Development of AAS resin by the emulsion–suspension polymerization method

In order to improve the weatherability of acryonitrile—styrene—butadiene rubber graft polymer (ABS resin), an attempt was made to develop a resin (AAS resin) in which acrylic rubber of good weatherability was used instead of butadiene rubber. First, by copolymerizing dicyclopentenyl-methacrylate (DCP-MA,3%) with butyl acrylate, crosslinked acrylic rubber was obtained. This also introduced grafting sites into the rubber. Next, methods of graft copolymerizing styrene and acrylonitrile with this rubber were examined. An emulsion–suspension polymerization method was developed in which the initial stage of the polymerization, emulsion polymerization, changed into suspension polymerization during the process. By this method of polymerization, rubber particles were combined and enlarged, bringing about a graft-type resin with high impact resistance. This polymerization method is industrially useful because particle-shaped resins are obtained without the need of a salting-out process. The AAS resin, obtained in this way, has much improved weatherability over ABS resin and shows strength equal to that of ABS resin. © 1992 John Wiley & Sons, Inc.     

Modification of epoxy resins with acrylic rubbers containing a pendant epoxy group

New acrylic rubbers with a pendant epoxy group were prepared by copolymerization of butyl acrylate (BA) with vinylbenzyl glycidyl ether (VBGE). The modification of an epoxy system (bisphenol-A diglycidyl ether/p,p′-diaminodiphenyl sulfone) with the acrylic rubbers was carried out in order to increase the toughness of the cured epoxy resin. The addition of 20 wt.-% of the copolymer containing 74% of BA and 26% of VBGE units resulted in a 30% increase in the fracture toughness (K_IC) of the cured resin at minimal expenses of strength and modulus of the resin. The modified epoxy resin had two-phase morphology in which the rubber particles with average diameter of 2 μm are dispersed in the epoxy matrix. The copolymer without the pendant epoxy group, prepared from BA and vinylbenzyl methoxyethyl ether, was ineffective as a modifier, indicating that the reaction of the pendant epoxide with the epoxy matrix resulted in good interfacial adhesion between the rubber particles and the matrix, and in the increased toughness. The epoxide-containing copolymers with 55 or 86% of BA units were also insufficient modifiers. The addition of the former yielded cured resins with homogeneous structure, whereas that of the latter resulted in macroscopic phase separation between the rubber and the epoxy resin.     

The influence of clay and elastomer concentration on the morphology and fracture energy of preformed acrylic rubber dispersed clay filled epoxy nanocomposites

The influence of toughener and clay concentration on the morphology and mechanical properties of three-phase, rubber-modified epoxy nanocomposites was studied. Nanocomposite samples were prepared by adding octadecyl ammonium ion exchanged clay to a dispersion of pre-formed acrylic rubber particles in liquid epoxy, so as to minimize alteration to the rubber morphology in the final cured specimen. The state of clay platelet exfoliation and rubber dispersion in the cured nanocomposites was studied using transmission electron microscopy. The amounts of clay platelet separation and dispersion of clay aggregates in the epoxy matrix were found to be sensitive to clay and toughener concentration, and clay platelets preferentially adsorb to the rubber particles. Tensile modulus and strength increase and ductility decreases with increasing organoclay content, while rubber has the opposite effects on the properties of epoxy resin. When both additives are present in epoxy resin, a favorable combination is produced: ductility is enhanced without compromising modulus and strength. Modulus and strength are improved by nano and micro dispersion of nanoclay in the epoxy matrix, whereas elongation and toughness are improved by clay adsorption to the rubber particle surface, which promotes cavitation. The glass transition temperature of epoxy resin remains relatively unchanged with clay addition.     

Fabrication of micro-dot arrays and micro-walls of acrylic acid/melamine resin on aluminum by AFM probe processing and electrophoretic coating

Micro-dot arrays and micro-walls of acrylic acid/melamine resin were fabricated on aluminum by anodizing, atomic force microscope (AFM) probe processing, and electrophoretic deposition. Barrier type anodic oxide films of 15 nm thickness were formed on aluminum and then the specimen was scratched with an AFM probe in a solution containing acrylic acid/melamine resin nano-particles to remove the anodic oxide film locally. After scratching, the specimen was anodically polarized to deposit acrylic acid/melamine resin electrophoretically at the film-removed area. The resin deposited on the specimen was finally cured by heating.It was found that scratching with the AFM probe on open circuit leads to the contamination of the probe with resin, due to positive shifts in the potential during scratching. Scratching of the specimen under potentiostatic conditions at −1.0 V, however, resulted in successful resin deposition at the film-removed area without probe contamination. The rate of resin deposition increased as the specimen potential becomes more positive during electrophoretic deposition. Arrays of resin dots with a few to several tens μm diameter and 100–1000 nm height, and resin walls with 100–1000 nm height and 1 μm width were obtained on specimens by successive anodizing, probe processing, and electrophoretic deposition.     

高性能室温固化环氧结构胶的制备与研究

为了改善环氧固化物的韧性,又保持其热稳定性及提高其抗冲击性能,采用超细全硫化羧基丁腈橡胶粒子改性环氧树指技术,并辅以玻璃微珠,球型硅微粉,ACR丙烯酸酯橡胶微球等抗冲剂填充,制备出一款高性能室温固化环氧结构胶.实验中采用高速搅拌球磨法在环氧树脂中分散超细全硫化羧基丁腈橡胶粒子,辅以填充物,制备的环氧树脂结构胶剪切冲击强...     

Study of water sorption in rubbers by acoustic microscopy

Acoustic microscopy has been used to examine changes during water swelling at the surface of a rubber previously treated with an acrylic monomer. Surface modification was carried out with acrylic acid either in aqueous solution or in the vapour phase, and a photografting reaction was achieved with an aqueous solution of acrylic acid in the presence of a photo‐initiator. Water sorption induces modifications of the mechanical properties, transforming a rigid polymer into a soft material. Therefore, the acoustic impedance of the material decreases during the swelling process and the evolution of acoustic reflection coefficient is followed. The potential of ultrasonic measurements as an in situ and non‐destructive dynamic analysis technique is demonstrated. Mapping of grafted and ungrafted areas on a rubber surface is obtained with acoustic microscopy. © 2000 Society of Chemical Industry     

路标漆用橡胶接枝丙烯酸树脂的制备

研制了路标漆用橡胶接枝丙烯酸树脂,以提高其耐磨性,由其配制路标漆的各项性能指标符合国标,介绍了该树脂及其路标漆的制法和性能指标。讨论了溶剂,橡胶用量,过氧化苯甲酰引发剂用量与加入方式,树脂的玻璃化温度对树脂和路标漆性能的影响。     

橡胶O型圈表面涂覆用水性PTFE改性涂料的制备及应用

使用水性聚氨酯、水性丙烯酸树脂、氨基树脂为改性树脂,与水性聚四氟乙烯PTFE乳液复配,经混合分散、砂磨、过滤等工艺过程,制备出涂覆橡胶O型圈表面的水性PTFE改性自润滑涂料。结果表明,研制的水性PTFE改性自润滑涂料通过滚喷工艺喷涂橡胶O型圈表面,固化后形成的涂层对橡胶O型圈表面附着力好、摩擦系数低,具有良好的自润滑性,方便橡胶O型密封圈的装配操作。     

胶粘剂国内外发展概况

本文综述了胶粘剂国内外发展概况,其中包括市场需要概况,主要工业化品种主要发展趋势和发展建议。涉及的胶粘剂类型有：三醛胶、水基胶、反应型胶、溶剂型胶、热熔胶和橡胶型胶等等。     

Synthesis and characterization of acrylic rubber/silica hybrid composites prepared by sol‐gel technique

The organic–inorganic hybrid composites comprising acrylic rubber and silica were synthesized through sol–gel technique at ambient temperature. The composites were generated through the acid‐catalyzed hydrolysis and subsequent condensations of inorganic tetraethoxysilane (TEOS) in the organic acrylic rubber (ACM), solvated in tetrahydrofuran. The morphology of the hybrid materials was investigated by using the transmission electron microscope (TEM) and scanning electron microscope (SEM). Transmission electron micrographs revealed that the silica particles, uniformly distributed over the rubber matrix, are of nanometer scale (20–90 nm). The scanning electron micrographs demonstrated the existence of silica frameworks dispersed in the rubber matrix of the hybrid composites. The X‐ray silicon mapping also supported that observation. There was no evidence of chemical interaction between the rubber phase and the dispersed inorganic phase, as confirmed from the infrared spectroscopic analysis and solubility measurements. Dynamic mechanical analysis indicated mechanical reinforcements within the hybrid composites. The composites containing in situ silica, formed by sol–gel technique, demonstrated superior tensile strengths and tensile modulus values at 300% elongations with increasing proportions of tetraethoxysilane. However, the improvements in physical properties with similar proportions of precipitated silica were not significant. Maximum tensile strength and tensile modulus were obtained when the rubber phase in the hybrid composites was cured with ammonium benzoate and hexamethylenediamine carbamate system, as compared with benzoyl peroxide cured system. Thermal stability of the hybrid composites was not improved appreciably with respect to the virgin rubber specimen. Residue analysis from thermogravimetric study together with infrared spectroscopic analysis indicated the presence of unhydrolyzed tetraethoxysilane in the hybrid composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2579–2589, 2004     

Structure and properties of epoxy resins modified with acrylic particles

The morphology and material properties of dicyandiamide (DICY)‐cured epoxy resins modified with acrylic particles consisting of a PBA (polybutyl acrylate) core and a PMMA (polymethyl methacrylate) shell and epoxy resins modified with acrylic rubber (PBA) particles alone were studied. It was found that the epoxy system modified with core/shell acrylic particles showed higher fracture toughness, indicating that the modification had a larger effect on improving the material properties of the epoxy resin. A characteristic shown by the core/shell acrylic particles is that they swell along with the epoxy resin under exposure to heat and gel before the latter cures. In this process, the epoxy resin penetrates the surface of the shell layer and a bond is formed between the epoxy matrix and the core/shell acrylic particles. This suggests that the epoxy matrix around the core/shell acrylic particles has the effect of increasing the level of energy absorption due to plastic deformation of the matrix. This is thought to explain why the epoxy resin modified with core/shell acrylic particles showed higher fracture toughness. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2955–2962, 1999     

氨基改性丙烯酸乳液处理剂的研究

用烷基化氨基树脂对现有的丙烯酸乳济型无纺布处理剂进行改性,在不影响原性能的基础上,具有优良的耐水性和增硬效果。本文叙述了烷基化氨基树脂的合成配方和操作工艺,讨论了烷基化氨基树脂与丙烯酸类聚合物的反应机理,使用配比以及交联反应温度对性能的影响。     

A study on morphology and physical properties of natural–acrylic rubber blends

Morphology and physical properties of natural–acrylic rubber blends were investigated as a function of blend compositions and mixing methods. In the first method, the masticated natural rubber was cross‐blended with the acrylic rubber for 15 min, followed by a sequential addition of vulcanizing chemicals (ZnO, stearic acid, MBT, sodium stearate, and sulfur), and the mixing was terminated within 15 min. In the second method, the masticated natural rubber was premixed with its relevant vulcanizing chemicals (excepting the sulfur) for 7 min, followed by blending it with the acrylic rubber and sodium stearate for 20 min. Finally, the sulfur was added and the mixing was continued for further 3 min before termination. The resulting blends were vulcanized to their optimum cure time in a compression mold. The rubber sheet was cut into a dumbbell‐shaped specimen, and tensile properties were determined at a cross‐head speed of 500 mm/min. The morphology of the blends was examined with scanning electron microscopy (SEM). The SEM specimen was prepared by cryo‐fracturing, followed by staining with OsO₄. It was found that all of the rubber blends were immiscible, as shown by there being two separated phases in the SEM micrographs. The result was in a good agreement with that from a thermal analysis (using a differential scanning calorimeter), which showed two glass transition temperatures. Morphology of the rubber blends changed from a cocontinuous morphology to a dispersed particle morphology as the natural rubber content was increased from 20% to 80% by weight. Increasing the natural rubber content enhanced tensile properties of the rubber blends at the expense of their oil and heat resistance. Most of these properties being examined seemed to be unaffected by the mixing method, with the exception of the retention of tensile strain after aging. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1532–1539, 2002     

高弹性水性聚氨酯橡胶涂料的研制

以水性丙烯酸改性聚氨酯(PUA)乳液为基料,加入功能性颜填料和助剂,制备出一种高弹性水性聚氨酯橡胶涂料。对高弹性水性聚氨酯涂料与传统橡胶涂料进行了一系列模拟涂覆橡胶管的对比试验,结果表明:高弹性水性聚氨酯涂料可以很好地满足工艺要求。     

环氧树脂改性方法研究进展

介绍了利用橡胶、有机硅、热致性液晶聚合物、互穿网络聚合物、核壳聚合物、纳米粒子、丙烯酸、腰果酚、微胶囊等改性环氧树脂的方法及其最新进展。     

Amphiphilic particulate phase semi-interpenetrating polymer networks based on recycled rubber matrix

The goal of this study is to enable the utilization of recycled rubber particles in aqueous media by producing amphiphilic particulate phase semi-interpenetrating polymer networks (PPSIPNs). Rubber granulates obtained from post-consumer rubber items were pulverized into fine particles using a solid state shear extrusion (SSSE) process. Reaction mixtures composed of toluene, acrylic acid (AA) monomer and azobisisobutyronitrile (AIBN) as an oil-soluble initiator were prepared and used to impregnate the produced rubber particles. Toluene was added as a co-swelling agent to induce more swelling of the rubber particles and, consequently, enhancement in the absorption of AA in the rubber network. The swollen particles were introduced into a micro-domain suspension polymerization reactor where the ionic strength of the aqueous phase was sufficient to prevent desorption of AA from the particles during the reaction. This resulted in formation and interpenetration of hydrophilic poly(acrylic acid) in the intermolecular structure of hydrophobic rubber network. The resulting composite particles are water dispersible and suitable for use in a variety of aqueous applications such as, additives to waterborne emulsions and vehicles for wastewater treatment.     

丙烯腈下游产品生产工艺及市场

介绍了丙烯腈主要下游产品腈纶、ABS树脂及丁腈橡胶的生产工艺、市场状况及未来的发展趋势。     

Studies on oil distribution in polymer blends

Oils and resins are widely used in rubber industries to improve or control the mechanical properties, viscoelastic behavior, processability, and tackiness of a rubber compound. Very few fundamental studies have been reported on the function and the mechanism of oils and resins in a rubber mixture. In this article oil or resin distribution to each phase in an immiscible binary elastomer blend was studied by measuring the change of thermodynamical parameters, such as glass transition temperature, melting point of crystallines, and heat at melt of each polymer component. Several independent approaches give consistent results. It was found that aromatic oil was favorably distributed to the polystyrene-butadiene (SBR) phase of an SBR/natural rubber (NR) blend. Similarly, unequal distribution of resin in a blend was observed for a natural resin (rosin) and a petroleum resin. © 1996 John Wiley & Sons, Inc.     

Preparation and Characterization of Two-component Waterborne Poly-urethane Comprised of Water-soluble Acrylic Resin and HDI Biuret

A two-component waterborne polyurethane （2K-WPU） was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU particles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI isocyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction between HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on performance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.     

Development of high performance,waterborne coatings. Part III: Characterization of coatings and cured film

High performance waterborne coatings were developed which could be utilized as an adhesive primer for sideseam bonded cans. The manufacturing process is unique; blending an epoxy / phenolic solution and an acrylic resin solution and dispersing the mixture in an aqueous medium by the phase transition method. The epoxy resins are neither chemically modified by grafting nor esterified by acrylic resin, which is thought to develop the excellent performance of epoxy / phenolic coatings. The morphology of the coatings and cured film was characterized and found to be quite different from the conventional waterborne coatings, i.e., the acrylic-modified epoxy resin systems. It was confirmed that acrylics and epoxy / phenolic resins exist in separate phases in the cured film, and that the epoxy / phenolic resin constitutes the continuous phase.