共查询到19条相似文献,搜索用时 62 毫秒
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单分散聚丙烯酸丁酯-二氧化硅核壳粒子的制备 总被引:3,自引:0,他引:3
近年来,有机-无机核壳材料因其具有可调的光、电、磁等特性而备受关注.无机物外壳可以增强粒子的热力学稳定性、机械强度和抗拉性能.高分子乳胶粒内核具有弹性,且易成膜,外部包覆无机物的乳胶粒可结合两者特性并产生协同效应. 相似文献
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硅丙型核壳结构乳胶粒子的制备及成膜过程 总被引:1,自引:0,他引:1
采用分步乳液聚合方法, 分别在不同步骤中将乙烯基硅氧烷单体作为共聚单体引入聚丙烯酸酯类乳液共聚合体系中, 制备出具有窄分布多层核壳结构形态的硅丙型乳胶粒子. 利用透射电子显微镜(TEM)表征, 乳胶粒子具有硅丙型核壳结构; 动态激光散射(DLS)分析得到的乳胶粒子的直径与TEM数据相符; 同时由多频调制差示扫描量热(TOPEM-DSC)技术分析得到的乳胶粒子的3个玻璃化转变温度与实验设计相符, 证实乳液粒子的核壳结构; 利用Horus成膜仪对乳胶粒子成膜过程进行全程监控. 利用多种助剂制得水性木器涂料, 其漆膜的硬度、耐丙酮性、耐水性、耐醇性及耐压痕等性能优异. 相似文献
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VAc/BA核壳乳液聚合乳胶粒形态演化 总被引:6,自引:0,他引:6
由两种单体分阶段种子乳液聚合制得的核壳型乳胶粒 ,可能存在着多种多样的形态 .由于不同的形态在使用中具有不同的性能 ,因此 ,核壳型乳胶粒的结构形态的研究一直受到人们的十分重视 .近年来 ,Sundberg[1] 等指出 ,正向、反向、两半球、两种孤立粒子等四种形态是热力学平衡形态 ,其他形态则是未达平衡的过渡形态 .并且提出用界面自由能最小的方法判别其中哪一种是最终平衡形态 .显然 ,自不平衡形态到平衡形态需要链迁移 ,Chen[2 ] 、Jonssen[3 ] 、Gonzalez[4] 等指出 ,链迁移的阻力是粘性力 .对于聚醋酸乙烯酯… 相似文献
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Soap-free hydrophilic-hydrophobic core-shell latex particles with high carboxyl content in the core of the particles were synthesized via the seeded emulsion polymerization using methyl methacrylate(MMA),butyl acrylate(BA), methacrylic acid(MAA),styrene(St)and ethylene glycol dimethacrylate(EGDMA)as monomers,and the influences of MMA content used in the core preparation on polymerization,particle size and morphology were investigated by transmission electron microscopy,dynamic light scattering and conductometric titration.The results showed that the seeded emulsion polymerization could be carried out smoothly using "starved monomer feeding process" when MAA content in the core preparation was equal to or less than 24 wt%,and the encapsulating efficiency of the hydrophilic P(MMA-BA-MAAEGDMA) core with the hydrophobic PSt shell decreased with the increase in MAA content.When an interlayer of P(MMAMAA -St)with moderate polarity was inserted between the P(MMA-BA-MAA-EGDMA)core and the PSt shell,well designed soap-free hydrophilic-hydrophobic core-shell latex particles with 24 wt%MAA content in the core preparation were obtained. 相似文献
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Dong-xia Huo~ 《高分子科学》2008,(1):39-45
A group of heterogeneous latexes poly(butyl acrylate)/poly(styrene-co-methyl methacrylate)(PBA/P(St-co-MMA)) were prepared by a semi-continuous seeded emulsion polymerization process under monomer starved conditions.The glass transition temperature(T_g)and the mechanical properties of the film formed from the composite latex changed with the evolution of the particle morphology.A photon transmission method was used to monitor the phase structure evolution of films which were prepared from core-shell PBA/... 相似文献
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近20年来,随着卤化银微晶合成技术的进步,合成出了诸如T-颗粒、核壳乳剂和外延复合颗粒乳剂等性能优异的微晶体,极大地提高了乳剂的感光性能.但这些乳剂也有一个共同的缺点,即大量消耗贵金属银,且未成影像的银均随定影过程而浪费.为改善此类乳剂的不足,各国科... 相似文献
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二氧化硅/聚苯乙烯单分散性核/壳复合球的制备 总被引:9,自引:0,他引:9
采用无皂乳液聚合包覆 ,制备了二氧化硅 聚苯乙烯单分散核 壳 (SiO2 PS)复合颗粒 ,包覆层厚度达到 10 0nm .选择 80~ 2 5 0nm二氧化硅粒径作为核颗粒 .为提高包覆效率 ,二氧化硅颗粒先用偶联剂甲基丙烯酰 (3 三甲氧基硅烷 )丙酯 (MPS)进行不同程度的表面改性 .控制MPS的结合率和单体的初始浓度可提高包覆效率 ,同时得到了单分散性复合颗粒 ,用透射电镜 (TEM)观察复合粒子的核 壳形态 .用动态光散射法 (DLS)测量表明所得复合颗粒具有单分散性 . 相似文献
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用于感光材料的卤化银微晶合成技术近二十年来取得了很大进展,合成出了诸如T-颗粒、核壳乳剂和外延复合颗粒等,使感光材料的性能日趋优异。但由于感光化学反应(如化学增感、光谱增感、潜影形成及显影过程等)基本上都发生在微晶的表面,而微晶核内部的卤化银却未发生作用,而随定影过程被溶解成废液,这样便造成贵金属银的浪费。 相似文献
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Rheology, morphology and mechanical properties of binary PE and EVA blends together with their thermal behavior were studied. The results of rheological studies showed that, for given PE and EVA, the interfacial interaction in PE-rich blends is higher than EVA-rich blends, which in turn led to finer and well-distributed morphology in PE-rich blends. Using two different models, the phase inversion composition was predicted to be in 45 and 47 wt% of the PE phase. This was justified by morphological studies, where a clear co-continuous morphology for 50/50 blend was observed. The tensile strength for PE-rich blends showed positive deviation from mixing rule, whereas the 50/50 blend and EVA-rich blends displayed negative deviation. These results were in a good agreement with the results of viscoelastic behavior of the blends. The elongation at break was found to follow the same trend as tensile strength except for 90/10 PE/EVA blend. The latter was explained in terms of the effect of higher co-crystallization in 90/10 composition, which increased the tensile strength and decreased the elongation at break in this composition. The results of thermal behavior of the blends indicated that the melting temperatures of PE and EVA decrease and increase, respectively, due to the dilution effect of EVA on PE and nucleation effect of PE on EVA. 相似文献
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聚烯烃共混物分散相尺寸梯度分布形态形成速度影响因素的研究 总被引:6,自引:1,他引:6
研究了聚烯烃高分子共混物的初始相形态及相间界面张力的改变对退火热处理条件下共混物分散相尺寸分布梯度形态形成速度的影响.通过控制共混物共混过程中Brabender转子的转速来控制共混物所受的剪切力大小,可达到控制共混物初始相形态的目的.通过SEM电镜观察相形态,并利用计算机图象分析仪得到分散粒子的粒径及其分布数据.研究结果表明,转子转速越大,即共混物所受的剪切力越大,分散相初始粒径越小,且分散也越均匀.初始粒径较小的样品退火后形成梯度的速度相对较快.选用体系聚丙烯(PP)/乙烯 醋酸乙烯酯共聚物(EVAc)、聚乙烯(PE)/EVAc及改变EVAc中的醋酸乙烯酯(VAc)含量与PE共混对比研究了不同相界面张力对梯度化速度的影响.结果表明,上述各体系退火热处理后均可形成梯度相形态,且相间界面张力越大.高分子共混物中梯度相形态形成速度也越快 相似文献