苯乙烯无皂乳液聚合接枝纳米TiO2的研究

采用无皂乳液聚合法，使苯乙烯单体（St）在烷基化预处理的纳米TiO2粒子的表面进行接枝聚合，得到了稳定的以纳米TiO2粒子为核、接枝聚苯乙烯为壳的复合颗粒（TiO2-g-PS）。研究了烷基化预处理以及聚合条件（单体浓度、引发剂浓度、反应时间）对TiO2表面接枝改性的影响，并对其聚合机理进行了探讨。结果表明：PS以化学键成功地接到纳米TiO2的表面，并且可以通过改变接枝聚合的条件来调节粒子上所接聚苯乙烯的结构，为进一步优化纳米粒子填充聚合物复合材料的结构和性能之间的关系建立基础。     

片状铝粉表面包覆SiO2薄膜的研究

采用溶胶-凝胶法在片状铝粉表面包覆SiO2薄膜，以改善其耐酸性能。分析了正硅酸乙酯（TEOS）水解一缩聚反应在粒子表面包覆SiO2膜的形成机理，并以此制备了SiO2／AI复合粒子。研究表明，最佳反应条件为：采用并流滴加TEOS、催化剂和蒸馏水的混合液的加料方式，msio2/mAl为20％，水硅比控制在30～50之间。采用IR、SEM、EDS及粒度分析等方法对包覆后的样品进行了分析与表征。     

自交联型聚丙烯酸酯对铝颜料包覆方法研究

基于自由基溶液聚合方法合成自交联型聚丙烯酸树脂，基于高分子溶液的相分离原理对铝粉进行包覆改性，系统研究了包覆工艺、包覆量、包覆剂玻璃化转变温度和交联度对改性后铝粉耐酸性能的影响。利用热失重（TG）对复合粒子表面包覆量进行表征，利用差示扫描量热（DSC）对样品的玻璃化转变温度进行表征，利用傅里叶变换红外（FT-IR）光谱对复合粒子的表面官能团进行表征，利用扫描电镜（SEM）对复合粒子表面形貌进行表征。实验研究表明：改性后的铝粉表面附有一层致密的聚合物膜，与有机小分子包覆的原料铝粉相比，其在酸液中的缓蚀率达到85%以上。     

丙烯酸丁酯原位乳液接枝纳米TiO2的研究

为了提高纳米二氧化钛（TiO2）粒予在聚合物基复合材料中的分散性,需要对粒子的表面进行改性。实验采用无皂乳液聚合法,使丙烯酸丁酯单体（BA）在偶联剂KH-570烷基化预处理的纳米TiO2粒子的表面进行接枝聚合,研究了偶联剂用量对烷基化预处理程度的影响,以及聚合条件对TiO2表面接枝效果的影响,并对其聚合机理进行了探讨。结果表明,PBA以化学键成功地接到纳米TiO2的表面,并且可以通过改变接枝聚合条件来调节粒子上所接聚丙烯酸丁酯的结构,为进一步优化纳米粒子填充聚合物复合材料的结构和性能之间的关系建立基础。     

紫外光诱导甲基丙烯酸甲酯/二氧化硅复合微粒的制备研究

紫外光诱导二氧化硅（SiO2）表面接枝聚合甲基丙烯酸甲酯（MMA），制备MMA／SiO2复合微粒。分析了紫外光、紫外光诱导时间、光引发剂二苯甲酮（BP）、除氧剂高碘酸钠、丙烯酰胺（AAM）对紫外光诱导化学接枝的影响。在MMA／SiO2溶胶体系，紫外光诱导60min，BP与SiO2质量比约3％，高碘酸钠的乙醇溶液质量浓度为0.3g／L的工艺条件可有效进行化学接枝反应，单体和SiO2之间形成了共价键，成功化学接枝到SiO2表面。诱导时间影响化学接枝，加入AAM单体后缩短诱导时间，AAM参与反应。XRD分析显示，高碘酸钠在紫外光诱导下与氧作用，生成碘酸钠和自由基，既起到了除氧的作用，又引发光化学接枝反应。     

线形低密度聚乙烯粉料固相光接枝丙烯酸的研究

采用接枝率测定、红外光谱、光电子能谱、接触角、剥离强度等测试，研究了紫外线（UV）引发丙烯酸（AA）固相表面接枝线形低密度聚乙烯（PBLLD）粉料的影响因素（温度、单体浓度和反应时间），接枝PE—LLD表面结构、微观形态和性能。结果表明：UV能高效地引发AA在PE-LLD材料表面接枝聚合，随辐照时间延长、温度升高和单体浓度增大，接枝率增大，在实验条件下达到满足实际应用所需接枝率（约0．5％质量含量）的反应时问可达分钟数量级。接枝改性后，PE-LLD与水的接触角下降，亲水性增强；对钢材和聚乙烯黏接强度提高。     

聚甲基丙烯酸甲酯／纳米SiO2复合粒子的制备与表征

采用甲基丙烯酸-3-甲氧基硅丙酯（MPs）对分散于甲基丙烯酸甲酯（MMA）中的纳米SiO2粒子进行偶联改性，得到了表面改性的纳米SiO2单体分散液，用原位悬浮聚合方法制备了不同SiO2含量的PMMA／纳米SiO2复合粒子。通过红外光谱、透射电镜、差示扫描量热分析和热重分析等方法对制备的纳米复合粒子进行了表征，结果表明，纳米SiO2粒子在PMMA中分散良好；MMA可通过与MPS的共聚而有效地接枝到SiO2粒子表面，当SiO2含量为6．6％（质量分数，下同）、MPS用量为0．06g／gSiO2时，其接枝率可达73．8％；同时，纳米SiO2的引入可提高PMMA的耐热性能，当Si02含量为14.7％时，其玻璃化转变温度和最大热分解速率时的温度分别提高了11．8℃和18．8℃。     

表面接枝制备PMMA/纳米TiO_2复合粒子的研究

采用表面接枝反应的方法,在纳米TiO2上接枝偶联剂KH-570引入化学键结合的不饱和双键,通过乳液聚合制备了化学接枝的PMMA/纳米TiO2复合粒子。研究了聚合条件对接枝率的变化和微观形态的影响。FT-IR和TGA分析结果表明,TiO2表面偶联剂接枝率为8.86%,聚合物接枝率达62.7%;TEM观察表明,偶联剂处理使纳米TiO2的亲油性提高且粒径没有增加,聚合物接枝后的复合粒子分散性提高。     

丙烯酰胺型氧氟沙星吸附材料的制备及性能研究

采用自由基聚合法,在溶液聚合体系中将功能单体丙烯酰胺（AM）接枝于聚丙烯伯胺树脂球（PSA）表面,制得了接枝微粒PAM/PSA,考察了主要因素对接枝聚合的影响,并探究了其对氧氟沙星的吸附行为。结果表明,在引发单体AM进行接枝聚合的反应中,适宜的条件为：在温度为30℃、单体浓度为11.1%、引发剂用量0.4 g的条件下,在乙醇溶液中反应8 h,可制得接枝度为476.9 mg·g^-1的接枝微粒,其对氧氟沙星的最大吸附量达到118 mg·g^-1。     

纳米二氧化硅颗粒表面接枝改性的研究

本工作选择马来酸酐和苯乙烯单体在纳米二氧化硅粒子表面进行接枝改性,首先对纳米粒子进行烷基化处理,引入双键,然后引发聚合,使得马来酸酐和苯乙烯与纳米粒子之间形成化学键合。详细研究了各种聚合条件(引发剂浓度、单体加入量的比例、反应温度等)对接枝效果的影响,认为烷基化改性后的纳米二氧化硅粒子在聚合体系中充当极性溶剂中心的作用,控制马来酸酐和苯乙烯在粒子表面的接枝。     

聚合物原位复合纳米碳酸钙增韧PP研究

通过有机单体原位聚合包覆的CaCO3与PP熔融混合制备了PP／CaCO3纳米复合材料，经过正交实验研究了填料饱覆聚合物比、接枝聚丙烯以及复合填料含量对PP缺口冲击强度的影响，结果表明：复合纳米CaCO3只需填加5％就可以将缺口冲击强度提高为原树脂的2倍左右。     

聚苯乙烯接枝包覆硫磺微胶囊的制备与表征

以合成硫磺为芯材,聚苯乙烯为壳材,采用原位接枝改性聚合方法制备了聚苯乙烯接枝包覆硫磺微胶囊,研究了不同苯乙烯/硫磺颗粒配比对微胶囊形貌的影响,制备了粒径均一分布的硫磺微胶囊,且分散均匀。结果表明苯乙烯的含量对微胶囊的表面形貌有很大影响,经包覆之后硫磺微胶囊的热稳定性提高。     

Preparation of nano-ZnO/PMMA composite particles via grafting of the copolymer onto the surface of zinc oxide nanoparticles

The grafting of polymers onto the surface of zinc oxide nanoparticles and radical copolymerization of methyl methacrylate (MMA) and methacrylic acid (MAA) were investigated. The copolymer chains encapsulating nanoparticles were anchored onto the surface of nano-ZnO through reactions of carboxyl groups with ZnO. Grafting percentage and grafting efficiency of composite particles were investigated by employing thermogravimetric analysis (TGA). FT-IR and ¹³C NMR showed that there existed a strong interaction at the interface of nano-ZnO and copolymer, which implied that the copolymer chains were grafted onto the surface of ZnO nanoparticles. Nano-ZnO being encapsulated by copolymer was confirmed by using transmission electron microscopy (TEM). Additionally, TGA plots showed that the presence of ZnO nanoparticles improved the thermal stability of copolymer to a certain extent. Another important finding is the copolymerization and grafting reaction did not alter the crystalline structure of the ZnO nanoparticles according to the X-ray diffraction patterns. It can also be seen from scanning electron microscope (SEM) that grafted polymer chains on nanoparticles interfere with the aggregation of ZnO nanoparticles in polymer matrix and improve their compatibility with the polymeric matrix.     

炭黑亲水性改性的研究进展

从炭黑的元素组成和表面官能团出发,介绍了增强炭黑亲水性改性的3种方法:氧化改性、接枝改性和包覆改性。氧化改性分为气相氧化、液相氧化、阳极氧化和等离子体氧化,接枝改性分为捕获性接枝、引发性接枝和反应性接枝,包覆改性的方法有微乳液聚合包覆和相分离法包覆。亲水性改性后的炭黑对水的润湿性增强,在水中分散更稳定。     

Preparation of monodispersed PNIPAm/silica composites and characterization of their thermal behaviors

Two types of thermosensitive poly(N-isopropylacrylamide) (PNIPAm)-silica organic/inorganic hybrid particles were successfully prepared in aqueous solution through a facile synthetic process. Silane coupler of vinyl organic groups connects the PNIPAm to silica. First, hybrid spheres were prepared by grafting PNIPAm polymers to VTMS (vinyl trimethoxysilane) silica spheres. The thickness of polymer shell on the silica surfaces could be easily controlled by varying the concentrations of NIPAm monomer. Second, another type of hybrid particle was fabricated by encapsulating PNIPAm polymer with silica materials. The PNIPAm polymers were completely encapsulated by silica shell. The morphologies and shell thickness were characterized through SEM and TEM. The variations of phase transition temperature of PNIPAm were measured using DSC.     

Nano‐reactors for controlling the selectivity of the free radical grafting of maleic anhydride onto polypropylene in the melt

This paper reports on a successful application of the concept of nanoreactors to effectively controlling the selectivity of the free radical grafting of maleic anhydride (MAH) onto polypropylene (PP) in the melt, an industrially relevant process. More specifically, a free radical initiator of type ROOR was first confined into (or encapsulated by) the galleries of an organically modified montmorillonite (o‐MMT) whose interdistance was 2.4 nm. Primary free radicals (RO ·) formed inside the o‐MMT galleries had to diffuse out before they could react with the PP backbone. The controlled release of the primary free radicals significantly increased the grafting degree of MAH onto PP and greatly reduced the level of the chain scission of the latter. Those results were better understood by electron spin resonance studies on model systems and by Monte Carlo simulations. POLYM. ENG. SCI. 46:1443–1454, 2006. © 2006 Society of Plastics Engineers.     

Preparation of cationic pigment dispersions by surface grafting of polystyrene‐maleic anhydride with glycidyltriethylammonium chloride

Novel cationic pigment dispersions, which have potential uses in inkjet inks and coloration of textile and paper, were prepared by grafting quarternary ammonium groups onto the surface of polystyrene‐maleic anhydride encapsulated C. I. pigment yellow 14 (PY 14) powder. It is shown that the Zeta potentials greatly rely on the reaction time and temperature. And also, when the weight ratio of glycidyltriethylammonium chloride (GTA) to encapsulated PY 14 powder was 3 : 1, the Zeta potential of modified pigment dispersion reached to + 35.05 mV. Just due to the high Zeta potential of the prepared cationic pigment dispersions, the prepared cationic pigment dispersion shows good dispersion stability and a narrow size distribution with the average particle size of 202.9 nm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

表面处理对PP/Al2O3性能与结晶的影响

为了改善无机粒子在聚合物基体中的分散性与相容性 ,采用 2种表面处理方法 :硅烷偶联剂KH5 70表面处理Al2 O3粒子得到烷基化粒子 ;另外在此基础上采用溶液聚合法在烷基化Al2 O3粒子表面进行MMA与单体的接枝聚合 ,制备PMMA包覆Al2 O3复合粒子Al2 O3-g -PMMA。采用XPS、IR研究烷基化粒子与复合粒子表面结构 ,同时通过无机粒子直接填充法与PP基体复合获得Al2O3/PP复合材料并研究其力学性能与结晶行为     

Study on Encapsulation of Diethyl Phenyl Acetamide in Calcium-Alginate Microsphere for Enhanced Repellent Efficacy

In this present study, diethyl phenyl acetamide (DEPA), a multi-insect repellent, was entrapped in a hydrophilic biodegradable polymer calcium alginate to increase its efficacy. For encapsulation, an emulsion technique followed by gelation method was adopted. Various characterizations of the formed DEPA-containing alginate microcapsules were carried out. Using UV-Vis spectrophotometer the λ_max of DEPA observed was at 259 nm. The particle size distribution of the encapsulated material was carried out by a dynamic light scattering (DLS) method and the mean diameter observed was (500 ± 50) nm. The entrapment of DEPA in the encapsulated material was confirmed by FTIR. The surface morphology, size, and shape of the encapsulated material was analyzed using atomic force microscopy (AFM), which showed encapsulated bead size around 250 nm with uniform distribution. The percentage entrapment of DEPA in the encapsulated samples was about (70 ± 5)%. A slow release study of DEPA from the encapsulated biopolymer (alginate) in isopropyl alcohol was also carried out, which showed continuous release up to five hours.     

Extraordinary aspects of bromo-functionalized multi-walled carbon nanotubes as initiator for polymerization of ionic liquid monomers

Two ionic liquid monomers, 1-(2-acryloyloxy-ethyl)-3-methyl-imidazol-1-ium iodide (AMImI) and 1-(2-acryloyloxy-ethyl)-3-methyl-benzoimidazol-1-ium iodide (AMBImI), were synthesized and polymerized through atom transfer radical polymerization (ATRP). Poly(AMImI)-grafted multi-walled carbon nanotubes (denoted as MWCNT-poly(AMImI)) could also be fabricated through “grafting from” method of ATRP using bromo-functionalized MWCNT (denoted as MWCNT–Br) as initiator but MWCNT-poly(AMBImI) could not. Based on the thermogravimetric analysis and high resolution transmission electron microscopy, AMBImI monomer has encapsulated the MWCNT–Br probably through the π-π and cation-π interactions invalidating the initiation capability of MWCNT–Br. Besides, by mixing AMBImI with MWCNT–Br directly at room temperature, the MWCNT–Br was coated with a thin layer of AMBImI, whereas MWCNT–Br could not physisorb AMImI. Both MWCNT-poly(AMImI) and AMBImI-encapsulated MWCNT were dispersed well in 1-methyl-3-propylimidazolium iodide ionic liquid.