非离子表面活性剂微乳液中苯乙烯聚合

在烷基葡萄糖苷（APG）／苯乙烯／水三元体系形成的WinsorI型多相微乳液介质中，通过聚合反应制得粒径37nm、单分散（P=0．17〈0．2）聚苯乙烯颗粒，聚合过程中没有出现分层现象。研究了温度、引发剂类型以及无机盐浓度对产物粒径和相对分子质量的影响，并比较了一次性加料和连续加料进行聚合对粒径的影响。结果表明，在水溶性引发剂、高温（60-70℃）条件下制得的是小粒径（37nm）、单分散的聚苯乙烯颗粒，且随着无机盐浓度增大，聚合物颗粒粒径变大（40hm），多分散度变小（P=0．05）。     

烷基葡糖苷微乳液中苯乙烯聚合的研究

在烷基聚葡糖苷(APG0810)/苯乙烯/水三元体系O/W微乳液中,选用水溶性K2S2O8作为引发剂,制得小粒径(46.6nm)、单分散(P=0.106<0.2)聚苯乙烯颗粒。着重研究了表面活性剂浓度、引发剂浓度以及无机盐浓度对产物粒径和多分散度的影响。最后得出随表面活性剂浓度的增加胶束数目增多,聚合所得颗粒粒径变小(44.3nm),单分散性变差;而随盐浓度的增加聚合物颗粒粒径变小(45.2nm),超过一定浓度时颗粒粒径有增大的趋势;随引发剂浓度的增加聚合物粒径变小(41.2nm)。     

二乙烯基苯对低密度聚苯乙烯密度及尺寸的影响

研究了悬浮聚合法合成氏密度聚苯乙烯（LDPS）微粒子过程中，二乙烯基苯（DVB）的加入对树脂粒径及密度的影响。结果表明，二乙烯基苯从单体分散阶段开始影响单体液滴的分散尺寸，加入DVB后，单体液滴尺寸变小，最终产物粒径变小。且在实验条件下，随DVB量增加，最终LDPS粒径减小，当用明胶做分散剂，二乙烯基苯与苯乙烯之比（DVB／St）大于1时，粒径减小变化趋于平缓；当有致孔剂存在时，LDPS的密度随DVB量增加而减小。     

单分散聚苯乙烯微球的制备

以苯乙烯单体为原料,过硫酸钾为引发剂,采用了无皂乳液聚合法制备单分散性较好的聚苯乙烯微球。为了使制备方法更加完善,主要研究了离子强度,引发剂浓度,聚合单体的浓度,乳化剂添加量等各因素对得到的聚苯乙烯微球粒径、分散度的影响,同时对得到的聚苯乙烯微球用扫描电镜(SEM),激光粒度仪进行表征,结果表明合成的聚苯乙烯微球表面光滑,单分散性好,球形度好,平均粒径约100nm。     

无皂乳液聚合法制备亚微米级单分散聚苯乙烯微球

采用无皂乳液聚合法制备了亚微米级聚苯乙烯(PS)微球,考察了苯乙烯(St)单体浓度、引发剂过硫酸钾(K2S2O8)浓度、离子强度(氯化钠浓度)与PS微球粒径及其分布的关系。然后通过加入微量乳化剂或β-环糊精对无皂乳液聚合法进行改进,研究了改进效果。结果表明,PS微球的粒径随St单体浓度和氯化钠浓度的增加而增加、随K2S2O8浓度的增加而减小,通过调节这3种原料的浓度,可制得粒径在450~1000 nm且单分散系数小于0.08的PS微球,但产品收率较低,仅为30%左右。在相同的合成条件下,加入微量乳化剂可制得粒径在100~350 nm且单分散系数小于0.05的PS微球,产品收率提高到75%左右;加入微量β-环糊精可制得粒径在300 nm左右且单分散系数小于0.08的PS微球,产品收率可达80%且反应时间大幅缩短,由原来的12 h缩减到5 h。     

苯乙烯-对氯甲基苯乙烯共聚物胶乳微球的制备及表征

以苯乙烯（St）和对氯甲基苯乙烯（VBC）为共聚单体,过硫酸钾（KPS）为引发剂,十二烷基苯磺酸钠（SDBS）为乳化剂,采用乳液聚合法制备了富含氯甲基的苯乙烯-对氯甲基苯乙烯共聚物功能微球。采用红外光谱（FT-IR）、扫描电镜（SEM）、激光粒度仪和X射线光电子能谱（XPS）对样品进行表征,研究了乳化剂用量、单体用量、引发剂用量、反应时间、反应温度等因素对微球粒径、乳液转化率的影响。结果表明,产物微球粒径均一,表面光滑、富含氯甲基功能基团,采用此方法可以制备粒径在100～250 nm的功能高分子微球。     

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。     

丁二烯-苯乙烯嵌段共聚物的表征

采用光散射-粘度-示差多检测凝胶渗透色谱（GPC）测定了自行合成的丁二烯-苯乙烯两嵌段共聚物以及苯乙烯-丁二烯-苯乙烯三嵌段共聚物（SBS）的Mark-Houwink常数。m（S）／m（B）=3／7的两嵌段共聚物的K=0．01673,α=0．743。m（S）／m（B）=3／7的三嵌段共聚物的K=0．03912,α=0．690。考察了不同结合苯乙烯含量和不同分子量的丁二烯-苯乙烯两嵌段共聚物在四氢呋喃（THF）中的特性粘数、均方旋转半径和流体力学半径。实验表明,随着分子量的增大和苯乙烯含量的减少,丁苯两嵌段共聚物在THF溶液中的“线团”舒展程度增加。     

沉淀法制备纳米α-Al2O3的工艺

利用硝酸铝溶液和碳酸铵溶液的沉淀反应制备一种氧化铝的前驱体-氢氧化铝。研究了pH值、溶液浓度、分散剂用量对纳米氧化铝粒径的影响。用差热、透射电子显微镜、比表面、激光粒度分析仪等测试手段对产物进行分析。结果表明,当反应温度45℃、pH=5．0、分散剂用量为1．0％（质量百分数）、铝盐浓度为0．1mol／L时,制得的产物经800℃煅烧1．0h,颗粒大小为5—10nm;在1210℃煅烧1．0h可转化为α-Al2O3,一次粒子粒径为40nm左右。     

α-Fe2O3纳米粉体的掺杂研究

采用溶胶-凝胶法制得Y2O3-α-Fe2O3（W（Y2O3）=0～7％）纳米粉体材料,利用透射电子显微镜对粉体的粒径和形貌进行了观测;利用XRD对产品的物相进行了分析．结合谢乐公式对晶体原始尺寸和晶胞进行了计算：对产品的干凝胶原粉做了TG-DTA分析以研究其热稳定性和相变温度。结果表明：合成的产物颗粒呈圆球形．粒径细小。其中W（Y2O3）=5％的α-FeO3纳米粉体粒径最小,达到22nm。     

The preparation of small polystyrene latex particles

The effects of several variables in the preparation of small-sized polystyrene latex particles are described. A semicontinuous preparation using microlatexes obtained by microemulsion polymerization as a seed is compared with a batchwise preparation employing the same ingredients. The particles in the batch products prove to be slightly larger in size but are more narrowly distributed. Furthermore, the effects of both the surfactant type and the ionic strength on the particle size in the batchwise emulision polymerization of styrene are reported. The systems do not obey the linear Smith–Ewart relationship with respect to the micellar surfactant concentration, although in the microemulsion polymerization of styrene the Smith–Ewart relationship is found to be valid with respect to the initiator concentration. Surfactants with a low critical micelle concentration increasingly promote the formation of smaller particle sizes. Salt is found to decrease the particle size when using a strong adsorbing surfactant. However, in the case of a weak adsorbing surfactant, an increase in particle size has been observed above a certain salt concentration.     

有机硅氧烷改性丙烯酸酯微乳液的合成与表征

采用种子乳液聚合法,以阴离子乳化剂DF-2和非离子乳化剂OP-10作为复合乳化剂,以FeSO4、K2S2O8和甲醛合次亚硫酸氢钠(SFS)作为氧化-还原引发剂,在65℃合成了有机硅改性丙烯酸酯聚合物微乳液。实验采用单体滴加工艺,用COULTERLS粒度仪和傅里叶变换红外光谱仪分别测定了共聚乳液的粒径分布和产物的结构,研究了加料方式、配方组成及操作方式对聚合稳定性、乳液的粒径分布以及产物性能的影响。结果表明,采用单体滴加工艺能得到平均粒径为50～80nm的单峰窄分布微乳液,并有效地将有机硅氧烷引入到共聚物大分子中。     

高分子量水溶性疏水缔合聚合物的合成条件研究

对合成AM/AHAC二元共聚物的引发体系进行了筛选,研究发现,用K2S2O8-DMAAM引发体系合成的聚合物相对分子量高于其它引发体系,并在此基础上进一步考察了DMAAM浓度、单体浓度、反应温度及反应时间对聚合物分子量的影响。结果表明,单体浓度为20%、K2S2O8浓度为80 mg/L,DMAAM浓度为60 mg/L,反应温度为30℃,反应时间为6 h条件下,合成的聚合物分子量较高。     

Emulsion polymerization of styrene in the presence of carbohydrate-based amphiphiles

Summary Novel amphiphilic N-alkyl-, N-decenyl-, and N-alkyl-N'-methyl-semicarbazones of maltose and maltotriose with C_nH_2n+1 alkyl chains and n=8,9,10,11,12,16 were applied as emulsifiers in styrene emulsion polymerization. Surfactant properties, emulsion polymerization, and rheology were examined as a function of amphiphile molecular architectures. Both critical micelle concentration and average polystyrene particle size increased with decreasing alkyl chain length. Using N-methyl-N-[11-(acryloylamino)-undecanoyl]-glucamine comonomer in a starved feed emulsion polymerization process, it was possible to prepare uniform polystyrene latex with glucamide surface.     

AM/NVP/DMMAC共聚物反相乳液聚合研究

采用反相乳液聚合方法,以煤油为介质,司班80为乳化剂,十二胺为助乳化剂合成了疏水缔合聚合物AM/NVP/DMMAC,研究了反应温度、引发剂用量、反应时间、疏水单体DMMAC用量、NVP用量等对反应和聚合物性能的影响。结果表明,合成聚合物的适宜条件为:引发剂浓度0.1%,疏水单体DMMAC加量为0.4%,NVP加量为5%,反应温度40℃。     

非甾体抗炎药布洛芬的含量测定

用氧化剂存在时布洛芬产生的极谱催化波提高分析灵敏度,用线性单极扫描谱法实现快速测定。在0.08mol/L HAc-NaAc(pH=4.2)支持电解质中,布洛芬于-1.06 V处产生一极谱波,当氧化剂K2S2O8存在时,K2S2O8氧化布洛芬羰基还原中间体自由基,使布洛芬再生,产生布洛芬的极谱催化波。其催化波的二次导数峰电流ip″与浓度在4.0×10-8~5.0×10-7mol/L范围内呈线性关系(r=0.9980,n=8),检测限为2.0×10-8mol/L。该方法可用于药物制剂中布洛芬含量的测定。     

Uniform star‐polystyrene nanoparticles prepared by emulsion atom transfer radical polymerization

Pentaerythritol (PT) was converted into four‐arm initiator pentaerythritol tetrakis(2‐chloropropionyl) (PT‐Cl) via reaction with 2‐chloropropionyl chloride. Uniform (monodisperse) star‐polystyrene nanoparticles were prepared by emulsion atom transfer radical polymerization of styrene, using PT‐Cl/CuCl/bpy (bpy is 2,2′‐dipyridyl) as the initiating system. The structures of PT‐Cl and polymer were characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The morphology, size and size distribution of the star‐polystyrene nanoparticles were characterized by transmission electron microscopy, atomic force microscopy and photon correlation spectroscopy. It was found that the average diameters of star‐polystyrene nanoparticles were smaller than 100 nm (30–90 nm) and monodisperse; moreover, the particle size could be controlled by the monomer/initiator ratio and the surfactant concentration. The average hydrodynamic diameter (D_h) of the nanoparticles increased gradually on increasing the ratio of styrene to PT‐Cl and decreased on enhancing the surfactant concentration or increasing the catalyst concentration. Copyright © 2011 Society of Chemical Industry     

Styrene polymerized in an oil-in-water microemulsion

Microemulsions of styrene dispersed in water using sodium dodecyl sulphate and pentanol and polystyrene, isolated after the polymerizations were carried out to completion, were studied by photon correlation spectroscopy and time-averaged intensity measurements. Microemulsions contained droplets 40.8 nm in diameter. It was found that the size distributions of polystyrene were bimodal. The results indicate that smaller droplets in a microemulsion provide an increased surface area which can complete with micelles in the capture of radicals. The bimodal nature of the products is evidence for two mechanisms of initiation and particle growth.     

微米级单分散聚苯乙烯微球的制备

以苯乙烯(St)为单体、偶氮二异丁腈(AIBN)为引发剂、聚乙烯吡咯烷酮(PVP)为分散稳定剂,在乙醇-水反应介质中,采用分散聚合法制备了微米级单分散聚苯乙烯(PS)微球。分别用电镜扫描和激光粒度仪表征了PS微球表面形貌、粒径及粒度分布,探讨了影响PS微球粒径及粒度分布的诸多因素。结果表明,AIBN用量(以单体质量计,下同)大于5.0%或PVP用量(以单体质量计,下同)小于2%时,PS粒子间有聚并现象;当St浓度为10%、AIBN用量为2.5%、PVP用量为5.5%、醇水质量比为90∶10、聚合温度为70℃时,制备的PS微球粒径为1.612μm、粒度分散系数为0.357,微球单分散性及球形度最佳。