共查询到17条相似文献,搜索用时 366 毫秒
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改性浇铸尼龙的研究进展 总被引:1,自引:0,他引:1
立足于浇铸尼龙的反应机理,结合对其在实际应用中的改性要求,阐述了改性浇铸尼龙的研究进展.尤其以聚合物改性浇铸尼龙为重点,从改性的机理和相形态等方面详细地介绍了其的研究情况,总结了最新的工作以及将来的发展方向,为尼龙材料的更加广泛应用提供一定的参考. 相似文献
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合成了14种由三种含喹(哑心)啉环的芳香化合物改性的聚己内酰胺(MC尼龙),并对其形态、抗冲击强度、吸水性及熔融行为等进行了表征。聚苯基单醚喹(哑心)啉(PPQ)单模型化合物对MC尼龙结晶部分几乎没有影响。少量(0.005—5.0%)吩嗪的引入使MC尼龙的颜色、形态及性能等发生巨大变化,改性体系被认为是氢键相互作用,PPQ双模型化合物的改性作用介于二者之间。 相似文献
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合成了14种由三种含喹(哑心)啉环的芳香化合物改性的聚己内酰胺(MC尼龙),并对其形态、抗冲击强度、吸水性及熔融行为等进行了表征。聚苯基单醚喹(哑心)啉(PPQ)单模型化合物对MC尼龙结晶部分几乎没有影响。少量(0.005—5.0%)吩嗪的引入使MC尼龙的颜色、形态及性能等发生巨大变化,改性体系被认为是氢键相互作用,PPQ双模型化合物的改性作用介于二者之间。 相似文献
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三氯乙酸刻蚀法观测尼龙球晶形态 总被引:1,自引:0,他引:1
筛选出特效刻蚀剂——三氯乙酸溶液,建立了简便、可靠且十分有效的表征本体尼龙-6球晶形态的方法,借助SEM首次对MC尼龙及其改性样品的结晶形态进行了直接观测,三维结构的球晶清晰可见,球晶直径为几十微米.利用三氯乙酸及其溶剂与各种添加剂的物理或化学作用,可有效地研究改性尼龙的球晶缺陷. 相似文献
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无机纳米粒子在环氧树脂增韧改性中的应用 总被引:8,自引:0,他引:8
无机纳米粒子能够给聚合物赋以卓越的综合性能,为此,纳米材料在聚合物改性中的应用已成为聚合物改性领域中的一个研究热点。本文就近年来在环氧树脂增韧改性中应用的无机纳米粒子的种类、环氧树脂/无机纳米复合材料的制备方法及其应用研究进展进行了综述。 相似文献
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ZSM-5/Y复合分子筛的酸性及其重油催化裂化性能 总被引:23,自引:0,他引:23
ZSM-5/Y是本研究组合成的一种新型复合分子筛材料. 用“两次交换,两次焙烧”和磷
酸氢二铵浸渍方法对该复合分子筛材料进行了改性,采用红外光谱表征了复合分子筛的酸性,研究了磷改性对复合分子筛样品羟基区谱学性质的影响,并与相应的机械混合分子筛样品进
行了对比. 红外光谱数据表明,磷改性后复合分子筛的B酸(主要是中强酸)增加,而机械混合分子筛在各个酸强度区域的B酸量和L酸量都减少. 以新疆重油为原料考察了改性后复合分子
筛样品和机械混合分子筛样品的催化裂化性能. 与相应的机械混合分子筛催化剂相比,磷改
性复合分子筛催化剂具有较高的柴油选择性,其柴油产率增加了4.1个百分点,柴汽比增加了0.11,总轻油产率与机械混合分子筛相当. 用气体产物中的CMR(裂化机理比)和C3/C4比
值分析了复合分子筛的催化性能与其聚集体结构的关系. 相似文献
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Three polycaprolactam samples modified by 0.05—0.50% polybenzimidazole (PBI) by weight were prepared. Their structure and mechanical properties were characterized by means of FT-IR, SEM, DTA, density tensile, impact and viscoelastic method. PBI delayed the superimposed polymerization-crystallization process of the activated anionic polymerization of caprolactam. The monomer casting (MC) nylons modified by PBI had lower crystallinities, lower T_g and more nearly perfect spherulites than MC nylon itself, and showed a typical toughening effect. 相似文献
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All-silica zeolite frameworks doped with methylene and amine groups are studied using density functional theory-based electron structure calculations. Strain energies are calculated in a novel way, by comparing zeolite energies with appropriate polymer reference systems. The modified zeolites are found to be mechanically stable structures with surprisingly little strain. Distortions due to impurities result in broadened Si-O-Si angle distributions in the lattice surrounding defects. Our results suggest that zeolites can accommodate both methylene and amine groups at high concentrations with minimal strain. The amine-doped zeolites are strong Lewis bases suggesting novel applications in base catalysis. 相似文献
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Three polycaprolactam samples modified by 0.05—0.50% polyphenylquinoxaline(PPQ)by weight were prepared.Their structure and mechanical properties were characterized by FT-IR, SEM, density, tensile, impact, DTAand visco-elastic method, PPQ induced the formation of "crystal grains" distributed evenly over nylon spherulites in modified samples, which were observed for the first time, and strengthened modified samples. Modified nylons had higher crystallinities, higher T_g, more nearly perfect spherulites than MC nylon itself, and showed typical reinforcing effect on mechanical properties. 相似文献
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Thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses were used to investigate the effect of the acidity behaviour of Y zeolites on the catalytic degradation of polyethylene (PE). The acidity behaviour of these zeolites was modified by ion exchange treatments. Two Y zeolites with similar Si/Al atomic ratios were subjected to an ion exchange treatment using NaNO3 for H-form (HY) and NH4NO3 for Na-form (NaY). The activity and the deactivation behaviour of the Y zeolites were determined in the samples by TGA measurements, using a polymer/catalyst ratio of 9:1. The sample residues obtained after an isothermic TGA, were analysed by DSC, in order to evaluate the crystallinity of each mixture. The HY zeolite, which has the strongest acidity, reduced the onset temperature resulting in more rapid degradation of the polymer. It is shown that the ion exchange treatment over Y zeolites enhances the selective catalytic degradation of polymer in detriment of the rapid deactivation. 相似文献
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催化剂用量对MC尼龙合成、形态与性能的影响 总被引:7,自引:0,他引:7
本文通过改变催化剂用量合成了三个系列MC尼龙,对其球晶形态及部分性能进行了表征.引发剂和活化剂用量对聚合速度,单体转化率和产物熔融指数都有很大影响.为保证MC尼龙有优良的综合性能,催化剂用量须控制在一定的范围内,减少催化剂用量是提高其抗冲击强度的有效途径. 相似文献
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Functionalization of nylon membranes via surface-initiated atom-transfer radical polymerization 总被引:2,自引:0,他引:2
Xu FJ Zhao JP Kang ET Neoh KG Li J 《Langmuir : the ACS journal of surfaces and colloids》2007,23(16):8585-8592
The ability to manipulate and control the surface properties of nylons is of crucial importance to their widespread applications. In this work, surface-initiated atom-transfer radical polymerization (ATRP) is employed to tailor the functionality of the nylon membrane and pore surfaces in a well-controlled manner. A simple two-step method, involving the activation of surface amide groups with formaldehyde and the reaction of the resulting N-methylol polyamide with 2-bromoisobutyryl bromide, was first developed for the covalent immobilization of ATRP initiators on the nylon membrane and its pore surfaces. Functional polymer brushes of 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol)monomethacrylate (PEGMA) were prepared via surface-initiated ATRP from the nylon membranes. A kinetics study revealed that the chain growth from the membranes was consistent with a "controlled" process. The dormant chain ends of the grafted HEMA polymer (P(HEMA)) and PEGMA polymer (P(PEGMA)) on the nylon membranes could be reactivated for the consecutive surface-initiated ATRP to produce the corresponding nylon membranes functionalized by P(HEMA)-b-P(PEGMA) and P(PEGMA)-b-P(HEMA) diblock copolymer brushes. In addition, membranes with grafted P(HEMA) and P(PEGMA) brushes exhibited good resistance to protein adsorption and fouling under continuous-flow conditions. 相似文献
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Cheng-shen Zhu Xin Kang Su-qin He Liu-yang Wang Li-yun Lu College of Materials Engineering Zhengzhou University Zhengzhou China 《高分子科学》2002,(6):551-557
The montmorillonites (MMTs), layered, smectite-type silicates, were premodified by two different methods priorto the polymer melt intercalation. In one case MMTs were modified with cetyltrimethylammonium bromide (CTAB), andtermed as organomontmorillonites (OMMTs); in the other case MMTs were modified by nylon, and the products were calledmodified montmorillonites (MMMTs). The effects of CTAB and nylon on the MMTs were investigated by using TG andWAXD. The results show that interlayer spacings of CTAN and nylon modified MMTs are larger than that of sodium MMTs.Then, polyamide 66 (PA 66)/MMT nanocomposites were obtained through the method of melt intercalation of polymers. Thenanocomposites were characterized by WAXD, TEM and Molau experiments. The results indicate that the MMTs dispersehomogeneously in the PA 66 matrix. The mechanical properties of nanocomposites, such as tensile properties and flexuralproperties, were also measured and show a tendency to increase with increase of MMT content and reach the maximumvalues at 5phr MMT content. The heat distortion temperature (HDT) of the nanocomposites (7 phr) is about 32 K higher thanthat of pure PA 66. 相似文献