Free radical copolymerization behavior of vinyl acetate with butyl acrylate in the presence of GeCl4 and BCl3

No alternating copolymers of vinyl acetate (VAc) and butyl acrylate (BA) were obtained by free radical copolymerization in the presence of GeCl₄ and BCl₃ (compared with the acrylic acid–vinyl acetate copolymerization system). By ultraviolet spectral analysis, it was concluded that both BCl₃ and GeCl₄ can form complexes with butyl acrylate. The BA–BCl₃ complex constants were determined by ¹H NMR; K_B=33·2 (25°C). The reason for the gel formation in the BA–Vac–BCl₃ copolymerization system was discussed. When vinyl acetate reacted with BCl₃, cationic polymerization probably occurred. A white gel product probably resulted from the polymerization of the BA–BCl₃ complex. © 1998 SCI.     

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     

Preparation and performance in paper coating of silicone‐modified styrene–butyl acrylate copolymer latex

Silicone‐modified styrene–butyl acrylate copolymer latex was synthesized by emulsion copolymerization by using octamethylcyclotetrasiloxane (D₄), styrene, and butyl acrylate as raw materials, potassium persulfate as initiator and propylmethacrylate triethoxysilane (KH‐570) as crosslinking agent. The infrared spectra studies showed that the vinyl monomers were completely copolymerized with D₄. The prepared silicone‐modified copolymer latex with the interpenetrating polymer networks tended to have higher stability, and better toluene and water resistance than styrene–butyl acrylate latex. The glossiness of coated paper was improved with silicone‐modified copolymer latex, and it was at a maximum when D₄ was about 3% of total monomers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 333–336, 2001     

ARGET ATRP法合成聚氯乙烯接枝丙烯酸丁酯共聚物

以不稳定氯含量高的聚氯乙烯（U-PVC）和氯乙烯-溴代异丁酸烯丙酯共聚物（PVC-co-ABrMP）为大分子引发剂,使用电子转移催化再生原子转移自由基聚合（ARGET ATRP）进行丙烯酸丁酯（BA）的溶液接枝共聚。在固定CuCl₂：三（2-吡啶甲基）胺：辛酸亚锡（摩尔比）时,当CuCl₂用量（相对于氯乙烯链节数）小于0.1%时,BA转化率随CuCl₂用量增加而明显增加;辛酸亚锡与CuCl₂摩尔比大于50时,辛酸亚锡用量对聚合速率的影响较小;相同催化体系用量下,采用PVC-co-ABrMP为引发剂,可获得更高的BA转化率。通过PVC-co-ABrMP酯基水解得到PBA支链,其分子量分布指数为1.29,符合“活性”自由基聚合的特征。接枝PBA对PVC有明显的内增塑效果,PBA摩尔分数为32.75%的PVC-g-BA的玻璃化温度为8.34℃。     

Damping of vinyl acetate–n‐butyl acrylate copolymers

A photopolymerization process at room temperature was devised to copolymerize vinyl acetate (VAc) and n‐butyl acrylate (BA) mainly to prepare rubber‐like damping sheet bearing pressure‐sensitive adhesive property in this study. The investigations using both the differential scanning calorimeter and rheometric dynamic analysis show the existence of two glass transition temperatures for each copolymer. The scanning electron microscopic pictures reveal that the degree of microphase separation increases with increasing annealing time at 70°C. It was suggested that the rubbery domain (formed by the PBA blocks) disperses in the glassy domain (constituted by the PVAc blocks), making an effective damping entity. Excellent damping was observed for the copolymer samples, with the tanδ peak values as high as 1.76–1.80 at a certain temperature range and with tanδ> 0.3 at quite wide temperature ranges. In addition, the copolymers containing more VAc tend to have the higher damping. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1396–1403, 2004     

聚苯乙烯和聚丙烯酸丁酯无皂核壳乳液聚合反应的研究

聚苯乙烯 (PS)和聚丙烯酸丁酯 (PBA)复合乳液是无皂乳液聚合反应生成的 ,采用丙烯酸丁酯加到聚苯乙烯种子微粒中反应得到的。PS/PBA复合微粒的结构通过红外光谱图明显的吸收峰特征而得到证实。纯PS微粒和低BA含量的PS/PBA微粒几乎是球形和规则的 ,而随着BA单体含量的增加 ,PS/PBA复合微粒的粒子尺寸变大和呈现类似高尔夫球形状。同时 ,本文进一步研究了PS/PBA复合微粒的表面形态学     

Study on synthesis and morphology control of poly(4‐vinylpyridine‐co‐butyl acrylate)/poly(styrene‐co‐butyl acrylate) composite microspheres

Monodispersed crosslinked cationic poly(4‐vinylpyridine‐co‐butyl acrylate) [P(4VP‐BA)] seed latexes were prepared by soapless emulsion polymerization, using 2,2′‐azobismethyl(propionamidine)dihydrochloride (V₅₀) as an initiator and divinylbenzene (DVB) or ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The optimum condition to obtain monodispersed stable latex was investigated. It was found that the colloidal stability of the P4VP latex can be improved by adding an adequate amount of BA (BA/4VP = 1/4, w/w), and adopting a semicontinuous monomer feed mode. Subsequently, poly(4‐vinylpyridine‐co‐butyl acrylate)/Poly(styrene‐co‐butyl acrylate) [P(4VP‐BA)/P(ST‐BA)] composite microspheres were synthesized by seeded polymerization, using the above latex as a seed and a mixture of ST and BA as the second‐stage monomers. The effects of the type of crosslinker, the degree of crosslinking, and the initiators (AIBN and V₅₀) on the morphology of final composite particles are discussed in detail. It was found that P(4VP‐BA)/P(ST‐BA) composite microspheres were always surrounded by a PST‐rich shell when V₅₀ was used as initiator, while sandwich‐like or popcorn‐like composite particles were produced when AIBN was employed. This is because the polarity of the polymer chains with AIBN fragments is lower than for the polymer with V₅₀ fragments, hence leading to higher interfacial tension between the second‐stage PST‐rich polymer and the aqueous phase, and between PST‐rich polymer and P4VP‐rich seed polymer. As a result, the seed cannot be engulfed by the PST‐rich polymer. Furthermore, the decrease of T_g of the second‐stage polymer promoted phase separation between the seeds and the PST‐rich polymer: sandwich‐like particles formed more preferably than popcorn‐like particles. It is important knowledge that various morphologies different from PST‐rich core/P4VP‐rich shell morphology, can be obtained only by changing the initiator, considering P4VP is much more hydrophilic than PST. The zeta potential of composite particles initiated by AIBN in seeded polymerization shifted from a positive to a negative charge. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1190–1203, 2002     

Poly(ethylene glycol)-block-poly(butyl acrylate). I. Synthesis

Prepolymers of poly(ethylene oxide) (Pre-PEO) were synthesized by reacting azoisobutyronitrile (AIBN) with poly(ethylene glycol) (PEG), and their structures were characterized by IR and UV. The molecular weight of pre-PEO was related to the feed ratio and reaction time. These prepolymers can be used to prepare block copolymers—poly(ethylene oxide)-block-poly(butyl acrylate) (PEO-b-PBA) by radical polymerization in the presence of butyl acrylate (BA). Solution polymerization was a suitable technique for this step. The yield and the molecular weight of the product were related to the ratio of the prepolymer to BA, the reaction time, and temperature. GPC showed that the molecular weight increased with a higher ratio of BA to pre-PEO. The intrinsic viscosity of the copolymers was only slightly dependent on reaction time, but decreased at higher reaction temperatures, as did the amount of PBA homopolymer. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1667–1674, 1997     

酶解淀粉-苯乙烯/丙烯酸丁酯接枝共聚物乳液的制备研究

采用无皂乳液聚合的方法,以过硫酸铵(APS)为引发剂,制备了酶解淀粉与苯乙烯(St)和丙烯酸丁酯(BA)的接枝共聚物。探讨了淀粉与单体配比、过硫酸铵用量、单体配比和反应温度对接枝反应的影响。结果表明,反应的优化条件为:m(淀粉)∶m(单体)=1∶3,(NH4)2S2O8的加入量为淀粉与单体总质量的0.5%,单体质量比为1∶1,反应温度为82℃,在此条件下,接枝率可达103.8%,接枝效率为37.4%,单体转化率为91.9%。红外光谱分析表明,苯乙烯和丙烯酸丁酯参与了接枝反应;SEM结果显示,接枝反应之后,淀粉形貌发生了变化,球状颗粒已经消失。     

溶胶-凝胶法聚丙烯酸丁酯/二氧化硅杂化材料弹性体的制备与表征

用丙烯酸丁酯与少量功能单体共聚,合成了分子链侧基带羟基的聚丙烯酸丁酯(PBA)乳液,然后与硅溶胶混合,用溶胶-凝胶法制备了PBA/SiO2杂化材料弹性体;研究了SiO2含量对杂化材料弹性体力学性能及透光率的影响,并用扫描电子显微镜、傅里叶变换红外光谱、差示扫描量热分析和动态力学性能分析对杂化材料弹性体的结构进行了表征。结果表明,PBA/SiO2杂化材料热压后成为一种力学性能优良的具有一定透光率的弹性体。随着SiO2含量的增加,杂化材料弹性体的力学性能提高,透光率和SiO2粒子的粒径增加,PBA基体的玻璃化转变温度和损耗因子下降;PBA共聚物分子链侧基所带羟基与SiO2粒子表面的硅醇基发生了缩合脱水反应,形成了Si—O—C共价键,使PBA基体与SiO2粒子构成的界面结合紧密,从而赋予杂化材料弹性体以优良的性能。     

Experimental study of the spontaneous thermal homopolymerization of methyl and n‐butyl acrylate

This article presents an experimental study of the spontaneous thermal homopolymerization of methyl acrylate (MA) and n‐butyl acrylate (nBA) in the absence of any known added initiators at 120 and 140°C in a batch reactor. The effects of the solvent type, oxygen level, and reaction temperature on the monomer conversion and polymer average molecular weights were investigated. Three solvents, dimethyl sulfoxide (DMSO; polar, aprotic), cyclohexanone (polar, aprotic), and xylene (nonpolar) were used. The spontaneous thermal polymerization of MA and nBA in DMSO resulted in a lower conversion and higher average molecular weights in comparison to polymerization in cyclohexanone and xylene under the same conditions. The highest final conversion of both monomers was obtained in cyclohexanone. The high polymerization rate in cyclohexanone was most likely due to an additional initiation mechanism where cyclohexanone complexed with the monomer to generate free radicals. Bubbling air through the mixture led to a higher monomer conversion during the early stage of the polymerization and a lower polymer average molecular weight in xylene and cyclohexanone; this indicated the existence of a distinct behavior between the air‐ and nitrogen‐purged systems. Matrix‐assisted laser desorption/ionization time‐of‐flight analysis of the polymer samples taken from nitrogen‐bubbled batches did not reveal fragments from initiating impurities. On the basis of the identified families of peaks, monomer self‐initiation is suggested as the principal mode of initiation in the spontaneous thermal polymerization of MA and nBA at temperatures above 100°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Grafting of styrene onto poly(butyl acrylate) in emulsion

The effect of time, temperature, the concentration of initiator and emulsifier, and the ratio of starting polymer to monomer on the degree of conversion (MC) of styrene and the grafting efficiency (GE) of polystyrene has been investigated. The reaction was initiated with potassium persulphate. It has been found that the degree of conversion of styrene and the grafting efficiency change in opposite directions when plotted as functions of the reaction parameters studied. The graft copolymerization is assisted by short reaction times and weight ratios of poly(butyl acrylate) to styrene greater than unity. The results obtained suggest that higher grafting efficiencies are obtained when the concentration of emulsifier is below its c.m.c. (critical micellar concentration) value. When using two different anionic emulsifiers it has been observed that the effect of initiator concentration on the degree of conversion of styrene and the grafting efficiency is complicated. Both the quantities studied (MC and GE) exhibit extrema in the range of initiator concentration studied (3.7?33.3 × 10^?5 mol dm^?3 of H₂O). No meaningful effect of temperature in the range 60°–90°C or that of dodecyl mercaptan (molecular weight regulator) used in an amount 0–0.4% in relation to poly(butyl acrylate) and styrene has been observed on the MC and GE values.     

Grafting of butyl acrylate and methyl methacrylate on butyl rubber using electron beam radiation

Being nonpolar in nature, butyl rubber (IIR) has poor compatibility toward polar polymers and fillers. It can be improved by grafting polar substrates on the butyl elastomer. Radiation‐induced polymer processing is getting increasing interest, as it leads to new and improved polymers with desirable and interesting properties. In this investigation, electron beam radiation has been used to graft methyl methacrylate (MMA) and butyl acrylate (BA) on IIR. This process has several advantages over conventional grafting processes such as cationic polymerization (which needs very low temperature and stringent reaction conditions) and solution radical polymerization (which often needs solvent removal and recycling). The grafted polymers were characterized by using ¹H NMR, IR, TGA, and SEM analysis. The degree of grafting increases with a decrease in irradiation dose as well as with an increase in monomer concentration. It was observed that there was a decrease in intrinsic viscosity in irradiated IIR samples, indicating the chain scission. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1340–1346, 2006     

含纳米二氧化硅粒子的丙烯酯丁酯细乳化

为了调控含纳米SiO₂的丙烯酸丁酯细乳化后液滴的粒径及粒径分布,研究了细乳化体系组成和超声分散条件对细乳化液滴粒径及粒径分布的影响.发现存在使细乳化液滴粒径及粒径分布趋于稳定的临界超声功率和超声时间;随着十二烷基硫酸钠（SDS）乳化剂浓度增加,液滴粒径减小,而十六烷浓度对液滴粒径影响较小;随着BA分散液中纳米SiO₂质量分数和BA分散液/水质量比的增加,液滴平均粒径增大,粒径分布变宽,这是由于纳米SiO₂粒子吸收了部分超声波能量,同时改变了分散相特性所致.当放置或聚合温度在65℃以下时,细乳化液或相应的聚丙烯酸丁酯/纳米SiO₂复合乳胶能稳定分散.     

Synthesis of polystyrene/poly(butyl acrylate) core–shell latex and its surface morphology

A polystyrene (PS)/poly(butyl acrylate) (PBA) composite emulsion was produced by seeded emulsion polymerization of butyl acrylate (BA) with PS seed particles which were prepared by emulsifier‐free polymerization of styrene with potassium persulfate (KPS) under a nitrogen atmosphere at 70°C for 24 h with stirring at 60 rpm and swelled with the BA monomer in an ethanol/water medium. The structure of the PS/PBA composite particles was confirmed by the presence of the characteristic absorption band attributed to PS and PBA from FTIR spectra. The particles for pure PS and PS/PBA with a low content of the BA monomer were almost spherical and regular. As the BA monomer content was increased, the particle size of the PS/PBA composite particles became larger, and more golf ball‐like particles were produced. The surface morphology of the PS/PBA composite particles was investigated by AFM and SEM. The T_g's attributed to PS and PBA in the PS/PBA composite particles were found at 110 and ?49°C, respectively. The thermal degradation of the pure PS and PS/PBA composite particles occurred in one and two steps, respectively. With an increasing amount of PBA, the initial thermal decomposition temperature increased. On the contrary the residual weight at 450°C decreased with an increasing amount of PBA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 595–601, 2003     

Core–shell particles designed for toughening poly(vinyl chloride)

A novel core–shell modifier (MOD) made up of polystyrene and poly(butyl acrylate) (PBA) grafted on a crosslinked styrene‐co‐butadiene core was synthesized by emulsion polymerization. This modifier was used for enhancing effectively the impact ductility of poly(vinyl chloride) (PVC) without losing its transparency. The effects of the MOD on the properties of PVC/MOD blends were explored. It was found that the butyl acrylate (BA) content of the MOD was an important factor affecting the properties of PVC/MOD blends. The Izod impact strength of these blends reached 1200 J m^?1 when the MOD contained 40 wt% BA. The dispersion morphology of the MOD in the PVC matrix was investigated using transmission electron microscopy, with a uniform dispersion of the MOD with higher BA content being obtained. The toughening mechanism of PVC/MOD blends was also investigated. The presence of BA in the MOD enhanced the ductility of the PVC blends due to the increased amount of soft phase (PBA). The dispersion morphology indicated that the interfacial interaction between MOD particles and PVC matrix was improved due to the presence of PBA graft chain in the MOD. TEM of impact fracture samples showed that shear yielding of the PVC matrix and debonding of MOD particles were the major toughening mechanisms for the PVC/MOD blends. Copyright © 2010 Society of Chemical Industry     

Synthesis and properties of metal poly(butyl acrylate)

Butyl acrylate colloids were obtained by codeposition at 77 K of the monomer with several metals such as Pd, Au, Ag, Cu, Zn, Cd, Ga, In, Ge, Sn, Sb, and Bi. The colloids were polymerized with different amounts of an initiator (AIBN) at 65°C for 0.5 h and a wide range of viscosity‐average molecular weights (M _v, 10⁴–10⁵ g/mol) were obtained depending upon the metal used. The metal colloid concentration and stability are reported. The thermal stability and metal composition are also described. The polymers are stable even at 400°C, with Ga–poly(butyl acrylate) being the most stable at 407°C. The metal content ranged between 0.10 and 1.32% w/w for the highest MW fraction and between 0.11 and 1.09% w/w for the lowest MW fraction. Polymers with several colors were obtained depending on the metal used. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 547–550, 1999     

Prediction and experiment of core–shell particle morphology of vinyl acetate and butyl acrylate

In this article, the particle morphology in emulsion polymerization of the poly(vinyl acetate) (PVAc)/poly(butyl acrylate) (PBA) system is investigated. With the use of the basic data in literature, the relevant interface tensions and viscosity are estimated with the equation proposed in literature. The time achieved to equilibrium morphology is predicted with cluster dynamics proposed by Gonzalez. The experiment result is consistent with that of prediction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2930–2937, 2002; DOI 10.1002/app.10297     

In-situ polymerization of n-butyl acrylate in poly(vinyl chloride)

The in situ polymerization of n-butyl acrylate with poly(vinyl chloride) has been studied. Butyl acrylate was polymerized using a peroxydicarbonate initiator and a thiol chain transfer agent in the presence of poly (vinyl chloride) beads suspended in water. The products were examined, after pressing into sheets, for optical clarity and by dynamic mechanical analysis. It was found that if 10% butyl acrylate was peesent in the mixture homogeneous blends were formed but if 15% or more butyl acrylate was present two phase mixtures were formed. If homogeneous blends prepared as above were reswollen in butyl acrylate, and the latter then polymerized, homogeneous blends containing more poly(butyl acrylate) could be prepared. The interaction parameters between both poly(vinyl chloride' and poly(butyl acrylate) and butyl acrylate were estimated by inverse gas chromatography. Using these and an estimate of the polymer/polymer interaction parameter the three component phase diagram could be qualitatively explained.