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以纳米SiO2为核。以MMA为壳层单体,进行了无皂乳液聚合。研究了单体加入方式、引发剂用量、聚合反应温度等对无皂乳液聚合的影响。核壳产物对PVC材料的力学性能有明显的提高。 相似文献
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丙烯酸酯核壳乳液合成及涂料耐沾污性的研究 总被引:1,自引:0,他引:1
讨论了丙烯酸酯乳液核壳单体中软硬单体的比例、壳层中掺交联单体、有机硅单体以及核壳乳液聚合中可聚合乳化剂的用量对丙烯酸酯外墙涂料沾污性的影响。结果表明,在壳层中HEMA的掺量以1.5%、可聚合乳化剂用量以1%~2%、有机硅单体掺量以4%时,有利于丙烯酸酯核壳乳胶涂料耐沾污性的提高。 相似文献
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采用核-壳乳液聚合法合成了各以硬、软单体为壳的可剥离丙烯酸酯乳液.研究了壳层单体性质及用量对乳液涂膜力学性能、成膜性能、水接触角及吸水率等的影响,利用TEM观察了乳胶粒的形貌和尺寸,并运用DSC考察了该核-壳结构聚合物的玻璃化温度.结果表明:合成的乳胶粒大小较为均一,具有核-壳结构;以硬单体为壳的涂膜拉伸强度较高,附着... 相似文献
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采用种子乳液聚合法,以聚氨酯(PU)乳液为种子(在聚合过程中为壳相),甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、甲基丙烯酸十二氟庚酯(DFMA)和γ-甲基丙烯酰氧丙基三甲氧基硅烷(KH-570)改性的纳米SiO2组成的混合物为核相,合成了具有核壳结构的纳米SiO2/聚氨酯-含氟丙烯酸酯(SiO2/FPUA)复合乳液。考察了纳米SiO2和DFMA用量对乳液聚合过程及乳胶膜性能的影响。通过傅里叶红外光谱(FT-IR)、接触角(CA)、透射电子显微镜(TEM)、热重(TG)、差示扫描量热仪(DSC)和力学性能测试(MPT)等表征乳液的结构形态、乳胶膜的表面性能和综合性能。结果表明:乳胶粒子呈现“反相核壳”结构,以聚丙烯酸酯(PA)相为核,PU相为壳;由于纳米SiO2和DFMA的协同作用,涂膜的疏水性和综合性能得到了较大的提高。 相似文献
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纳米SiO2粒子对PP结晶行为的影响 总被引:6,自引:1,他引:6
通过X-射线光电子能谱(XPS)对经偶联剂处理的纳米SiO2粒子(简称烷基化SiO2纳米粒子)和聚甲基丙烯酸甲酯(PMMA)接枝包覆SiO2纳米粒子(简称SiO2-g-PMMA复合纳米粒子)的表面组成进行分析。将纳米SiO2粒子,烷基化SiO2纳米粒子,复合纳米粒子分别与基体PP复合制备复合材料,通过DSC,WAXD和TEM等测试方法详细研究了PP/SiO2复合材料的结晶行为与力学性能,结果发现:纳米SiO2粒子与烷基化SiO2纳米粒子并不改变基体PP的结晶形态,而复合纳米粒子诱发了基体PP的β晶型结晶,复合纳米粒子比较均匀地分散于PP基体中,对复合材料的力学性能有较大的改善。 相似文献
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用浓乳液双相法合成PBA,通过在合成过程中添加不同用量的DVB交联剂和MMA硬单体调节PBA粒子的硬度及性能,研究了不同DVB及MMA加入量的PBA对PVC力学性能的影响。并通过复合材料断面微观形态分析验证了实验结果。结果表明:在BA单体中加入硬单体MMA和交联剂DVB均可提高PBA粒子的硬度,当MMA和DVB用量较大时,会导致粒子呈现刚性,不利于PBA对PVC改性;PBA粒子与硬质PVC共混后能较好地分散在PVC中,并能在提高材料冲击强度的同时,拉伸强度也有所改善;DVB和MMA的用量均为2mL时,PBA异形粒子对硬质PVC的改性效果最好。此配方PBA粒子与PVC相容性好、界面结合力强。 相似文献
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可聚合乳化剂合成含氟丙烯酸酯无皂乳液及其性能 总被引:4,自引:2,他引:4
以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、甲基丙烯酸六氟丁酯(HFMA)等为主要原料,采用预乳化种子乳液聚合法合成了含氟丙烯酸酯无皂乳液,考察了可聚合乳化剂烯丙氧基壬基酚聚氧乙烯(10)醚硫酸铵(DNS-86)和HFMA的用量对无皂乳液的电解质稳定性和涂膜耐水性的影响。利用傅里叶红外光谱、差示量热扫描仪及热重分析对氟丙乳液涂膜进行了表征。结果表明:与传统乳液聚合得到的乳液及相应的涂膜相比,无皂乳液的耐电解质性能和涂膜的耐水性都有一定的提高,含氟单体有效地参与了聚合,涂膜的疏水性大大增强,耐热性显著提高。 相似文献
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The influences of polymerization temperature, initiator and monomer concentrations, ionic strength of the aqueous phase, as well as ethylene glycol dimethacrylate (EGDM) co-monomer, on the kinetics of the emulsifier-free emulsion polymerization of methyl methacrylate (MMA) and on the properties of the resulting poly(methyl methacrylate) (PMMA) lattices were studied. The polymerizations were carried out using potassium persulfate (KPS) as the initiator. Monodisperse PMMA lattices with particle diameters varying between 0.14–0.37 μm and polymer molecular weights of the order 0.4 × 106 to 1.2 × 106 g/mol were prepared. The initial rate of polymerization increases with increasing temperature, KPS-MMA mole ratio, EGDM content, or with decreasing ionic strength of the aqueous phase. It was shown that the bead size can be limited by reducing the monomer concentration or by using the cross-linking agent EGDM. The ionic strength of the aqueous phase has a dominant effect on final particle diameter and polymer molecular weight. The uniformity of the latex particles increases as the temperature increases or as the initiator concentration decreases. The experimental results can be reasonably interpreted by the homogeneous nucleation mechanism of the emulsifier-free emulsion polymerization of MMA. © 1996 John Wiley & Sons, Inc. 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