氨基功能化聚苯乙烯纳米微球的制备及其CO2吸附性能研究

以苯乙烯(St)和甲基丙烯酸缩水甘油酯(GMA)为共聚单体,通过细乳液聚合法制备出聚苯乙烯纳米微球,并研究了单体配比与反应条件对纳米微球粒径大小与分布的影响。然后利用GMA上的活性环氧基团将有机胺接枝到纳米微球表面,并将其应用于CO2吸附。采用动态激光散射、扫描电子显微镜、红外光谱、元素分析等方法对纳米微球进行了结构表征。结果表明,所制备的纳米微球最小粒径为67 nm,粒径大小均一可控,而且纳米微球表面成功地接枝上有机胺;乙二胺改性纳米微球的CO2吸附量为2.45 mmol/g,并且吸附循环稳定性较好。     

壳层交联剂对聚合物中空微球形貌的影响

以含羧基的乳胶粒为核,采用种子乳液聚合制备多层核壳聚合物微球,经碱液处理后可得聚合物中空微球。通过TEM、SEM、激光粒度和zeta电位仪等对制备的微球进行表征,研究了壳层交联剂DVB用量对聚合过程和微球形貌的影响。结果表明,控制单体滴加速度有利于含羧基核乳胶粒的制备;DVB用量过多会导致种子乳液聚合不稳定,凝胶量增多;随着壳层交联剂用量的增加,碱处理后的聚合物微球依次呈现塌陷和中空结构,空心率可达35.4%。     

α-甲基苯乙烯与丙烯腈共聚物交联纳米微球的制备及其与橡胶界面作用研究

以α-甲基苯乙烯(α-MSt)与丙烯腈(AN)为共聚单体,二乙烯基苯(DVB)为交联剂,采用乳液聚合工艺制备α-MSt与AN共聚物(MStAN)纳米微球,并对其性能进行研究。结果表明:MStAN纳米微球在二元乙丙橡胶(EPM)中的分散性较好,其表面含有一定量的悬挂双键,可参与硫化过程中的交联反应。随着交联剂DVB含量的增大,微球表面双键含量先增大后减小;随着引发剂过硫酸铵含量的增大,微球表面双键含量减小。与EPM胶料相比,MStAN/EPM复合材料的物理性能显著提高。MStAN纳米微球表面双键含量越大,其对橡胶的补强效果越好。     

MMA/AN/DVB乳液交联聚合动力学

为制备甲基丙烯酸甲酯(MMA)-丙烯腈(AN)-二乙烯基苯(DVB)刚性微粒,在75℃、过硫酸钾(KPS)作引发剂、恒搅拌速率下研究了MMA/AN/DVB乳液共聚动力学,考察了KPS用量、单体配比、交联剂DVB对共聚速率的影响.结果表明乳液共聚速率Rp与KPS浓度的0.699次幂成正比,而且随着AN质量分数增加而下降.引发剂浓度指数偏离Smith-Eward理论模型可解释为体系中单体AN具有较大的水溶性,使成核胶粒数目增加的结果.当DVB用量在3%～5%时,聚合速率随DVB用量的增加而略有下降, 在DVB用量为6%时,共聚速率明显上升.随交联剂DVB用量增加,共聚物粒径变大且分布变宽.     

环氧树脂/活化纳米氧化铝复合材料的固化动力学

采用氢氧化钠溶液将纳米氧化铝表面活化,利用Y-缩水甘油醚氧丙基三甲氧基硅烷(KH560)和环氧树脂对活化纳米氧化铝进行表面处理而引入环氧基团.采用差示扫描量热法(DSC)研究复合材料的非等温固化行为,分析了活化纳米氧化铝及其环氧功能化产物对环氧树脂固化动力学参数与机理的影响,运用等转化率方法包括Friedman方法与K...     

单分散羧基化PS微球的制备及自组装

通过无皂乳液聚合法制备羧基化的聚苯乙烯(PS)微球,并讨论了甲基丙烯酸(MAA)用量、引发剂过硫酸铵(APS)用量对单体转化率、微球粒径及其分布的影响。分别使用漂浮自组装法、单基片垂直沉积法和双基片垂直沉积法对聚合物微球进行自组装。结果表明:当MAA的摩尔分数为2%~8%,APS用量为0.168~0.504 g时,可制备单分散性良好的聚合物微球,且随着MAA,APS用量的增加,单体转化率增大,聚合物微球的粒径减小。与漂浮自组装法和单基片垂直沉积法相比,使用双基片垂直沉积法,当乳液固体质量分数为1.0%,微球自组装效果好,排列规整有序。     

单分散窄分布聚苯乙烯微球的制备研究

以苯乙烯为单体,聚乙烯基吡咯烷酮(PVP)为分散剂,偶氮二异丁腈(AIBN)为引发剂,甲醇为分散介质,利用分散聚合法制备了微米级单分散聚苯乙烯微球。通过傅立叶红外分析(FT-IR),扫描电子显微镜(SEM),激光粒度分析(LPS)等方法对微球进行测试表征。研究了PVP用量对微球产物的影响。结果表明:单体的转化率随PVP用量的增加而增大,PS微球的粒径随着PVP用量的增大而减小,其粒径分布先变窄后变宽。当PVP用量为1.5%时微球的粒径分布最窄,单分散性最好。改变PVP用量可以得到不同粒径的PS微球。     

壳聚糖磁性微球的制备及其对牛血清白蛋白的吸附性能研究

以Fe/C为磁性内核、液体石蜡为分散介质、Span-80为乳化剂、环氧氯丙烷为交联剂,采用反相悬浮包埋法制备了壳聚糖磁性微球.对微球表面的活性基团含量进行了测定.研究了用戊二醛活化、Cibacron Blue 3G-A修饰后的微球对牛血清白蛋白的吸附性能.结果表明,小粒径壳聚糖磁性微球经戊二醛活化后对牛血清白蛋白的饱和吸附量为46.3 mg·g-1,经Cibacron Blue 3G-A修饰后对牛血清白蛋白的饱和吸附量为66.2 mg·g-1.     

苯乙烯-丙烯酸共聚纳米微球的制备及表征

以苯乙烯为单体,丙烯酸为功能单体,采用细乳液聚合法合成了苯乙烯-丙烯酸共聚纳米微球,采用zeta电位及激光粒度仪、透射电镜(TEM)、傅立叶变换红外光谱仪(FTIR)、热重分析仪(TG)、电导率仪对微球的粒径、形态结构、热性能、表面羧基含量等进行了表征。结果表明,微球粒径范围在50~70 nm,随着丙烯酸的加入量增多,羧基红外特征峰面积增大;微球粒径随之变小;表面电荷密度增大;产物的热重分析曲线也体现出了一定的聚丙烯酸的热分解特征。这些结果说明聚苯乙烯微球表面成功带上了羧基,并可以通过控制单体比例调节其表面的羧基含量。     

不同链长杂化单体合成及光聚合性能研究

通过三步反应合成了三种不同链长的新型杂化单体。使用傅里叶红外光谱和核磁共振仪对相应产物进行了表征。同时使用傅里叶实时红外(FT-RTIR)对三种杂化单体的光聚合性能进行了研究。考察了引发剂种类、不同浓度光引发剂以及链长对杂化单体的光聚合性能的影响。结果表明,光引发剂硫钅翁盐的引发性能要优于碘钅翁盐,随着光引发剂浓度的增大,杂化单体双键及环氧基团的转化率都相应提高,随着链长的增长,相应单体中的双键的转化率降低,但是相应单体中环氧基团的转化率随之升高。     

Preparation of uniform poly(glycidyl methacrylate) porous microspheres by membrane emulsification–polymerization technology

Uniform poly(glycidyl methacrylate‐divinyl‐benzene) (P(GMA‐DVB)) and poly(glycidyl methacrylate‐ethylene dimethacrylate) (P(GMA‐EGDMA)) porous microspheres with several 10 μm were successfully prepared by membrane emulsification–polymerization technology. Conventional suspension polymerization method was first investigated by examining the effects of recipe components on the morphologies of P(GMA‐DVB), including stabilizer, diluent, and crosslinker to select a optimum recipe. The membrane emulsification–polymerization process was developed to prepare uniform PGMA porous microspheres as the following: the oil phase composed of monomer, diluent and initiator was pressed through membrane pores into the aqueous phase to form uniform droplets, and subsequent suspension polymerization was carried out. GMA and 4‐methyl‐2‐pentanol in the selected recipe were relatively hydrophilic, and therefore oil phase could wet the hydrophilic glass membrane and bring about polydispersed droplets. However, when isooctane was added as a component of diluents, the uniform droplets could be prepared by membrane emulsification method. In the membrane emulsification–polymerization, the coagulation between microspheres obviously decreased while yield of microspheres slightly increased. To extend the application of PGMA, as a trail, uniform P(GMA‐EGDMA) porous microspheres were also successfully prepared by membrane emulsification–polymerization with a isooctane contained diluent, even though EGDMA was more hydrophilic than DVB. Therefore, recipe was found the important factor to prepare uniform PGMA porous microspheres using membrane emulsification–polymerization method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5018–5027, 2006     

环氧基多孔磁性复合微球的制备及性质

以聚醚为致孔剂,通过悬浮聚合法制备了表面带有环氧基的多孔磁性复合微球。用红外光谱(FTIR)、扫描电子显微镜(SEM)、磁强计(VSM)、压汞法等对其进行了表征,考察了分散剂质量分数对多孔磁性微球性能的影响。结果表明,该微球粒径为35～50μm,表面有不规则孔道,w(Fe3O4)≈15.8%,饱和磁化强度8.98 emu/g。水相中w(PVA)由1.5%升至3%时,微球平均粒径由130μm变为40μm,而平均孔径亦由144 nm降为39 nm。     

分散聚合法制备环氧基磁性复合微球

采用化学共沉淀法制备了油酸包覆的Fe3O4磁性纳米粒子,以此为核·采用分散聚合法制备了表面带有环氧基团的Fe3O4／聚甲基丙烯酸缩水甘油酯（PGMA）磁性复合微球,探讨了聚合工艺、聚合条件对甲基丙烯酸缩水甘油酯（GMA）利用效率的影响规律,并用傅立叶变换红外光谱仪（FTIR）、热重分析仪（TGA）、振动样品磁强计（VSM）和扫描电镜（SEM）等对磁性复合微球的结构、磁性能和包覆量进行了表征．采用盐酸一丙酮法测定了磁性复合微球表面环氧基的含量。结果表明,在优化的条件下。GMA利用效率高达61．26％。磁性复合微球具有良好的单分散性·粒径为1～2μm．具有超顺磁性．比饱和磁强度为17．12emu·g^-1。环氧基含量达3．5mmol·g^-1。     

Independent control of mechanical and chemical properties of monodispersed polystyrene–divinyl benzene microspheres by two-step polymerization

Monodispersed polystyrene (PS) latices of the particle size ranging between 4 and 10 μm were prepared by a conventional dispersion polymerization technique using poly-(acrylamide) as a stabilizer. Styrene containing 2–20% of divinyl benzene (DVB) was subsequently polymerized on the surface of the latex by a seeded polymerization technique for the purpose of modifying the thermo-mechanical and chemical properties of the microspheres. The softening temperature during hot pressing and the resistance against the dissolution on swelling in toluene or methyl ethyl ketone increased with increasing amount of DVB. The state of seeded polymerized particles was revealed to depend more on the total amount than the composition of the monomer added. By using the present technique, it is possible to prepare chemically stable, monodispersed microspheres with their diameters and softening temperature varying from 4.5 to 12 μm and from 106 to 126°C, respectively, with a free combination by choosing the appropriate dispersion polymerization condition and the amount of DVB during subsequent seeded polymerization.     

Highly crosslinked poly(glycidyl methacrylate-co-divinyl benzene) particles by precipitation polymerization

Stable and smooth surface poly(glycidyl metharylate-co-divinylbenzene) (GMA-co-DVB) microspheres composed of various concentrations of DVB from 20 to 90 mol% in acetonitrile medium were prepared without a significant coagulum by precipitation polymerization. The number-average diameter of the microspheres linearly increases from 2.63 to 3.34 μm and the particle size distribution becomes narrower by decreasing the uniformity from 1.10 to 1.02 with the DVB concentration from 20 to 90 mol%. The yield of polymerization increased from 28.9 to 79.7% with the DVB concentration as well. The FT-IR spectrum shows the characteristic peaks at 1725-1650 cm⁻¹ assigned to the confirmation of the polymerization between GMA and DVB. No glass transition temperature and the onset of the thermal degradation temperature at higher temperature indicate that the poly(GMA-co-DVB) is crosslinked; this is evidenced by the swelling ratio measurement relevant to the crosslinking density of the poly(GMA-co-DVB). The swelling test suggested that the poly(GMA-co-DVB) particles would be a core/shell type structure composing of a highly crosslinked DVB rich-phase in the core part and slightly crosslinked GMA rich-phase in the shell part.     

甲基丙烯酸缩水甘油酯-苯乙烯-丙烯腈聚合物的合成

采用悬浮聚合方法,使甲基丙烯酸缩水甘油酯(GMA)、苯乙烯(St)和丙烯腈(AN)单体发生自由基聚合,获得数均摩尔质量M_n=7×10~4g/mol,分散度D=2.36,外观无色透明的三元共聚物珠粒.通过红外分析发现其在1727 cm~(-1)处有羰基的强烈伸缩振动吸收峰,在1253 cm~(-1)(环氧基团的对称振动吸收峰)、915 cm~(-1)和861 cm~(-1)(环氧基团的不对称振动的两个吸收峰)处的红外吸收峰,表明了环氧基团的存在;3200～3600 cm~(-1)范围没有明显的羟基吸收峰,说明聚合物中GMA的环氧基团很少或基本上没有开环,据此可以初步认定GMA单体在参与聚合反应时,是以打开双键的形式进行加成聚合反应.     

Surface functionalization of Si3N4 nanoparticles by graft polymerization of glycidyl methacrylate and styrene

To improve dispersibility and interfacial interaction of nano‐Si₃N₄ particles in epoxy‐based composites, graft of glycidyl methacrylate (GMA) and styrene (St)/GMA onto the nanoparticles' surface was carried out in terms of emulsion polymerization method. The grafting polymers proved to be chemically attached to the nanoparticles via the double bonds introduced during the coupling agent pretreatment. The factors affecting the graft parameters, such as monomer concentration, initiator consumption, reaction time, etc., were investigated. It was shown that higher concentrations of monomer and initiator are favorable for the graft polymerization. When St/GMA was employed as the grafting monomer, the nanoparticles were found to play the role of polymerization loci. The grafted nanoparticles exhibit greatly improved dispersibility in cured epoxy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 992–999, 2006     

单分散多孔聚合物微球的制备及其反相色谱应用

用分散聚合的方法制得单分散微米级聚苯乙烯微球(PS),以此聚苯乙烯微球作为种子,以邻苯二甲酸二丁酯为溶胀剂,苯乙烯为单体,二乙烯基苯为交联剂,甲苯为致孔剂,采用种子溶胀聚合的方法制得粒径分布较窄的多孔高交联的聚苯乙烯-二乙烯基苯微球(PS-DVB)。研究了交联剂与致孔剂的加入量对微球形貌、粒径及孔结构参数的影响。结果表明,所得多孔微球球形圆整,库尔特测得平均粒径为5.067~5.520μm,粒径分布窄,D90/D10为1.23~1.56,孔结构可控,并以此多孔微球作为反相色谱填料基质,理论塔板数每米可达6 000~15 000,可以用作高效液相色谱(HPLC)填料。     

Preparation of narrow‐dispersion or monodisperse polymer microspheres with active hydroxyl group by distillation–precipitation polymerization

Narrow‐dispersion or monodisperse polymer microspheres with active hydroxyl groups were prepared by distillation–precipitation polymerization in the absence of any stabilizer. The monomer hydroxyethyl methacrylate (HEMA) was copolymerized with either commercial divinylbenzene (DVB) (containing 80 % of DVB isomers) or ethyleneglycol dimethacrylate (EGDMA) as crosslinker by distillation–precipitation polymerization technique with 2,2′‐azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile. The effects of the crosslinker and the crosslinking degree on the morphology and the loading of the active hydroxyl group of the resultant microspheres were investigated. The agitation caused by distilling off a portion of the polymerization solvent during the polymerization avoided coagulation and resulted in the narrow‐dispersion or monodisperse polymer microspheres for the distillation precipitation technique. Copyright © 2005 Society of Chemical Industry