Water‐soluble copolymers. III. Two‐step terpolymerization of acrylamide,acrylic acid,and acryloyloxyethyl trimethylammonium chloride

Terpolymerization of acrylamide (AM), acrylic acid (AA), and acryloyloxyethyl trimethylammonium chloride (DAC) was studied in aqueous solution by a two‐step polymerization method, consisting of adiabatic polymerization until reaching a maximum temperature and following retaining temperature for maturation. A redox agent:promotor triad‐initiating system was employed as an initiator. The effects of various parameters on terpolymerization were investigated. The optimum values were obtained at the DAC:AA molar feed ratio and the total monomer concentration, at the oxidant:reductant ratio and total redox agent concentration, and at the promotor concentration and redox agent:promoter ratio. The structure of the terpolymer was identified by Fourier transform infrared (FTIR) and ¹³C NMR spectroscopy. And the terpolymer composition was agreed favorably with feed ratio. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3278–3284, 2007     

Ionomer synthesis by emulsion polymerization of styrene and sodium acrylate

The emulsion copolymerization of styrene and sodium acrylate is reported using either a water-soluble initiator (potassium persulfate, or KPS), or an oil-soluble one [2,2-azoisobutyronitrile (AIBN)]. Reaction rates are fast with both KPS and AIBN. With KPS, conversions >90% are achieved in 50 min, with AIBN, conversions reach 85% in 100 min. Particle size, measured by quasielectric light scattering (QLS), increases with conversion. Particle size in final latices is ∼ 70–80 nm. Copolymer formation is confirmed by infrared (IR) spectroscopy, plasma emission spectroscopy (PES), and scanning electron microscopy (SEM). IR and PES indicate that mainly sodium acrylate reacts at the beginning of the reaction and then styrene is incorporated in the copolymer backbone. The copolymer produced with KPS contains more sodium acrylate than the one made with AIBN. These differences can be explained in terms of the reactivities and partitioning (local concentrations) of the monomers and of the type of initiator used. Thermomechanical analysis (TMA) of the copolymers reveals two transitions: one at ∼ 100°C, which is due to the glass transition temperature (T_g) of polystyrene blocky segments in the copolymer, and another one at higher temperatures, which is associated to the T_g of segments composed of alternated sodium acrylate and styrene units. The higher-temperature transition shifts to lower values as the reaction proceeds because these segments become richer in styrene. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 879–889, 1997     

Inverse suspension polymerization of sodium acrylate

A superwater-absorbent sodium polyacrylate was synthesized by inverse suspension polymerization, using Span60 as the dispersant, cyclohexane as the organic phase, N,N′-methylene bisacrylamide as the crosslinking agent, and potassium persulfate as the initiator. The effect of reaction conditions such as reaction time, crosslinking agent, and dispersant on deionized-water and saline solution absorbability, average particle size, and distribution of the sol–gel of the resin is discussed. The deionized-water and saline solution absorbabilities of sodium polyacrylate prepared at proper conditions were 300–1200 and 50–120, respectively; the number-average particle size was 10–50 μm and the gel portion was 20–85% by weight. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 789-794, 1997     

Inverse suspension polymerization of sodium acrylate: Synthesis and characterization

Crosslinked Poly(acrylic acid) was synthesized by inverse suspension polymerization. This process was investigated to determine the influence of different parameters like temperature, stirring speed, solution pH, and crosslinker concentration and to obtain the best control of the kinetics. An aqueous phase containing partially neutralized acrylic acid, crosslinking agent, and initiator agent was dispersed in an organic phase and stabilized by a surfactant. The inverse suspension was carried out in heptane as the organic phase with a different ratio of neutralization of the monomer, different crosslinker concentrations, and several stirring speeds. The polymerization was initiated by potassium persulfate (K₂S₂O₈) with N‐N′‐methylenebisacrylamide (MBA_C) as the crosslinker and sorbitan monooleate as the surfactant. The influence of several parameters on the bead size and the swelling capacity was investigated. Particle diameters ranged from 10 to 130 μm. The kinetic results obtained by differential scanning calorimetry showed that conversion and polymerization rates are a function of the solution pH, and they fell when the concentration of the crosslinking agent was higher than 7.5% in the mass of MBA_C. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2621–2630, 2000     

Water‐soluble/dispersible cationic pressure‐sensitive adhesives. II. Adhesives from emulsion polymerization

In our previous work, we reported that cationic water‐soluble pressure‐sensitive adhesives (PSAs) could be synthesized in ethanol or methanol. These cationic water‐soluble adhesives would not cause a stickies problem during paper recycling and can be easily removed from the papermaking system by adsorbing on wood fibers. In this study we report the synthesis and application of water‐based cationic PSAs using miniemulsion polymerization. A redox initiator system of cumene hydroperoxide/tetraethylenepentamine was used to force interfacial polymerization. The end‐use properties of the PSAs were evaluated, and the repulpability of the PSAs in paper recycling was studied. It was found that the cationic PSA from miniemulsion polymerization itself was insoluble and nondispersible in water during the paper recycling process. However, if this water‐insoluble cationic PSA from miniemulsion was formulated with a water‐soluble cationic PSA made from ethanol, the solubility or dispensability of the former PSA in water was improved. The molecular weight and degree of crosslinking of the PSA polymer have significant effects on the properties and dispersability of PSA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 347–353, 2004     

Water‐soluble copolymers. I. Biodegradability and functionality of poly[(sodium acrylate)‐co‐(4‐vinylpyridine)]

As a biodegradable functional polymer, poly[(sodium acrylate)‐co‐(4‐vinylpyridine)] [P(SA‐co‐4VP)] containing a small amounts of 4‐vinylpyridine groups were prepared and their biodegradability, dispersity, and complex performance were analyzed. The polymers can be useful as detergent builders and dispersants. It was found that the biodegradation of P(SA‐co‐4VP) was more conspicuous when content of the 4‐vinylpyridine in the copolymer was larger. This indicates that the 4‐vinylpyridine, which acts as biodegradable segments, should be incorporated into the polymer main chain in such a manner that they are digested by activated sludge. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1953–1957, 1999     

Ultrasonically initiated emulsion polymerization of n‐butyl acrylate

Ultrasonically initiated emulsion polymerization of n‐butyl acrylate (BA) without added initiator has been studied. The experimental results show that high conversion of BA can be reached in a short time by employing an ultrasonic irradiation technique with a high purge rate of N₂. The viscosity average molecular weight of poly(n‐butyl acrylate) (PBA) obtained reaches 5.24 × 10⁶ g mol^?1. The ultrasonically initiated emulsion polymerization is dynamic and complicated, with polymerization of monomer and degradation of polymer occurring simultaneously. An increase in ultrasound intensity leads to an increase in polymerization rate in the range of cavitation threshold and cavitation peak values. Lower monomer concentration favours enhancement of the polymerization rate. ¹H NMR, ¹³C NMR and FTIR spectroscopies reveal that there are some branches and slight crosslinking, and also carboxyl groups in PBA. Ultrasonically initiated emulsion polymerization offers a new route for the preparation of nanosized latex particles; the particle size of PBA prepared is around 50–200 nm as measured by transmission electron microscopy. © 2001 Society of Chemical Industry     

静态反相悬浮聚合法合成聚丙烯酸钠

以过氧化氢为引发剂,以食用植物油如菜子油、花生油、茶油、葵花油、大豆油或者玉米油为分散相,采用静态反相悬浮聚合工艺合成聚丙烯酸钠,研究了引发剂用量、分散相以及反应温度对聚丙烯酸钠分子量的影响。结果表明,随过氧化氢浓度增大、丙烯酸钠单体浓度降低、聚丙烯酸钠的分子量降低;玉米油为分散相时聚丙烯酸钠的分子量最大;随反应温度升高,聚丙烯酸钠的分子量增大;但反应温度超过60℃时,聚丙烯酸钠的分子量随反应温度升高而降低。     

Preparation and properties of poly(WPSF‐co‐butyl acrylate) copolymer emulsion with ultrasonic radiation II. Monomer conversion rate and characterization

A stable emulsion of poly(WPSF‐co‐butyl acrylate) based on butyl acrylate, waste polystyrene foam was synthesized through emulsion polymerization using sodium dodecyl sulfate and octyl phenyl polyoxyethylene ether as surfactant, ammonium persulfate and sodium hydrogen bisulfate as mixed redox initiator, under ultrasound irradiation in the absence of inert gas. The effects of various copolymerization conditions on the monomer conversion were reported. The copolymers were characterized by means of IR, ¹HNMR, and gel permeation chromatography. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

D_4改性丙烯酸酯乳液的合成研究

以甲基丙烯酸甲酯、丙烯酸丁酯为主要单体,加入八甲基环四硅氧烷(D4)进行共聚改性,制备出有机硅改性丙烯酸酯乳液。探讨了D4用量、反应温度、预乳化工艺等条件对乳液性能的影响。红外光谱和DSC分析表明D4与其它单体发生了共聚。     

Preparation and properties of poly(silicone‐co‐acrylate)/montmorillonite nanocomposite emulsion

Poly (silicone‐co‐acrylate)/montmorillonite nanocomposite emulsion were prepared by in situ intercalative emulsion polymerization of acrylate and organosilicone, in the presence of organic modified montmorillonite (OMMT) with different OMMT contents (0, 0.5, 1, 1.5, and 2 wt %). The nanocomposite emulsions were characterized with X‐ray diffraction (XRD), laser light scattering, fourier transform infrared (FTIR), rheological measurements, surface tension, drying speed, and water absorption property. Results showed that OMMT could improve the properties of emulsion, in other words, the properties of nanocomposite emulsion were better when compared with those of the silicone–acrylate emulsion. The properties of nanocomposite emulsion containing 1 wt % OMMT was the best one, and obtained the following advantages: smaller particle size, faster drying speed, shorter curing time, smaller surface tension, bigger apparent viscosity, and improved resistant water by the incorporation of OMMT. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3963–3970, 2006     

丙烯酰胺与甲基丙烯酰氧乙基三甲基氯化铵反相乳液聚合动力学

以丙烯酰胺（AM）和甲基丙烯酰氧乙基三甲基氯化铵（DMC）为单体,失水山梨糖醇脂肪酸酯（Span 80）和失水山梨醇单油酸酯聚氧乙烯醚（Tween 80）为乳化剂,液体石蜡为油相,2,2'-偶氮二异丙基咪唑啉二盐酸盐（VA-044）为引发剂,研究AM与DMC反相乳液聚合动力学,反相乳液聚合速率方程为R_p=k[M]^2.12[I]^0.55[E]^0.65,AM与DMC反相乳液聚合表观活化能为80.65 kJ·mol^-1。通过反相乳液聚合速率随时间的变化关系得出其成核机理倾向于单体液滴成核。用Fireman-Ross法研究了共聚单体竞聚率,分别为r_AM=0.23、r_DMC=1.93,AM与DMC在聚合物链上发生无规共聚反应。单体量增大、引发剂量减少、乳化剂量增大、聚合温度降低均使共聚产物的特性黏数增大。     

Semibatch emulsion polymerization of butyl acrylate. II. Effects of emulsifier distribution

The effects of emulsifier distribution ratio between the initial charge and the feed on particle formation and kinetics of butyl acrylate emulsion polymerization, using sodium lauryl sulfate as emulsifier and potassium persulfate as initiator, were investigated. The number of particles increased with initial emulsifier concentration in the reactor charge. It was shown that traditional ranking, in terms of number of particles produced, of semibatch emulsion polymerization with monomer emulsion feed is not always justified and a semibatch emulsion polymerization can produce far more particles than a conventional batch emulsion polymerization. The number of polymer particles was found to be practically independent of the emulsifier distribution ratio between the charge and the feed for a high overall emulsifier concentration, while for a low overall emulsifier concentration, the number of particles increased with initial loading of the emulsifier. The polydispersity index (PDI) of the final latexes showed a minimum with emulsifier distribution. A bimodal particle size distribution, and a latex with a large PDI, was obtained when there was no emulsifier in the charge. As the initial emulsifier charge increased, a unimodal PSD with a smaller PDI was obtained. With higher proportions of emulsifier in the initial charge, the PDI rose again due to particle nucleation at monomer‐starved conditions, and a skewed unimodal PSD was obtained. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 582–597, 2001     

Molecular weight development in emulsion copolymerization of n‐butyl acrylate and styrene

The seeded emulsion copolymerization of n‐butyl acrylate and styrene in a weight ratio of 50/50 was investigated. The effect of the type of process (batch vs. semicontinuous) and the amounts of initiator and emulsifier charged into the reactor on the time evolution of the fractional conversion, number of polymer particles, and weight‐average molecular weight (M_w) was analyzed. It was found that the M_w depends to a slight extent on the type of process and the emulsifier concentration and to a larger extent on the initiator concentration. The molecular weight distributions (MWDs) and the gel content of the final latexes were also analyzed. In the absence of chain transfer agents (CTAs), the fraction of gel was higher in the semicontinuous processes. It was also found that the gel content increased with increasing initiator concentration in the recipe. The addition of 1 wt % CTA avoided gel formation and led to an important reduction of the M_w. Nevertheless, the MWDs presented a shoulder or even a second peak at high molecular weights that was due to reactions of chain transfer to the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1918–1926, 2003     

乳液型丙烯酸酯压敏胶的研制

采用乳液聚合制备了乳液型聚丙烯酸酯压敏胶,讨论了软单体的用量、硬单体用量、交联单体的种类及用量、引发剂的用量、交联剂的用量和乳化剂的配比对压敏胶性能的影响。实验表明,在相同的条件下,丙烯酸的改性效果比丙烯酸羟乙酯好,当m（EHA）∶m（VAc）=82∶10时,压敏胶的综合性能最佳。交联剂的加入明显提高了剥离强度,当其质量分数为0.3%时,剥离强度达到357.33 N/m。     

有机硅改性丙烯酸酯乳液聚合及应用研究

摘要：采用乳液聚合方式合成有机硅改性丙烯酸酯类涂料印花粘合剂,讨论各种因素对乳液聚合的影响。结果显示,该粘合剂具有良好的性能,整理后的织物摩擦牢度、皂洗牢度、手感等各项指标优良。     

新型丙烯酸酯乳液胶粘剂的应用研究

以丙烯酸乙酯(EA)和丙烯酸丁酯(BA)为软单体、甲基丙烯酸甲酯(MMA)为硬单体、甲基丙烯酸(MAA)和丙烯酸(AA)为功能单体,采用种子乳液聚合法制备出一种新型丙烯酸酯乳液胶粘剂。结果表明:当m(EA)∶m(BA)∶m(MMA)=19.2∶6.4∶6.4、m(MAA)∶m(AA)=2.00∶1、w(MAA+AA)=w(BA)=6%～8%以及经氨水中和后胶液的pH为7~8时,该胶粘剂具有良好的综合性能,其初粘强度大、干燥速率快、耐冷藏性能好、不起皱、不掉标且易清洗,完全满足啤酒瓶贴标用胶粘剂的使用要求。     

自交联含氟丙烯酸酯共聚物乳液的制备

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)等为主要单体,甲基丙烯酸六氟丁酯(HFMA)为含氟单体,N-羟甲基丙烯酰胺(NMA)为交联单体,采用种子乳液聚合法制备了自交联含氟丙烯酸酯共聚物乳液。研究了HFMA、NMA、复合乳化剂(SDS OP-10)、引发剂(KPS)用量、聚合温度、聚合时间和搅拌速度等因素对聚合反应最终转化率和乳液稳定性的影响,结果表明在m(MMA)∶m(BA)=1∶1及搅拌速率210 r/min条件下,HFMA、NMA、SDS OP-10和KPS加入量分别为总单体量的7%、3%、3%和0.5%(均为质量分数),以及聚合温度75℃、反应时间4 h时,制备得到的乳液单体总转化率高,乳液凝聚率低,聚合反应稳定,涂膜的综合性能优良。此外,含氟乳胶膜的FT-IR及TG-DSC分析结果表明,HFMA有效地参与了共聚反应,提高了涂膜的耐热性。     

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     

MA-TA-AA-AM-SAS共聚物的反相乳液合成及其性能

为了提高产率,减少副反应,以环己烷为分散介质,油/水比例为1.6,Span80-Tween80为乳化剂,使用过硫酸钾作为引发剂,用新方法反相乳液合成了高分子聚合物马来酸酐-牛磺酸-丙烯酸-丙烯酰胺-烯丙基磺酸钠。通过静态阻垢实验评定表明:阻垢剂投加量达到10 mg/L时对碳酸钙和磷酸钙阻垢率较佳,分别为90.4%和91.8%;在高温、高pH、高硬度等恶劣条件下对碳酸钙仍分别有60.2%,46.4%,53.2%的较好阻垢率;投加量达到5 mg/L时对氧化铁分散性能最佳,透光率为46.1%。该共聚物是一种耐恶劣条件的优良阻垢分散剂。