水溶性偶氮引发剂的合成与应用进展

总结了水溶性偶氮引发剂的分类、合成及应用现状.水溶液聚合和乳液聚合是自由基聚合机理重要的实施手段.它们使用环保水来做分散相,可采用水溶性的偶氮引发剂来进行聚合反应.研究表明,相比于油溶性的偶氮引发剂或常规的氧化还原引发体系,水溶性偶氮引发剂不论足在引发、聚合及产品特征方面都有明显的优势.最后对我国水溶性偶氮引发剂的发展...     

水溶性光引发剂及研究进展

水溶性光引发剂既具有良好的引发光聚合反应的能力,又有优良的水溶性,属自由基型引发剂,其按结构可分为芳酮类、稠环芳烃类、聚硅烷类、酰基膦酸盐类、偶氮类及金属有机配合物类,其中芳酮类中的硫杂蒽酮类光引发剂是近年来光引发剂研究的热点.介绍了水溶性光引发剂(WSP)的研究背景、现状及进展,分别途述了这些典型的光引发剂的结构特性、光化学行为等,并对其前景进行了展望.     

引发剂对丙烯酸类乳液聚合反应的影响

本文探讨了引发剂对丙烯酸类乳液聚合反应影响的诸因素,引发剂用量对聚合反应的转化率、分子量分布有影响;引发剂浓度增大,使乳胶粒子增大;用过硫酸铵或过硫酸钾作引发剂,得到的乳液其涂膜性能有所不同;当引发剂分批加入时,将使聚合物分子量增加.     

吡咯烷基-N-甲酸-丙烯酸乙二醇酯光聚合动力学的研究

采用实时红外技术对所合成的活性稀释剂吡咯烷基-N-甲酸-丙烯酸乙二醇酯的聚合动力学进行了测试.研究了光强、引发剂浓度及引发剂种类对其光聚合的影响.结果表明光强越强、引发剂浓度越大,聚合速率越高,但是反应的最终双键转化率基本不变,均能达到100%左右.引发剂种类对其光聚合的最终双键转化率的影响不是特别明显,但对聚合速率有一定的影响.     

引发剂对于PP/LDPE反应挤出共混改性效果的影响

采用常用的过氧化物引发剂对PP/LDPE体系进行反应增容,制得高熔体黏度的共混物,并研究了引发剂类型和含量对改性效果的影响.反应挤出共混改性过程中体系产生相内、相间交联和PP的降解反应;引发剂的类型决定了共混物中PP的降解和交联反应,采用活性较弱的BPO为引发剂时可以有效的抑制PP的降解,产生有效的交联;引发剂的含量对改性效果的影响也取决于引发剂的类型,采用活性较强的引发剂DCP和双2,5时,随着引发剂含量的增加,改性体系的交联度缓慢增加而MFR显著增大,体系的交联来源于其中的PE组分,当采用BPO为引发剂时,可以有效的引发PP和PE的相内和相间交联,随着引发剂含量的增加,体系的交联度快速增加,MFR显著降低.     

糊化淀粉接枝共聚丙烯酰胺制备高吸水树脂

以过硫酸钾为引发剂,通过糊化淀粉接枝丙烯酰胺制备了高吸水树脂.考察了淀粉的物理状态、交联剂的用量、引发剂的浓度、共聚合温度等对产品吸水率的影响.确定接枝反应最佳工艺条件为:交联剂质量分数0.0016%、引发剂浓度6 mmol·L-1、共聚合温度60℃.     

2-(4-甲氧基苯基)-4,6-双(三氯甲基)-S-三嗪光引发剂的合成及其光聚合动力学性能研究

以对甲氧基苯甲腈和三氯乙腈为原料合成了光引发剂2-(4-甲氧基苯基)-4,6-双(三氯甲基)-S-三嗪(MBTT),通过傅里叶红外光谱仪、核磁共振仪和紫外吸收光谱对所合成的产物结构进行了表征.并利用实时红外(RT-IR)对该引发剂进行了光聚合反应动力学研究,考察了单体、引发剂浓度和光强对引发速率及单体转化率的影响.结果表明,MBTT是一种高效的紫外光引发剂,在引发剂用量为0.1%时光聚合的单体转化率就能达到90%;随着光强的增大,单体的双键转化率和最大反应速率都增大,诱导期缩短;双丙烯酸酯类单体的双键转化率比三丙烯酸酯类单体的双键转化率要高.     

IA/AA/AMPS三元共聚物的合成及阻垢性能研究

以水作溶剂,过硫酸铵为引发剂,衣康酸(IA)、丙烯酸(AA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,合成了IA/AA /AMPS三元共聚物.探讨了引发剂用量、链转移剂用量、反应温度等对共聚物阻垢性能的影响.结果表明,引发剂用量为单体总质量的4.5%,链转移剂用量为单体总质量的9.5%,反应温度为95℃时,共聚...     

EVA-g-MAH反应挤出研究及其在LDPE/MH体系中的应用

采用同向双螺杆研究了不同熔融指数的复合EVA熔融接枝马来酸酐,考察了引发剂用量、MAH用量对接枝率及熔体流动速率的影响.结果表明,接枝率随着马来酸酐、引发剂用量的增加而增加,熔体流动速率随着引发剂用量的增加而减少.通过制备的接枝物添加到阻燃体系中,考察了接枝率对体系性能的影响.     

不饱和聚酯树脂紫外光固化的研究

本文研究了光引发剂、稀释剂对191#不饱和聚酯树脂紫外光固化速度的影响.研究表明, 光引发剂种类、稀释剂含量对固化速度都有影响且它们的含量有最佳值.     

端羟基ECH-THF共聚醚合成的可控性研究

首次以三羟乙基异氰脲酸酯( THEIC)为起始剂开展了环氧氯丙烷(ECH)与四氢呋喃( THF)的聚合研究,考察了催化剂种类、共聚温度及投料比等因素对ECH-THF共聚可控性的影响,确定了该体系下ECH-THF可控聚合的优化条件为:以BF3·THF为催化剂,nECH/nTHEIC≤30/1,nECH/ nTHF ≥2/...     

丙烯腈/醋酸乙烯酯/甲基丙烯磺酸钠三元水相共聚体系竞聚率的研究

根据该AN/VAC/SMAS三元共聚体系特征,根据竞聚率计算的原理,融合二元共聚和三元共聚的基础理论,利用核磁共振技术测定共聚物组成,用Mayo-lewis共聚物组成方程拟合实验数据计算竞聚率.同时研究了AN/VAC/SMAS三元水相共聚反应体系的特征,测定了该三元共聚体系表现竞聚率.     

Surface photografting polymerization of vinyl acetate,maleic anhydride,and their charge‐transfer complex. VIII. Charge‐transfer complex (4)

In view of the complexity of surface photografting polymerization of vinyl acetate/maleic anhydride (VAC/MAH) binary monomer systems, a novel method was adopted in the present article to obtain insight into the relevant grafting copolymerization mechanism. This method includes two steps: semibenzopinacol dormant groups were first introduced onto LDPE film by UV‐irradiation and then thermally reactivated to produce LDPE macromolecular free radicals, which initiated the grafting copolymerization of VAC and MAH. It was demonstrated that, in the first step, the solvent used to introduce benzophenone (BP) to LDPE film largely affected the subsequent grafting copolymerization, which was closely related to the affinity of the solvent toward the substrate. The monomer feed composition had considerable influence on both the grafting and nongrafting copolymerization; however, the maximum copolymerization rates did not appear in the polymerization system with [VAC]/[MAH] being 1 : 1, but, in the system with a bit more VAC than MAH, as the total monomer concentration was raised, the maximum copolymerization rates tended to appear in the system with [VAC] equal to [MAH]. The relationship between the total copolymerization rate (RP) and monomer concentration was determined to be LnRP ∝ [VAC + MAH]^1.83. All of these results indicated that both charge transfer (CT) complex formed by VAC and MAH and free monomers took part in grafting copolymerization. This feature differentiated the surface grafting copolymerization of VAC/MAH from the well‐studied thermally induced alternating copolymerization of VAC/MAH. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

苯乙烯/丙烯酸丁酯交联体系乳液聚合动力学研究

以十二烷基苯磺酸钠(SDBS)为乳化剂,过硫酸钾(KPS)引发苯乙烯/丙烯酸丁酯(St/BA)乳液共聚,加入二甲基丙烯酸乙二醇酯(EGDMA)、聚丁二烯生胶(PB)作为交联剂,研究了聚合温度、引发剂浓度、乳化剂浓度、单体配比对聚合速率的影响。实验结果表明,共聚体系的表观活化能为70.67kJ/mol,聚合初始速率与引发剂浓度的0.43次方、乳化剂浓度的0.56次方和单体BA的0.49次方成正比。     

丙烯腈/醋酸乙烯酯/甲基丙烯磺酸钠共聚体系竞聚率的研究

利用核磁共振技术测定共聚物组成,用Ｍａｙｏ－Ｌｅｗｉｓ共聚物组成方程拟合实验数据计算竞聚率。得到的丙烯腈／醋酸乙烯酯（ＡＮ／ＶＡｃ）本体共聚的竞聚率数据用于分析间歇聚合反应试验,理论计算与试验数据吻合。并研究了丙烯腈／醋酸乙烯酯／甲基丙烯磺酸钠（ＡＮ／ＶＡｃ／ＳＭＡＳ）三元水相共聚反应体系的特征,测定了该三元共聚体系表观竞聚率     

Effect of Mono- and Multichlorinated Organic Compounds—Chlorocyclohexane and Hexachloro-p-xylene—On the Catalytic Properties of Titanium–Magnesium Catalysts in the Homo- and Copolymerization of Ethylene with 1-Hexene

Ethylene polymerization and ethylene/1-hexene copolymerization over the titanium–magnesium catalytic system in the presence of chlorocyclohexane (CHC) and hexachloro-p-xylene (HCPX) has been studied. Modification of TMC with chlorocyclohexane and hexachloro-p-xylene increased catalyst activity severalfold for both ethylene polymerization and ethylene/1-hexene copolymerization. The key kinetic regularities of ethylene homopolymerization and ethylene/1-hexene copolymerization in the presence of CHC and HCPX were determined, and the copolymerization constants were measured. Molecular characteristics and the copolymer composition were determined for the synthesized samples of ethylene homopolymers and ethylene/hexene copolymers. Modification of the titanium–magnesium catalyst with chlorinated organic compounds reduced 1-hexene content in the copolymer; polymerization was sensitive to 1-hexene as a regulator of polymer molecular weight. The potential mode of action of chlorinated organic modifiers on catalytic properties of titanium–magnesium catalyst is discussed.     

多米诺催化乙烯聚合制备PE-LLD的研究进展

综述了以乙烯为唯一单体制备线性低密度聚乙烯的多米诺催化体系,按照催化方式的不同,分别介绍了齐聚主催化剂/共聚主催化剂/助催化剂体系、主催化剂/齐聚助催化剂/共聚助催化剂体系两大类型,其中按照不同类型主催化剂的组合进行了分类.着重阐述了各类乙烯多米诺催化体系的特点、制备的聚合物的特征及乙烯多米诺催化的优缺点等.     

Free radical copolymerization behavior of myrcene

Summary Myrcene (7-methyl-3-methylene-1,6-octadiene) binary copolymers with styrene, methyl methacrylate or p-fluorostyrene were synthesized. Polymer compositions were measured by H-NMR and reactivity ratios were calculated using a nonlinear least squares error-in-variables method. For myrcene-styrene copolymerizations the polymer radicals have a marked preference for myrcene monomer. In the case of the myrcene-MMA copolymerization the growing polymer chains prefer to add the other monomer, i.e. the crossover reaction dominates. The same is true for the myrcene/p-fluorostyrene copolymerization, although the myrcene radical has a higher preference for myrcene monomer in this copolymerization than it does in the myrcene-MMA copolymerization.     

DMDAAC/DMC/IA三元共聚合动力学的研究

以二甲基二烯丙基氯化铵(DMDAAC)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)和衣康酸(IA)为共聚合单体,以过硫酸钾-亚硫酸氢钠作氧化还原引发剂,采用膨胀计测定共聚合动力学速率方程和表观活化能,用红外光谱(FT-IR)、热失重分析(TGA)和差示热扫描(DSC)表征两性高分子絮凝剂p(DMDAAC-co-DMC-co-IA)。共聚合热力学计算表明,在T820.5 K的条件范围内,共聚合自由能变化ΔG0。结果显示,共聚合速率方程为Rp∝k[DMDAAC]1.43[DMC]1.36[IA]0.97[引发剂]1.5,表观活化能Ea=33.3 k J/mol。     

Kinetic study of copolymerization of acrylonitrile with ammonium acrylate

Ammonium acrylate was first used to successfully copolymerize with acrylonitrile. Kinetics of copolymerization of acrylonitrile with ammonium acrylate was investigated in a H₂O/dimethylsulfoxide (DMSO) mixture. The rate of copolymerization and particle size were measured. Kinetic equation of the copolymerization was obtained. Effect of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium acrylate copolymers was studied in comparison. Values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. It has been found that monomer apparent reactivity ratios in water‐rich reaction medium [H₂O/DMSO>80/20] are approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), apparent reactivity ratios are similar to those in solution polymerization system. With an increase in polarity of solvent, values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increase in the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4679–4683, 2006