正交实验法优化氟硅丙乳液的制备工艺

利用L25(56)正交实验设计方法,研究了引发剂,乳化剂,有机硅、氟的用量以及聚合温度,单体配比等因素对乳液单体转化率的影响.在本实验条件下,得出制备氟硅丙乳液的最佳工艺条件为:乳化剂用量为4%,引发剂用量为ω=0.6%,单体配比为n(BA):n(MMA)=44:54,有机硅用量ω=10%,有机氟用量ω=4%,聚合温度...     

有机硅改性丙烯酸酯共聚乳液合成方法及胶膜性能的研究

用一次投料法、单体乳液滴加法和引发剂滴加法有机硅改性丙烯酸酯共聚乳液，聚合过程、胶粒形态及乳液稳定性的观测结果表明：单体乳液滴加法是合成该类乳液的最佳方法，研究了单体乳液滴加法中有机硅含量与聚合反及胶膜性能的关系，结果表明：有机硅含量在１５％以下时，聚合反应可以顺利进行，胶膜性能不仅依赖于聚合时有机硅单体的总量，而且还依赖于有机硅单体中活性硅氧烷所占的比例。     

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     

有机硅-丙烯酸酯聚合物乳液合成及粒径分析

通过种子乳液半连续法合成了有机硅改性丙烯酸酯聚合物乳液,并对其粒子形态及分布进行分析。结果表明:通过种子乳液半连续聚合工艺可制备出固含量42wt%,乳化剂含量4wt%(基于单体量)、窄分布纳米粒子的有机硅改性丙烯酸酯聚合物乳液。随反应进行,粒径分布变窄,平均粒径逐渐增大。随乳化剂中SDS与OP-10的摩尔比减少,粒径增大。     

有机硅改性丙烯酸酯乳液的合成

乳液聚合;涂料;有机硅改性丙烯酸酯乳液的合成     

反应性乳化剂对有机硅-丙烯酸酯乳液共聚合的影响

有机硅改性丙烯酸酯;乳液聚合;反应性乳化剂对有机硅-丙烯酸酯乳液共聚合的影响     

有机硅-丙烯酸酯微乳液的合成与表征

采用高温乳化种子单体滴加法制备了有机硅-丙烯酸酯共聚微乳液。对合成条件及微乳液的性能进行了研究。用红外光谱(FT-IR)、透射电镜(TEM)、动态激光粒度仪(PCS)对微乳液的结构和粒子形态进行了表征。结果表明:有机硅氧烷与丙烯酸酯发生了共聚反应,生成的微乳液粒子大致为球形结构,粒子大小比较均一,粒径较小。     

丙烯酸酯乳液压敏胶的研制

本文介绍了丙烯酸乳液压每胶的研制,并研究了单体、乳化剂、加料方式及温度等因素对乳液压敏胶性能的影响。结果表明,软、硬单体的合适配比、乳化剂的种类及用量是制得粘度接性好,稳定性高的乳液压敏胶的必要条件,采用全连续法加料及严格控制反应温度乳液压敏胶的优异性能具有重要作用。     

含氟/硅丙烯酸酯核壳型乳液的合成及性能

采用半连续种子乳液聚合法, 在十二烷基硫酸钠(SDS)/辛基苯基聚氧乙烯醚(TX-10)复合乳化剂的作用下, 合成了以丙烯酸丁酯(BA)为核, 以甲基丙烯酸甲酯(MMA)、甲基丙烯酸十二氟庚酯(DFHMA)、3-(甲基丙烯酰氧)丙基三甲氧基硅烷(MPTMS)和甲基三甲氧基硅烷(MTMS)为壳的核壳型含氟/硅丙烯酸酯聚合物乳液. 利用FTIR, TEM, SEM-EDX和DSC等手段对乳液组成、乳胶粒子结构、膜表面及断面形态等进行了表征, 讨论了氟/硅含量对聚合物膜性能的影响. 结果表明, 核-壳粒子尺寸为20~30 nm, 乳液膜的性能与膜表面氟和硅的含量及相容性有较大的相关性, 当m(氟)∶m(硅单体)=3∶1时, 形成的膜均匀透明, 吸水率较低, 尺寸稳定性较好.     

多乙烯基硅油改性丙烯酸酯乳液的合成及性能

以自制阳离子型乳化剂H、多乙烯基硅油和丙烯酸类单体为主要原料,采用一步法和半连续种子乳液聚合法合成有机硅改性丙烯酸酯乳液。研究了不同聚合方法、不同有机硅含量对硅丙乳液乳胶膜的吸水率、疏水性能的影响,通过纳米粒度-Zeta电位分析仪、接触角仪、红外光谱、透射电镜对乳液及聚合物结构进行了表征。结果表明有机硅单体参与了聚合,乳液稳定性好、平均粒径小。采用半连续种子乳液聚合法合成乳液,有机硅最大添加量为40%(占壳层单体总量),乳胶膜的吸水率只有3.2%,对水的接触角达到105.2o。     

Kinetics of the potassium persulfate-initiated inverse emulsion polymerization of sodium acrylate solutions

The kinetics of the K₂S₂O₈-initiated inverse emulsion polymerization of aqueous sodium acrylate solutions in kerosene with Span 80 as the emulsifier has been studied. The conversion-time curves are S-shaped. The following expressions have been obtained for the maximum rate of polymerization and the molecular weight of the polymers under the experimental conditions investigated: R_max ∞ [K₂S₂O₈]^0.78[sodium acrylate]^1.5[Span 80]^0.1, (OVERLINE)M(/OVERLINE)_u ∞ [K₂S₂O₈]^−0.37[sodium acrylate]^2.9[Span 80]^−0.2. The activation energy for the maximum rate of polymerization is 94.8 kJ mol^−1. The results suggest a monomer–droplet–nucleation mechanism for the system studied. © 1996 John Wiley & Sons, Inc.     

Preparation of PEG-modified urethane acrylate emulsion and its emulsion polymerization

In order to improve stability and reduce droplet size, the PEG-modified urethane acrylates were synthesized by the reaction of polyethylene glycol (PEG) with residual isocyanate groups of urethane acrylate to incorporate hydrophilic groups into the molecular ends. The droplet sizes of the PEG-modified urethane acrylate emulsions were much smaller than those of unmodified urethane acrylate emulsions at the same surfactant composition, and the droplet sizes of these emulsions were significantly effected not by surfactant compositions and types, but by the reaction molar ratio of PEG, because the urethane acrylate containing polyoxyethylene groups as terminal groups aided the interfacial activity of surfactant molecules and acted as a polymeric surfactant. The actions of PEG-modified urethane acrylate were confirmed by the investigation of adsorption of urethane acrylate in a water/benzene interface.For polymerization of emulsions, the stability of emulsion in the process of emulsion polymerization was changed by the type of surfactant or initiator. In the case of emulsion polymerization with a water soluble initiator (K₂S₂O₈), the emulsions prepared using TWEEN 60 were broken in the process of polymerization. However, polymerization of these emulsions could be carried out using an oil soluble initiator (AIBN). The conversion of emulsion polymerization changed with the type of urethane acrylates, that is, the reaction molar ratio of PEG to 2-HEMA.     

乙烯基硅烷-丙烯酸酯乳液共聚动力学研究

以乙烯基三乙氧基硅烷(VTES)、丙烯酸酯为单体,乙氧基醇磺基琥珀酸二钠(A—102)为乳化剂,合成了有机硅改性丙烯酸酯共聚乳液。研究了乳化剂、引发剂、VTES、反应温度以及功能性单体甲基丙烯酸羟乙酯(HEMA)对乳液共聚反应速率的影响。结果表明:聚合速率随乳化剂浓度、引发剂浓度、HEMA浓度的增大及反应温度的升高而增大,但随VTES浓度增大而逐渐减小。由实验得出恒速阶段聚合反应速率R_p与乳化剂浓度C_E、引发剂浓度C_1及有机硅单体浓度C_(VTES)的关系为R_p∝C_E~(0.35)C_I~(0.48)C_(VTES)~(-0.64),表观活化能E_a为81.1kJ·mol~(-1)。     

The influence of RAFT on the rates and molecular weight distributions of styrene in seeded emulsion polymerizations

Seeded emulsion polymerizations of styrene in the presence of two reversible addition–fragmentation chain‐transfer (RAFT) agents were studied. We designed the seed to be small to observe the effects of exit and, we made the seed of poly(methyl methacrylate) so that the molecular weight distributions of poly(styrene) by gel permeation chromatography could be obtained independently by UV detection. The rates were significantly retarded by the presence of a RAFT agent, with the retardation being greater with an EMA RAFT agent [2‐(ethoxycarbonyl)propyl‐2‐yl dithiobenzoate] than with a cumyl RAFT agent (2‐phenylprop‐2‐yl dithiobenzoate). We propose that exit from the particles after fragmentation was the main cause of retardation. In addition, the number‐average molecular weight and polydispersities (broad) did not resemble the characteristic living behavior found in bulk or solution. This was a result of the continuous transportation of RAFT agent into the particles during interval II and the transportation of a small amount during interval III. A conspicuous red layer was also observed at the beginning of the polymerization. The red layer consisted of low molecular weight dormant species swollen with monomer. Once the switch from interval II to interval III occurred, the low molecular weight species coalesced to form a red coagulant. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3864–3874, 2000     

Preparation and characterization of pure polyacrylate polymer colloid through emulsion polymerization using a novel initiator

A series of acrylic polymer colloids were prepared via semi-continuous seeded emulsion polymerization of BA and MMA in water phase when OP-10 and AIBI is used to be emulsifier and initiator, respectively. FTIR spectrum identifies the formation of copolymers of P (MMA-co-BA). DSC confirms that the colloid is a kind of random copolymer and the consistency among the chain segment is fairly good. The emulsion polymerization conditions of preparing acrylic polymer colloid are optimized. Results show that the conversion rate is high and the coagulum is low and the particle size of the acrylic polymer colloids is small when the amount of AIBI is 0.75 g. The polymerization temperature is 70 °C, which is lower than the one that the emulsion polymerization is initiated with the persulfate.     

Tailoring of carboxyl‐decorated magnetic latex particles using seeded emulsion polymerization

In this research, submicron and carboxyl‐functionalized magnetic latex particles were elaborated by using seeded emulsion polymerization technique in presence of oil‐in‐water (o/w) magnetic emulsion as seed. The polymerization conditions were optimized in order to get well‐defined latex particles with magnetic core and polymer shell bearing carboxylic (–COOH) functionality. Starting from (o/w) magnetic emulsion as seed, synthesis process was performed by copolymerization of styrene (St) monomer with the cross‐linker divinylbenzene (DVB) in presence of 4,4′‐azobis(4‐cyanopentanoic acid) (ACPA) as a carboxyl‐bearing initiator. The prepared magnetic latex particles were first characterized in terms of particle size, chemical composition, morphology, magnetic properties, magnetic content, and colloidal stability using various techniques, e.g. particle size analyzer using dynamic light scattering (DLS) technique, Fourier transform infrared, transmission electron microscopy, vibrating sample magnetometer, thermogravimetric analysis, and zeta potential measurements as a function of pH of the dispersion media, respectively. The prepared magnetic latex particles were then used as second seed for further functionalization with methacrylic acid (MAA) in order to enhance carboxylic groups on the magnetic particle's surface. The results showed that final magnetic latex particles possessed spherical morphology with core‐shell structure and enriched carboxylic acid functionality. More importantly, they exhibited superparamagnetism with high magnetic content (58.42 wt%) and high colloidal stability, which considered as the main requirements for their application in the biomedical diagnostic domains. Copyright © 2017 John Wiley & Sons, Ltd.     

聚有机硅丙烯酸酯/蒙脱土纳米复合乳液的流变性

本文采用原位插层聚合的方法,单体插层插入有机蒙脱土片层中,然后引发原位聚合,制备了聚有机硅丙烯酸酯与有机蒙脱土的复合乳液。并用旋转粘度计对其流变性进行了研究。发现乳液的表观粘度(ηa)、稠度系数(K)、零剪切粘度(η0)、粘流活化能(Ea)随有机硅含量增加而增加,而流动指数(η)则减小;ηa、K、η0、Ea随有机蒙脱土含量的增加先增大后减小,当蒙脱土含量为1％时达最大值,n则为最小值。     

Seeded microemulsion polymerization of butyl acrylate

The seeded microemulsion polymerization of butyl acrylate was studied with γ-rays. The hydrodynamic diameter and its distribution of polymer particles in the seeded microemulsion before and after polymerization were determined with photon correlation spectroscopy (PCS). Though there were micelles in the microemulsion, it was found that new particle formation could be ignored during polymerization. The polymerization kinetics of the seeded microemulsion was investigated. The polymerization rate increases with the dose rate and added monomer content and decreases with the seed fraction. It was completely different from that for seeded emulsion polymerization. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2631–2635, 1998