共查询到19条相似文献,搜索用时 281 毫秒
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以壬基酚、1,6-二溴己烷、氯磺酸为主要原料合成的阴离子Gemini磺酸盐表面活性剂9 B-6-9 B为乳化剂,苯乙烯(St)、丙烯酸丁酯(BA)为单体,合成了乳胶粒径小于100 nm且分布均匀的苯乙烯-丙烯酸丁酯共聚物纳米乳液,考察了聚合温度、乳化剂用量、引发剂用量、单体配比、单体含量对乳液的影响,探讨了乳胶粒子成核机理。结果表明,随着温度的升高,乳胶粒子的平均粒径减小,转化率与凝胶率增大;随着乳化剂或引发剂用量的增加,乳胶粒子的平均粒径和凝胶率减小,转化率增大;随着软单体比例的增加,乳胶粒子的平均粒径与转化率增大,粒径分布变宽,凝胶率减小;单体用量增大,乳胶粒子的平均粒径与凝胶率增大,转化率降低;乳胶粒子的粒径呈单峰分布,可能是按胶束成核机理形成的。 相似文献
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以甲基丙烯酸甲酯(MMA)为硬单体、丙烯酸丁酯(BA)为软单体、丙烯酸(AA)为功能单体和过硫酸铵为引发剂,采用不同的反应性乳化剂合成了固含量为50%~60%的丙烯酸酯无皂乳液。讨论了反应性乳化剂的种类及用量对无皂乳液性能及粒径等影响。结果表明:当反应温度为80~85℃、反应性乳化剂为烯丙氧基壬基酚聚氧乙烯硫酸铵(DNS-86)且w(DNS-86)=4%~5%时,无皂乳液的固含量高达60%左右、凝胶率几乎为零且粒径相对较小。 相似文献
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用半连续种子乳液聚合法制备了纳米级核/壳型聚(甲基丙烯酸甲酯-丙烯酸丁酯)[P(MA-BA)]乳液,保持水:单体:乳化剂:引发剂的质量比为60:40:1.5:0.3不变,考查了无丙烯酸存在下,反应温度、种子单体用量和壳层单体滴加速度等对核/壳型乳胶粒径的影响,结果表明适当提高反应温度、降低种子单体用量和降低壳层单体的滴加速度都可降低乳胶粒的粒径,当反应温度为85℃、种子单体占单体总量的10%和壳层单体滴加速度为0.23 mL/min时,可以获得粒径为74 nm,转化率为98.78%的P(MA-BA)乳液. 相似文献
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超高相对分子质量聚乙烯纤维粘合涂层用水乳型聚丙烯酸酯微乳液的合成 总被引:1,自引:0,他引:1
以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯酸(AA)及丙烯酸羟乙酯(HEA)为单体,以十二烷基硫酸钠(SLS)、OP-10和正辛醇的复合物为乳化剂,当m(BA)∶m(MMA)∶m(AA)∶m(HEA)=50∶50∶3∶10、w(乳化剂)=13%、反应温度为80℃及反应时间为3h时,合成了可用于超高相对分子质量聚乙烯纤维粘合涂层的水乳型聚丙烯酸酯微乳液,单体转化率为99 8%,乳胶粒径为30nm,乳液膜的玻璃化温度为-28℃,应用工艺简单,涂层粘附性好、柔软、耐磨。 相似文献
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乙烯基环四硅氧烷制备高硅含量硅丙乳液 总被引:3,自引:1,他引:2
以丙烯酸酯单体和四甲基四乙烯基环四硅氧烷(D4V1)为原料,采用种子乳液聚合法制备了以聚丙烯酸酯为核、聚丙烯酸酯-有机硅共聚物为壳的核-壳型高硅含量硅丙乳液.研究了引发剂、乳化剂、D4V1用量及反应温度对聚合反应的影响;并用IR、纳米粒度及Zeta电位分析仪对乳液及其乳胶膜进行表征.结果表明,最佳反应温度为75℃,引发剂、乳化剂(SDS与OP-10的质量比为1:1)的用量分别为单体总质量的0.3%、4%;在此条件下可制得有机硅质量分数达到20%以上(计算值)的硅丙乳液,且体系凝胶率低而单体的转化率较高,乳液的各项稳定性能较好,乳胶膜的吸水率小于20%.随聚合反应的进行,乳胶粒的粒径逐渐增大. 相似文献
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VAc/MA/AA三元无皂乳液共聚的研究 总被引:4,自引:1,他引:4
以过硫酸钾(KPS)为引发剂,对VAc/MA/AA三元无皂乳液共聚进行了研究。探讨了引发剂用量、功能单体用量(AA)对乳液稳定性、胶乳粒子粒径、粒径分布及胶乳粘度、粘接强度等性质的影响。结果表明: 引发剂用量小于单体总质量的0.7%时,随着KPS用量的增加,胶乳粒子粒径减小,粒径分布变窄;引发剂用量大于单体总质量的0.7%时,随着KPS用量的增加,胶乳粒径及分布都增大,KPS用量为单体总质量的6%时,单分散性好;共聚乳液的粒径随AA用量的增加而增加,粒径分布则随AA用量的增加而减小,乳液粘度随AA用量增大而降低,而粘接强度随AA用量增大而增加,耐水性下降。 相似文献
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Stable and high solid content (about 50 wt%) St/BA emulsifier-free latexes were successfully synthesized using emulsifier-free
emulsion polymerization with the addition of a small amount of reactive emulsifier AMPS. Properties of the latexes, such as
the average particle diameter and its distribution, the morphology of latex particles, and stability were investigated. Physical
properties of the latex films, i.e., glass transition temperature (T
g), water resistance, and solvent resistance were investigated as well. The size of latex particles is 400–600 nm in diameter,
which is larger than that prepared by conventional emulsion polymerization. And the particle size distribution is narrow and
uniform. It was found that the diameter of the latex particles decreases with the increasing content of the initiator KPS
and the reactive emulsifier AMPS. Compared with the film prepared by conventional emulsion polymerization, water resistant
and solvent resistant of the films prepared by emulsifier-free emulsion polymerization are improved greatly. 相似文献
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Yuhong Zhang Shanshan Pan Shulun Ai Hang Liu Haiping Wang Peixin He 《Iranian Polymer Journal》2014,23(2):103-109
The emulsifier-free emulsion polymerization of vinyl acetate (VAc) and butyl acrylate (BA) in the presence of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) was carried out by a semi-continuous process. AMPS was a reactive surfactant in the aqueous emulsion, due to its amphiphilic structure and the unsaturated double bonds. Potassium persulfate (KPS) was used as initiator. The following factors were mainly examined: quantity of AMPS, BA and KPS concentrations, which could significantly affect the particle size and its distribution, conversion, gel content, minimum film-forming temperature, etc. The particle size and its distribution were characterized by dynamic laser particle size analyzer, and morphology of the latex particles was characterized by transmission electron microscopy (TEM). Fourier transform infrared spectroscopy was used to characterize chemical structure of copolymers. The results indicated that AMPS was successfully reacted onto the resulted copolymer of vinyl acetate and butyl acrylate. A hydrophilic sulfonic acid group in the molecular structure of AMPS tended to be distributed in particles surface after polymerization. As a result, an electrostatic repulsion between the particles was produced in order to maintain stability of the system. Thermogravimetric analysis curves suggested that as BA content increased, thermal stability of the polymer increased accordingly. The conversion-time plots with varying AMPS and initiator contents were obtained, which illustrated that the initiator concentration could greatly influence the polymerization rate and the final conversion. The TEM micrographs of the final emulsifier-free latex particles for P(VAc/BA/AMPS) system revealed small particle size in monodisperse polymer latex. The particles of the latex were measured as about 150 nm. 相似文献
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采用种子乳液半连续法合成了具有高有机硅含量的聚硅氧烷/丙烯酸酯核壳结构复合乳液,研究乳化剂的种类、复配比例及质量浓度对有机硅/丙烯酸酯壳核乳液性能与乳胶粒径、分布和结构的影响.结果表明:阴离子乳化剂十二烷基硫酸钠(SDS)、十二烷基磺酸钠(SDS-2)、十二烷基苯磺酸钠(SDBS)所合成的乳胶粒子粒径依次增大,SDS与非离子型乳化剂OP-10复配使用时,随OP-10质量分数的增加,聚合速率和转化率降低,化学稳定性增加,乳胶粒子粒径增大,分布变宽,确定了复合乳化剂的最佳配比.随复合乳化剂浓度的增加,聚合速率加快、转化率增加,乳胶粒子粒径减小而分布加宽.通过改变乳化剂加入方式可减小乳胶粒子的粒径分布.为减少壳层聚合物新粒子的产生,需严格控制乳化剂的浓度,使加入的壳层单体处于“饥饿”状态,在乳胶粒子表面富集、引发聚合,形成表层“过渡层”,最终形成核壳结构复合粒子. 相似文献
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Role of acrylic acid in the synthesis of core‐shell fluorine‐containing polyacrylate latex with spherical and plum blossom‐like morphology 下载免费PDF全文
The core‐shell fluorine‐containing polyacrylate latex was successfully synthesized by two‐stage semicontinuous emulsion copolymerization of methyl methacrylate (MMA), butylacrylate (BA), acrylic acid (AA), and dodecafluoroheptyl methacrylate (DFMA). The fluorine‐containing polyacrylate latex was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC). The effects of AA content on monomer conversion, polymerization stability, particle size, corsslinking degree, carboxyl groups distributions (latex surface, aqueous phase or buried in latex), as well as mechanical properties and water absorption rate of latex film were investigated. The obtained fluorine‐containing polyacrylate latex exhibited core‐shell structure with a particle size of 120–150 nm. The introduction of AA was beneficial for the increase of monomer conversion and the polymerization stability, and had little effects on the mechanical property of latex film. However, the hydrophilicity of AA made the water resistance of latex film get bad. With the increase of AA content, the carboxyl groups preferred to distribute on aqueous phase, and the possibility of homogeneous nucleation increased and more oligomers particles were formed. Moreover, the oligomers would distribute to the latex and continued to grow up, making the latex morphology changed from spherical to plum blossom‐like. The core‐shell latex had two Tg corresponding to the rubber polyacrylate core and hard fluorine‐containing polyacrylate shell, and the latex film possessed excellent thermal stability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42527. 相似文献
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St-BA-BVP无皂共聚物阳离子乳胶粒大小及形态研究 总被引:1,自引:0,他引:1
合成阳离子共单体 1-丁基 ,4 -乙烯吡啶溴化铵 ( BVP) ,并以偶氮二异丁基咪盐酸 ( A IBA)作引发剂 ,制备苯乙烯 /丙烯酸丁酯 ( St/ BA )共聚物乳液 ,通过 TEM研究改变 BVP的浓度、St/ BA主单体的配比及单体加料方式对 P( St/ BA / BV P)乳胶粒大小形态的影响 ,结果表明批量法和单体全滴加法制备的乳胶粒形状规则、分布均匀、半连续法制备的乳胶粒子呈多分散分布 ,粒径相差很大 ,且 P( St) / P( BA)得到的乳胶粒呈明显的核壳结构。 相似文献
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Summary Stable organosilicon-acrylate copolymer latexes with high silicon content were prepared by seeded semibatch emulsion polymerization
of butyl acrylate (BA), methyl methacrylate (MMA) with a novel branched organosilicon monomer 3-methacryloxypropyl tris(trimethylsiloxy)
silane (MPTS). Monomer conversion, evolution of the particle size and its distribution were monitored by dynamic light scattering.
The effects of MPTS on the polymerization kinetics, the nucleation mechanism and properties of latex were investigated. The
results indicated that, in addition to micellar nucleation, a coagulative nucleation step was also observed as a result of
the addition of the organosilicon monomer, accordingly, the particle number of the silicon-acrylate latexes increased, the
average particle diameter decreased and the polymerization rate accordingly increased compared to those of the acrylate latexes
without organosilicon monomer. Moreover, the particle size distribution presented bimodal curves, which indicated that there
were large particles formed at an early stage. However, the particle size distribution curves became monomodal at the later
stage, and the final latex shows a narrow particle size distribution. It was found that the properties of latex and latex
film were obviously influenced by MPTS content. With increasing MPTS content, latex film glass transition temperature and
water absorption ratio decreased, the degradation temperature and water contact angle were increased. Hence, the resulting
latex films containing MPTS showed lower glass transition temperature and excellent water-resistance, which probably due to
the incorporation of the bulky branched hydrophobic group of MPTS into the copolymer chains. 相似文献
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Using large-sized and mono-dispersed seeded latex as medium plus a semi-continuous monomer-feeding technology was an effective
method for preparing high-solid content (HSC) latex. A series of runs indicated that the influence of key factors, such as
surfactant, monomer composition, seed particle size, reaction temperature, and feeding rate were the most sensitive issues
in maintaining the stability during preparation of HSC Poly (methyl methacrylate/n-butyl acrylate/acrylic acid) [P(MMA/BA/AA)] latex. It was also shown that the effect of these factors on the coagulum content
played an important role in preparation process. In addition, the amount of gel content was more related to re-nucleation
and particle size distribution (PSD) control. And the results seemed to be more different from that of produced in a low disperse
phase system by conventional semi-continuous emulsion polymerization. 相似文献