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 -hydrory- 1 -Propanesulfonate salt) wassynthesized to use in emulsifier-Ne emulsion polymerization of BA/BMa/MMA systemfor high solid content latexes. Storage stability klow behavior of the latexes,morphology of the obtained latex particles, dynamic viscoelastic behavior, tensilestrength and water resistance properties of the resulted copolymers were investigated.The experimental results show that with the addition of AHPS, stability of the emulsionis greatly improved that there appears no apparent precipitation dunring thepolymerization and storage at room temperature for 6 months and at -10℃ for fourmonths. Flow of the latexes follows the Bingham body laws, diameter of the latexparticles is about 0.6μn, of which is larger than that of by conventional emulsionpolymerization(0.12μm). In addition, not only water resistance of the copolymersobtained by emulsifier-free emulsion polymerization is greatly improved, but alsotensile 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。

硅烷改性环氧苯丙乳液的合成及性能研究

利用硅烷偶联剂KH-560和环氧E-51,通过种子乳液聚合的方法,对传统苯丙乳液进行有机硅与环氧树脂改性,制备了新型的硅烷改性环氧苯丙乳液,并探索了工艺条件对乳液性能和涂膜性能的影响。结果表明:乳化剂用量为6.5%、软硬单体比例为1.6∶1、环氧树脂E-51用量为5%、硅烷偶联剂KH-560用量为10%时,合成出的新型硅烷改性环氧苯丙乳液具有较高的固含量与转化率,分别为43.75%、87.5%,具有较低的凝胶率和吸水率,分别为0.98%、71.43%,乳液外观呈乳白带明显蓝相,乳液稳定性良好。初步研究了硅烷偶联剂KH-560和环氧树脂E-51对苯丙乳液的改性机理。

无氟拒水剂成膜表面形貌及其拒水性能研究

为考察无氟拒水乳液的成膜形貌对拒水性能的影响,将细乳液聚合得到的聚丙烯酸十八酯-丙烯酸丁酯[P(SA-BA)]胶乳分别与四种粒径的聚丙烯酸十八酯/γ-甲基丙烯酰氧基丙基三甲氧基硅烷[P(SA-A174)]胶乳按比例共混后,采用涂覆和浸轧两种工艺整理玻璃片和面料,以SEM和AFM考察了整理得到的两种基材表面形貌,并考察了对拒水性的影响。结果表明:P(SA-BA)和P(SA-A174)分别具有成膜和保型能力,二者复合而成的胶乳可形成具有纳米“指突”形貌的拒水膜,使整理基材的拒水性能明显提升。随着P (SA-A174)粒径的增大和用量的提高,涂层整理膜的“指突”高度和面密度同时增加,而浸轧整理时,仅“指突”高度增加,面密度和拒水性能变化不大。之后,通过降低浸轧液pH值,胶乳对织物亲和力以及吸附效率增强,浸轧整理织物拒水性能明显提升。

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。

纳米丁腈橡胶胶乳的制备与催化加氢

采用常规乳液聚合法结合低温间歇聚合工艺制备了丁腈橡胶胶乳,使用自制钌系催化剂对该胶乳进行乳液加氢,系统研究了催化剂用量和氢气压力对丁腈橡胶胶乳加氢效果的影响规律。结果表明,所制备丁腈橡胶胶乳的平均粒径为69.13 nm,加氢前后胶乳的粒径基本保持不变且胶乳稳定性良好;氢气压力越大催化加氢效果越好;当催化剂质量分数为0.017 5%时,可制得氢化度为99%以上且不含凝胶的产品。

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。

高取代度阳离子淀粉基苯丙乳液的合成和应用研究

以苯乙烯(St)、丙烯酸正丁酯(BA)、丙烯酸叔丁酯(tBA)为单体,H2O2-FeSO4为引发体系,高取代度阳离子淀粉(HCS)为乳化剂,开展了苯丙表面施胶剂的无皂乳液聚合。探讨了HCS的用量、分子量(以特性黏度表示)、取代度对乳液聚合的影响,使用多种方法评价了乳液的理化性能与应用性能。所制备得的高取代度阳离子淀粉基苯丙乳液胶粒平均粒径小(126.2 nm)、正电性强(Zeta电位为25.8 mV)、贮存稳定性优良;将其应用在瓦楞原纸上,施胶纸张的Cobb值为21.6 g/m^(2),水滴接触角达121.6°,与低取代度阳离子淀粉基苯丙乳液相比,其应用效果具有明显优势。研究对其能赋予纸张更佳施胶效果的原因也提出了机理性的解释。

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。