聚甲基丙烯酸酯高分子微球的研究

通过分散聚合法制各了微米级单分散聚甲基丙烯酸甲酯微球.考察了不同聚合单体浓度、引发剂、稳定剂浓度和分散介质等因素对聚合体系的稳定性、微球粒径及分布的影响.通过研究发现,粒径随着聚合温度、引发剂浓度、单体用量的增加而增加;而随着稳定剂(PVP)的浓度的增大而减小.     

保护膜用压敏胶剥离强度增幅研究

采用预乳化半连续聚合法合成了保护膜用乳液型压敏胶(PSA),探讨了单体、乳化剂、引发剂、缓冲剂和交联剂等对乳液型PSA剥离强度增幅的影响。结果表明:乳液型PSA剥离强度增幅随丙烯酸丁酯(BA)或复合乳化剂用量的增加呈先降后升的态势,随丙烯酸(AA)或缓冲剂用量的增加而增大,随苯乙烯(St)、丙烯酸-2-羟丙酯(HPA)或引发剂用量的增加而减小;当w(BA)=85%时,剥离强度增幅最小;大分子有机硅和交联剂的加入能明显降低PSA剥离强度增幅,当w(大分子有机硅)=1.0%时,剥离强度增幅最小;当加入相同用量的交联剂GA240或SC-100时,前者使PSA的剥离强度增幅更低。     

单分散微米级PMMA微球的制备

以聚乙烯吡咯烷酮(PVP)为分散剂,乙醇和水为反应介质,偶氮二异丁腈为引发剂,甲基丙烯酸甲酯(MMA)为单体,采用分散聚合工艺,制备了单分散微米级PMMA微球。研究了乙醇/水介质的配比、反应温度、分散剂用量、单体用量、引发剂用量对PMMA微球粒径和粒径分布的影响。结果表明,PMMA微球粒径随乙醇用量的增加先增大后减小;随反应温度的升高先增大后减小,粒径分布先变窄再变宽;随单体用量的增加先增大后减小,随引发剂用量的增加而增大;随PVP用量的增加而减小,粒径分布先变窄再变宽。     

微波辐射无皂乳液聚合法制备PS微球

采用无皂乳液聚合法制备聚苯乙烯（PS）微球，以微波辐射加热方式代替传统油浴或水浴加热方式，研究了聚合体系中引发剂过硫酸钾的浓度、交联剂二乙烯苯与稳定剂α-甲基丙烯酸的体积比、微波功率大小对PS微球形貌、粒径及其分布的影响。结果表明，较传统加热方式，微波辐射加热方式极大地改善了PS微球的球形度和表面形貌。PS微球粒径随着引发剂浓度的增加呈现减小的趋势，随着交联剂与稳定剂体积比及微波功率的增加均呈现先减小后增大的趋势。当引发剂浓度为6.06×10^–3 mol/L、交联剂与稳定剂体积比为2∶1、微波辐射功率为300 W时所制备的PS微球表面光滑、球形度高、粒径分布均匀，平均粒径约为240 nm。PS微球表面带负电荷且分散性良好，并通过Hertz接触理论计算得到PS微球的压缩弹性模量约为2.75 GPa。     

高固含量聚丙烯酰胺反相微乳胶的制备

依据绘制的Span 80/Tween 80-煤油-水(丙烯酰胺水溶液)拟三元相图,选择高单体质量分数〔如w(丙烯酰胺)=39.2%〕微乳液体系,在反应温度为40℃,引发剂用量为单体质量0.2%的条件下,通过反相微乳液聚合反应,制得了w(聚丙烯酰胺)=39.0%,相对分子质量为5.8×106(引发剂为过硫酸铵)和7.6×106(引发剂为偶氮二异丁腈)的透明、稳定的聚丙烯酰胺微乳胶。考察了相关因素对丙烯酰胺微乳液聚合反应的影响。发现所得聚丙烯酰胺的相对分子质量随着单体、乳化剂质量分数的增加而增大;随反应温度的升高而减小,随引发剂质量分数和反应时间的增加呈现先增大后减小的变化趋势。     

反向悬浮聚合法制备载药淀粉微球的研究

以可溶性淀粉为原料,N,N′-亚甲基双丙烯酰胺(MBAA)为预交联剂,环氧氯丙烷(ECH)为交联剂,采用反相悬浮法制备了载药淀粉微球,以淀粉微球的平均粒径和溶胀度为指标,考察引发剂用量、MBAA用量、油水两相体积比、反应时间等因素对微球合成的影响。利用粒度分析仪、扫描电镜、红外光谱等对产物进行了表征。结果表明:淀粉微球的平均粒径随引发剂用量的增加先增大后减小,随反应时间的增加逐渐增大;溶胀度随引发剂用量的增加先增大后降低,随反应时间的增加降低。MBAA用量和油水比对淀粉微球的平均粒径和溶胀度影响较大。制备所得淀粉微球粒度分布范围较窄,球形圆整,表面粗糙多孔,可用作良好的药物载体和吸附剂。     

温度和pH双重刺激响应型水凝胶的溶胀性能研究

以丙烯酰胺、丙烯酸和双丙酮丙烯酰胺为原料,以N,N'-亚甲基双丙烯酰胺为交联剂,2-酮戊二酸为引发剂,采用光引发聚合方法制备出系列新型温度和pH响应型水凝胶。考察了交联剂用量、水凝胶组成、温度和pH值对凝胶溶胀性能的影响。结果表明,随交联剂用量的增加,凝胶的溶胀率减小,随凝胶组成中AA含量的增加,凝胶的溶胀率增加。凝胶的溶胀率随温度的升高而减小,随pH值的增大而增加,表现出显著的温敏和pH敏感性。     

含环氧基三元共聚乳液的合成与性能

本文研究了甲基丙烯酸甲脂＝丙烯酸丁酯－甲基丙烯酸缩水甘油酯三元乳液共聚合体系中，乳化剂，引发剂，聚合温度和官能团单体ＧＭＡ含量对聚合过程转化率的影响及它们对乳液粘度和电解质稳定性的影响。聚合动力学研究表明，本聚合体系与经典乳液聚合理论存在某些偏差：反应速度Ｒｐ随乳化剂浓度的增加而增大，到某一值后又随乳化剂浓度增大而减小。     

甲基丙烯酸甲酯-丙烯酸乙酯乳液共聚动力学研究

为了合成适于药物包衣用的甲基丙烯酸甲酯-丙烯酸乙酯(MMA-EA)共聚物胶乳,对以非离子型乳化剂OP-10为乳化剂、过硫酸钾为引发剂的MMA-EA乳液共聚动力学进行了研究。发现初期共聚速率随着乳化剂浓度、引发剂浓度和聚合温度的增加而增大,这是由于共聚物乳胶粒子平均粒径随着乳化剂、引发剂浓度和聚合温度的增加而减小,乳胶粒子数目增加所致。通过调节乳化剂、引发剂以及反应温度可以达到合适的聚合反应速率,最终合成出转化率大于95%的MMA-EA共聚乳液。     

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.     

废聚苯乙烯泡沫塑料接枝丙烯酸丁酯改性白乳胶的研制

通过对聚苯乙烯泡沫塑料进行乳化研究，获得了稳定的聚苯乙烯乳液。再采用丙烯酸丁酯（BA）和功能单体对聚苯乙烯进行接枝改性，制成水乳型胶粘剂。研究了溶剂比、乳化剂与稳定剂用量、改性单体及功能单体的用量、引发剂及交联剂用量等因素对粘接性能的影响。     

Ab initio reversible addition–fragmentation chain transfer emulsion polymerization of styrene/butyl acrylate mediated by poly(acrylic acid)‐block‐polystyrene trithiocarbonate

Ab initio reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization of styrene/butyl acrylate was investigated with the trithiocarbonate macro‐RAFT agent poly(acrylic acid)‐block‐polystyrene (PAA‐b‐PS) as a stabilizer and a RAFT agent. Influences of the amount of ammonium persulfate (APS), the amount of PAA‐b‐PS and the mass ratio of monomers on emulsion polymerization and film properties are discussed. The particle morphology exhibited spherical‐like structure with particles of about 90 nm in diameter and relatively narrow particle size distribution characterized using transmission electron microscopy and dynamic laser scattering. Fourier transform infrared and ¹H NMR spectra showed that the styrene/butyl acrylate emulsion was successfully synthesized. The monomer conversion increased initially with increasing amount of APS, from 0.4 up to 0.8 wt%, and then decreased. The particle size increased and its distribution decreased gradually with increasing amount of APS. The monomer conversion increased from 76.83 to 94.21% as the amount of PAA‐b‐PS increased from 3 to 4 wt%, and then decreased with further increase of PAA‐b‐PS. The particle size decreased and its distribution increased with increasing amount of PAA‐b‐PS. The water resistance and solvent resistance of the polymer films initially increased and then decreased with decreasing mass ratio of butyl acrylate to styrene. © 2014 Society of Chemical Industry     

用废聚苯乙烯制备无溶剂型纸张表面施胶剂的研究

用相容性较好的乙烯基类单体溶解回收废聚苯乙烯泡沫材料(EPS),并通过乳液聚合方法制备出一种稳定的低成本无溶剂型纸张表面施胶剂,将其与糊化好的氧化淀粉复配可制取质量分数为4%的施胶液。结果表明:制备施胶剂的最佳工艺条件为m(十二烷基硫酸钠)∶m(OP-10)=2∶1,w(引发剂)=0.5%~0.6%,反应时间为80min,w(废EPS)=5%~10%(相对于复合单体而言);采用质量分数为4%的施胶液对纸张表面进行施胶,可使纸张的施胶度、挺度和环压强度分别提高17倍、33%和21%。     

乳液法聚苯乙烯纳米微球的制备

采用十二烷基硫酸钠为乳化剂、过硫酸盐为引发剂、苯乙烯为单体,在低水油比的条件下,采用乳液聚合方法合成了聚苯乙烯纳米微球,探讨了乳化剂用量、乳化时间、反应温度、引发剂用量和反应时间对单体转化率及产物分子量的影响.结果表明:在低水油比条件下,反应参数对苯乙烯的转化率和聚苯乙烯的分子量具有一定的影响.在最优条件下苯乙烯的转化率达到98%、聚苯乙烯的分子量达到32万.激光粒度分布测试结果显示,所得产物为单分散纳米微球.     

Preparation and characterisation of styrene—methyl methacrylate and styrene–methacrylic acid copolymer latices

Series of styrene-methyl methacrylate and styrene-methacrylic acid copolymer latices have been prepared by emulsion polymerisation using polyoxyethylene nonyl phenyl ether as emulsifier and potassium persulphate as initiator. the effects of surfactant concentration and monomer composition on the ultimate particle size and conversion were investigated. The ultimate particle diameters decreased with increasing surfactant concentration, while the conversions were found to be almost independent of surfactant concentration. The ultimate particle diameters were notably decreased by increasing the content of methacrylic acid. Trace carboxyl groups were detected both in polystyrene latex and styrene-methyl methacrylate copolymer latices. The number of sulphate groups on the polystyrene latex surface was about five times that of carboxyl groups.     

Morphology of latex particles formed by poly(methyl methacrylate)-seeded emulsion polymerization of styrene

Poly(methyl methacrylate)–polystyrene composite particle latexes were prepared by poly(methyl methacrylate)-seeded emulsion polymerization of styrene employing batch, swelling-batch, and semibatch methods. The changes in particle morphology taking place during the polymerization reaction were followed by electron microscopy. Anchoring effect exerted by ionic terminal groups introduced by ionic initiator was found to be the main factor in controlling the particle morphology. The polymer particles obtained by oil-soluble hydrophobic initiators such as azobisisobutyronitrile and 4,4′-azobis-(4-cyanovaleric acid) gave the inverted core-shell morphology. Water-soluble hydrophilic initiator, K₂S₂O₈, also gave the inverted core-shell morphology. However, in this case the occurrence of the halfmoonlike, the sandwichlike, and the core-shell morphologies were also observed depending upon the polymerization conditions. The distribution of terminal ? SO groups on the surface area of polystyrene particles could be controlled by initiator concentration and polymerization temperature. Viscosity of polymerization loci dictated the movement of polymer molecules, thus causing the unevenness of particle shape and phase separation at high viscosity state. Viscosity was controlled by the styrene/poly(methyl methacrylate) ratio, the addition of a chain transfer agent or a solvent which is common to polystyrene and poly(methyl methacrylate).     

一种分散稳定剂的合成及应用

文章合成了一种阴离子型分散聚合稳定剂;特性粘数2～4dL/g,浓度20%,表观粘度200～300mPa·s该稳定剂兼有高分子和表面活性剂的特点,具有优异的分散稳定作用;使用该稳定剂合成的聚丙烯酸分散液,分散粒子总比表面积0.28m2/g,表面积平均粒径19.33μm,体积平均粒径为228.82μm。稳定期大于半年。     

乳化法明胶亚微米粒子的制备

以A型明胶为原料,石蜡油为油相,采用乳化化学交联方法制备了明胶亚微米粒子. 用扫描电子显微镜(SEM)观察了明胶亚微米粒子的形貌和粒径. 研究了影响微球粒径的多种因素,包括明胶溶液浓度、乳化搅拌速度、乳化温度、乳化剂和固化剂. 结果表明,采用戊二醛为固化剂、增加明胶的浓度、提高乳化搅拌速度、使用混合性的乳化剂都有利于降低明胶粒子的粒径. 此外,对制备工艺进行了优化,并在7000 r/min左右高速搅拌的条件下,得到了成球性较好的粒径约为450 nm的明胶亚微米粒子.     

Kinetic study of emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol,stabilized with poly(ethylene oxide)–block–polystyrene–block–poly(ethylene oxide) triblock copolymer

The kinetics of emulsion copolymerization of ethyl methacrylate (EMA)/lauryl methacrylate (LMA) in propylene glycol is very similar to the emulsion copolymerizations of water‐soluble monomers in water because of the high solubility of EMA/LMA in propylene glycol. The initial rate of polymerization depends only on initiator concentration and is not affected by either monomer concentration or stabilizer concentration. The overall rate of polymerization is only slightly dependent on monomer concentration and stabilizer concentration and is independent of initiator concentration. The final particle number density increases with increasing amount of stabilizer and decreases with increasing monomer concentration. The total surface area increases with stabilizer concentration and is not governed by either initiator concentration or monomer concentration. Homogeneous nucleation is the dominant mechanism of particle nucleation, as shown by the kinetic data on seeded polymerization and monomer partition behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1691–1704, 2001     

单组分自乳化水性环氧树脂的合成及其涂膜性能研究

用有机硅、甲基丙烯酸及其酯类单体接枝改性环氧树脂,合成了具有自乳化性能的水性环氧树脂乳液。用激光粒度分析仪测定乳液的粒径及其分布,用傅里叶红外、热重分析仪对聚合产物作了结构表征和热分析。考察了温度、引发剂用量对接枝率及接枝率对乳液成膜性能的影响;甲基丙烯酸、有机硅及单体总量对乳液稳定性、成膜物耐水性和耐盐水性的影响。结果表明:当配方选用引发剂、有机硅用量分别为单体总质量的5.5%、2.5%,m(单体总量)∶m(环氧树脂)=1∶2,丙烯酸及其酯类单体的玻璃化温度Tg为30℃,体系酸值为35 mgKOH/g,接枝温度为110℃时,制得的水性环氧树脂乳液具有良好的稳定性、耐水性及耐盐水性。