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51.
Polypropylene (PP) nanocomposites with three different clay loadings were prepared by solution mixing technique. The solution‐mixed nanocomposites were extruded to fibers using a single screw extruder. The PP nanocomposite fibers obtained were uniformly dyed with three distinct disperse dyes at different levels of shade. The enhanced dyeability of PP nanocomposite fibers was characterized by spectrophotometric measurements. Satisfactory wash, light and crock fastness results were also achieved. Mechanical properties and degree of crystallinity of nanocomposite fibers with different clay loadings were also investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
52.
Novel nanocomposite films of TiO2 nanoparticles and hydrophobic polymers having polar groups, poly (bisphenol‐A and epichlorohydrin) or copolymer of styrene and maleic anhydride, with high refractive indices, high transparency, no color, solvent‐resistance, good thermal stability, and mechanical properties were prepared by incorporating surface‐modified TiO2 nanoparticles into polymer matrices. In the process of preparing colloidal solution of TiO2 nanoparticles, severe aggregation of particles can be reduced by surface modification using carboxylic acids and long‐chain alkyl amines. These TiO2 nanoparticles dispersed in solvents were found not to aggregate after mixing with polymer solutions. Transparent colorless free‐standing films were obtained by drying a mixture of TiO2 nanoparticles colloidal solution and polymer solutions in vacuum. Transmission electronic microscopic studies of the films suggest that the TiO2 nanoparticles of 3–6 nm in diameter were dispersed in polymer matrices while maintaining their original size. Thermogravimetric analysis results indicate that the nanocomposite film has good thermal stability and the weight fraction of observed TiO2 nanoparticles in the film is in good accordance with that of theoretical calculations. The refractive index of nanocomposite films of TiO2 and poly(bisphenol‐A and epichlorohydrin) was in the range of 1.58–1.81 at 589 nm, which linearly increased with the content of TiO2 nanoparticles from 0 to 80 wt %. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
53.
Hydrophilic coatings based on 3‐glicidoxy propyl trimethoxy silane (GPTMS) and polyethylene glycol (PEG) were prepared with the incorporation of tetramethoxysilane (TMOS) and silica nanoparticle colloidal suspension by a sol–gel process. Characterization of the coatings has been performed by Fourier Transform Infrared (FTIR) and Attenuated Total Reflectance Infrared (ATR‐IR) techniques. Morphological properties were characterized by Scanning Electron Microscopy (SEM). The distribution of Si atoms in the hybrid system was obtained by Si mapping. The particle size in sol solution of the coating was measured by light scattering analyzer. Optical properties were characterized by using UV–vis spectrophotometer. The hydrophilicity of the coating was determined by contact angle measurements, and also the results have been confirmed by surface energy and water uptake investigations. The obtained results indicate that the surfactants affected the contact angles remarkably but did not change the transparency. It has been found that applying silica nano particles leads to coatings with different properties than those using TMOS, while siloxane contents were the same in these two set of coatings. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5322–5329, 2006 相似文献
54.
Konstantinos G. Gatos 《Polymer》2005,46(9):3069-3076
The effects of primary and quaternary amine modified montmorillonite (MMT) on the nanocomposite formation in an ethylene/propylene/diene rubber (EPDM) were studied. The organoclay was introduced in 10 parts per 100 rubber (phr) amount in the related recipes. X-ray diffraction spectra (XRD) were recorded in various stages of their processing in order to get information about the intercalation process. The curatives found to play a crucial role, as they promote the intercalation/exfoliation phenomena. Incorporation of MMT modified with octadecylamine (MMT-PRIM) in the EPDM and its more polar version (contains maleic anhydride grafted EPDM, EPDM-MA) resulted in intercalated and exfoliated structures, respectively. Deintercalation of the clay (collapse of the layers), generated in both EPDM and EPDM-MA during vulcanization, was attributed to the reactivity of the PRIM and to its ability to participate in complex formation with the curatives (vulcanization intermediates). This explanation was supported by the non-collapse of the MMT layers when the less reactive modifier, viz. octadecyltrimethylamine served as MMT intercalant (MMT-QUAT). In the latter case the corresponding nanocomposite contained mostly intercalated clay layers based on XRD and transmission electron microscopic (TEM) results. 相似文献
55.
56.
层状硅酸盐 /聚合物纳米复合材料的研究现状与前景 总被引:13,自引:0,他引:13
基于1996年以后的40余篇文献和作者的研究成果,综述了层状硅酸盐/聚合物纳米复合材料在制备技术、新品种、新性能、相关理论及应用等方面的最新研究进展,并总结出了以下观点:(1)粘土的有机化是制备纳米复合材料的第一关键要素,单体、预聚体、聚合物熔体与有机土的相容性是制备纳米复合材料的必要条件,外界剪切力可提供帮助;(2)剥离型结构最能体现层状硅酸盐/聚合物纳米复合材料的性能优势,是层状硅酸盐/聚合物纳米复合材料的制备方向;(3)聚合物熔体插层法为简单,是重要的发展方向,要形成剥离型结构,需要同时考虑热力学和动力学因素,基体或相容剂与层间环境的相容性要适中;(4)聚合物乳液共混共凝法有利于传统的制备方法,适合于具有乳液形成的聚合物;(5)在聚合物中原位生成硅酸盐片层的方法具有新意;(6)层状硅酸盐/聚合物纳米复合材料的主要特点是高刚性、高强度、高耐热性、高阻隔性、较好的阻燃性、质轻,目前,该的制备研究正向所有的聚合物品种扩展。汽车部件、包装材料将是层状硅酸盐/聚合物纳米复合材料先应用的两大领域;(7)层状硅酸盐/聚合物纳米复合材料的理论研究进展延慢。界面区状态以及结构-性能间的关系是理论研究的两个主题。 相似文献
57.
The grafting of acrylamide onto a chitosan backbone was carried out at three acrylamide concentrations (polymer/monomer ratio = 1:1, 1:2, and 1:3). The synthesis of the grafted polymer was achieved by K2S2O8‐induced free‐radical polymerization. Microspheres of polyacrylamide‐g‐chitosan crosslinked with glutaraldehyde were prepared to encapsulate nifedipine (NFD), a calcium channel blocker and an antihypertensive drug. The microspheres of polyacrylamide‐g‐chitosan were produced by a water‐in‐oil emulsion technique with three different concentrations of glutaraldehyde as the crosslinking agent. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were used to characterize the grafted copolymers, and the microspheres were prepared from them. FTIR and DSC were also used to analyze the extent of crosslinking. The microspheres were characterized by the particle size; the water transport into these microspheres, as well as the equilibrium water uptake, were studied. Scanning electron microscopy confirmed the spherical nature of the particles, which had a mean particle size of 450 μm. Individual particle dynamic swelling experiments suggested that with an increase in crosslinking, the transport became case II. The release of NFD depended on the crosslinking of the network and on the amount of drug loading. Calculating the drug diffusion coefficients with the initial time and later time approximation method further supported this. The drug release in all 27 formulations followed case II transport, and this suggested that the time dependence of the NFD release followed zero‐order kinetics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2940–2949, 2003 相似文献
58.
纳米复相陶瓷的烧结与普通陶瓷的烧结不同,在纳米复相陶瓷的烧结过程中需要采取相应的措施尽可能地控制晶粒的长大。目前,国内外研究者主要是通过改进传统烧结技术或采用新型烧结技术烧结制备纳米复相陶瓷。文章综述了目前国内外用的比较多的几种制备纳米复相陶瓷的烧结技术,并对其特点和应用情况进行了总结。 相似文献
59.
原位乳液聚合制备聚苯乙烯丁二烯橡胶/凹凸棒石纳米复合材料 总被引:6,自引:0,他引:6
采用原位乳液聚合制备了聚苯乙烯丁二烯橡胶(SBR)/凹凸棒石(AT)纳米复合材料。凹凸棒石的存在一定程度上降低了乳液聚合速率,但对最终聚合产物的分子质量及分子质量分布影响不大。凹凸棒石以长0.5~5μm、直径为20~50nm的棒状纤维均匀的分散在SBR基体中。在硫化过程中,凹凸棒石纤维与橡胶形成互穿网络结构,增加了橡胶的交联密度。随着凹凸棒石的填充量增加,纳米复合材料的300%定伸应力和拉伸强度与纯SBR相比均提高了20%~100%,其补强效果明显高于等量的炭黑N330,还表现出良好的耐磨性能。 相似文献
60.
Nanocomposites of epoxy resin with montmorillonite clay were synthesized by swelling of different proportions of the clay in a diglycidyl ether of bisphenol‐A followed by in situ polymerization with aromatic diamine as a curing agent. The montmorillonite was modified with octadecylamine and made organophilic. The organoclay was found to be intercalated easily by incorporation of the epoxy precursor and the clay galleries were simultaneously expanded. However, Na‐montmorillonite clay could not be intercalated during the mixing or through the curing process. Curing temperature was found to provide a balance between the reaction rate of the epoxy precursor and the diffusion rate of the curing agent into the clay galleries. The cure kinetics were studied by differential scanning calorimetry. The exfoliation behavior of the organoclay system was investigated by X‐ray diffraction. Thermogravimetric analysis was used to determine the thermal stability, which was correlated with the ionic exchange between the organic species and the silicate layers. The morphology of the nanocomposites was evaluated by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2201–2210, 2004 相似文献