丙酮对MMA-St无皂乳液聚合速率的影响

运用溶剂热法,以丙酮-水为分散介质,过硫酸钾为引发剂引发甲基丙烯酸甲酯(MMA)和苯乙烯(St)共聚,制备了P(MMA-St)。讨论了丙酮含量对MMA,St均聚和MMA-St共聚的影响。实验结果表明：随着丙酮含量的增加,MMA成核速率先减小后增大,聚合速率先减小后增大再减小;St成核速率先增大后减小再增大,聚合速率先增大后减小;丙酮含量对MMA-St共聚的聚合速率的影响与单体比例有关,当V(MMA)：V(St)=1：1时,聚合速率随丙酮的增加逐渐降低,当V(MMA)：V(St)=1：3和3：1时,聚合速率随丙酮的增加先增大后逐渐减小;当丙酮含量高于40％后,MMA,St各自均聚和共聚的反应速率均明显减小。     

丙烯腈──苯乙烯/聚丙烯接枝共聚合

丙烯腈（AN）—苯乙烯（St）与聚丙烯（PP）非均相接枝共聚，得杨梅形树脂。研究了AN／St摩尔比对接枝聚合的影响，发现苯乙烯相对含量增大时，非接枝物产量增加，接枝率和接枝效率相应下降。从接枝物的C、H、N分析可计算出聚丙烯、丙烯腈和苯乙烯的组成比例。此外，用二乙烯基苯（DVB）作交联剂，制备了PP－g－（AN－co－St－co－DVB）接枝共聚物—交联型薄壳树脂，交联剂的存在使单体转化率和接枝效率高达100％。     

荧光法研究交联聚苯乙烯氯甲基化过程的结构形态衍变

本文以St/DVB凝胶、St/DVB超髙交联凝胶为参比网络结构,用荧光光谱方法跟踪研究了St/DVB交联凝胶氯甲基化反应过程中网络结构形态的衍变.发现随着凝胶中氯百分含量的增加,其苯基激基缔合物320nm荧光谱带趋于消失;在最初反应阶段.苯基多环聚集体420nm荧光谱带强度迅速上升.而后急剧下降,同时在488nm左右出现一新的荧光谱带,与超高交链凝胶荧光谱带相近似:红外光谱证实了氯甲基化凝胶中亚甲基交联桥的增加.结果表明,伴随氯甲基化反应发生的后交联反应可使交联凝胶疏松网络区结构趋向紧密,使溶剂难以逾渗的微凝胶核松弛解体,从而使St/DVB交联凝胶网络涨落趋向均匀.     

苯乙烯-甲基丙烯酸甲酯悬浮-乳液复合聚合过程中聚合物复合粒子组成的变化

采用苯乙烯(St)悬浮聚合过程中滴加甲基丙烯酸甲酯(MMA)乳液聚合组分,悬浮乳液复合聚合(SECP)方法,制备大粒径聚苯乙烯聚甲基丙烯酸甲酯(PS- PMMA)复合粒子.采用FTIR、1H- NMR、13C- NMR分析方法,研究SECP各个时期复合粒子中MMA- St链节摩尔比,发现悬浮粒子中MMA St链节摩尔比逐渐增大,而PMMA乳胶粒子中逐渐减少,表明悬浮相和乳液相间存在物质传递过程.悬浮粒子中MMA链节质量与MMA总投料质量比主要由乳胶粒子生成速率和乳胶粒子向悬浮粒子凝聚速率决定.最终得到的复合粒子除含PS和PMMA均聚物外,还含少量MMA-St共聚物.     

可聚合乳化剂制备纳米色料的形貌及其影响因素

以α-烯烃磺酸钠(AOS)为可聚合乳化剂、苯乙烯(St)为非极性单体、甲基丙烯酸甲酯(MMA)为极性单体、二乙烯基苯(DVB)为交联剂、十六烷(HD)为助稳定剂,通过细乳液聚合法制备了聚合物包覆蒽醌类染料的纳米色料。利用透射电子显微镜(TEM)、激光粒度仪(DLS)等研究了可聚合乳化剂、极性单体和交联剂的用量对纳米色料形貌的影响。结果表明:该纳米色料具有明显的核壳结构,且乳液的稳定性好。随着乳化剂用量的增加,粒子粒径变小;少量极性单体的加入有助于得到粒径分布较窄的核壳结构纳米粒子,交联剂和单体彼此极性的差异会导致粒子表面粗糙。以St为聚合单体,当DVB的质量小于St质量的30%时,能够得到结构规整的纳米粒子,超过30%时,纳米粒子表面不再光滑。而以MMA为聚合单体,当DVB的质量为MMA的8%~30%时,粒子表面均凹凸不平。     

酚羟基修饰的超高交联聚苯乙烯树脂对苯酚吸附及脱附性能的研究

对超高交联聚苯乙烯树脂进行酚羟基修饰得到修饰后的超高交联聚苯乙烯树脂(JN-2),将该树脂与大孔吸附树脂(Amberlite XAD-4)和超高交联树脂(NDA-150)在水溶液中对苯酚进行吸附-脱附性能比较,经过酚羟基修饰的超高交联聚苯乙烯树脂(JN-2)对苯酚的吸附性能有所提高,同时脱附性能明显改善,该树脂可望在含酚废水治理中得到广泛应用.     

具有核壳结构磁性复合微球的制备与表征

采用两步法制备了具有核壳结构的Fe3O4/P(MMA/DVB)(core)-P(St/GMA/DVB)(shell)磁性复合微球.首先,用改进的细乳液聚合制备了Fe3O4/P(MMA/DVB)微球;然后,加入总量不同的苯乙烯(St)、甲基丙烯酸缩水甘油酯(GMA)和二乙烯基苯(DVB),通过种子乳液聚合,制备了不同磁含量的核壳结构的磁性复合微球.分别用X-射线衍射(XRD)、高倍透射电镜(HR-TEM)、热重分析(TGA)、振动样品磁力计(VSM)等手段对磁性微球的性能进行了表征.实验结果表明,Fe3O4/P(MMA/DVB)微球的磁含量为84 wt%;通过改变加入壳层单体的量,核壳复合微球的磁含量可控在20 wt%~76 wt%之间.该微球具有超顺磁性,相应的饱和磁化强度为12~50Am2/kg.     

悬浮-乳液复合聚合聚苯乙烯-聚甲基丙烯酸甲酯复合粒子的颗粒特性和成粒机理

采用在苯乙烯 (St)悬浮聚合过程中滴加甲基丙烯酸甲酯 (MMA)乳液聚合组分的悬浮 乳液复合聚合方法 ,制备大粒径聚苯乙烯 聚甲基丙烯酸甲酯 (PS PMMA)复合粒子 .研究聚合物粒径分布和颗粒形态的变化发现 ,在St悬浮反应中期滴加MMA乳液聚合组分后 ,聚合体系逐渐由悬浮粒子与乳胶粒子并存向形成单峰分布复合粒子转变 ,最终形成核 壳结构完整的大粒径PS PMMA复合粒子 ;在St悬浮反应初期滴加MMA乳液聚合组分 ,St与MMA一起分散成更小液滴 ,反应后期凝并成非核 壳结构复合粒子 ;在St悬浮反应后期滴加MMA乳液聚合组分 ,PMMA乳胶粒子与PS悬浮粒子基本独立存在 .根据以上结果 ,提出了St MMA悬浮 乳液复合聚合的成粒机理 .     

石蜡或聚丁二烯填充型高吸油树脂的合成及其性能比较

以过氧化二苯甲酰 (BPO)为引发剂、二甲基丙烯酸乙二酯 (EGDMA)为化学交联剂、甲基丙烯酸十二酯 (DMA)和苯乙烯 (St)为单体、石蜡 (Paraffin)或聚丁二烯 (PB)为填充剂 ,用悬浮聚合法合成了填充型高吸油树脂 .研究了单体配比、填充剂用量以及化学交联度对树脂吸油性能及凝胶分率的影响 .对石蜡和PB填充的高吸油树脂进行比较 ,发现PB填充的高吸油树脂中存在物理交联 ,而石蜡填充的树脂中不含物理交联 ;PB填充的高吸油树脂随PB用量的增加 ,吸油倍率提高 ,凝胶分率上升 ,脱油速率增大 ;而石蜡填充的树脂随石蜡用量的增加 ,吸油倍率提高 ,但凝胶分率和脱油速率变化不大     

大孔吸附树脂的合成及其对黄芩甙的吸附性能

用吸附树脂纯化分离中药黄芩中的黄苓甙是天然药物研究新技术。但吸附树脂交联聚苯乙烯疏水性强,水相与树脂之间的界面能较大,通过氯甲基化引入极性基团可以改善树脂的吸附性能。本文通过对氯甲基化后的交联聚苯乙烯(氯球)进行后交联以改善树脂孔结构,并通过胺化反应增加树脂的极性和亲水性,研究所合成一系列大孔吸附树脂的碱基含量对黄苓甙的静态吸附性能的影响。     

SYNTHESIS AND PROPERTIES OF ACRYLIC-BASED SUPERABSORBENTS WITH ENHANCED CROSSLINKING ON PARTICLE SURFACE

A series of acrylic-based superabsorbent resins were synthesized by inverse suspension polymerization, using potassium persulfate as the initiator, N, N＇-methylene bisacrylamide （BIS） and divinylbenzene （DVB） as the multiple crosslinking agents. The morphology of the resulting superabsorbent resins revealed by SEM demonstrated that a hard shell layer was indeed formed due to surface crosslinking. The swelling and deswelling properties, and the mechanical strength of superabsorbents were investigated. The results indicated that the adding time of DVB and the amount of DVB participated in the crosslinking show a significant influence on the properties of superabsorbents. When DVB was added in polymerization later, the amount of DVB participated in reaction decreases and the surface crosslinked shell becomes thinner. It is suitable for DVB to be introduced in the later stage of the polymerization process, because the absorption rate of resin is efficiently improved in conjunction with higher water absorption. Furthermore, it was found that the mechanical strength of swollen superabsorbent with surface crosslinking was indeed enhanced in comparison with that of the conventional one.     

Site–site interactions in a polymer matrix: The effect of polymer backbone structure on the transformation of crosslinked resins with substituted hydrazines

Crosslinked chloromethylated polystyrene ( 1 ) and crosslinked copoly(styrene-p-nitro-phenylacrylate) ( 3 ) readily reacted with 1,1-dimethylhydrazine, but the course of the reaction was strongly dependent on the structure of the backbone. Monofunctionalization was observed with chloromethylated polystyrene ( 1 ) giving the 1,1,1-dimethylhydrazinium chloride derivative ( 2 ), while high degree of additional crosslinking took place with crosslinked copoly(styrene-p-nitrophenylacrylate) ( 3 ), and additional crosslinking was also observed in functionalization with N-aminopiperidine and N-aminomorpholine. The additional crosslinking suggested a higher backbone mobility in acrylate beads ( 3 ) compared to chloromethylated polystyrene ( 1 ). The type of transformation and the degree of additional crosslinking also depended on the starting crosslinking of copoly(styrene-p-nitrophenylacrylate) ( 3; 3a , 2% DVB; 3b , 4% DVB; 3c , 10% DVB). Replacement of p-nitrophenol groups in copoly(styrene-p-nitrophenylacrylate) ( 3 ) with hydrazino units resulted in enhanced swelling abilities of the hydrazine derivatives ( 4, 5, 6 ) in methanol, dimethylformamide, and chloroform, while formation of the hydrazinium chloride derivative ( 2 ) from chloromethylated polystyrene ( 1 ) caused enhancement of swelling in methanol but diminished it in toluene. The degree of crosslinking of copoly(styrene-p-nitrophenylacrylate) ( 3 ) also influenced the swelling abilities of 3 and its hydrazino derivatives, being higher with 2% cross-linked resins and lower with 4% and 10% crosslinked resins. © 1996 John Wiley & Sons, Inc.     

丙烯腈系大孔螯合树脂的合成及研究 Ⅱ.AS树脂的FT-IR研究

<正> 二乙烯基苯(DVB)用于树脂的合成时,并非所有的乙烯基都参与交联反应,共聚物中总存在一些悬挂双键。用红外及拉曼光谱对聚合过程中DVB悬挂双键含量变化的动力学研究已有报道。作者用Nicolet 170 SX:付里叶变换红外光谱仪(FT-IR),以积分强度法测定及研究了大孔型丙烯腈-苯乙烯-二乙烯基苯共聚物(大孔AS树脂)中悬     

Morphological investigations of crosslinked polystyrene microspheres by seeded polymerization

 Crosslinked polystyrene microspheres with novel surface and inner morphologies were synthesized by seeded polymerization following a seed-swelling method, using uncrosslinked polystyrene microspheres as seeds and a mixture of toluene, styrene (St), and divinylbenzene (DVB) as the swelling agent. With the increasing toluene/ (St+DVB) ratio, the crosslinked particles changed from smooth-surfaced spheres to deformed spheres with dimples or heavy dents at the surface. A single hole inside the spherical particles was produced at low St/DVB ratio, while higher St/DVB ratios gave irregular dented or dimpled particles. Ultrathin cross-section observation by TEM revealed a non-uniformly crosslinked inner structure. Received: 20 January 1998 Accepted: 14 April 1998     

Effect of the acylating agent on the selectivity of anion-exchange resins and separation efficiency

Anion-exchange resins have been prepared by a two-step process that comprises the acylation of polystyrene/divinylbenzene (PS/DVB) with 50% crosslinking and subsequent amination with trimethylamine. The spacer arm between the quaternary ammonium functionality and the polymer backbone in these resins contains three, four, or five carbon atoms. An increase in the spacer arm improves the separation efficiency, affects the selectivity, and produces more symmetric peaks.     

蒸馏沉淀聚合过程中交联度对单分散聚合物微球形成的影响书

以苯乙烯为单体、二乙烯基苯（DVB）为交联剂，过氧化二苯甲酰（BPO）为引发剂研究了蒸馏沉淀聚合法制备聚合物微球过程中交联单体二乙烯苯的用量对单分散聚合物微球成球的影响。结果表明，增加二乙烯基苯的比例，即提高交联度有利于形成单分散的聚合物微球。     

交联剂对无皂P(MMA-EA-MAA)种子聚合乳胶粒成孔的影响

采用完全无皂种子乳液聚合技术合成了粒径窄分布的P(MMA-EA-MAA)乳胶粒,通过对上述胶乳进行碱处理,制备出了具有空腔结构和多孔结构的聚合物乳胶粒,研究了交联剂的种类和用量对聚合过程、胶粒特性及胶粒结构形态的影响.结果表明,体系中加入交联剂后,单体转化率都有不同程度的提高;随交联剂用量的增加,乳胶粒粒径略有减小,交联剂用量较高时,乳胶粒粒径分布加宽;二乙烯基苯(DVB)的交联效率稍高于双甲基丙烯酸乙二醇酯(EGDMA);不加入交联剂及EGDMA用量低于0.5%时,处理后乳胶粒呈空腔结构,加入DVB及EGDMA用量高于1.0%时,处理后乳胶粒呈多孔结构,并且乳胶粒体积增量随交联剂用量的增加而减小.     

Crosslinking‐induced morphology change of latex nanoparticles: A study of RAFT‐mediated polymerization in aqueous dispersed media using amphiphilic double‐brush copolymers as reactive surfactants

Amphiphilic double‐brush copolymers (DBCs) with each graft site quantitatively carrying both a hydrophilic poly(ethylene oxide) (PEO) graft and a hydrophobic polystyrene (PSt) graft are synthesized by sequential reversible addition‐fragmentation chain transfer (RAFT) polymerization and ring‐opening metathesis polymerization (ROMP). These DBCs are used as both surfactants and polyfunctional RAFT agents in the radical polymerization of St in aqueous dispersed media. Miniemulsions with narrowly dispersed St‐based nanodroplets are readily obtained after ultrasonication of the reaction mixtures. Without the presence of crosslinker, chain‐extension polymerization of St from the DBCs yields well‐defined polymeric latexes with narrow size distributions. However, with the presence of divinylbenzene (DVB) as the crosslinker, vesicular polymeric nanoparticles are formed as the major product. Such crosslinking‐induced change in morphology of the resulting latex nanomaterials may be ascribed to the increase of interfacial curvature in the heterophase systems during crosslinking polymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3250–3259     

Polystyrene resins with immobilized polyamines: Preparation,characterization, and ability to bind Cu(II) ions

Three polyamine ligands, ethylenediamine (EDA), diethylenetriamine (DTA), and triethylenetetramine (TETA), were bound to three chloromethylated “popcorn” polystyrene resins (16, 50, and 100% phenyl ring substitution) with the use of pyridine as the reaction medium. The rate of chloride displacement decreased with increasing molecular weight of the amine and higher degree of resin chloromethylation, while the extent of multiple attachments to the polymer matrix increased. The additional crosslinking, a result of multiple attachments, caused the polyamine resins to swell to a lesser extent in pyridine and water. The ability of the insoluble polyamine–polystyrene resins to chelate Cu²⁺ ions from dilute solutions (200 ppm) was determined at pH 5. With EDA resins the capacity for Cu²⁺ increased with increasing amount of the bound polyamine, with DTA it remained unchanged, while with TETA it was found to decrease.     

Precipitation polymerization in acetonitrile and 1‐propanol mixture: synthesis of monodisperse poly(styrene‐co‐divinylbenzene) microspheres with clean and smooth surface

Precipitation polymerization of styrene (St)–divinylbenzene (DVB) has been carried out using acetonitrile/1‐propanol mixture as the reaction media and 2,2′‐azobisisobutyronitrile (AIBN) as initiator. Monodisperse micron‐sized poly(St‐co‐DVB) microspheres with clean and smooth surface were synthesized in the absence of any stabilizing agent such as surfactants or steric stabilizers. The effects of various polymerization parameters such as 1‐propanol fraction in the reaction media, initiator and total monomer concentration, DVB content, polymerization time and polymerization temperature on the morphology, particle size and size distribution were investigated. It was found that smoothly shaped stable particles were obtained when less than 70 vol% of 1‐propanol was used in the media. The particle size increased with the AIBN concentration, whereas the change of uniformity was less obvious. Monodisperse microspheres were obtained when the total monomers loading ranged from 0.5 to 3 vol%. The particle diameter ranged from 2.73 to 1.87 µm with an increasing DVB content and the uniformity was enhanced. In addition, the yield of microspheres increased with the increasing total monomer, initiator, and DVB concentration and polymerization time. Copyright © 2010 John Wiley & Sons, Ltd.