丁烯酸乙烯酯的提取及聚合应用

丁烯酸乙烯酯存在于醋酸乙烯酯生产的工业废液中,可用蒸馏法提取及纯化,具有一些独特的性质:如在一定条件下会聚合形成环状结构;用于以聚醋酸乙烯酯为基础的乳胶漆交联改性时,无须引发剂和加热,只是简单混合即可使耐洗刷次数增加几倍,还可与其它乙烯基酯、氯乙烯、苯乙烯、马来酸酐等多种单体共聚,主要起提供交联的作用.     

巴豆酸乙烯酯的提取及聚合应用

巴豆酸乙烯酯存在于醋酸乙烯酯生产的工业废液中,在一定条件下聚合会形成环状结构。用于改性以聚醋酸乙烯酯为基础的乳胶漆无须引发剂和加热,只是简单混和即可使耐洗刷次数增加几倍,还可与其它乙烯基酯、氯乙烯、苯乙烯、马来酸酐等多种单体交联共聚。     

Graft polymerization of vinyl acetate onto silica

A method is reported for the surface grafting of polyvinyl acetate (PVAc) onto modified, nonporous silica. The silica surface was modified by silylation with vinyl(triethoxy) silane followed by graft polymerization of vinyl acetate. The graft yield was measured by thermogravimetric analysis and the monomer conversion was monitored by UV spectral analysis. The rate of the graft polymerization and the graft yield were proportional to the initial monomer concentration. Vinyl acetate conversion followed first-order kinetics and displayed a trend of increasing initial rate with increasing monomer concentration.     

氯乙烯/异丁基乙烯基醚乳液共聚物的合成

以(NH4)2S2O8／Na2SO3／CuSO4为氧化-还原引发体系、十二烷基硫酸钠(SDS)为乳化剂，采用间歇乳液聚合合成氯乙烯／异丁基乙烯基醚(VC／IBVE)共聚物。结果表明，当投料单体中IBVE质量分数增加时,相同聚合时间的聚合转化率和共聚物特性粘度明显降低。当转化率小于70％时，共聚物平均组成变化不大；聚合温度增加使聚合速率增加，但共聚物特性粘度减小；SDS浓度对聚合速率和共聚物特性粘度的影响很小；随引发体系浓度增加．聚合速率增加，共聚物特性粘度变化不大。     

氯乙烯-醋酸乙烯悬浮共聚树脂的开发与研究

采用悬浮聚合工艺制备出氯乙烯-醋酸乙烯(VC-VAC)共聚树脂,考察了聚合配方、聚合温度、搅拌速度及分散剂种类及用量对VC-VAC共聚树脂性能的影响。     

The in situ polymerization of vinyl chloride in poly(butyl acrylate)

The in situ polymerization of vinyl chloride with poly(butyl acrylate) has been studied. Vinyl chloride was polymerized using a peroxydicarbonate initiator in sealed ampoules in the presence of various weights of poly(butyl acrylate). The products were examined by dynamic mechanical analysis and electron microscopy. It was found that if about 50% or less vinyl chloride was present in the mixture homogeneous blends were formed. If more than 50% vinyl chloride was present the polymerization passed through a two phase region in the three component phase diagram and inhomogeneous blends were formed. If homogeneous blends prepared as above were reswollen with vinyl chloride and the latter polymerized, then homogeneous blends containing more poly(vinyl chloride) could be prepared, avoiding the two phase region. The interaction parameters between vinyl chloride and both poly(vinyl chloride) and poly(butyl acrylate) were estimated using inverse gas chromatography. Using these and an estimate of the polymer/polymer interaction parameter the three component phase diagram could be qualitatively explained.     

Partial esterification of poly(vinyl alcohol) with acid chlorides

This work deals with some features of the reaction of organic acid chlorides with poly(vinyl alcohol). The structure of the modified polymers was determined by means of IR, UV and NMR spectroscopy as well as by chemical analysis. Vinyl alcohol-vinyl butyrate copolymers were obtained by reaction of poly(vinyl alcohol) with n-butyryl chloride without any catalyst. The reaction appeared to satisfy a second order kinetics for conversions no higher than 50%. The activation energy found was of 9.9 kcal/mol. The use of pyridine as a catalyst involved a noticeable increase of the reaction rate, but this effect was found to be independent of the acid chloride used. When triethylamine was used as a catalyst, β-keto ester groups were found to be grafted onto the polymer chain. The steric hindrance of these groups were thought to be sufficiently important for the conversion to reach a limit of about 30%. The observed swelling in water of vinyl alcohol-vinyl butyrate copolymers made it reasonable to conclude that the hydrophilic character of the copolymers decreased progressively when the ester group content increased.     

The kinetics of vinyl acrylate photopolymerization

The photopolymerization of vinyl acrylate has been investigated using real-time FTIR. The acrylate and vinyl groups exhibit different polymerization kinetics with the acrylate functionality polymerizing at a much faster rate. Vinyl acrylate not only self-initiates its own free-radical polymerization, but also photoinitiates the polymerization of mono- and difunctional acrylates. Kinetic studies using a model monomer system indicate that it is essential for the acrylate and vinyl group to be part of the same molecule in order to function as an effective initiator for acrylate polymerization.     

回收氯乙烯精制技术的研究及应用

在防自聚物堵塞精馏塔上采用外循环精馏技术和深度脱水技术对聚合工序回收氯乙烯进行精制,去除其中残留助剂．采用该技术回收的氯乙烯基本达到新鲜氯乙烯的质量指标。     

Polymerization studies using modified Ziegler-Natta catalysts: 2. Polymerization of vinyl fluoride

Vinyl fluoride has been polymerized by modified Ziegler-Natta catalysts. As in the case of vinyl chloride the most effective catalyst system at 30°C is the soluble system prepared from vanadium oxytrichloride, tri-isobutylaluminium and tetrahydrofuran. All three components are necessary for the formation of an active catalyst. The overall kinetics of polymerization follow the general pattern observed in many Ziegler-Natta systems and that observed in the polymerization of vinyl chloride by the same catalyst system.     

氯乙烯-丙烯酸丁酯共聚树脂的性能优化及应用

通过调整生产工艺或聚合配方,对氯乙烯-丙烯酸丁酯共聚树脂(以下简称氯丙树脂)中丙烯酸丁酯的含量及分布,氯丙树脂的分子质量及其分布、颗粒特性、热稳定性进行了优化;比较了优化后的氯丙树脂与普通PVC树脂的加工性能和力学性能,并将其应用于PVC型材和注塑管件的生产。结果表明:①氯丙树脂中丙烯酸丁酯的质量分数以5%～10%为宜;②通过调整生产工艺或聚合配方,可制得丙烯酸丁酯分布均匀、分子质量分布集中、粒度分布集中、热稳定性优良的氯丙树脂;③氯丙树脂可提高PVC树脂的加工性能和力学性能,可部分替代ACR或CPE等助剂;④经氯丙树脂改性生产的PVC型材和注塑管件性能合格,可简化注塑生产工艺,提高碳酸钙的用量,从而降低产品成本。     

Miniemulsion and macroemulsion copolymerization of vinyl acetate with vinyl versatate

The miniemulsion and macroemulsion polymerization of vinyl acetate with vinyl versatate in batch and semibatch systems was investigated. Vinyl versatate was added either as an emulsion with the vinyl acetate, or as a neat liquid stream. In the batch runs, there is a poor dispersion of vinyl versatate during the nucleation period for the runs in which the vinyl versatate was added neat at the beginning of the polymerization. This led to smaller particles, lower polymerization rate, and different polymer composition evolution when compared with runs in which the vinyl versatate was emulsified with the vinyl acetate. In seeded semibatch runs, residual surfactant in the seed latex, along with the propensity for homogeneous nucleation in vinyl acetate emulsions, resulted in continuing nucleation during the entire semibatch interval. The polymerization rate was primarily affected by monomer feed rate rather than the feeding mode. The effect of monomer feeding mode on copolymer composition was weak when the semibatch feed rate was low, indicating some level of vinyl versatate mass transfer resistance. In all runs, only one glass transition temperature was observed, indicating effective copolymerization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2219–2229, 2002     

Preparation of high‐molecular‐weight poly(vinyl alcohol) with high yield by solution polymerization of vinyl acetate in methanol using 4,4′‐azobis(4‐cyanovaleric acid)

Vinyl acetate (VAc) was solution‐polymerized at 40°C and 50°C using 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) as an initiator and methanol as a solvent, and effects of polymerization temperature and initiator concentration were investigated in terms of conversion of VAc into poly (vinyl acetate) (PVAc), degree of branching (DB) for acetyl group of PVAc, and molecular weights of PVAc and resulting poly(vinyl alcohol) (PVA) obtained by saponifying with sodium hydroxide. Slower polymerization rate by adopting ACVA and lower viscosity by methanol proved to be efficient in obtaining linear high‐molecular‐weight (HMW) PVAc with high conversion and HMW PVA. PVA having maximum number–average degree of polymerization (P_n) of 4300 could be prepared by the saponification of PVAc having maximum P_n of 7900 polymerized using ACVA concentration of 2 × 10^?5 mol/mol of VAc at 40°C. Moreover, low DB of below 1 could be obtained in ACVA system, nevertheless of general polymerization temperatures of 40°C and 50°C. This suggests an easy way for producing HMW PVA with high yield by conventional solution polymerization without using special methods such as low‐temperature cooling or irradiation. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 4831–4834, 2006     

Synthesis and polymerization of 1-(2-N-aziridinoethyl)-4-vinylbenzene

An addition reaction of aziridine onto 1,4-divinylbenzene (DVB) catalyzed by lithium aziridide was studied. It was found that 1-(2-N-aziridinoethyl)-4-vinylbenzene (AEVB) and 1,4-bis (2-N-aziridinoethyl)-benzene(BAEB) can be prepared selectively under appropriate conditions. On the basis of kinetic studies, the reactivity of aziridine toward DVB was compared with that of diethylamine. Vinyl polymerization and ringopening polymerization of AEVB were also carried out to obtain poly [1-{4-(2-aziridinoethyl)phenyl}ethylene] (poly(AEPE)) and poly[{(4-vinylphenethyl) imino}-ethylene](poly(VPIE)), respectively.     

乙烯基酯树脂的合成

以双酚A型环氧树脂和丙烯酸为原料合成了乙烯基酯树脂，简单评述了反应配比、反应温度、阻聚剂用量对反应的影响。用四溴双酚A、环氧氯丙烷和丙烯酸为原料合成了阻燃型乙烯基酯树脂，其阻燃性能良好。     

Preparation and characterization of porous poly(vinyl ester) resin monoliths as separation media

Porous poly(vinyl ester) resin monolithic supports were first prepared by radical polymerization of the continuous phase of oil in water high‐internal‐phase emulsions. Vinyl ester (VE) resin was used as the monomer, ethylene glycol dimethacrylate was used as a crosslinker, and poloxamer 127 was used as the emulsifier in the emulsion polymerization. The prepared columns were evaluated by scanning electron microscopy, mercury intrusion porosimetry, and Fourier transform infrared spectroscopy to observe the morphological characteristics and confirm the absorbance based on the VE resin polymer. The obtained monolith showed not only higher column permeability but also lower back pressure and higher column efficiency. To investigate the absorption performance of the monolithic column, a maximum loading capacity experiment was also applied with lysozyme (Lys), and the results show that the maximum adsorption of the poly(vinyl ester) resin monolith was 1.579 mg/g. Moreover, the capabilities of separation on this column in conjunction with high‐performance liquid chromatography were investigated. Immunoglobulin could be separated from human plasma and chicken egg yolk with high resolution within 4 min. Additionally, fast separation of two mode proteins (interleukin‐18 and Lys) was achieved on the monolith within 2 min at the rate of 1445 cm/h, which demonstrated the potential of the poly(vinyl ester) resin monolith for the fast separation of proteins. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Vinyl carbazole (VC) functionalized mesoporous silica polymer nanocomposites (SBA/VC) for the antibacterial activity studies

Vinyl carbazole (VC) functionalized ordered mesoporous silica polymer nanocomposites (SBA/VC) were synthesized by in situ radical polymerization of monomers inside the mesoporous framework and characterized for the antibacterial activity studies against gram positive and gram negative bacteria. Powder X-ray diffraction and N₂ adsorption isotherms of SBA/VC nanocomposites showed the presence of mesoporous nature. The antimicrobial activity results showed increasing trend with the increase in the concentration of vinyl carbazole (VC) and the maximum antibacterial activity was achieved with SBA/VC₆₄ nanocomposites.     

Preparation of monodisperse poly(methyl methacrylate) particles by radiation-induced dispersion polymerization using vinyl terminus polysiloxane macromonomer as a polymerizable stabilizer

Monodisperse poly(methyl methacrylate) particles were prepared directly by radiation-induced dispersion polymerization in hexane-ethanol media using vinyl terminus polysiloxane (PSI) macromonmer as a polymerizable stabilizer at room temperature. This method takes advantage of the specialties of radiation-induction, which may result in the formation of uniform polymer particles. The gel effect is evident from the polymerization kinetics curves. Vinyl terminus PSI macromonomer acted as not only a comonomer, but also as a stabilizer. The characterization of PMMA particles was carried out by the scanning electron microscope (SEM), FT-IR, ¹H-NMR and X-ray photoelectron spectroscope (XPS). XPS results show that the graft PSI macromonomers were anchored on the surface of PMMA particles to provide a steric stabilization to the PMMA particles.     

The Synthesis of Chitin-g-Poly(vinyl acetate) Copolymers with a Redox Initiator

Vinyl acetate monomer was graft polymerized onto chitin with a redox initiator, cerium ammonium nitrate. Both the graft copolymerization and emulsion polymerization of pure poly(vinyl acetate) (PVAc) were observed during the reaction and a stable dispersion solution was obtained after the reaction. After the PVAc homopolymer was removed by acetone extraction, the grafting efficiency and grafting percentage were calculated from the weight balance. Transmission and scanning electronic microscope were used to observe the morphologies of the reaction product. Experimental results indicated that at initial stage of reaction, graft copolymerization, which occurred on the surface of chitin particles, dominated over the emulsion polymerization. After that, the rate of emulsion polymerization increased greatly and became dominant. The existence of chitin not only provided the stability of the emulsion particles, but also increased the polymerization rate. Structures of copolymers were evidenced with the techniques of Fourier transform infrared and differential scanning calorimeter.     

Synthesis of side chain liquid crystalline poly(vinyl ether)s containing 2,2′-dimethyl-4-methoxy-4′-[undecanyloxy-4-benzoyl]ester biphenyl side group

The synthesis and characterization of 2,2′-dimethyl-4-methoxy-[(11-vinyloxy)undecanyloxy-4-benzoyl]ester biphenyl (7), its cationic polymerization to side chain liquid crystalline polymers with relative number average degrees of polymerization (DP) of 2, 8 and 19 are presented. The mesogenic vinyl ether monomer displays an inverse monotropic nematic phase. The oligomers with DP = 2 and DP = 8 display an enantiotropic nematic, while the polymer with DP = 19 exhibits an inverse monotropic smectic A and an enantiotropic nematic phase. All the liquid crystalline polymers display only liquid crystalline phases and do not undergo side chain crystallization even though eleven methylenic units are used as the flexible spacer. Received: 28 February 1997/Accepted: 23 May 1997