苯丙乳液最低成膜温度的影响因素分析

采用复合乳化剂体系和预乳化法核壳乳液聚合工艺,制得苯乙烯-丙烯酸异辛酯共聚乳液.研究了乳胶粒粒径、形态、乳化剂和核壳结构组成对聚合物的最低成膜温度(MFT)和玻璃化温度(Tg)的影响.     

核壳纯丙乳液的结构形态对Tg及MFT影响的研究

研究了核壳纯丙乳液聚合中乳液结构对其玻璃化转变温度、最低成膜温度的影响，以及单体种类、核壳比、核壳设计Tg对乳液性能的影响，还通过TEM、AFM研究了乳液颗粒形态及核壳乳液成膜后的表面形态。     

核-壳苯丙微乳液最低成膜温度的研究

通过核-壳微乳液聚合技术合成了具有较高玻璃化转变温度(Tg)的苯丙微乳液,研究了核-壳单体用量比、壳单体组成、交联剂、聚合物极性对乳液最低成膜温度(MFT)的影响;同时比较了三种成膜助剂对乳液MFT的作用。研究发现,成膜温度随核-壳比的增大而上升;交联剂羟甲基丙烯酰胺(NMA)能有效地降低成膜温度;醇酯—12是一种良好的成膜助剂,同一成膜助剂对极性不同的乳胶粒子MFT的降低效果明显不同。     

多层核壳乳胶粒子的控制合成及其成膜机理研究

首先采用多步法的聚合工艺,利用壳层交联乳液聚合的方法,制备出具有窄分布、多层核壳结构形态的乳胶粒子。利用TEM、DLS对乳胶粒子进行分析,在TEM照片中,可以清晰地看出乳胶粒子多层核壳结构;乳液粒子的核壳结构进一步被DLS数据所证实,即本乳胶粒子具有多层核壳结构;并且由DLS分析得到乳胶粒子的直径与TEM照片中得到数据相符。利用Horus成膜仪对乳胶粒子成膜过程进行全程监控,从而可以得到成膜助剂的最佳使用量。     

核壳型乳液聚合研究进展

综述了近年来核/壳结构聚合物乳液的聚合工艺、性能及核/壳结构的表征方法进行,讨论了影响核/壳结构聚合物乳胶粒子形态的各种因素。     

核壳结构聚硅氧烷/丙烯酸酯复合乳液(Ⅰ)乳化剂对乳液聚合过程及粒径分布和粒子形态的影响

采用种子乳液半连续法合成了具有高有机硅含量的聚硅氧烷/丙烯酸酯核壳结构复合乳液,研究乳化剂的种类、复配比例及质量浓度对有机硅／丙烯酸酯壳核乳液性能与乳胶粒径、分布和结构的影响.结果表明：阴离子乳化剂十二烷基硫酸钠(SDS)、十二烷基磺酸钠(SDS-2)、十二烷基苯磺酸钠(SDBS)所合成的乳胶粒子粒径依次增大,SDS与非离子型乳化剂OP-10复配使用时,随OP-10质量分数的增加,聚合速率和转化率降低,化学稳定性增加,乳胶粒子粒径增大,分布变宽,确定了复合乳化剂的最佳配比.随复合乳化剂浓度的增加,聚合速率加快、转化率增加,乳胶粒子粒径减小而分布加宽.通过改变乳化剂加入方式可减小乳胶粒子的粒径分布.为减少壳层聚合物新粒子的产生,需严格控制乳化剂的浓度,使加入的壳层单体处于“饥饿”状态,在乳胶粒子表面富集、引发聚合,形成表层“过渡层”,最终形成核壳结构复合粒子.     

成膜温度对漆膜表面形态的影响

采用种子乳液法合成了核壳结构苯丙乳液，用原子力显微镜(AFM)对不同成膜温度漆膜表面形态，尤其是乳化剂在漆膜表面的分布进行了研究。发现控制乳液的成膜温度略高于Tg，可以得到粒子排列整齐的均一膜，膜的耐水性等性能更好。     

红外干燥高玻璃化温度乳液的成膜研究

采用具有核壳结构的丙烯酸酯自交联乳液,研究其在红外干燥下的成膜及性能,并利用Routh-Russel模型优化确定其成膜机理,优化了成膜条件。研究表明,通过红外干燥可以实现高玻璃化温度(Tg)乳液的快速成膜。聚合物乳液Tg和湿膜厚度H能够改变Routh-Russel模型的参数λ和Pe,继而影响乳胶粒子的成膜性能。Tg58℃及H≤400μm时,乳胶粒子受毛细管力变形,形成连续透明的聚合物膜,其硬度相比于室温自然干燥的涂膜高出2~5倍,且耐水性显著增加。原子力显微镜(AFM)表征证实红外干燥确实能够促进乳胶粒子的融并变形。     

醋酸乙烯的种子核／壳乳液聚合研究

用聚氯乙烯种子为核进行了VAc的核／壳乳液聚合，测试了乳胶粒子的平均直径和聚合物的玻璃化温度，发现该PVC／PVAc核壳聚合乳胶粒子有不同于均聚合物的两相结构，测试了乳液的应用性能。     

梯度苯丙乳液的合成

以苯乙烯(St)和丙烯酸丁酯(BA)为主要核单体,甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为主要壳单体,甲基丙烯酸(MAA)和甲基丙烯酸羟丙酯(HPMA)为功能性单体,采用梯度乳液聚合法制备了硬核软壳型苯丙乳液。考察了聚合工艺,乳化剂的配比及含量,引发剂浓度,反应温度以及功能性单体含量对乳液聚合过程及性能的影响。结果表明:乳化剂占单体总量的1%,DSB/OP-10的质量比为2∶1,引发剂占单体总量的0.5%,反应温度为80℃,功能性单体含量为4%时,聚合稳定,凝胶量少,乳液性能优异,且采用梯度乳液聚合方式可有效降低乳液的最低成膜温度。通过红外光谱测定了苯丙共聚物的结构组成,透射电镜(TEM)对粒子结构进行分析,验证了其梯度结构形态。     

The Preparation of Core–Shell P(St-MMA)–SiO2 Hybrid Nanoparticles and Filling in the Styrene/n-butyl Acrylate Adhesive

In this study, core–shell poly(styrene-methyl methacrylate) (P(St-MMA))–SiO₂ hybrid nanoparticles were prepared successfully by emulsion polymerization. Firstly, nanosilica particles were modified by oleic acid (OA) in order to introduce the polymerization active vinyl groups and hydrophobic groups onto the nanosilica. This was followed by graft copolymerization onto the modified nanosilica particles to obtain P(St-MMA)–SiO₂ hybrid nanoparticles. The hybrid nanoparticles were characterized by: transmission electron microscope (TEM); Fourier transform infrared spectroscopy (FT-IR); dynamic light scattering (DLS); and thermal gravimetric analysis (TGA). The results indicate that the hybrid particles had a regular spherical morphology with a diameter ranging from 50 to 80 nm. A reasonable mechanism for the preparation of the core–shell hybrid nanocomposites was presented. The obtained hybrid nanoparticles were subsequently (incorporated into) filled in the poly(styrene-n-butyl acrylate) (PSBA) latex. The effect of (hybrid nanoparticle concentration) filling content on the physicochemical properties of PSBA latex and the resulting node strength per monofilanment of the fibre glass gridding cloth was investigated. The results indicated that the node strength/monofilanment of the fibre glass gridding cloth coated with the PBSA latex filled with 1.0 wt% hybrid nanoparticles demonstrated greatest improvement among all the investigated PSBA latex. This result is related to the rheological properties of the latex. Moreover, the water-resistance property of PSBA composite film was found to be enhanced when compared with that of unfilled PSBA film.     

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.     

细乳液聚合法制备PY-17/PE蜡/PS复合乳胶粒子

通过细乳液聚合法制备彩色墨粉用多组分复合乳胶粒子,即通过细乳液聚合法制备聚苯乙烯包覆有机颜料PY-17和聚乙烯蜡的三元复合乳胶粒子。通过透射电子显微镜、激光粒度仪、紫外可见分光光度计和热失重分析仪对制备的复合乳胶粒子形貌、粒度、热学和光学特性进行表征,着重研究了乳化剂种类及用量、颜料用量和聚乙烯蜡用量对复合乳胶粒子粒径和形貌的影响,并对复合乳胶粒子的热学及光学特性进行了表征。结果表明,使用复合乳化剂,颜料PY-17用量不大于单体量8%、聚乙烯蜡用量占单体量不大于10%时,制备的复合乳胶粒子粒径较小,分布窄,包覆较为完整;并且复合乳胶粒子的热学及光学特性发生了一定的改变。     

PSt乳胶纳米粒子的制备

采用乳液原子转移自由基聚合法,成功制备出了聚合物乳胶纳米粒子。用光子相关光谱(PCS)和透射电子显微镜(TEM)对聚合物乳胶粒子的形貌、粒径和粒径分布进行了表征,结果表明:聚合物乳胶粒子的粒径小于100nm。研究了乳化剂的用量对乳胶粒子粒径大小的影响,研究发现:聚合物乳胶粒子的粒径随乳化剂用量的增大而减小。     

Fabrication and properties of polysilsesquioxane-based trilayer core–shell structure latex coatings with fluorinated polyacrylate and silica nanocomposite as the shell layer

Polysilsesquioxanes (PSQ)-based core–shell fluorinated polyacrylate/silica hybrid latex coatings were synthesized with PSQ latex particles as the seeds, and methyl methacrylate, butyl acrylate, 3-(trimethoxysilyl) propyl methacrylate (MPS)-modified SiO₂ nanoparticles (NPs), 1H,1H,2H,2H-perfluorooctyl methacrylate (PFOMA) as the shell monomers by emulsifier-free miniemulsion polymerization. The results of Fourier transform IR spectroscopy, transmission electron microscopy, and dynamic light scattering suggested the obtained hybrid particles emerged with trilayer core–shell pattern. Contact angle analysis, x-ray photoelectron spectroscopy, and atom force microscopy results indicated that the hybrid film containing SiO₂ NPs showed higher hydrophobicity, lower surface free energy and water absorption, in comparison with the control system (without SiO₂ NPs). Compared with the control system, the hybrid latex film containing SiO₂ NPs in the fluorinated polyacrylate shell layer showed the higher content of fluorine atoms and a rougher morphology on the film surface. Additionally, thermogravimetric analysis demonstrated the enhanced thermostability of PSQ-based nanosilica composite fluorinated polyacrylate latex film.     

乳液复合微粒的形态及其热力学预测

介绍了乳液复合微粒的形态结构，并对其形成的影响因素从加料方式，单体亲水性，引发剂，热力学和动力学等方面作了总结；对乳液复合微粒形态的热力学预测方法进行了评述，对乳液复合微粒形态的设计进行了概括。     

端羟基聚丙烯酸酯分子量对PUA性能的影响

异佛尔酮二异氰酸酯(IPDI)、聚己内酯二醇(PCL)为主要原料合成聚氨酯预聚体,甲基丙烯酸甲酯和丙烯酸丁酯合成端羟基共聚物,两者共聚并在水中分散,得到丙烯酸酯改性水性聚氨酯(PUA)。PUA乳液形貌表征结果表明,当聚丙烯酸酯数均分子量达到9 041时,复合乳液的稳定性变差;复合乳液平均粒径随聚丙烯酸酯(PA)分子量增大而增加,但都小于150 nm,并呈现典型的核壳结构。FTIR测试表明,随着PA链段分子量增大,其氢键相互作用相对减弱。DSC测试显示在PA分子量较低时,PA和PU链段是相容的。TG和拉伸测试结果显示,PUA的热稳定性及力学性能都得到明显改善。     

Synthesis and characteristics of poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles

In this work, the poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles was synthesized by three processes. The first process was to synthesize the poly(methyl methacrylate-co- methacrylic acid) (poly(MMA–MAA)) copolymer latex particles by the method of soapless emulsion polymerization. The second process was to polymerize MAA, N-isopropylacrylamide (NIPAAm) and N,N′-Methylenebisacrylamide (MBA) in the presence of poly(MMA–MAA) latex particles to form the linear poly(MMA–MAA)/crosslinking poly(MAA-NIPAAm) core–shell latex particles, and then the core–shell latex particles were heated in the presence of ammonia solution to form the poly(MAA-NIPAAm) thermosensitive hollow latex particles. In the third process, the poly(MAA-NIPAAm) hollow latex particles reacted with ZnO nanoparticles to form the poly(MAA-NIPAAm)/ZnO thermosensitive composite hollow latex particles on which the ZnO nanoparticles were adsorbed. Besides, a novel process was used to synthesize the poly(MAA-NIPAAm)/ZnO composite latex particles in which the ZnO nanoparticles were encapsulated. The effects of various variables on the morphology of poly(MAA-NIPAAm)/ZnO composite hollow latex particle were studied.     

丙烯酸丁酯/VAE互穿聚合物乳液的研究

以互穿聚合物网络(IPN)方法合成丙烯酸丁酯与VAE共聚物乳液。研究了乳化剂、交联剂、溶胀时间、反应时间等条件对转化率的影响。以红外光谱、透射电子显微镜表征互穿共聚物乳胶膜的微观结构。通过吸水性及乳胶膜对水接触角的测定，证明其耐水性较VAE乳胶膜明显增强。。YEM照片表明互穿聚合物胶粒形态结构较VAE乳胶粒发生了明显变化。     

Growth mechanism and pH-regulation characteristics of composite latex particles prepared from Pickering emulsion polymerization of aniline/ZnO using different hydrophilicities of oil phases

A Pickering emulsion polymerization of aniline, using different hydrophilicities of oil phases, was stabilized by ZnO nanoparticles and performed to synthesize composite latex particles of polyaniline/ZnO. Ammonium peroxydisulfate (APS) was used as an oxidizing agent. The morphologies and growth mechanisms of the resulted composite latex particles were studied. The pH-regulation capacity of the composite latex particles was discussed. When toluene was used as the oil phase, the composite latex particles showed hollow structure, irregular morphology, and hundreds of nanometer in size. It was ascribed to the polymerization of aniline on the interfaces of droplets/water. ZnO nanoparticles, with 50-100 nm in size, acted as surfactants to stabilize the emulsion. When THF was used as an oil phase, the composite latex particles showed spherical morphology and enwrapping ZnO nanoparticles. It was attributed to the homogeneous nucleation of polyaniline in the aqueous phase. ZnO nanoparticles acted as templates for the polyaniline particles. The stability of the Pickering emulsion polymerization was affected by the volume ratio of the oil phase to water. The aqueous solution with pH 3-9 could simply be regulated to about pH 7 by the composite latex particles. It was contributed by the dissolution of ZnO nanoparticles and doping-dedoping of polyaniline in the acidic and alkaline aqueous solutions.