MMA/BA半连续乳液聚合过程中乳胶粒径及其分布

以甲基丙烯酸甲酯(MMA)与丙烯酸丁酯(BA)进行聚合制备丙烯酸酯乳液,研究半连续种子乳液聚合过程中乳化剂浓度c(E)、引发剂浓度c(I)、反应温度T及MMA的摩尔分率f(MMA)对乳胶粒粒径及其分布(PSD)的影响.实验结果表明:在半连续种子乳液聚合中,当c(E)增大、c(I)减小和f(MMA)增大时,整个聚合过程中同一反应时间的乳胶粒径分布变窄;而反应温度T对PSD的影响是非单向的,当T从70 ℃上升到85℃时,PSD逐渐变窄,而在90℃时,PSD在成核阶段迅速增大,粒子分散度Fmax已超过85℃时的值,且在后期也一直保持较窄的分布.聚合过程的PSD测试表明在种子半连续乳液聚合过程中,乳胶粒子的粒径一直呈增长趋势,而粒径分布则是在成核阶段由窄变宽,待成核结束一段时间后反应稳定进行,乳胶粒子的分布又开始变窄,最终保持一个较低的分散度.     

水性含氟丙烯酸酯核壳乳液的合成与性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、甲基丙烯酸六氟丁酯(HFMA)为主要原料,在十二烷基硫酸钠(SDS)和辛基酚聚氧乙烯醚(OP-10)复合乳化剂的作用下,采用预乳化-半连续种子乳液聚合法,合成了具有核壳结构的含氟丙烯酸酯共聚物乳液。研究了核壳单体的配比、乳化剂用量、引发剂的用量、含氟单体的用量对乳液聚合过程以及乳胶膜性能的影响。通过红外光谱法(FT-IR)、激光粒径分析仪、透射电镜(TEM)对乳液及乳胶膜组成、结构和形貌进行了表征,通过接触角(CA)、热重分析(TG)和拉伸测试表征了含氟丙烯酸酯共聚物乳胶膜的表面性能、热稳定性能与力学性能。结果表明:当m(MMA)∶m(BA)=1∶1,核/壳单体比为3∶2,乳化剂用量为3%,引发剂的用量为0.6%,含氟单体的用量为10%时,制备的含氟丙烯酸酯共聚乳液具有明显的核壳结构,且含氟基团富集于壳层,乳胶膜的综合性能明显优于不含氟乳液,达到"低氟高效"的效果。     

乳化剂对核壳乳液聚合体系的影响

本文采用半连续-预乳化工艺制备了表层羧酸化的聚丙烯酸丁酯／聚（甲基丙烯酸甲酯-衣康酸）（PBA／P（MMA—ITA））核壳乳液。通过对乳液粒径及其分布、凝聚率和表面张力的分析研究了乳化剂种类、配比、用量以及功能单体等因素对聚合体系稳定性的影响,采用非水滴定法、傅立叶红外光谱仪（FTIR）、差示扫描量热仪（DSC）、透射电子显微镜（TEM）等方法对乳胶粒子进行了表征。实验结果表明：OP—10引入乳化体系,使聚合体系的稳定性增加,但随着OP—10用量的增加,乳胶粒子粒径增大、粒径分布变宽,聚合体系的稳定性降低;复合乳化剂SDS／OP—10用量增加,乳胶粒子粒径减小,聚合体系的稳定性增加;极性单体ITA的使用导致聚合体系的稳定性降低。分析结果还证明ITA已成功参与了壳层的聚合反应,乳胶粒子具有明冠的核/壳结构。     

BA-VAc-MA乳液共聚机理的研究

目前,对乳液聚合反应发生的场所尚有争议。按 Smith-Ewart 经典理论的观点,聚合反应发生在增溶胶束或聚合物乳胶粒子内部;Medvedev 则认为聚合反应是在粒子表面上的单体吸附层中进行。本文就丙烯酸丁酯(BA),醋酸乙烯酯(VAc)和顺丁烯二酸酐(MA)三元乳液共聚体系进行了研究,发现聚合机理不仅与前人强调的聚合     

氟硅丙烯酸酯共聚物乳液的制备

以十二烷基苯磺酸(DBSA)为催化剂,将甲基丙烯酸甲酯(MMA)、丙烯酸正丁酯(BA)、三(甲基三氟丙基)环三硅氧烷(D3F)与乙烯基三乙氧基硅烷(VTES)进行乳液共聚反应,制备了氟硅丙烯酸酯聚合物乳液。考察了不同单体及催化剂用量对乳液聚合的影响。结果表明:当氟硅单体D3F用量为20%,VTES用量为3%,DBSA用量为0.7%时,聚合过程及乳液的稳定性较好,乳胶的粒径大小在88nm左右;经氟硅改性的丙烯酸酯乳胶膜的热稳定性要高于聚丙烯酸酯乳胶膜,热分解温度提高了30℃;氟硅单体用量为5%时,乳胶膜的吸水率明显下降。     

核壳型苯丙胶乳的制备及其成膜性研究

以苯乙烯、丙烯酸丁酯和二乙烯基苯为单体,通过间歇-半连续细乳液聚合,制备不同交联度的核壳型胶乳.分别采用激光粒度仪和透射电镜测定了不同聚合阶段胶乳的粒径大小、分布和形态.并用场发射扫描电镜考察胶乳膜液氮淬断制得的断面形貌.结果表明,随着聚合阶段深入,胶乳粒径变大,聚合过程未发生二次成核;乳胶粒具有核壳结构;随交联剂二乙烯基苯浓度的提高,膜中初始乳胶粒的形态越加明显,膜的连续性下降,交联结构抑制聚合物链在乳胶粒间的扩散,破坏膜结构的连续性.     

核壳结构丙烯酸酯共聚物乳液的合成研究

以丙烯酸丁酯为核单体,甲基丙烯酸甲酯和丙烯酸乙酯为壳单体,十二硫醇为壳层聚合的链转移剂,采用种子乳液共聚方法制备核壳结构的丙烯酸酯共聚物.研究单体、链转移剂的用量对壳层聚合物的玻璃化温度、黏流温度和熔体流动速率的影响,用扫描电子显微镜对乳胶粒结构进行研究.实验结果表明:加入丙烯酸乙酯或十二硫醇,可以降低壳层聚合物的玻璃化温度和黏流温度,增加熔体流动速率,加入质量分数为0.1%的十二硫醇可以使壳层共聚物(m(MMA)/m(EA)=80/20)的熔体流动速率提高到0.863 g/min,提高了2个数量级,核壳聚合物乳胶粒径在100～200nm之间,粒径分布较窄.     

KPS-SHS 引发丝胶与甲基丙烯酸甲酯接枝共聚的研究

采用过硫酸钾(KPS)-亚硫酸氢钠(SHS)氧化还原引发体系,在水介质中,引发丝胶(SS)和甲基丙烯酸甲酯(MMA)进行接枝聚合,借助FTIR对接枝共聚物进行表征,结果表明MMA被成功接枝到SS大分子链上.此外,考察了单体浓度、引发剂浓度、反应温度和时间对接枝聚合反应的影响,在保持丝胶质量浓度为10g/L不变的情况下,得到接枝聚合反应的最佳聚合条件如下:[MMA]=0.4mol/L;[KPS]=[NaHSO3]=6.25×10-4mol/L;t=70℃;t=60min,并提出了可能的接枝聚合机理.     

紫外光稳定化核壳弹性体的合成

将一种聚合型的受阻胺光稳定剂,4-丙烯酰氧基-1,2,2,6,6-五甲基哌啶(PMPA)与丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)通过乳液聚合制备出一种具有紫外光稳定能力的核壳结构弹性体粒子。并研究了乳化剂用量、引发剂用量及反应温度对聚合反应的影响。核磁共振氢谱(1H-NMR)分析结果证实光稳定基团已成功接枝到乳胶粒子中。透射电镜(TEM)观察结果显示,乳胶粒子具有核壳结构,且粒径约为100 nm。热分析(TGA)结果表明,受阻胺基团的引入可以改善乳胶粒子的热稳定性,而且可以极大地提高其初始分解温度。     

发泡剂存在下的偏氯乙烯悬浮共聚合成粒过程

为了探究悬浮聚合体系中加入发泡剂对聚合成粒过程的影响,在不同沸点烷烃发泡剂存在下进行偏氯乙烯-甲基丙烯酸甲酯(VDC-MMA)悬浮共聚,采用在线激光粒度分析仪和光学显微镜跟踪聚合过程中液滴和聚合物颗粒粒径和形貌的演变,并根据液滴和聚合物颗粒形貌、聚合物/油相溶胀特性和聚合物玻璃化温度随聚合过程的变化,分析核-壳结构VDC-MMA共聚物/烷烃粒子的形成机理.结果表明,当不加发泡剂时,VDC-MMA(质量比为70/30)悬浮共聚得到的颗粒形貌规整、内部密实,粒径变化与珠状悬浮聚合成粒相符.当添加发泡剂后,成粒的准稳态和增长阶段持续时间缩短,恒定阶段粒子收缩不明显,得到的粒子为表面褶皱、核-壳结构较完善的微胶囊粒子.     

Influence of carboxyl groups on the particle size and rheological properties of polyacrylate latices

The PAL was synthesized with BA,MMA and some monomers containing carboxyl groups(for example,acrylic acid(AA) and methacrylic acid(MAA)) as co-monomers by semi-continuous seeded emulsion polymerization technique.The influences of alkalinization temperature,the feeding manner of AA or MAA on the particles size,rheological properties and carboxyl distribution of the latex were discussed,and the rheological mechanism was analyzed.The experimental results show that the PAL system has preferable viscosity and particle size when the alkalinization temperature is 50 ℃.Different distribution of carboxyl group in the particles and different resultant rheological properties are obtained by different feeding manner of AA or MAA into the system.The TEM images show that the particle is a smooth globe with carboxyl group concentrating on the surface and stabilized with electric double layer and nonionic adsorbed layer.The concentration of carboxyl functional group on the surface of particles can be achieved by the specific polymerization technique.The rheologyical properties are determined by accretion of particle volume and variation of the two phase volume ratio resulted from the carboxyl group spreading layer.     

聚丙烯酸酯乳液的合成及其性能研究

制备了一种以阴离子与非离子混合表面活性剂为乳化剂、以丙烯酸丁酯和甲基丙烯酸甲酯及一些官能团单体为原料的聚合物乳液，并详细讨论了单体配比、乳化剂、官能单体、温度及聚合工艺等因素对乳液性能的影响．     

水溶性单体类型对BA-MMA-St微皂乳液性能的影响

用甲基丙烯酸(MAA)或丙烯酸(AA)和N-羟甲基丙烯酰胺(N-MA)或丙烯酰胺(AM)共聚,实现了BA-MMA-St的微皂乳液聚合。考察了水溶性单体(羧酸类单体、非离子水溶性单体)对微皂乳液聚合性能的影响。实验结果表明,采用微皂乳液聚合明显地改善了涂膜的耐水性和附着力。     

Preparation of self-crosslinked fluorocarbon polymer emulsion with core-shell structure by the method of soap-free emulsion polymerization

Using methyl methacrylate (MMA), butyl acrylate(BA) and hexafluorobutyl acrylate(HFBA) as main raw materials, we prepared self-crosslinked fluorocarbon polymer emulsion with core-shell structure via soap-free emulsion polymerization when the conception of particle design and polymer morphology was adopted. Moreover, the influence of mole ratio of BA to MAA, pH value on the oligomer was studied. And the effects of the added amount of oligomer, self-crosslinked monomer and HFBA, mass ratio of BA to MMA, reaction temperature and the initiator on the polymerization technology and the performance of the product, were investigated and optimized. The structure and performance of the fluorocarbon polymer emulsion were characterized and tested with FTIR, TEM, MFT and contact angle and water absorption of the latex film. The experimental results show that the optimal conditions for preparing fluorocarbon polymer emulsion are as follows: for preparing the oligomer, mol ratio of BA to MAA is equal to 1.0: 1.60, and pH value is controlled within the range of 8.0 and 9.0; for preparing fluorocarbon polymer emulsion, the added amount of oligmer[P(BA/MANa)] is 6%; mass ratio of BA to MMA is 40: 60; the added amount of self-crosslinked monomer is 2%, the added amount of HFBA is 15%; reaction temperature is 80 °C; the mixture of potassium persulfate and sodium bisulfite is used as the initiator. The film-forming stability of the fluorocarbon polymer emulsion and the performance of the latex film, which is prepared with the soap-free emulsion polymerization, are better than that prepared with the conventional emulsion polymerization. Funded by the Jiangsu Provincial Creative Fund for Scientific and Technical Small and Medium-size Enterprise     

蓄电池玻纤隔板乳液粘合剂的性能研究

本文考察了单体类型、Ｓｔ、ＢＡ、ＡＡ含量及加料方式等对蓄电池玻纤隔板乳液粘合剂应用特性的影响。结果表明,当单体是Ｓｔ、ＭＭＡ、ＢＡ、ＢＭＡ及ＡＡ,其中Ｓｔ、ＢＡ、ＡＡ的含量分别是６３％左右、１７％或１８％及６％,采用种子乳液聚合两段加料法时,合成的乳液粘合剂具良好的应用特性,如增稠性、粘接性、不粘网、耐酸性、热稳定性及产泡破裂且不聚集等。     

微波辐射丙烯酸酯乳液聚合动力学研究

利用Discover微波精确有机合成系统,以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为聚合单体、过硫酸钾(KPS)为引发剂、十二烷基硫酸钠(SDS)为乳化剂进行乳液聚合。考察了微波辐射功率对乳液聚合反应的影响,分别考察了引发剂的质量,乳化剂质量,甲基丙烯酸甲酯质量,丙烯酸丁酯质量及反应温度,还对微波聚合反应动力学方程进行了研究。利用热重分析仪,差示扫描量热仪和傅立叶变换红外光谱仪对聚合物乳液的性能进行了测试与结构表征。实验结果表明,反应体系选择60 W为微波辐射条件,m(KPS)为0.06 g、m(SDS)为0.27 g、m(MMA)和m(BA)均为3 g,反应温度为343 K,测得聚合反应的活化能Ea=96.957 1 kJ/mol,建立了单模聚焦微波辐射乳液聚合的动力学方程:Rp=k[n(KPS)]1.107 9[n(SDS)]0.616 4[n(MMA)]1.205 9[n(BA)]-0.228。     

含氟丙烯酸酯防水防油整理剂的制备及表征

采用半连续乳液聚合的方式,以十二烷基苯磺酸钠(SDBS)和脂肪醇聚氧乙烯醚(AEO-9)为复配乳化剂,从基础单体甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯酸异辛酯(EHA)和功能单体甲基丙烯酸十二氟庚酯(G04)入手,制备出稳定的含氟丙烯酸酯防水防油整理剂。并通过对合成的含氟丙烯酸酯防水防油整理剂用红外光谱(FT-IR),热重分析(TGA)、凝胶色谱(GPC)和X射线光电子能谱(XPS)等进行分析表征。     

Preparation of self-crosslinked acrylate emulsion with high elasticity and its rheological properties

Using butyl acrylate（BA）,methyl methacrylate（MMA）,methacrylic acid（MAA） and mixed emulsifier as raw materials,the self-crosslinked emulsion was prepared via pre-emulsified and semi-continuous seeded emulsion polymerization technology in the presence of N-hydroxymethyl acrylamide and poly solidum maleate. The influence of mass ratio of BA to MMA,amount of N-hydroxymethyl acrylamide and poly solidum maleate on the rheological properties of the self-crosslinked emulsion was studied. Possible cross-linked mechanism of self-crosslinked monomer was investigated. And the relationship between emulsion viscosity and shear rate was investigated. The results show that the self-crosslinked acrylate emulsion with high elasticity can be synthesized when the mass fractions of BA is 60%,MMA is 40%,and added amount of N-hydroxymethyl acrylamide is 2.5%-3.0% and added amount of poly solidum maleate is 0.3%-0.4%. The self-crosslinkage process of N-hydroxymethyl acrylamide involves two steps. One is copolymerization of N-hydroxymethyl acrylamide and acrylate,the other is cross-linkage among polymer molecules via condensation reaction of methylol. The emulsion is of rheological properties of pseudo-plastic fluid and belongs to non-Newtonian fluid.