Emulsion Semi-Batch Terpolymerization Process Using Hybrid Emulsifiers for Synthesizing New Emulsion Pressure Sensitive Adhesives (EPSAs)

In order to obtain a suitable formulation of designing direct synthesis of acrylic latexes to be used as emulsion pressure sensitive adhesives (EPSA), having high shear resistance together with high peel strength and tack, free radical emulsion polymerization of hard monomers, such as styrene (St), vinyl acetate monomer (VAM), methyl methacrylate (MMA) and butyl methacrylate (BMA), and soft monomers, butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA) along with multifunctional monomers, namely acrylic acid (AA), were carried out. The effect of the type of hard and soft acrylic monomers, the type and level of emulsifiers, and the initiator concentration on the emulsion polymer stability and final properties of the EPSA were investigated. The results obtained showed an optimized composition. This composition led to a significant increase in shear strength and peel strength to 909 kPa and 0.45 N/mm, respectively, while the synthesized PSA was still too tacky, 5.5 cm, according to adhesion performance testing. For making this successful balance of the conflicting adhesion properties of PSA, a series of anionic and nonionic emulsifiers were investigated. It was interestingly found out that the hybrid emulsifiers (anionic coupling with nonionic) with the optimized compositions could enhance the stability of the emulsion system and improve the properties of PSA compared with the mono-emulsifier. We also tried to adjust the initiator concentration with the level of the optimized hybrid emulsifier, polyoxyethylene alkyl phenyl ether (K30), dioctyl sulfosuccinate (DOSS), and sodium vinyl sulfonate (SVS) with the ratio 2:1:1, resulting in a highly preferred proportion of the 0.5 part of the initiator versus 1.25 parts of the hybrid emulsifier in terms of the total weight of the monomers.     

Effect of hybrid emulsifier (reactive coupling with anionic) on the properties of acrylic emulsion

In this article, a series of emulsifiers were investigated to prepare acrylic latex by seeded semi-continuous emulsion polymerization. The cloud point of nonionic emulsifiers was introduced to explain the emulsifier effects on the emulsification ability during changeable temperature. It was found that, under the same temperature and other experiment conditions, the hybrid emulsifiers (reactive coupling with anionic) could stabilize the pre-emulsion and latex very well. What was studied in detail was the stability of emulsion polymerization, the appearance of the emulsion system and other properties of latex film by changing the adding method, and content and proportion of hybrid emulsifiers. Water absorption of latex film was determined by the gravimetric method. When 2-acrylanmido-2-methylpropane sulfonic acid (AMPS) to sodium dodecyl sulfate (SDS) was less than 2:1, the content of the hybrids reached about 2–3% and when the pre-emulsifying used 2/3 of them, the copolymer emulsion was found to have excellent stability and small particle size with narrow distribution and its film to have low water absorption than those of the latex prepared with SDS alone. What is more, a small amount of hybrid emulsifier could achieve the same emulsification effect compared with SDS alone. And the chemical structure was characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry.     

水性防锈涂料用苯丙乳液的研究

研究了多元苯丙乳液体系的聚合方式、共聚单体、软／硬单体配比、阴／非离子乳化剂配比、乳化剂用量、引发剂用量和聚合温度对乳液性能的影响,确定了制备苯丙乳液的最佳工艺参数,由其配制性能优良的水性防锈涂料。     

Heterocoagulation behavior of carbon black with surface encapsulation through emulsion polymerization

Nanocomposite microspheres containing styrene–acrylate resin, wax, and carbon black (CB) with desired CB dispersion were prepared through heterocoagulation. The CB surface was modified using conventional anionic emulsifier and anionic dispersants with different lengths of nonionic chains and reactivities or through polymer encapsulation via emulsion polymerization to regulate the dispersion and concentration of CB in the microspheres. Experimental results showed that anionic dispersants with long nonionic chains effectively dispersed and stabilized CB particles. Polystyrene (PS) was then encapsulated on the CB surface by using a reactive dispersant and a water‐soluble initiator of polymerization. The CB particles exhibited comparable pH stability with other heterocoagulation components. Overall, encapsulation through emulsion polymerization can be used to obtain not only high CB content but also improved CB distribution in the resulting microspheres. High coagulation efficiency can also be achieved using polystyrene‐encapsulated dispersed CB because of its high affinity to emulsifiers and reactive dispersants during dispersion. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43516.     

反应性乳化剂对丙烯酸酯胶粘剂性能的影响

用半连续乳液聚合法合成了丙烯酸酯胶粘剂,比较了常规乳化剂和反应性乳化剂对丙烯酸酯胶粘剂性能包括初粘性,持粘性,180°剥离强度,聚合稳定性等的影响。结果表明:与常规乳化剂相比,由反应性乳化剂烯丙氧基壬基酚聚氧乙烯(10)醚双磷酸(ANPEO10-P2)所制得胶粘剂的综合性能较好。     

Synthesis of acrylate polymers by a novel emulsion polymerization for adhesive applications

Pressure‐sensitive adhesives (PSAs) are viscoelastic–elastomeric materials that can adhere strongly to solid surfaces with light contact pressure and a short contact time. Polyacrylates produced by solution polymerization are used widely because of their good adhesive properties. A novel emulsion polymerization was established to improve the low physical properties of PSA on the basis of conventional poly(n‐butyl acrylate) (PBA) by emulsion polymerization. PBA latex was synthesized by the emulsion polymerization of 50 wt % n‐butyl acrylate mixed with 15 wt % ethyl acetate (EA) with Emal‐10P and Emulgen‐920 as anionic and nonionic surfactants, respectively, at 70°C. Potassium persulfate (KPS) or a combination of KPS and dicumyl peroxide (DCP) was used as the initiator. The KPS/DCP system gave a very high‐molecular‐weight PBA of a narrow molecular weight distribution with a weight‐average molecular weight/number‐average molecular weight value of 1.01–1.03 in 15 min. The PSA tape was prepared by the casting of the PSA latex onto a corona poly(ethylene terephthalate) film as an adherent to obtain a 50‐μm‐dry‐thickness film. The PSA tape produced from PBA by the novel emulsion polymerization showed better adhesive properties, such as 180° peel adhesion, shear holding power, and rolling ball tack tests according to JIS and ASTM standards, than PSA tape produced from solution polymerization. The occlusion of a small amount of EA in emulsion particles before polymerization was found to give higher properties than those of PBA prepared by the addition of EA to the PBA latex after polymerization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:413–421, 2006     

含羟基叔氟微乳液的合成及水性双组分聚氨酯清漆的制备

以叔碳酸乙烯酯、丙烯酸六氟丁酯、含羟基单体、反应型阴离子乳化剂、非离子乳化剂、（甲基）丙烯酸及其酯类单体等为原料制备了新型含羟基叔氟共聚物乳液。考察了反应温度、乳化剂用量、乳化剂配比、引发剂用量、有机氟单体等对乳液聚合过程的影响；并对制备的乳液进行了红外、机械稳定性等的表征，确定了最佳反应条件。利用该新型乳液和水性固化剂，制备了常温固化水性双组分聚氨酯涂料，并进行了测试表征。     

高固体分无凝胶丙烯酸酯乳液合成工艺探讨

为制备高固体分无凝胶丙烯酸酯乳液,探讨了聚合方法,单体和引发剂的加料方式,乳化剂用量和种类,以及保护胶体种类对丙烯酸酯乳液性能的影响。结果表明：全部预乳化效果最佳,4h内无凝胶产生;半连续滴加较一次性或分批加入更有利于乳液体系稳定;采用阴离子与非离子乳化剂复配及加入保护胶体有利于提高聚合体系的固含量。筛选出最佳的制备工艺条件：采用全部预乳化、半连续种子乳液聚合;以十二烷基硫酸钠（SDS）与烷基酚聚氧乙烯醚（OP-10）为复合乳化剂（质量比为1：1）,其用量为3％;保护胶体量为0．8％;引发剂量为0.3％;反应温度为78℃;反应时间为4h;搅拌速率为400r／min。此条件下可合成固含量达60．03％的带蓝光乳白色丙烯酸酯乳液。     

Fluoro-silicone Modified Polyacrylate Latex Emulsified with Green Surfactants

Fluoro‐silicone modified polyacrylate latex was successfully prepared by semi‐continuous seeded emulsion polymerization in the presence of a green mixed emulsifier consisting of cashew phenol polyoxyethylene ether sulfonate (BCE‐10B) anionic surfactant and alkyl polyglycoside (APG) nonionic surfactant, in which the mixed monomers were initiated with potassium persulfate (KPS). The structure and properties were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle (CA), respectively. Results show that the optimal conditions of synthesizing the novel emulsion are as follows: the total concentration of mixed emulsifiers is 5.0%; the optimum mass ratio of APG to BCE‐10B is 2:1; the amount of initiator is 0.6%; the composition of main monomers of MMA:BA = 1:1; and the concentrations of HFMA and VTES are 4.0 and 6%, respectively. In this case, the resultant emulsion showed good thermal stability and hydrophobicity.     

有机硅氧烷改性醋酸乙烯酯-丙烯酸酯乳液的合成与性能

采用种子乳液聚合,引入乙烯基三甲氧基硅烷(A-171),以十二烷基苯磺酸钠(DSB)和壬基酚聚氧乙烯(20)醚(OP-10)作复合乳化剂,以过硫酸钾(KPS)为引发剂,在反应温度为78±2℃条件下,合成了A-171改性醋酸乙烯酯(VAc)-丙烯酸酯共聚乳液。实验采用单体滴加工艺,考察了配方中丙烯酸丁酯(BA)、甲基丙烯酸(MAA)和A-171用量对共聚物性能和乳液聚合过程的影响,并用红外光谱仪(FTIR)、粒度仪和差示量热扫描仪(DSC)对共聚物的结构及性能进行了表征。结果表明,引入w(BA)=10%~15%(相对于配方中单体总质量,下同)、w(MAA)=4%、w(A-171)=1%到VAc-丙烯酸酯共聚物乳液中,共聚物乳液涂膜的吸水率<5.0%,耐寒性通过10个循环,60℃加速贮存稳定性>100 d。     

Anionic ring-opening polymerization of octamethylcyclotetrasiloxane in emulsion above critical micelle concentration

Batch anionic ring-opening polymerization of octamethylcyclotetrasiloxane in emulsion using nonionic and cationic emulsifiers was studied. The concentration of emulsifiers was set above their critical micelle concentration. Effects of emulsifier concentration, nonionic/cationic emulsifier ratio and cationic emulsifier/initiator (KOH) ratio on the kinetics, average particle size and distribution and on the average molecular weight and distribution were investigated and discussed. At the beginning of the polymerization, empty micelles, active micelles (polymer particles) and monomer droplets co-exist in emulsion. The transport of monomer from monomer droplets toward empty micelles was confirmed by monomer droplets and empty micelles disappearance and by formation of smaller particles. The transport of monomer from monomer droplets toward polymer particles was not confirmed, since the average polymer particle size did not increase during polymerization. It was proposed, that at lower conversions, monomer diffuses from polymer particle interior to particle surface, while at higher conversions, the monomer diffuses from larger to smaller polymer particles. Emulsifier concentration, nonionic/cationic emulsifier ratio and cationic emulsifier/KOH ratio have an evident effect on the kinetics and on the average molecular weight, thus demonstrating that cationic emulsifier participates to the initiation reaction.     

Functions of emulsifiers in food systems

The function of food grade emulsifiers in various food products (emulsions, starch based food, yeast raised bakery products, etc.) are reviewed. The stability of emulsions against coalescence of dispersed droplets is among other factors dependent on monoor multimolecular interfacial films with viscoelastic properties formed by adsorbed emulsifier molecules. Agglomeration of fat globules in whippable emulsion is needed to obtain desired foam stability and texture and can be controlled by lipophilic emulsifiers. Complex formation with starch components (amylose) is influenced both by the chemical structure of an emulsifier and by its physical behaviour in water. Interaction with proteins takes place primarily with anionic emulsifiers or very hydrophilic, nonionic types, which thereby improves the rheological properties of wheat gluten. Emulsifiers are also used as crystal modifying agents in fats where polymorphic changes during storage creates texture problems.     

低乳化剂含量丙烯酸酯微乳液的合成与性能

以脂肪醇聚氧乙烯醚硫酸钠(AES)/辛基酚聚氧乙烯醚(OP-10)为阴/非离子型复合乳化剂,制备了低乳化剂含量的丙烯酸酯微乳液。探讨了搅拌速率、聚合温度、复合乳化剂类型和用量、pH值及聚合中期引发剂补加方式等对丙烯酸酯微乳液的稳定性、透光率、粒径及其分布等影响。结果表明:当搅拌速率为120~160 r/min、聚合温度为75~76℃、复合乳化剂中w(AES+OP-10)=2%且m(AES)∶m(OP-10)=3∶1时,丙烯酸酯微乳液的稳定性最高(凝胶率为0),并且其透光率为68.7%、平均粒径为37.8 nm且粒径分布较均匀。     

乳化剂对丙烯酸酯乳液增稠剂影响的研究

研究了非离子型乳化剂和阴离子型乳化剂两者配比及其用量对丙烯酸酯乳液稳定性和增稠性能的影响,并对这两种乳化剂对乳液的钙离子稳定性的影响做了详细的分析.实验结果表明:采用非离子型乳化剂较多的复合乳化剂配比有利于提高乳液的钙离子稳定性,复合乳化剂的配比和用量对乳液增稠剂的增稠能力和耐电解质能力有着明显的影响.     

新型低温型聚丙烯酸酯乳液的合成

采用种子乳液聚合法合成新型低温反应型聚丙烯酸酯乳液粘合剂,即以丙烯酸丁酯（BA）、丙烯酸异辛酯（EHA）、苯乙烯（St）为软、硬单体,丙烯酸（AA）为功能单体,以过硫酸钾为引发剂,并选用一种适当的交联单体合成了性能优良的聚丙烯酸酯涂料印花粘合剂。讨论了引发剂用量、乳化剂用量、阴／非离子乳化剂的配比、乳液滴加时间、保温时间等对聚合物的影响。确定了乳液聚合最佳工艺条件：乳化剂用量为o8％,阴／非乳化剂质量比为4：3,引发剂用量为0．8％,乳液滴加时间60min,保温时间60min。     

氟聚合物-聚丙烯酸酯互穿网络聚合物乳液的合成

采用互穿网络的方法来制备乳液．以聚四氟乙烯为种子乳液．用丙烯酸酯单体对其进行溶胀．加入聚偏氟乙烯后滴加单体聚合，整个实验中采用阴离子乳化剂和非离子乳化剂复配体系、并且添加少量的保护胶。通过正交实验得到涂层具有最大接触角的聚合配方．然后用红外光谱、扫描电镜和透射电镜对乳液涂层进行表征．结果表明氟聚合物与丙烯酸酯之间有较好的相容性．乳液稳定且乳液涂层性能优异。     

反应型乳化剂对保护膜用丙烯酸酯乳液型压敏胶性能的影响

采用预乳化法制备了丙烯酸酯压敏胶乳液,探讨了不同乳化剂体系对压敏胶物理性能的影响。FTIR测试表明,反应型乳化剂参与了反应;TEM测试显示,反应型乳化剂体系所得乳液粒径小,分布均匀。实验结果表明:当w(复合乳化剂)=3%,m(ANPEO10)∶m(DNS-458)∶m(DNS-501)=1.5∶1.1∶0.4时,所得乳液的固体分质量分数为48.03%,单体转化率达到97.66%,乳液黏度为38.8 s,平均粒径为238 nm,压敏胶的初粘力能吸住8号钢球,持黏性大于24 h,180°剥离强度达到0.304 N/mm。贴在不锈钢表面的保护膜经80℃烘烤24 h后,不锈钢表面无残胶和雾影。     

Photo‐induced emulsion polymerization of vinyl acetate in the presence of poly(oxyethylene) nonyl phenyl ether,a nonionic emulsifier (II)

Synthesis of high molecular weight poly(vinyl acetate) having less branched structure via photo‐induced emulsion polymerization of vinyl acetate in the presence of poly(oxyethylene)₂₀ nonyl phenyl ether, a nonionic emulsifier, was attempted at 0°C or even below 0°C in the presence of methanol. It was found that 100% conversion is always achieved in all runs and poly(vinyl acetate) having the number‐average degree of polymerization of 9000 with less branched structure (degree of branch < 0.5) can be obtained from this photo‐induced emulsion polymerization system. Mechanisms of the polymerization were also discussed on the basis of the kinetic results. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2153–2158, 2002     

氢化松香/丙烯酸酯复合细乳液的制备及其性能研究

以氢化松香(HR)作为增黏树脂,采用细乳液聚合法制备了HR/丙烯酸酯复合细乳液。探讨了乳化剂、HR等因素对该乳液及其胶膜性能的影响。结果表明:与常规乳液聚合相比,细乳液聚合制得的乳液粒径更小、粒径分布更窄、单体转化率更高、凝聚率更低、Zeta电位更高且体系更稳定;HR能有效改善PSA(压敏胶)的粘接性能,并且当w(HR)=5%时,PSA的初粘力(9#钢球)、180°剥离强度(11.2 N/25 mm)和持粘力(47 min)相对较好。     

反应型乳化剂对苯丙微皂乳液聚合及性能的影响

采用不同结构类型的反应型乳化剂应用于苯丙微皂乳液的聚合,讨论了聚合方式、乳化剂的结构类型和用量等对乳液聚合及性能的影响。借助DSC、粒径分布仪、FT-IR、拉力机、TEM等仪器及分析技术对制得的苯丙乳液的性能进行表征分析,发现通过半连续核壳乳液聚合方式,采用合适的反应型乳化剂复配体系,可以制备出综合性能优异,粒径小于100 nm的苯丙微皂乳液。