Syntheses and Properties of New Acrylic Size Latex

An acrylic size 8K is synthesized by emulsion polymeriza-tion,the properties of which depend on the monomersparticipating in copolymerization and reaction tech-niques.The structure of the size molecule is character-ized by infrared spectrum.The hardness of the size filmis characterized by the glass transition temperature of thesynthesized copolymer which is a flexion point of DSCcurve.The micro state of the size adhering to yarns isshown by scanning electron microscopy.According tomeasurements,the acrylic size Size 8K has good adhesivepower and low water absorption,proper viscosity andhigh thermal stability,strong abrasion resistance andgood compatibility with other sizing agents.It aslo im-proves yarn breaking strength, yet has limited elongationloss.The acrylic size is a potential size to replace PVAand to apply to high speed looms.

Measurement methods of particle size distribution in emulsion polymerization

The particle size distribution of polymer always develops in emulsion polymerization systems,and certain key phenomena/mechanisms as well as properties of the final product are significantly affected by this distribution.This review mainly focuses on the measurement methods of particle size distribution rather than average particle size during the emulsion polymerization process,including the existing off-line,on-line,and in-line measurement methods.Moreover,the principle,resolution,performance,advantages,and drawbacks of various methods for evaluating particle size distribution are contrasted and illustrated.Besides,several possible development directions or solutions of the in-line measurement technology are explored.

Effect of Polymerization Condition on Particle Size Distribution in St/BA/MAA Emulsion Polymerization Process

A series of St/BA/MAA emulsion polymerizations was carried out. By using PCS (photon correlation spectroscopy), the particle size distribution (PSD) of the whole St/BA/MAA emulsion polymerization process was gotten easily and quickly. The effect of polymerization condition on PSD in St/BA/MAA emulsion process was discussed.

PARTICLE MORPHOLOGY OF POLY(VINYL CHLORIDE)RESIN PREPARED BY SUSPENDED EMULSION POLYMERIZATION

Suspended emulsion polymerization was used to prepare poly(vinyl chloride) (PVC) resin. Fine PVC particleswere formed at low polymerization conversions. The amount of fine panicles decreases as conversion increases anddisappears at conversions greater than 30%. Scanning electron micrographs show that PVC grains are composed of looselycoalesced primary particles, especially for PVC resins prepared in the presence of poly(vinyl alcohol) dispersant. The size ofprimary particles increases and porosity decreases with the increase of conversion. In view of the particle features of PVCresin, a particle formation mechanism including the formation of primary particles and grains is proposed. The formationprocess of primary particles includes the formation of particle nuclei, coalescence of particle nuclei to form primary particles,and growth of primary particles. PVC grains are formed by the coagulation of primary particles. The loose coalescence ofprimary particles is caused by the colloidal stability of primary particles and the low swelling degree of vinyl chloride in the primary particles.

Influence of Suspended Emulsion Polymerization Conditions on Particle Characteristics of Polyvinyl Chloride Resin

Suspended emulsion polymerization of vinyl chloride was carried out in a 5 L autoclave. The influence of agitation, polymerization conversion, dispersant and surfactant on the average particle size (PS) and particle size distribution (PSD), particle morphology and porosity of polyvinyl chloride (PVC) resin was investigated. It showed that the agitator had great influence on the smooth operation of polymerization, PS and PSD. The PS increased and PSD became narrow as polymerization conversion became high. The porosity decreased with the increase of conversion. A convenient choice of additives, both dispersants and non-ionic surfactants, allows one to adjust PS and PSD. The PS decreased with the addition of polyvinyl alcohol or hydroxypropyl methylcellulose dispersants,and increased with the addition of Span surfactants. The addition of dispersants or surfactants also affected the morphology and porosity of resin, and PVC resin with looser agglomeration and homogeneous distribution of primary particles was prepared.

Nonionic Polymerizable Emulsifier in High-Solids-Content Acrylate Emulsion Polymerization

Stable high-solids-content acrylate emulsion were obtained with a nonionic polymerizable emulsifier allyloxy nonylphenoxy poly （ethyleneoxy） （10） ether （ANPEO10）, and a conventional emulsifier OP-10 as a reference sample. 1H NMR proves that the polymerizable emulsifier ANPEO10 has been incorporated into the resulted acrylate polymers. TEM demonstrates that there are some differences in the particle morphologies. AFM proves that the polymerizable emulsifier ANPEO10 migrating to the surface of the emulsion film was much less than the conventional emulsifier OP-10. The polymerizable emulsifier ANPEO10 can enhance the adhesion with glass plate compared to the conventional emulsifier. Furthermore, with increasing amount of emulsifier, the surface free energy of the films first decreased and then increased, and the adhesion with glass plate is initially enhanced and then attenuated. The water-resistance and solvent-resistance of the films prepared by the polymerizable emulsifier ANPEO10 are superior to those prepared by the conventional emulsifier OP-10.

SEED SEMICONTINUOUS EMULSION MULTI-COPOLYMERIZATION OF (METH) ACRYLATES WITH HIGH-SOLID CONTENT: EFFECT OF THE OPERATION CONDITIONS

The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate (HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solid content. The effects of monomer emulsion feed rates (R(a)) and (R/E)(E) values, the ratio of emulsifier amount between the initial charge (R) and the addition monomer emulsion (E), on the polymerization reaction features, the viscosities, surface tensions,particle sizes and particle sizes distributions of latexes, T-g and the insoluble fractions of films, the 180 degrees peel strength, tack and holding power of pressure-sensitive adhesive (PSA) tapes, prepared from the latexes, were studied. Experimental study shows that the grafting and crosslinking fraction in the PSA tapes must be controlled within a suitable range to keep the balance of the 180 degrees peel strength, tack and holding power.

STUDIES ON HIGH SOLID CONTENT AND STABLE EMULSIFIER—FREE EMULSION POLYMERIZATION

In this article,AHPS(3-allyloxy-2-hydroxy-1-propanesulfonate salt) was synthesized to use in emulsifier-free emulsion polymerization of BA/BMA/MMA system for high solid content latexes.Storage stability,flow behavior of the latexes,morphology of the obtained latex particles,dynamic viscoelastic behavior,tensile strength and water resistance properties of the resulted copolymers were investigated.The experimental results show that with the addition of AHPS,stability of the emulsion is greatly improved that there appears no apparent precipitation during the polymerization and storage at room temperature for 6 months and at -10℃ for four months.Flow of the latexes follows the Bingham body laws,diameter of the latex particles is about 0.6μm,of which is larger than that of by conventional emulsion polymerization(0.12μm).In addition,not only water resistance of the copolymers obtained by emulsifier-free emulstion polymerization is greatly improved,but also tensile strength is obviously enhanced.

水乳型自消光丙烯酸酯共聚物涂层的制备

以苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)为主单体,选择同时带长亲水链段和长疏水链段的二十二烷基醇聚氧乙烯醚-25甲基丙烯酸酯(BEM)为功能单体,连同BEM混合液中含有的甲基丙烯酸(MAA)通过乳液共聚制备了丙烯酸酯共聚物乳液,并以此乳液制备了涂层。在BEM用量为15.0%(以3种主单体St、BA和MMA总质量为基准,下同)的条件下,考察了3种乳化剂复配比例、缓冲剂(Na HCO_(3))加入方式对聚合稳定性、单体转化率的影响;在固定乳化剂复配比例、Na HCO_(3)全部随引发剂溶液同时加入的条件下,考察了BEM用量(0、5.0%、10.0%、15.0%、20.0%)对涂层光泽度和透光率的影响。采用FTIR、SEM、AFM表征了涂层的结构组成和表面形貌。结果表明,利用乳化剂与功能单体BEM长烷基链之间的疏水相互作用,通过复配乳化剂及随引发剂共同滴加缓冲剂Na HCO_(3)的方式,可提高聚合稳定性(絮凝率为0.38%)和单体转化率(≥98%)。利用长链烷基自迁移构建粗糙表面可提高涂层自消光性能,在BEM用量为20.0%时可保持高透光率(≥89%)和低光泽度(35.4%),实现了涂层消光性能和透光性能的统一。

微波辐射无皂乳液聚合法制备单分散交联PMMA微球及其性能研究

采用无皂乳液聚合法,以二乙烯苯为交联剂,氯化钾为电解质,过硫酸钾为引发剂,在微波辐射条件下制备了聚甲基丙烯酸甲酯(PMMA)微球。研究了过硫酸钾和氯化钾的物质的量浓度对PMMA微球的平均粒径和多分散性指数的影响,分析了微波功率、搅拌速度与PMMA微球形貌和粒径的关系。检测了不同pH值时PMMA乳液的电动(Zeta)电位,表明PMMA表面产生负电荷,使PMMA微球呈现稳定的分散状态。制备的PMMA呈现类球形,粒径为100~400 nm,在过硫酸钾物质的量浓度为5.69×10^(-3)mol/L及氯化钾物质的量浓度为1.03×10^(-2)mol/L时,微球的多分散性指数<0.1。原子力显微镜检测了最优工艺条件下,PMMA微球的力—位移曲线并分析了其弹性力学性能。

IBVE/AANa/VAc无皂乳液的合成与性能

本文以异丁基乙烯基醚、丙烯酸钠和醋酸乙烯酯为反应单体合成无皂乳液。研究了AANa的用量对乳液稳定性的影响,考察了VAc/IBVE的比例与聚合物性能的关系,同时分析了乳胶粒的形貌。结果表明,亲水性单体AANa对乳液的稳定性、粒径大小影响较大。调整反应单体VAc/IBVE的比例可以得到不同分子量、不同玻璃化转变温度的聚合物,该无皂乳液具有明显的核壳结构。

阳离子型苯丙乳液施胶剂的改性及物性研究

为改善阳离子型苯丙乳液施胶剂的环保性,采用来源广泛、成膜性好且易生物降解的明胶和壳聚糖进行复合改性,确定了壳聚糖用量为阳离子型苯丙乳液施胶剂质量的0.35%,明胶用量应不高于0.35%,重点研究了明胶用量对明胶-壳聚糖改性阳离子型苯丙乳液施胶剂的分散性、pH、表面张力和固含量等物性的影响,结果表明:随着明胶用量的逐渐增加,明胶-壳聚糖改性阳离子型苯丙乳液施胶剂的静置稳定性、离心稳定性高,分散性为一级,pH保持2.30不变,固含量变化大,而表面张力和纸张白度变化小。

聚丙烯酸酯无皂乳液的构建及对水性油墨性能的影响

以丙烯酸(AA)、丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、丙烯酸羟丙酯(HPA)、2-甲基丙烯酸羟乙酯(HEMA)、乙烯基三异丙氧基硅烷(A-173)为单体,过氧化苯甲酰(BPO)、过氧化苯甲酸叔丁酯(TBPB)为引发剂,合成了丙烯酸酯大分子乳化剂,再通过无皂乳液聚合法合成了聚丙烯酸酯无皂乳液,将其与颜料等混合制备了水性油墨。采用FTIR、DSC、TEM、SEM对聚合物的结构及性能进行了表征,考察了不同BPO用量对丙烯酸酯大分子乳化剂的影响,不同AA添加量对乳液及水性油墨的影响。结果表明:当BPO用量为单体总质量的4.18%时,丙烯酸酯大分子乳化剂具有最低表面张力40.43mN/m;当AA添加量为单体总质量的1.00%时,聚丙烯酸酯无皂乳液具有合格的储存稳定性,乳胶膜拉伸强度可达5.00 MPa,断裂伸长率为200%,玻璃化转变温度为18.5℃,所制备的水性油墨黏度为23.79mPa·s,附着牢度90.75%,耐摩擦性4.5级。

自交联疏水型丙烯酸树脂乳液的制备及性能

制备了封闭单体,并以丙烯酸十八酯(SA)、封闭单体、甲基丙烯酸异冰片酯(IBOMA)为主要原料,十八烷基三甲基氯化铵(1831)和脂肪醇聚氧乙烯醚(AEO-9)为乳化剂,采用乳液聚合方法制备了自交联疏水型丙烯酸树脂乳液。通过红外光谱、粒径、DSC、热重分析等对封闭单体及丙烯酸树脂乳液进行了表征,利用扫描电镜对丙烯酸树脂处理后的织物表面形貌进行了表征,分析了封闭单体解封温度,测定了织物表面的接触角及滚动接触角,研究了封闭单体用量及温度对织物表面丙烯酸树脂疏水性能的影响。结果表明,封闭单体的解封温度为87℃,当封闭单体质量分数为6%时制备的丙烯酸树脂乳液性能稳定,在织物表面接触角可达132.4°,防水性能良好。

高固含量聚丙烯酸乳液的合成与应用

探索合成固含量在50%以上的丙烯酸酯乳液,以甲基丙烯酸甲酯、丙烯酸乙酯、丙烯酸、苯乙烯、丙烯腈,丙烯酸丁酯、丙烯酸异辛酯等为混合单体,以K_(12)和S-90作为复合乳化剂,以过硫酸铵为引发剂制取聚丙烯酸酯乳液。通过改变预乳化的水量及控制条件、引发剂的用量、固含量的高低等条件进行多组实验,以探索各影响因素对乳液性能的影响,并筛选其最佳合成条件。实验还通过在乳液聚合完成之后,通过加入氧化还原体系引发剂,来处理乳液中的残留单体,筛选出各体系下氧化剂和还原剂的最佳用量比。实验发现采用还原剂FF6M和70%叔丁基过氧化氢氧化还原体系,当FF6M占乳液质量的比值约为0.2%,70%叔丁基过氧化氢占乳液质量的比值约为0.2%时,效果最佳。

辐射乳液聚合羧基型丙烯酸酯橡胶的性能评价

评价了辐射乳液聚合羧基丙烯酸酯橡胶的加工性能、力学性能、耐热空气老化性能、压缩永久变形以及耐油性能,并与国外牌号的丙烯酸酯橡胶进行性能对比。结果表明,辐射法丙烯酸酯橡胶加工性能优异,焦烧时间合适,硫化速度快,相对分子质量大,交联网络完整,其硫化胶力学性能和耐油性能优异;其热空气老化性能和压缩永久变形能与国外品牌丙烯酸酯橡胶媲美。

FT-IR Study on Crosslin king Reaction of Acrylates Copolymer Emulsions

Introduction The emulsion of acrylate copolymers with actively functional groups have been widely developed and used as coating, adhesive and handling agent in spinning and weaving industry. Bessett, D. R. et al. studied the thermoset of N-(isobutoxymethyl) acrylamide by thermal evolution analysis and thermal gas chromatogram. Krejcar,

STUDY ON THE FORMATION MECHANISM OF MONODISPERSE PARTICLES IN THE EMULSIFIER-FREE EMULSION POLYMEAIZATION OF METHYL METHACRYLATE AND BUTYL ACRYLATE

The formation mechanism of monodisperse polymer latex particles in the emulsifier-free emulsion polymerizationof methyl methacrylate and butyl acrylate with potassium persulfate as initiator was investigated. A multi-step formationmechanism for the monodisperse polymer particles was proposed. The nucleation mechanism is considered to be thecoagulation of the precursor particles by homogeneous nucleation when the primary particles reach a critical size with highsurface charge density and sufficient stability. It had been proved by a special experiment that the early latex particles formedby the coagulation were stable. The primary particles grow by absorbing monomers and radicals in the polymerization systemand then become colloidally unstable again due to the understandable decrease of particle surface charge density, which leadsto the aggregation of the growing particles and the formation of larger latex pedicles therefrom. Aner the nucleation period,the preferential aggregation of the smaller particles in the propagation process leads to the change of the particles towards auniform size and narrower particle size distribution. The coexistence and competition of homogeneous nucleation,coagulation, propagation and aggregation result in the increase of the polydispersity index (U = D_(43)/D_(10)) in the first Stage,then its decrease in the later stage because of the competition of propagation and aggregation, and the gradual formation ofthe monodisperse particles.

A Novel Fluorinated Acrylic Copolymer:Synthesis,Characterization,and Its Applications on Cotton Fabric

In order to prepare water-oil repellent and fire retardant textile finishing agent,1H,1H,2H,2H-perfluorooctyl acrylate(FA) and acryloyloxy-1,3-bis(diethylphosphoramidate)propan(BisDEAEPN) were copolymerized with 2-hydroxyethyl acrylate(HEA) and stearyl methacrylate(SMA) by emulsion polymerization to form fluorinated phosphorus-containing acrylate copolymer(PFPA).The copolymer was characterized by Fourier transform infrared spectroscopy(FT-IR) and the thermal stability was investigated by thermogravimetric analysis(TGA).The emulsion was applied on cotton fabric and the surface properties of treated fabric were studied.The treated surface showed good repellent properties as contact angle for water reached 145° and for n-dodecane 110° respectively.The surface also showed some flame retardant property with 22.5% of limited oxygen index(LOI).

PREPARATION AND STUDY ON SILICONE ACRYLATE MICRO-EMULSION OF MULTIPOLYMER

A silicone acrylate micro-emulsion of multipolymer was prepared by seed emulsion polymerization. The effects of polymerization process, emulsifier rate and amount, initiator rate and amount, polymerization temperature, functional monomers, titration time on performances of emulsion have been discussed in detail.