室温自交联丙烯酸酯乳液的制备与表征

使用3种含不饱和双键硅氧烷,乙烯基三(β-甲氧基乙氧基)硅烷(A172)、乙烯基三乙氧基硅烷(VTES)和γ-甲基丙烯酰氧丙基三甲氧基硅烷(A174)为功能单体,采用半连续乳液聚合法制备了室温自交联丙烯酸酯乳液,探讨了硅氧烷功能单体在不同pH条件下水解情况以及其种类和用量对乳液及乳胶膜性能的影响.结果表明,pH在7～9之间时硅氧烷功能单体水解最慢;A172在pH为8.4时5h内就水解完全;增加VTES和A174的用量均能提高乳胶膜的交联度、力学性能和耐水性.控制聚合过程的pH值以抑制硅氧烷功能单体的水解并调节乳液成膜时的pH值以加速硅氧烷功能单体的水解从而增强胶膜的交联程度,发现酸性或碱性条件下得到乳胶膜比中性条件下胶膜的力学和耐水性能均有不同程度的提高,并且在酸性条件下胶膜的性能提高最多.对比使用A174和VTES制备的胶膜,发现这种方法对含有A174胶膜的效果不明显,而含VTES胶膜的性能提高最为显著.     

室温固化聚丙烯酸酯涂料

聚丙烯酸酯类涂料以优良的保光、保色、耐候、耐水等性能而在许多领域得到应用 ,为提高涂膜的机械强度、耐久性、耐热和耐溶剂等性能 ,通常需要在涂膜的同时使大分子链相互交联 ,常用的室温交联固化体系主要有环氧 /胺基 [1] 、羟基 /异氰酸根 [2 ] 等 ,其中环氧固化体系的交联密度大 ,但固化产物脆性大且易于光降解 .而基于异氰酸基的固化体系则由于异氰酸酯的毒性和价格问题而受到限制 ,迫切需要研制出新的交联固化技术 .羟基与酸酐的反应已有深入研究 ,但将该反应用于漆膜的交联固化反应却少有报道 .本文以廉价的马来酸酐为原料 ,合成了…     

GAD室温自交联乳液的合成及其涂膜性能

合成了含有缩水甘油基、羧基和胺基的多层核壳型室温自交联乳液，研究了聚合温度、乳化剂用量和加料速率对所得乳液性能及其涂膜性能的影响。研究表明，聚合温度升高使乳胶膜的交联密度降低，而涂膜耐水性和乳液贮存稳定性在50℃呈现最佳值。在乳化剂含量为2%时，涂膜的交联密度最大且耐水性最佳，而乳液的贮存稳定性能随乳化剂量的增加而增大。加大乳化单体滴加速率，乳液贮存稳定性降低，乳胶膜的交联密度增大。     

GHD室温自交联乳液的聚合及贮存稳定性

采用半连续种子乳液聚合技术合成了含甲基丙烯酸缩水甘油酯(GMA)、甲基丙烯酸羟乙酯(HEMA)和甲基丙烯酸二甲氨基乙酯(DMAEMA)的室温自交联乳液(GHD).实验结果表明,在甲基丙烯酸甲酯(MMA)-丙烯酸丁酯(BA)-GMA种子乳液存在下,聚合温度升高,聚合过程稳定性下降,但乳液的贮存稳定性提高;乳化单体滴加速度加快,种子聚合物的玻璃化温度升高,可减少聚合过程的交联凝聚作用,提高聚合过程的稳定性;而HEMA和DMAEMA用量增加对聚合过程的稳定性没有明显影响,但使乳液的贮存稳定性下降.官能团间的交联凝聚作用可能是影响室温自交联乳液聚合及贮存过程稳定性的关键因素.     

氟聚合物改性聚丙烯酸酯乳液的制备

氟聚合物改性聚丙烯酸酯乳液的制备;氟改性;聚四氟乙烯;聚丙烯酸酯乳液     

钙离子室温交联聚丙烯酸酯无皂水溶胶的研究

研究了Ca^2 聚丙烯酸酯无皂水溶胶交联乳液的制备条件，考察了交联温度、交联剂用量对涂膜性能的影响。结果表明Ca^2 加入无皂水溶胶中的最低温度为40℃，交联反应于室温下即完全发生，交联膜具有较好的耐热、耐水性能。用TEM以及电导滴定对交联机理进行了初步探讨，发现交联反应主要发生在胶乳表面．COO^-与Ca^2 之间。     

丙烯酸酯共聚物乳液自交联反应的研究

本文研究了含环氧基的丙烯酸酯四元共聚物乳液交联后的溶胀度、自交联反应及动力学.结果表明:交联共聚物的溶胀度Q随甲基丙烯酸环氧丙酯单体含量的增加而降低,共聚物在受热的情况下,环氧基因在羧基的作用下开环而发生交联反应,产生网状结构.     

聚氨酯一聚丙烯酸酯共聚乳液的合成研究

以甲基丙烯酸β－羟乙酯封端的聚氨酯大分子单体与丙烯酸酯类单体进行乳液共聚，合成了以聚丙烯酸酯（PA）为主链、聚氨酯（PU）为侧链的接枝共聚物（PA－g－PU）乳液，用IR光谱和^1H NMR光谱对该聚氨酯大分子单体及PA－g－PU接枝共聚物进行了表征，并对影响聚氨酯－聚丙烯酸酯共聚合的因素进行了探讨。结果表明：聚氨酯大分子单体的加入对乳液聚合的速率造成较大的影响。该体系的表观活化自由能为99.39KJ/mol,Rp∝[I]^0.87,Rp∝[S]^0.12。     

聚氨酯/聚丙烯酸酯复合乳液的研制进展

概述聚氨酯－聚丙烯酸酯复合乳液的制备方法。特别对聚氨酯－聚丙烯酸酯复合乳液共聚法作了较为系统的介绍和讨论。     

单组分室温交联聚合物乳液研究进展

水性聚合物产品具有环境友好、成本低、节约资源和能源等优点,因而油漆、涂料、粘合剂等重要化学品的水性化是社会发展的必然需求.而聚合物乳液作为水性聚合物产品的成膜物,其适当的交联是提高产品性能的重要途径之一.本文对不同交联机理的单组分室温交联水性聚合物乳液进行了综述,着重介绍了该领域的一些重要交联体系和进展情况.     

苯乙烯-丙烯酸酯微乳液的合成研究

目前国内外许多专家学者积极研发低污染、低能耗、高性能的胶粘剂,以代替传统的毒性大、成本高、稳定性差的溶剂型胶粘剂[1]。苯乙烯-丙烯酸酯微乳液(苯-丙微乳液)是重要的胶粘剂之一。与常规乳液胶粘剂相比,它具有以下几个特点[2]:(1)是热力学稳定体系,可以自发形成;(2)分子粒     

Morphology of epoxy/acrylic polymer‐dispersed liquid‐crystal film in DICY thermal cure

A polymer‐dispersed liquid‐crystal (PDLC) film was prepared from UV‐curable acrylic, thermally curable epoxy, and a liquid‐crystal (LC) mixture with a fixed LC content of 40 wt %. The UV irradiation and heat treatments were in sequential steps. At first, a phase diagram of a binary mixture of LC (E63) and epoxy [diglycidyl ether of polypropylene glycol (DER736)] was established to understand their miscibility. Then, the phase‐separation temperatures and morphologies of pre‐UV‐cured films with different equivalent DER736/dicyandiamide (DICY) molar ratios were observed. Finally, the polymerization‐induced phase‐separation behavior and morphology of the PDLC film were studied by real‐time observation while the film was maintained at 130 °C under the microscope. The results showed that the acrylic network would not affect the phase‐separation behavior of the E63/DER736 mixture. In both thermally induced and polymerization‐induced phase separations, the undissolved DICY particles acted as nucleation agents and were capable of inducing E63 to separate out early. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2033–2042, 2000     

环境气氛作用下煤灰在刚玉质耐火板上的表面结渣行为

采用了扫描电镜、能谱分析仪、X射线衍射等方法对不同环境气氛下熔融煤灰在刚玉耐火板上煅烧渣样进行了测试，并就渣样的形貌、成分分布及与刚玉质耐火板之间的高温烧结特性进行了分析研究。研究结果表明，氧化性气氛下，碱性氧化物促进了煤灰在刚玉耐火板上的黏结作用，特别是Al含量较高的耐火板更有利于促进其发生共晶反应。还原性条件下，煤灰中生成的FeO具有很强的助熔效果，促使矿物之间产生低熔点的共熔物，同时Fe、Cr、Ti的扩散偏析减弱，加强了熔融煤灰对耐火板的黏结作用。     

Investigation of reactive acrylic monomers for their effect on the temperature range and operating voltage of polymer-stabilised optically isotropic liquid crystal blue phases

Synthesis of various reactive acrylic monomers (RMs) to be used as components in liquid crystalline blue phase (LCBP) mixtures has been carried out in order to investigate their effect on temperature range and operating voltage. All the newly synthesised RMs were fully purified and characterised. These were added in various molar ratios to LCBP mixtures, which were stabilised by ultraviolet polymerisation, and improvements in the operating voltage and temperature range were studied. The compatibility of LCBP and monomer side-chains was investigated in terms of polarity and alkyl chain length.     

淀粉/丙烯酸反相乳液体系的稳定性研究

以丙烯酸(AA)单体的水溶液为水相,液体石蜡为油相,失水山梨醇三油酸酯(Span 85)和辛基苯基聚氧乙烯醚(Opan 10)为复合乳化剂,合成了淀粉/丙烯酸反相乳液;考察了乳化剂亲水亲油平衡值(HLB值)、油水比、乳化剂用量、单体浓度、温度对乳液稳定性和类型的影响.结果表明,合成淀粉/丙烯酸稳定反相乳液体系的适宜条件...     

Radiation-induced graft polymerization of acrylic acid onto fluorinated polymers. I. Kinetic study on the grafting onto poly(tetrafluoroethylene-ethylene) copolymer

Direct radiation-induced grafting of aqueous acrylic acid (AAc) onto poly(tetrafluoroethylene-ethylene) (ET) film has been studied. The effect of grafting conditions such as monomer concentration, exposure dose, dose rate, and film thickness on the grafting yield was investigated. The dependence of the grafting rate on monomer concentration was found to be 1.2 order. The dependence of the grafting rate on dose rate was found to be 0.6 order regardless of the film thickness. The relationship between the grafting rate and film thickness gave a negative first-order dependence. The results suggest that the grafting process is mainly controlled by monomer diffusion, and it was concluded that this grafting system proceeded by the front mechanism. The swelling behavior increases linearly with degree of grafting. The electrical conductivity and mechanical properties for the trunk and grafted polymer were investigated at different irradiation doses in air and under vacuum irradiations. © 1992 John Wiley & Sons, Inc.     

Synthesis and Properties of IPN Hydrogels Based on Konjac Glucomannan and Poly（acrylic acid）

As a random copolymer of β-(1,4) linked D-mannose and D-glucose, konjac gluco- mannan (KGM) is a naturally occurring water-soluble polysaccharide, and has been paid attention in the field of drug controlled release carriers potentially used in colon1,2. …     

Effect of synthesis method and buffer composition on the LCST of a smart copolymer of N‐isopropylacrylamide and acrylic acid

Responsive polymers have been the focus of many studies during the past decade because of their ability to change according to environmental stimuli. In this paper, we report on the development of a method to synthesize a pH/temperature‐sensitive linear copolymer, poly(N‐isopropylacrylamide‐ co‐acrylic acid)(poly(NIPAAm‐co‐AAc)), with a molecular weight of about 10⁶–10⁵ Da in water using azobisisobutyronitrile (AIBN) as the initiator. The effects of the following on the lower critical solution temperature (LCST) of the copolymer and homopolymer of NIPAAm were investigated: the type of buffer salts and pH changes of test solutions, molecular weight and concentration of homopolymer/copolymer solutions, and AAc monomer molar feed ratio (mol%). The effects of different synthesis methods on the molecular weight and on the AAc content were also evaluated. The mechanism of action in environments with different pH values is discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Long‐term stability of an ambient self‐curable latex based on colloidal dispersions in water of two reactive polymers

An ambient self‐curable latex (ASCL) was prepared via the blending of colloidal dispersions in water of a chloromethylstyrene‐functionalized copolymer and a tertiary‐amine‐functionalized copolymer. Upon casting and drying under ambient conditions, the ASCL could generate crosslinked continuous polymer films. The crosslinking occurred via the Menschutkin reaction (quaternization) between the two types of functional groups. Because this reaction was reversible at high temperatures, the films could be decrosslinked and hence were self‐curable. The prepared ASCL exhibited excellent colloidal and chemical stability during long‐term storage: no significant changes in the colloidal properties, such as the particle size, electrophoretic mobility, and crosslinking reactivity, were observed after 48 months of storage. The electrophoretic measurements indicated that the electrostatic repulsion between the negatively charged particles of the ASCL was responsible for the excellent stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2598–2605, 2005     

Study on affecting factors of curing rate in ultraviolet curing adhesives containing modified acrylic ester prepolymers

Abstract

Ultraviolet (UV) curing adhesives have been extensively utilized in fields of health care and electronic components due to low energy consumption and solvent pollution. The most used system is modified acrylic ester system whose merits are low cost, high reliability and tensile strength. However, higher UV curing rate is still pursued especially in field of quick dry adhesives as well as influencing factors of curing rate are very complex. For clarifying affecting factors of curing rate as well as achieving higher curing rate, in this work, several UV curing adhesives with acrylic photosensitive resin prepolymers modified by epoxy and polyurethane were prepared. The impacts of class and content of radical photo-initiators, prepolymers and reactive diluents on UV curing rate were deeply researched. Moreover, the influence of oxygen polymerization inhibition on curing rate was discussed as well. The significantly elevated curing rates were obtained in as-prepared adhesives, in comparison with commercial ones. This work might offer a facile and effective strategy to obtain the promising high-performance modified acrylic ester prepolymer bearing UV curing adhesives with a significantly elevated high curing rate by well controlling these investigated affecting factors.