共查询到19条相似文献,搜索用时 171 毫秒
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利用纳米SiO2粒子所具有的特殊性能,研制出新的有机硅基纳米SiO2防护涂料.纳米SiO2粒子在有机硅中的分散和稳定性问题是制备纳米SiO2有机硅涂料的关键.为了解决纳米SiO2粒子在有机硅中的分散性和稳定性,对纳米SiO2粒子进行了表面改性处理,从而改变了纳米SiO2粒子表面的理化性能,同时利用物理分散和化学分散相结合的方法进行纳米SiO2在有机硅涂料中的分散,采用适合的制造工艺制备纳米SiO2有机硅涂料.通过透射电镜(TEM)、傅立叶变换红外光谱(FTIR)等技术分析了纳米SiO2粒子在有机硅涂料中的分散性和稳定性. 相似文献
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SiO2粒径对PP发泡行为和力学性能的影响 总被引:1,自引:0,他引:1
通过把改性过的不同粒径SiO2以不同用量加入到聚丙烯(PP)中,制备PP/SiO2复合材料母粒,在二次开模条件下制备微发泡PP/SiO2复合材料.通过对不同粒径的SiO2粒子对PP纳米复合材料发泡行为的影响研究,讨论了超细SiO2在聚合物微孔发泡中的作用机理,分析了超细SiO2对PP的力学性能及泡孔结构的影响规律.结果表明,不同粒径的SiO2粒子的加入都能够显著降低PP的泡孔直径和增加泡孔密度;SiO2粒子使PP的缺口冲击强度升高,发泡材料的拉伸强度低于未发泡材料的拉伸强度. 相似文献
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反应体系组成对纳米SiO2/PS复合粒子粒径及分布的影响 总被引:1,自引:1,他引:0
研究了在纳米SiO2粒子表面的苯乙烯原位聚合反应中,反应体系的组成(单体、引发剂、稳定剂及纳米SiO2粒子用量)对纳米SiO2/PS复合粒子的形态、粒径大小及分布的影响。结果表明,当纳米SiO2粒子与单体质量比为5%,苯乙烯质量分数为25%,引发剂及稳定剂用量分别为单体用量(质量比)的0.15%和1.5%时,制备出的纳米SiO2/PS复合粒子呈球形,表面光滑无明显缺陷,颗粒之间分散性很好,粒径为0.923μm,分散系数为0.108。 相似文献
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采用不同硫化体系动态硫化制备三元乙丙橡胶/聚丙烯热塑性硫化胶(EPDM/PP TPVs),并在制备的过程添加不同量的纳米SiO2。结果表明酚醛树脂2402动态硫化得到的EPDM/PP TPVs性能最佳。随着纳米SiO2添加量的增加,EPDM橡胶粒子的粒径先减小后增大,当纳米SiO2的添加量为10份时,EPDM橡胶粒子的粒径达到最小。流变性能研究表明添加纳米SiO2使EPDM/PP TPVs的加工性能变差。动态机械分析仪(DMA)研究表明纳米SiO2提高了TPVs中PP相的玻璃化转变温度。当纳米SiO2的添加量为10份,TPVs的拉伸强度达到最高为23.7MPa,提高了19.1%,断裂伸长率达到最大为431%,提高了11.1%。纳米SiO2使EPDM/PP TPVs的热稳定性和耐热老化性能变好。 相似文献
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PP/纳米SiO2/POE复合材料的研究 总被引:8,自引:2,他引:8
采用熔融共混法制备PP/纳米SiO2/POE复合材料,并通过力学性能测试、DSC分析以及材料断面形貌分析等手段,对增强增韧效果进行研究.结果表明纳米SiO2和POE微粒显现了比较明显的协同增韧效果,当PP/纳米SiO2/POE为100/4/15时,综合力学性能最优.纳米SiO2的成核作用提高了PP的结晶温度和结晶速率.两种微粒在PP基体中达到均匀分散,其中纳米SiO2粒子平均粒径为150nm,与其二次粒子直径相当,表明熔融过程并未造成纳米粒子的团聚. 相似文献
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Oleic acid (OA)-modified CaCO3 nanoparticles were prepared using surface modification method. Infrared spectroscopy (IR) was used to investigate the structure of the modified CaCO3 nanoparticles, and the result showed that OA attached to the surface of CaCO3 nanoparticles with the ionic bond. Effect of OA concentration on the dispersion stability of CaCO3 in heptane was also studied, and the result indicated that modified CaCO3 nanoparticles dispersed in heptane more stably than unmodified ones. The optimal proportion of OA to CaCO3 was established. The effect of modified CaCO3 nanoparticles on crystallization behavior of polypropylene (PP) was studied by means of DSC. It was found that CaCO3 significantly increased the crystallization temperature, crystallization degree and crystallization rate of PP, and the addition of modified CaCO3 nanoparticles can lead to the formation of β-crystal PP. Effect of the modified CaCO3 content on mechanical properties of PP/CaCO3 nanocomposites was also studied. The results showed that the modified CaCO3 can effectively improve the mechanical properties of PP. In comparison with PP, the impact strength of PP/CaCO3 nanocomposites increased by about 65% and the flexural strength increased by about 20%. 相似文献
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PP/SBS/纳米CaCO3复合材料结构与性能研究 总被引:5,自引:2,他引:5
研究了PP/SBS/纳米CaCO3复合材料的力学性能以及SBS分散相颗粒和纳米CaCO3粒子在PP基体中的分散状况。结果表明,纳米CaCO3粒子的加入使复合材料的缺口冲击强度、弯曲弹性模量、拉伸强度均得到提高。透射电镜观察发现,纳米CaCO3粒子的加入使复合体系的熔体黏度增大,对弹性体SBS的分散起到剪切细化、均化的作用,从而起到协同增韧效应。 相似文献
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Oleic acid (OA)-modified CaCO3 nanoparticles were prepared using surface modification method. Infrared spectroscopy (IR) was used to investigate the structure of the modified CaCO3 nanoparticles, and the result showed that OA attached to the surface of CaCO3 nanoparticles with the ionic bond. Effect of OA concentration on the dispersion stability of CaCO3 in heptane was also studied, and the result indicated that modified CaCO3 nanoparticles dispersed in heptane more stably than unmodified ones. The optimal proportion of OA to CaCO3 was established. The effect of modified CaCO3 nanoparticles on crystallization behavior of polypropylene (PP) was studied by means of DSC. It was found that CaCO3 significantly increased the crystallization temperature, crystal-lization degree and crystallization rate of PP, and the addition of modified CaCO3 nanoparticles can lead to the for-mation of β-crystal PP. Effect of the modified CaCO3 content on mechanical properties of PP/CaCO3 nanocompo-sites was also studied. The results showed that the modified CaCO3 can effectively improve the mechanical proper-ties of PP. In comparison with PP, the impact strength of PP/CaCO3 nanocomposites increased by about 65% and the flexural strength increased by about 20%. 相似文献
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Polypropylene (PP)/layered double hydroxide (LDH) nanocomposites were prepared via melt intercalation using dodecyl sulfate anion modified LDH and maleated PP as compatibilizing agent. Evidently the interlayer anions in LDH galleries react with maleic anhydride groups of PP-g-MA and lead to a finer dispersion of individual LDH layers in the PP matrix. The nanostructure was characterized by XRD and TEM; the examinations confirmed the nanocomposite formation with exfoliated/intercalated layered double hydroxides well distributed in the PP matrix. The nonisothermal crystallization behavior of resulting nanocomposites was extensively studied using differential scanning calorimetry (DSC) technique at various cooling rates. In nonisothermal crystallization kinetics, the Ozawa approach failed to describe the crystallization behavior of nanocomposites, whereas the Avrami analysis and Jeziorny method well define the crystallization behavior of PP/LDH nanocomposite. Combined Avrami and Ozawa analysis (Liu model) also found useful. The results revealed that very small amounts of LDH (1%) could accelerate the crystallization process relative to the pure PP and increase in the crystallization rates was attributed to the nucleating effect of the nanoparticles. Polarized optical microscopy (POM) observations also support the DSC results. The effective crystallization activation energy was estimated as a function of the relative degree of crystallinity using the isoconversional analysis. Overall, results indicated that the LDH particles in nanometer size might act as nucleating agent and distinctly change the type of nucleation, growth and geometry of PP crystals. 相似文献
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In this study, various polypropylene (PP) nanocomposites were prepared by melt blending method. The effects of different spherical nanofillers, such as 50 nm CaCO3 and 20 nm SiO2, on the linear viscoelastic property, crystallization behavior, morphology and mechanical property of the resulting PP nanocomposites were examined. Rheological study indicated that coincorporation of nano‐SiO2 and nano‐CaCO3 favored the uniform dispersion of nanoparticles in the PP matrix. Differential scanning calorimeter (DSC) and polarizing optical microscopy (POM) studies revealed that the coincorporation of SiO2 and CaCO3 nanoparticles could effectively improve PP crystallizability, which gave rise to a lower supercooling temperature (ΔT), a shorter crystallization half‐life (t1/2) and a smaller spherulite size in comparison with those nanocomposites incorporating only one type of CaCO3 or SiO2 nanoparticles. The mechanical analysis results also showed that addition of two types of nanoparticles into PP matrix gave rise to enhanced performance than the nanocomposites containing CaCO3 or SiO2 individually. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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以溴化苄为疏水改性剂,采用双分子亲核取代反应(SN2)制得苄基接枝海藻酸衍生物(BAD)。通过动态光散射技术,考察了在不同p H和离子强度下BAD对Ti O_2纳米粒水悬浮液分散稳定性的影响。并采用红外光谱和扫描电镜对BAD/Ti O_2纳米粒复合物的官能团和表面形貌进行了测试。结果表明,通过SN2反应成功地合成了具有胶体性能的BAD。BAD胶束的平均水动力学粒径(dH)大小为423.4 nm,Zeta电位值为-27.4 m V,表现出较好的胶体性能。在不同p H下,BAD的吸附可提高Ti O_2纳米粒的带电性,使其Zeta电位均低于-30 m V,而且其dH相比单一的Ti O_2纳米粒显著减小。在不同离子强度下,BAD可明显削弱反离子对Ti O_2纳米粒静电屏蔽作用的影响,使Ti O_2纳米粒的团聚行为大大降低,dH显著减小。BAD分子链不仅能够提高Ti O_2颗粒间的静电斥力,而且还能提供有效的空间位阻,提高Ti O_2纳米粒在不同p H和离子强度下的分散稳定性。红外和扫描电镜分析结果表明,BAD和Ti O_2纳米粒主要通过氢键作用来实现BAD在Ti O_2纳米颗粒上的吸附,从而提高Ti O_2纳米颗粒间的空间位阻作用使其稳定分散。 相似文献
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Baljinder K. Kandola Gillian Smart A. Richard Horrocks Paul Joseph Sheng Zhang T. Richard Hull John Ebdon Barry Hunt Andy Cook 《应用聚合物科学杂志》2008,108(2):816-824
The dispersion of nanoclays in nonpolar polypropylene (PP) is difficult without the use of a small fraction (1–3%) of modified grafted PP as a compatibiliser. This work reports the effect of different graft‐modified polypropylenes on the dispersion of nanoclays in PP, and thermal stability and flammability of the blends. PP has been compounded in a Brabender compounder with a selection of modified PP polymers as compatibilisers. The grafts include maleic anhydride, N‐ethylmaleimide, diethylmaleate, diethyl‐p‐vinylbenzyl phosphonate, and acrylic acid‐2‐[(diethoxyphosphoryl)methylamino] ethyl ester. Films were cast from the blends by compression molding and the nanocomposite structures assessed using X‐ray diffraction. Thermal characterization was performed using DSC and TGA, the burning behavior was observed using limiting oxygen index measurements, and cone calorimetry where samples were exposed to 35 kW/m2 external heat flux. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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Weitao Wan Demei Yu Xiusheng Guo Yunchuan Xie 《Polymer-Plastics Technology and Engineering》2013,52(4):433-442
Polypropylene (PP)/CaCO3 nanocomposites were prepared by melt-blending method using a Haake-90 mixer. The CaCO3 nanoparticles were surface modified with a coupling agent before compounding. A fine dispersion of the modified nanoparticles in the nanocomposites was observed by transmission electron microscopy (TEM). Effects of surface treatment of CaCO3 nanoparticles on the nonisothermal crystallization behavior and kinetics of PP/CaCO3 nanocomposites were investigated by differential scanning calorimetry (DSC). Jeziorny and Mo methods were used to describe the nonisothermal crystallization process. It was shown that the crystallization temperature of the nanocomposites increased due to the heterogeneous nucleation of the surface-treated nanoparticles. It was found that the nanoparticles modified with a proper content range of coupling agent could facilitate the nonisothermal crystallization of the nanocomposites under certain conditions (the cooling rate and the relative degree of crystallinity). This may be a potential application for the crystallization controlling of composites in manufacturing. In addition, the activation energy of crystallization for the nanocomposites and the nucleation activity of the nanoparticle were estimated by using Kissinger and Dobreva's methods, respectively. It could be concluded that the surface-treated nanoparticles had a strong nucleating activity, which caused the decrease of the activation energy of the nanocomposites. 相似文献