甲基丙烯酸甲酯反相无皂微乳液聚合

以偶氮二异丁腈(AIBN)为引发剂,对甲基丙烯酸甲酯／丙烯酸(AA)／水构成的反相无皂微乳液体系的聚合进行了研究,结果发现可以得到具有多孔结构的聚合物材料,而且聚合速率(dC／dt)随AIBN和AA用量的变化分别有dC／dt∝[AIBN]^1.0与dC/dt∝[AA]^1.7的动力学关系。     

丙烯酸/甲基丙烯酸甲酯低温快速共聚反应体系的研究

比较了常规乳液聚合和无皂乳液聚合对丙烯酸(AA)/甲基丙烯酸甲酯(MMA)共聚物性能的影响,探讨了各种氧化还原引发体系、氧化剂用量、单体配比、搅拌速率以及还原剂的滴加速率对单体转化率的影响。研究结果表明,采用无皂乳液聚合法,以过硫酸钾(KPS)/亚硫酸氢钠(SHS)为氧化还原引发体系,当引发反应温度为50℃、m(KPS)∶m(SHS)=1∶2、氧化剂KPS用量为0.15～0.25g、m(MMA)∶m(AA)=10∶1、搅拌速率为450r/min和还原剂SHS溶液滴加时间为30min时,AA/MMA无皂自乳化聚合反应能够快速顺利进行,并且能获得单体转化率较高、性能较好的稳定乳液。     

AA—TFEMA—AC无皂含氟乳液共聚反应动力学的研究

采用无皂乳液聚合制备得到甲基丙烯酸三氟乙酯/丙烯酸/氯丙烯(TFEMA/AA/AC)含氟丙烯酸酯共聚物.考察了单体比例、引发剂、单体浓度、反应温度对亲水性单体AA、疏水性单体TFEMA和AC的无皂乳液共聚反应速率的影响,得到了相应的聚合速率方程:Rp=Kp[M]0.48[I]0.54,聚合反应表观活化能Ea=91.742 kJ/mol,由聚合速率方程可知引发剂用量对该体系的影响效果采用摄像显微技术对该共聚物的乳液形貌进行观察,结果表明:制备的含氟乳液的乳胶粒呈圆形,粒径分布窄.     

蓖麻油聚氨酯-丙烯酸酯复合乳液的合成

采用甲基丙烯酸甲酯（MMA）与蓖麻油水性聚氨酯乳液共聚反应制备聚氨酯丙烯酸酯（PUA）复合乳液,研究了蓖麻油水性聚氨酯性能、MMA添加量、引发剂种类和聚合温度对PUA复合乳液及涂膜性能的影响,并应用傅里叶红外光谱（FTIR）测定反应产物的结构.研究发现,用外观半透明或微透明的PU-M分散液制备的PUA乳液及涂膜性能优良.油溶性引发剂（AIBN）比水溶性引发剂（K₂S₂O₈）更适合本体系的乳液聚合.随着MMA含量增大,PUA复合乳液胶粒粒径增大,黏度减小,涂膜光泽度下降,机械性能变好,耐水性增加.合适的MMA含量为体系总固含量的20%～30%.提出了PUA复合乳液胶粒形成及粒径长大机理.     

反光布用聚丙烯酸酯无皂乳液的研制及应用

以过硫酸铵（APS）为引发剂,甲基丙烯酸甲酯 MMA 为硬单体,丙烯酸丁酯 BA 和丙烯酸乙酯（EA）为软单体,丙烯酸 AA 为功能单体,阴-非复合可聚合乳化剂（WE-9）为乳化剂,采用预乳化法合成了一种聚丙烯酸酯无皂乳液。讨论了各单体用量和乳化剂用量对其性能的影响。结果表明,当w（BA+EA）=80%、w（MMA）=15%、w（AA）=5%和w（WE-9）=1.2%时,该无皂乳液有优良的综合性能,可满足反光布生产要求。（）（）（）     

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.     

紫外光引发MMA/BA/AA的三元共聚乳液的研究

采用紫外光引发体系合成了MMA/BA/AA三元共聚乳液,利用红外光谱表征了共聚物的结构。讨论了光照时间、AA含量、乳化剂配比和光引发剂等因素对乳液的影响。实验结果表明,单体转化率随光照时间延长而增加,在光引发剂浓度为3%时单体转化率最高,而后下降。当AA含量为3%且阴/非离子乳化剂配比为1∶3时乳液性能最好。     

甲基丙烯酸甲酯/丙烯酸丁酯的无皂乳液共聚

以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为主要原料,过硫酸铵为引发剂,进行无皂乳液聚合.结果表明:在不添加乳化剂的情况下,当MMA/BA=1:1、引发剂用量为0.24%、反应温度为80℃、反应时间8.0h时,所得乳液最稳定,单体转化率为81.84%,此无皂乳液对牛皮纸的粘接性比常规乳液好.     

高固含量交联型苯丙微乳液制备及表征

以苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、丙烯酸(AA)原料,以N-羟甲基丙烯酰胺(NMA)为功能件单体,用十二烷基硫酸钠(SDS)为乳化剂,过硫酸铵(APS)为引发剂,采用种子乳液聚合法合成了高固含量交联型苯丙微乳液.研究了种子聚合阶段引发剂用量、种子用量、St用量、NMA用量对微乳液性能的影响,利用粒径分析仪、红外光谱(FT-IR)、差示热量扫描(DSC)等对微乳液进行了表征.结果表明:在乳化剂用量为单体总量1%的条件下合成的微乳液固含量为43.6%,平均粒径69.7 nm,分散度0.079;合成的苯丙微乳液所有单体发生共聚反应,机械稳定好.     

丙烯酸酯无皂乳液的研制

以过硫酸铵（APS）为引发剂,甲基丙烯酸甲酯（MMA）为硬单体,丙烯酸丁酯（BA）为软单体,丙烯酸（AA）为功能单体,阴-非复合表面活性剂（WE-9）为乳化剂,采用预乳化法合成了一种聚丙烯酸酯无皂乳液。讨论了引发剂和乳化剂用量对乳液性能的影响。结果表明：当w（WE-9）=0．6％,w（APS）=0．5％,该无皂乳液具有优良的综合性能。     

Microemulsion polymerization of styrene using developed redox initiation system and study of rheological properties of obtained latices

Microemulsion polymerization of styrene was kinetically studied using a potassium persulfate (KPS)/P‐methyl benzaldehyde sodium bisulfite (MeBSBS) adduct as the developed redox pair initiation system. The rate of microemulsion polymerization of styrene was found to be dependent on the initiator, emulsifier, and monomer to the powers of 1.4, −0.77, and 0.83, respectively. The apparent Arrhenius activation energy (E_a) estimated for the microemulsion polymerization system was 6.5 × 10⁴ J/mol. Also, the morphological parameters were studied at different initiator concentrations. The rheological measurements for the prepared microemulsions were carried out to investigate the effect of the preparation parameters on the rheological behavior of the polystyrene microemulsions. The rheological flow curves of the polystyrene microemulsion latices prepared at different temperatures were carried out, and we found that the plastic viscosity and Bingham yield values of the flow curves increased with an increasing reaction temperature. That may be due to the cage effect of the prepared polymer particles, which trapped the medium molecules. The plastic viscosity increased with increasing emulsifier concentration while the Bingham yield value decreased. For the polystyrene microemulsion prepared in the presence of different initiator concentrations, the plastic viscosity and Bingham yield increased with increasing initiator concentration. This trend was found to be the same for the microemulsion latices prepared in the presence of different monomer concentrations. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1240–1249, 2000     

微波辅助下MMA/AA无皂乳液聚合的反应性研究

在微波辐照条件下,采用无皂乳液聚合的方法合成甲基丙烯酸甲酯和丙烯酸的共聚物,考察一定条件下引发剂用量、单体配比、微波辐射时间对单体转化率的影响;利用场发射扫描电镜和红外光谱对共聚物的形状、大小、结构进行分析。结果表明：引发剂用量控制在0.1%～0.5%,VMMA∶VAA控制在（10∶1）～（5∶1）,微波辐射时间为45 min时,可以得到单体转化率较高、均一稳定的乳胶粒子;并且粒径随着引发剂用量的增大而减小,随着AA所占比例的增大而增大。     

丙烯酸酯反相微乳液聚合动力学

对以甲基丙烯酸甲酯/丙烯酸丁酯混合单体为连续油相、十二烷基硫酸钠为乳化剂、丙烯酸为反应性助乳化剂构建的反相微乳液体系,以偶氮二异丁腈引发微乳液聚合,系统考察了引发剂浓度、乳化剂浓度、助乳化剂浓度、水相质量分数及反应温度对表观聚合速率的影响.讨论结果表明,微乳液聚合中液滴成核相当重要,聚合速率随体系中引发剂浓度、丙烯酸浓度、水相质量分数及聚合温度的升高而加快,随体系中乳化剂浓度的增大而降低,并得出动力学关系式,且聚合反应表观活化能为114 kJ•mol^-1.     

高固含量苯丙微乳液的制备

采用种子半连续微乳液聚合法合成苯丙微乳液。以苯乙烯、丙烯酸丁酯和丙烯酸为单体,辛基酚聚氧乙烯醚(OP-10)和十二烷基硫酸钠(SDS)为乳化剂,过硫酸钾为引发剂,考察了乳化剂、引发剂、丙烯酸单体和电解质对聚合反应的稳定性和粒径大小及其分布的影响,并由此确定了适宜的合成条件,制备了固含量在48%左右,粒径在60~70 nm的苯丙微乳液。     

Polymerization of acrylamide in styrene containing inverse microemulsions: polymerization kinetics and polymer product composition studies

The kinetics of free‐radical homopolymerization and copolymerization of acrylamide (AAm) and styrene (S) initiated by water‐soluble ammonium peroxodisulfate, (APS) or by toluene‐soluble dibenzoyl peroxide (DBP) in inverse microemulsion toluene/S/AOT (sodium bis(2‐ethylhexyl)sulfosuccinate)/water/AAm characterized by a low volume fraction of the aqueous phase (Φ_aw ≈ 0.08) as a function of the concentration of S in the oil phase of the inverse microemulsion system have been studied. S strongly decreases the rate of AAm/S (co)polymerization. This is valid for both APS and DBP initiators. Kinetic measurements indicate the important role for cross‐initiation of water soluble AAm growing chains and of oil soluble S analogues activated by the primary free‐radicals generated from APS (or from DBP) in the dispersed water droplets (or in the continuous oil‐phase) of the inverse microemulsion, respectively. With inverse microemulsions containing toluene (70.73 %)/S (2.44 %)/AOT(17.56 %)/water (7.32 %)/AAm (1.95 %), after polymerization (initiator APS, 3.04 × 10⁻² mol dm⁻³ of water) and separation of the polymeric components, the following yields were obtained: AAm/S (co)polymer (89.20 mass%; ie 62.24 mass% of AAm structural units and 26.96 mass% of S structural units), polyacrylamide (9.4 mass%) and polystyrene (1.4 mass%). © 2000 Society of Chemical Industry     

Effect of homogeneity of methanol/water/monomer mixture on the mode of polymerization of MMA: Soap-free emulsion polymerization versus dispersion polymerization

The soap-free emulsion polymerization of methyl methacrylate (MMA) was carried out with varying amount of methanol in the aqueous medium. As methanol content increased, the phase of polymerization mixture (methanol/water/monomer) changed from heterogeneous to homogeneous state and the transition occurred at 30 wt% methanol. In order to identify the mechanism of the polymerization in heterogeneous and homogeneous mixture, the properties of the prepared PMMA particles were analyzed in terms of the effects of methanol content on the conversion at 1 h, initiator concentration and polymerization temperature. With the heterogeneous mixture in the range of 0-20 wt% methanol, the polymerization product and polymerization behavior resembled those typically observed in the soap-free emulsion polymerization. On the other hand, the characteristics of the polymerization products were similar to those typically obtained in the dispersion polymerization under the homogeneous mixture ranging 40-60 wt% methanol. Thus, the homogeneity in the aqueous methanol mixture can be a critical factor in determining the polymerization modes between the soap-free emulsion and dispersion polymerization.     

PMMA/PAN核-壳粒子制备工艺研究

加入适量的引发剂,通过无皂乳液聚合,以聚甲基丙烯酸甲酯( PMMA)核体为种子乳液,制备了PMMA/PAN核-壳乳液.实验中分别对引发剂量、丙稀腈( AN)滴加量对PMMA/PAN壳层厚度及其粒径和粒径分布的影响进行了较详细的研究,确定了种子乳液聚合法制备PMMA/PAN核-壳结构聚合物粒子的实验方法及条件.通过激光粒度仪、扫描电镜和透射电镜对核-壳粒子的形态结构进行了表征,证明了PMMA/PAN复合粒子的核-壳结构.     

N—己基马来酰亚胺微乳液聚合动力学研究

配制了ＳＤＳ／ＮＨＭＩ／ Ｈ２Ｏ 三组分Ｏ／ Ｗ 微乳液，对其相行为进行了分析。用过硫酸钾引发该体系进行微乳液聚合，并对聚合动力学进行了研究。结果表明，Ｎ－ 己基马来酰亚胺的微乳液聚合动力学基本上符合常规乳液聚合中的Ｓｍｉｔｈ － Ｅｗａｒｔ 理论，但乳化剂对聚合的影响比较特殊。     

微乳液聚合研究进展

概述了微乳液的性质,并对国内外正相微乳液聚合、反相微乳液聚合、双连续微乳液聚合的研究进行了简要综述。