二醇和十六醇相比,十六烷（HD）更能抑制甲基丙烯酸甲酯（MMA）液滴的Ostwald熟化效应,当MMA占TiO2质量分数的60%,HD对单体质量分数的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵（DNS-86）占整个体系的质量分数为2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。     

细乳液聚合制备聚丙烯腈/纳米SiO2复合粒子

由含甲基丙烯酸-3-三甲氧基硅烷(MPS)改性纳米SiO2的丙烯腈细乳液聚合制备聚丙烯腈/纳米SiO2复合粒子.研究了纳米SiO2的改性及含量、十二烷基硫酸钠(SDS)乳化剂和十六烷(HD)助乳化剂浓度对细乳化液滴粒径的影响.结果表明,直接采用未改性纳米SiO2,细乳化后出现双峰分布,纳米SiO2粒子未有效进入单体液滴;用10%MPS改性纳米SiO2后,细乳化液滴呈单峰分布.随着纳米SiO2粒子含量的增加,细乳化液滴的平均粒径增大,分布变宽.含纳米SiO2粒子的细乳化液滴体的平均粒径随SDS浓度和HD浓度增大而减小.透射电镜观察发现,细乳液聚合产物的连续相中无纳米SiO2粒子分布,复合粒子呈非规整结构,纳米SiO2>粒子在聚丙烯腈基体中基本呈初级粒子分布.     

国内期刊荟萃

水性聚氨酯-SiO2/TiO2复合涂料的制备与研究魏阳等.聚氨酯工业,2004,19(6):17采用溶胶-凝胶法制备了SiO2/TiO2纳米复合微粒,将其分散在聚醚型水性聚氨酯中,制备了新型水性聚氨酯-SiO2/TiO2复合涂料。经FTIR和TEM测试表明,纳米TiO2颗粒表面成功地包覆上SiO2。在聚氨酯乳液中复合微粒粒径为60nm左右;分光光度法测试表明TiO2质量分数为20%的复合微粒在聚氨酯水乳液中具有良好的分散性能;而加入质量分数为1%的十二烷基磺酸钠后,对SiO2/TiO2纳米粉末的分散性能改善最大;力学性能测试表明加入SiO2/TiO2纳米复合微粒质量分数为0.6%时…     

Heterocoagulation behavior of carbon black with surface encapsulation through emulsion polymerization

Nanocomposite microspheres containing styrene–acrylate resin, wax, and carbon black (CB) with desired CB dispersion were prepared through heterocoagulation. The CB surface was modified using conventional anionic emulsifier and anionic dispersants with different lengths of nonionic chains and reactivities or through polymer encapsulation via emulsion polymerization to regulate the dispersion and concentration of CB in the microspheres. Experimental results showed that anionic dispersants with long nonionic chains effectively dispersed and stabilized CB particles. Polystyrene (PS) was then encapsulated on the CB surface by using a reactive dispersant and a water‐soluble initiator of polymerization. The CB particles exhibited comparable pH stability with other heterocoagulation components. Overall, encapsulation through emulsion polymerization can be used to obtain not only high CB content but also improved CB distribution in the resulting microspheres. High coagulation efficiency can also be achieved using polystyrene‐encapsulated dispersed CB because of its high affinity to emulsifiers and reactive dispersants during dispersion. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43516.     

聚苯乙烯和聚丙烯酸丁酯无皂核壳乳液聚合反应的研究

聚苯乙烯 (PS)和聚丙烯酸丁酯 (PBA)复合乳液是无皂乳液聚合反应生成的 ,采用丙烯酸丁酯加到聚苯乙烯种子微粒中反应得到的。PS/PBA复合微粒的结构通过红外光谱图明显的吸收峰特征而得到证实。纯PS微粒和低BA含量的PS/PBA微粒几乎是球形和规则的 ,而随着BA单体含量的增加 ,PS/PBA复合微粒的粒子尺寸变大和呈现类似高尔夫球形状。同时 ,本文进一步研究了PS/PBA复合微粒的表面形态学     

聚苯乙烯-聚甲基丙烯酸甲酯核-壳粒子的制备

由种子乳液聚合法制备了聚苯乙烯-聚甲基丙烯酸甲酯核-壳粒子。以过硫酸钾(KPS)为引发剂,辛基酚聚氧乙烯醚(OP-10)为乳化剂,合成了聚苯乙烯(PS)种子核;连续滴加甲基丙烯酸甲酯(MMA),在核表面富集MMA,制备了粒径范围在0.16~0.67μm的核-壳粒子;当单体苯乙烯与甲基丙烯酸甲酯(St/MMA)的比为30∶70(质量比)时,所得粒径在0.18μm,粒径分布为0.012。差示扫描量热(DSC)研究显示,复合粒子的玻璃化转变温度(Tg)为97.2℃,峰形单一,表现出良好的热性能。     

Synthesis and characterization of poly(butyl acrylate)/silica and poly(butyl acrylate)/silica/poly(methyl methacrylate) composite particles

Poly(butyl acrylate)/poly(methyl methacrylate) (PBA/PMMA) core–shell particles embedded with nanometer‐sized silica particles were prepared by emulsion polymerization of butyl acrylate (BA) in the presence of silica particles preabsorbed with 2,2′‐azobis(2‐amidinopropane)dihydrochloride (AIBA) initiator and subsequent MMA emulsion polymerization in the presence of PBA/silica composite particles. The morphologies of the resulting PBA/silica and PBA/silica/PMMA composite particles were characterized, which showed that AIBA could be absorbed effectively onto silica particles when the pH of the dispersion medium was greater than the isoelectric potential point of silica. The critical amount of AIBA added to have stable dispersion of silica particles increased as the pH of the dispersion medium increased. PBA/silica composite particles prepared by in situ emulsion polymerization using silica preabsorbed with AIBA showed higher silica absorption efficiency than did the PBA/silica composite particles prepared by direct mixing of PBA latex and silica dispersion or by emulsion polymerization in which AIBA was added after the mixing of BA and silica. The PBA/silica composite particles exhibited a raspberrylike morphology, with silica particles “adhered” to the surfaces of the PBA particles, whereas the PBA/silica/PMMA composite latex particles exhibited a sandwich morphology, with silica particles mainly at the interface between the PBA core and the PMMA shell. Subsequently, the PBA/silica/PMMA composite latex obtained had a narrow particle size distribution and good dispersion stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3425–3432, 2006     

Preparation of polystyrene/poly(methyl methacrylate) core‐shell composite particles by suspension‐emulsion combined polymerization

Suspension‐emulsion combined polymerization process, in which methyl methacrylate (MMA) emulsion polymerization constituents (EPC) were drop wise added to styrene (St) suspension polymerization system, was applied to prepare polystyrene/poly(methyl methacrylate) (PS/PMMA) composite particles. The influences of the feeding condition and the composition of EPC on the particle feature of the resulting composite polymer particles were investigated. It was found that PS/PMMA core‐shell composite particles with a narrow particle size distribution and a great size would be formed when the EPC was added at the viscous energy dominated particle formation stage of St suspension polymerization with a suitable feeding rate, whereas St‐MMA copolymer particles or PS/PMMA composite particles with imperfect core‐shell structure would be formed when the EPC was added at the earlier or later stage of St suspension polymerization, respectively. It was also showed that the EPC composition affected the composite particles formation process. The individual latex particles would exist in the final product when the concentrations of MMA monomer, sodium dodecyl sulfate emulsifier, and potassium persulfate initiator were great in the EPC. Considering the feature of St suspension polymerization and the morphology of PS/PMMA composite particles, the formation mechanism of PS/PMMA particles with core‐shell structure was proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of polystyrene/poly(butyl acrylate) core–shell latex and its surface morphology

A polystyrene (PS)/poly(butyl acrylate) (PBA) composite emulsion was produced by seeded emulsion polymerization of butyl acrylate (BA) with PS seed particles which were prepared by emulsifier‐free polymerization of styrene with potassium persulfate (KPS) under a nitrogen atmosphere at 70°C for 24 h with stirring at 60 rpm and swelled with the BA monomer in an ethanol/water medium. The structure of the PS/PBA composite particles was confirmed by the presence of the characteristic absorption band attributed to PS and PBA from FTIR spectra. The particles for pure PS and PS/PBA with a low content of the BA monomer were almost spherical and regular. As the BA monomer content was increased, the particle size of the PS/PBA composite particles became larger, and more golf ball‐like particles were produced. The surface morphology of the PS/PBA composite particles was investigated by AFM and SEM. The T_g's attributed to PS and PBA in the PS/PBA composite particles were found at 110 and ?49°C, respectively. The thermal degradation of the pure PS and PS/PBA composite particles occurred in one and two steps, respectively. With an increasing amount of PBA, the initial thermal decomposition temperature increased. On the contrary the residual weight at 450°C decreased with an increasing amount of PBA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 595–601, 2003     

聚苯乙烯-聚甲基丙烯酸甲酯核-壳粒子的制备及性能

由种子乳液聚合法制备了聚苯乙烯-聚甲基丙烯酸甲酯核-壳粒子。以过硫酸钾（KPS）为引发剂，分别以非离子型辛基酚聚氧乙烯醚（OP—10）和复合十二烷基硫酸钠（SDS）／OP—10（质量比为1：4）为乳化剂，合成了聚苯乙烯种子核。连续滴加甲基丙烯酸甲酯（MMA），以OP—10乳化的种子乳液可以制备粒径范围在0．16～0．67μm的核-壳粒子，当单体苯乙烯与甲基丙烯酸甲酯（St／MMA）的质量比为3：7时，所得粒径为0．18μm，粒径分散系数为0．012。而以OP-10／SDS质量比为4：1制备的种子乳液所得核壳粒子直径在毫米级。差示扫描量热研究显示，以OP-10乳化所得种子乳液制衢的复合粒子的玻璃化转变温度为97．2℃，峰形单一，表现山良好的热性能。     

A convenient approach to synthesize stable silver nanoparticles and silver/polystyrene nanocomposite particles

In this study, silver nanoparticles were prepared by the reduction of silver nitrate in SDS+ isopentanol/styrene/H₂O reverse microemulsion system using sodium citrate as reducing agent. The Ag/PS nanocomposite particles were prepared by in situ emulsion polymerization of the styrene system containing silver nanoparticles that did not separate from the reaction solution. The polymerization dynamic characteristic was studied, at the same time, silver nanparticles and the encapsulation of composite particles were characterized by Fourier‐transform‐infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X‐ray diffraction (XRD) measurement, UV–vis diffuse reflectance spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The results of TEM and UV–vis absorption spectra showed that well‐dispersed silver nanoparticles have a narrow size distribution. XRD showed that Ag and Ag/PS nanocomposite particles were less than 10 and 20 nm in size, which is similar to those observed by TEM. The results of XPS spectra revealed that the microemulsion system can stabilize the silver nanoparticles from aggregation and provided supporting evidence for the polystyrene encapsulated silver nanoparticle structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

紫外光引发乳液聚合制备P(St-co-MMA)复合微球

以十二烷基硫酸钠为乳化剂,2,2-二甲氧基-2-苯基苯乙酮等为引发剂,在水中由紫外光引发苯乙烯(St)和甲基丙烯酸甲酯(MMA)进行乳液聚合,研究了引发剂种类及乳化剂用量对反应收率和微球粒径的影响,并与光引发分散聚合体系进行了比较。结果表明,乳液聚合速率大于分散聚合,由乳液聚合得到的P(St-co-MMA)微球的粒径均一,可控制在70～140 nm之间。     

细乳液聚合制备二氧化钛/聚苯乙烯复合微球及其形貌分析

采用细乳液聚合法,以γ-甲基丙烯酰氧基丙基三甲基硅烷改性的TiO2粒子为核,制备了核壳结构的TiO2/聚苯乙烯(PS)复合微球。研究了超声细乳化时间、乳化剂十二烷基硫酸钠(SDS)的浓度、TiO2用量对细乳液粒径及其分布的影响。通过纳米粒度与Zeta电位分析仪、红外光谱、透射电镜等分析手段对产物进行了表征。结果表明,随着超声细乳化时间的增加,初始液滴的粒径变小。聚合后的乳胶粒粒径随着SDS浓度的增大而减小;TiO2用量不足导致乳胶粒粒径分布变宽,且出现双峰;制备所得的TiO2/PS复合微球粒度分布较为均匀,平均直径为176.5 nm,球形规整度较好。