Synthesis and surface properties of PDMS–acrylate emulsion with gemini surfactant as co-emulsifier

Composite latex particles of acrylate and polydimethylsiloxane (PDMS) with high PDMS content was prepared by emulsion copolymerization and characterized by particle size analyzer, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR). With gemini surfactant as the co-emulsifier in the system, the PDMS content in the system reached 50%, which was far higher than the other reported values. Through the characterization of the particle size analyzer, the particle size augmented with the increase of the amount of PDMS, which could be said that the polysiloxane had participated into the reaction and had been introduced into the colloid particle. The results of FTIR indicated that almost all the monomer had been exhausted in the reaction because there was no C=C and D₄ characteristic peaks in the spectrum. Besides the surface properties also were measured by surface tension analysis, water absorption, and the static contact angle, it could be found that with the increase of polysiloxane content, the excellent properties acquired by PDMS were clearly revealed by the findings, such as the decrease of surface tension and water absorption, and the increase of static contact angle. All the measurements were consistent with the conclusion that the composite latex particles of polysiloxane and acrylate with high siloxane content had been prepared successfully.     

离子型共聚单体参与下的全氟丙烯酸酯无皂乳液共聚

离子型共聚单体参与下的全氟丙烯酸酯无皂乳液共聚;全氟烷基丙烯酸酯;无皂乳液;离子型共聚单体     

Emulsifier-free latex of fluorinated acrylate copolymer

Emulsifier-free latices of fluorinated acrylate copolymers were prepared by semicontinuous polymerization method, with perfluoroalkylethyl methacrylate (Zonyl TM) as a fluoromonomer. Ultrasonic at 40 kHz was adopted to help monomers disperse well in water. The relationships of polymerization conditions between the final conversion and polymerization stability were discussed in detail and the optimal polymerization condition was given. A fluorinated acrylate copolymer was finally obtained and its T_g was 54 °C. The average particle size of the latex was about 601 nm and the particle size distribution of the latex was narrow. The latex film exhibited a low surface free energy and good surface property. By using 6% Zonyl TM, the water contact angle of the film-air interface increased significantly and reached to 110.2°. Compared with the latex film of fluorine-free polyacrylate prepared under the similar polymerization condition, the fluorinated latex film had a better water-resistance and thermal stability.     

Preaparation of cationic latexes of poly(styrene-CO-butyl acrylate) and their properties evolution in latex dilution

Cationic latexes were prepared through emulsion copolymerization of styrene(St) and butyl acrylate(BA) with a cationic surfactant,cetyl trimethyl ammonium bromide(CTAB).Latex properties,including particle size,size distribution,ζpotential,surface tension and monomer conversion,were determined for latexes prepared with different CTAB amounts. Evolution of these properties during emulsion polymerization was followed in order to understand the mechanism of the particles formation.Results showed that both particle size andζpotential were function of polymerization time and latex solids.Parallel emulsion polymerizations with cationic,anionic charged initiator and charge-free initiators were also carried out,the latex properties were determined at different polymerization time.All these results were attentively interpreted based on the mechanisms of emulsion polymerization,surfactant adsorption and latex particle stabilization.     

Properties and characterization of novel cationic polyacrylate latex containing fluorine and silicon prepared with soap-free emulsion polymerization

The novel cationic polyacrylate latex containing fluorine silicon was successfully prepared via soap-free emulsion polymerization of butyl acrylate, methyl methacrylate, vinyltriethoxysilane and hexafluorobutylmethacrylate in water phase, which were initiated with water soluble azo initiator and emulsified with the mixed surfactants polymerizable emulsifier and OP-10. The films of the resultant latex were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA) determinator, respectively. In comparison with the conventional polyacrylate latex, the thermal stability and water resistance of novel latex film are improved. The conditions of preparing the novel cationic acrylate latexes were optimized. The optimum conditions of preparing the novel latex are as follows: the amount of emulsifiers and the initiator are 6.0% and0.3%, respectively; both the amount of VETS and amount of HFMA are 6.0%. In this case, the conversion is high and the polymerization stability is good.     

功能单体α-烯烃磺酸钠用于无皂乳液共聚合

用工业原料α-烯烃磺酸钠(AOS)作为功能单体与甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)进行了乳液共聚合,通过测定AOS与MAA的竞聚率,确定了适宜的聚合方式为连续加料法.使用5%AOS制备了高固含量(>60%)的胶乳,并与用十二烷基硫酸钠(SDS)作乳化剂时该体系的乳液共聚合进行了比较.AOS是影响乳液稳定性和胶粒大小的主要因素,当AOS含量为单体总质量的1%时可以得到固含量大于40%粒径小于100 nm的乳液;当AOS含量为5%时可以得到固含量大于60%的乳液.两种情况下胶粒粒径分散性均较窄,明显优于同样条件下用SDS制备的胶乳.使用1%AOS制得的胶乳静置1年后粒径及其分布基本保持不变.     

Reactive Surfactant in the Emulsion Copolymerization of Methyl Methacrylate and Octyl Acrylate

The emulsion copolymerization of methyl methacrylate and octyl acrylate was studied using a reactive surfactant ammonium sulfate allyloxy nonylphenoxy poly(ethyleneoxy) (10) ether (DNS‐86), and a conventional surfactant sodium dodecylbenzene sulfonate (DBS) with a similar structure as a comparison sample. A series of latex samples have been prepared with two kinds of surfactants, and their properties have been characterized and compared. ¹H‐NMR proves that the reactive surfactant has been incorporated into the resulting copolymers. The atomic force microscopy (AFM) proves that the reactive surfactant DNS‐86 migrate to the surface of the latex film to a much less degree than the conventional surfactant DBS. Transmission electron microscopy (TEM) demonstrates that there are some differences in the particle morphologies. The stability and water‐resistance of the latex films prepared by reactive surfactant DNS‐86 are better than those prepared by the conventional surfactant DBS.     

Preparation of MMA－BA－DMAEMA Nanosized Latex

The terpolymer latex of methyl methacrylate (MMA)/butyl acrylate (BA)/ dimethyl aminoethyl methacrylate (DMAEMA) with diameter of less than 100 nm was prepared by seeding semi-continuous emulsion copolymerization using APS (ammonium pcrsulfate) / TMEDA (N,N,N,N-tetramethylethylenediamine) as the redox initiators and SDS (sodium dodecylsulfate) and OP (P-octylpolyethylene glycol phenylether) as co-emulsifiers. The factors that influenced the process stability of the copolymerization and the particle size of the latex were investigated. The addition of aqueous ammonia as coagulation inhibitor provided better process stability of the copoly- merization. The addition of acetic acid as the acidification agent caused a remarkable reduction of the latex particle size.     

STUDY ON THE POLYMERIZATION KINETICS AND STABILITY OF P(UA)/MMA MICROEMULSION*

 Urethane acrylate anionomer (APUA) as a kind of new type polymerizable emulsifier was synthesized using 2,4-toluene diisocyanate (TDI), polypropylene glycol (PPG), 2-hydroxyethyl methacrylate (HEMA) and dimethylolpropionic acid (DMPA). The critical micelle concentration (CMC) of APUA was measured by the methods of conductance and surface tension. The comparative studies between polymerizable emulsifier AUPA and conventional emulsifier sodium dodecyl sulfate (SDS) were carried out in the emulsion polymerization of methyl methacrylate (MMA). Polymerization kinetics,stability, size and morphology of the latex particles were investigated. It was found that in APUA both water soluble initiator potassium persulfate (KPS) and oil soluble initiator 2,2'-azobisisobutyronitrile (AIBN) can start the reaction of MMA, and the polymerization rate and yield were very high. On using AIBN as an initiator, the conversion-time behavior of MMA with APUA as emulsifier was different to that of SDS as emulsifier, signifying a different nucleation mechanism of the polymer latex particle. The average size of the two kinds of particles is about 50 nm. The particle size decreases with increasing emulsifier concentration. On using KPS as the initiator, APUA as emulsifier, cross-linking hydrogel of PMMA would be formed, but SDS was used as emulsifier and the hydrogel of PMMA was not present.     

Nonionic latices in aqueous media part 1. Preparation and characterization of polystyrene latices

A series of non-ionic polystyrene latices in aqueous media containing particles with a narrow size distribution have been prepared using a nonyl phenol poly(ehylene glycol) condensate as the surfactant, methoxy poly(ethylene glycol methacrylate) as the comonomer/stabilizer, and ascorbic acid/hydrogen peroxide as the initiator system. As a control synthesis for comparison with the above latex, a charge stabilized polystyrene latex was prepared, using an anionic surfactant and potassium persulphate as the initiator. Latices employing a combination of charge plus steric stabilization mechanisms were also prepared, in order to investigate the effect of the non-ionic surfactant and the comonomer/stabilizer. The particle size of the latices was measured by transmission electron microscopy, the surface charge density by conductimetric titration and the glass transition temperature of the polymer by differential scanning calorimetry. The latex prepared using non-ionic ingredients, showed no titratable charge and exhibited a profound lowering of the glass transition temperature, with respect to the charge stabilized latex. On the basis of these results, schematic models for the polymerization mechanism and the morphology of the latex particles are proposed.     

Effect of cationic monomer on properties of fluorinated acrylate latex

Cationic fluorinated acrylate latex was prepared via semi-continuous emulsion copolymerization of cationic monomer and other monomers.The resultant latex and its film were characterized with dynamic light scattering detector and contact anglc meter. Influences of amount of DMDAAC on the propcrtics of resultant latex and its film were investigated in detail.Results show that the particle size of the latex has the minimum value and the zeta potential of the latex is increased when the amount of DMDAAC is increased.In addition,the particle size of the latex is unimodal distribution when the amount of DMDAAC is not more than 2.5%. However,the particle size of the latex is bimodal distribution when the amount of DMDAAC is more than 2.5%.The contact angle is varied slightly with the increase of amount of DMDAAC when it is not more than 2.5%.Nevertheless,the contact angle is decreased with the increase of the amount of DMDAAC when it is more than 2.5%.     

光致变色含氟丙烯酸酯涂层的制备及性能

选取十二烷基硫酸钠(SDS),辛基苯基聚氧乙烯醚(OP-10)为复合乳化剂,过硫酸钾(KPS)为引发剂,将2-(全氟己基)乙基甲基丙烯酸酯(PFM)与丙烯酸酯类单体采用预乳化-半连续种子乳液聚合法进行乳液共聚,再将羟基螺吡喃(SPOH)与乳液进行物理共混,制得光致变色含氟丙烯酸酯乳液。 通过多种表征手段研究丙烯酸正丁酯(n-BA)和甲基丙烯酸甲酯(MMA)软硬单体的质量比,SPOH的用量对聚合反应和乳胶膜性能的影响。 结果表明,加入含氟单体后乳胶膜与水、油的接触角提高,热稳定性提高;加入SPOH的质量分数为1.25%时,乳胶膜具有较好的光致变色性能。     

Semibatch Emulsion Polymerization of Butyl Acrylate: Effect of Functional Monomers

Abstract

The concentration of sodium lauryl sulfate (SLS) in the initial reactor charge is the most important parameter in determining the latex particle size during semibatch emulsion polymerization of butyl acrylate in the presence of acrylic acid (AA), methacrylic acid, or hydroxyethyl methacrylate. The final latex particle size decreases with increasing concentration of SLS, NP-40, or functional monomer. The carboxylic monomer AA is the most efficient functional monomer to nucleate and then stabilize the latex particles. The plot of log N _f vs log SLS shows a slope of 0.4–0.8, which is more consistent with Feeney's analysis based on the coagulative nucleation mechanism. Experimental data also show that the particle size first decreases to a minimum and then increases with an increase in the concentration of the neutralizing agent NaHCO₃. The optimal concentration NaHCO₃ for achieving the smallest latex particle size occurs at a point close to 0.15–0.29%. Experimental data of the particle size distribution and molecular weight distribution show that the aqueous phase reaction can play a very important role during the particle nucleation period.     

Hydrophilicity of polymer effects on controlled particle coagulation in batch emulsion polymerization

The poly(methyl methacrylate-co-styrene) was prepared by batch emulsion polymerization to clarify the effect of characteristics of polymer on particle coagulation. Experimental results showed that the size of final latex particle increased with increasing methyl methacrylate in initial recipe, ranged from 84 to 193 nm, which was attributed to the particle coagulation. With the methyl methacrylate increased, the hydrophilicity of polymeric particle improved, thus led to the surfactant molecules packed loosely on the polymer surface, further, enhanced particle coagulation occurred. On the contrary, the surfactant molecules adsorbed on tightly the polymeric particle surface (methyl methacrylate content low) surface led to the electrostatic repulsion energy of polymer particle improved, and polymer particle stability was also improved. Thus, combined with the results previously reported by us (Colloid Polym Sci 291: 2385–2398, 2013 and Colloid Polym Sci 292: 519-525, 2014), the particle coagulation depended not only on the aqueous phase such as electrolyte concentration and methanol content, but also on the nature of polymer such as hydrophilicity.     

Large-scale and narrow dispersed latex formation in batch emulsion polymerization of styrene in methanol–water solution

This work is an extension of previous research results reported by our team (Colloid Polym Sci 291:2385–2389, 2013), where monodisperse, large-scale, and high-solid-content latexes of poly(n-butyl acrylate) were obtained with the particle coagulation method induced by the electrolyte. However, large-scale polystyrene latex particle is difficult to synthesize with this approach; moreover, demulsification phenomena easily take place especially in high solid content. In this article, a new approach to prepare large-scale polystyrene latex particle was proposed. Methanol was added to aqueous phases to decrease the interfacial tension between the polymer particle surface and continual phases, further decreasing interfacial free energy. Consequently, the surfactant molecules would loosely pack on the polymer particle surface, which is favored by particle coagulation. Experimental investigations showed that the final polystyrene particle scale only reaches to 93.5 nm when the methanol/water ratio is equal to 0:100, but the particle size attains 270 nm when the methanol/water ratio is equal to 30:70. These results indicated that polystyrene particle coagulation can be induced by methanol by varying the surfactant molecule adsorption on the particle surface. This investigation also provided a new simple approach to prepare large-scale, stable latex particles.     

Preparation and Characterization of Styrene/Butyl Acrylate Emulsifier-Free Latex with 2-Acrylamido-2-Methyl Propane Sulfonic Acid as a Reactive Emulsifier

A kind of emulsifier-free latex (FL) was successfully synthesized from styrene (St) and butyl acrylate (BA) with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) as a reactive emulsifier. The particle size of latex particles, stability against electrolytes, minimum film forming temperature (MFT) and water contact angle (CA) were evaluated and compared with a conventional latex (CL). Test results show that FL has larger particle size, better stability against electrolytes and lower MFT value compared with CL; higher AMPS content leads to smaller particle size and smaller water CA.     

氧化-还原低温引发甲基丙烯酸甲酯/丙烯酸丁酯超浓乳液聚合研究

以乳化剂十二烷基硫酸钠 (SDS)和共乳化剂十六烷醇 (HD)作为复合乳化体系 ,过氧化二苯甲酰(BPO)和N ,N 二甲基苯胺 (DMA)作为氧化还原引发体系 ,甲基丙烯酸甲酯 丙烯酸丁酯 (MMA BA)作为混合单体 ,制备了分散相占 83 %以上的稳定的超浓乳液 ,然后在低温下引发聚合 .探讨了引发剂浓度、氧化剂与还原剂的摩尔比、乳化剂的浓度、液膜增强剂的种类、聚合温度等因素对聚合稳定性和聚合速率的影响 ,测定并计算得到了聚合速率的公式 ;用激光散射粒度分布仪测定了聚合物乳胶粒子的大小及粒径分布 ,用透射电子显微镜观察了聚合物乳胶粒的形态 ,讨论了乳化剂浓度、聚合温度等对乳胶粒形态、大小的影响     

Structure and properties of novel fluorinated polyacrylate latex prepared with reactive surfactant

The novel fluorinated polyacrylate latex was successfully prepared by emulsion polymerization of perfluorononylene allyl ether, butyl acrylate and methyl methacrylate initiated by potassium persulfate in water and emulsified with the reactive surfactant. Films of the novel fluorinated polyacrylate latex were prepared by coating the latex directly on the clean glass sheet and allowed to dry at 80°C in the bake oven. The characteristics of the film such as hydrophobicity and glass transition temperature were studied; its structure was investigated by FTIR spectrometry and NMR. The influence of the fluorinated monomer content on the emulsion polymerization and performance of the latex were also studied. It was shown that the hydrophobicity and glass transition temperature of the latex are improved when the fluorinated monomer is introduced to copolymerize with other monomers, however, the stability of emulsion polymer and the conversion rate is decreased with the increase of its content.     

Determination of the latex particle size in emulsion polymerization of methyl methacrylate with low emulsifier concentrations

The mean size of the latex particles formed in emulsion polymerization of methyl methacrylate under definite conditions (water: monomer volume ratio 15: 1, 80°C, potassium persulfate concentration 0.07 wt %) decreases from 200 to 9–10 nm as the concentration of an ionic surfactant (anionic Disponil AES 60, SDS, cationic C₁₉H₄₂BrN) is increased from 0.0 to 1.0 wt %. The nonionic surfactants studied influence the size of the latex particles formed differently: with ALM-10, the particle size decreases from 200 to 150–190 nm, whereas with ALM-7 and ALM-2 it increases from 200 to 320 nm as the surfactant concentration is increased from 0.0 to 1.0 wt %. An increase in the concentration of F127 amphiphilic ternary block copolymer from 0.0 to 1.0 wt % leads to a monotonic decrease in the size of the poly(methyl methacrylate) latex particles formed from 200 to 53 nm.     

无皂乳液聚合法制备P(St-MMA-SPMAP)单分散乳胶颗粒

利用无皂乳液聚合 ,分别用一步法和两步法合成了单分散的聚 (苯乙烯 甲基丙烯酸甲酯 甲基丙烯酸丙基磺酸钾 ) (P(St MMA SPMAP) )乳胶颗粒 .在该聚合体系中 ,当水溶性磺酸基单体SPMAP的浓度小于 17mmol L时 ,为均相成核过程 ,能制备单分散的乳胶颗粒 .其中 ,用两步法制备的乳胶颗粒相互之间无粘连 .此外 ,还对一步法合成苯乙烯 甲基丙烯酸甲酯 甲基丙烯酸辛基磺酸钠 (P(St MMA SOMAS) )乳胶颗粒进行了初步研究 .