共查询到20条相似文献,搜索用时 15 毫秒
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世界聚酞胺市场主要在美国,年需求量超过100万吨,中国为48万吨,台湾为41.6万吨,这三个国家和地区的聚酞胺占总产量的50%。对于聚酞胺工业丝而言,2003年世界70多家尼龙6纤维的总产量达到82万吨,尼龙66纤维总产能估计为46万吨。 杜邦公司预计,目前世界PA66总产能(包括纤维和树脂)为260万吨,2003年产量约为230万吨(开工率为87%)。尼龙66纤维的产能为190万吨,其中81%来自中间体/纤维一体化生产商,独立生产商只有12%的产能,为21.9万吨/年,其中民用丝占43%、工业丝占42%,只有14%用作地毯丝。全球PA66市场为:地毯30%、民用丝27%、工业丝24%、… 相似文献
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Pravin L. Shah 《Polymer Engineering and Science》1994,34(9):759-764
This paper describes a new approach to the rheological characterization of engineering plastics such as nylon 6, 66, and 46 polyamides using a capillary rheometer. The melt viscosity data as a function of temperature, shear rate, and residence time were measured and evaluated to demonstrate how to accurately predict critical extrusion parameters, such as barrel temperature profile, stock temperature window, and the screw design requirements, for extruding strip, tubing, and profiles. The results of this work provide a practical and simple quality control tool to select a polyamide resin for optimum processing, and to develop critical processing parameters for extrusion. 相似文献
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D. W. Vere 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1988,43(4):373-378
To secure safety it is essential to know risks and to understand them. There are many problems in understanding risks related to drug effects. These include problems at the scientific level and among the community. The latter includes the singular problem that the general understanding of risk is of one kind, whereas the legal understanding of it is different. Examples are given and discussed of difficulties at each of these levels and some analysis made of ethical duty on the part of research workers, manufacturers and society at large in relation to each of them. 相似文献
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The literature on stain blockers, which are employed for reducing the staining of nylon fibres used in carpeting, has been reviewed. These compounds include the reaction products of sulphonated phenolic compounds and formaldehyde. They may be applied as a spin finish immediately after the extrusion of the nylon fibres or to the fibres after the carpets have been made. The composition of stain blockers, the methods of application to nylon fibre and the resulting properties are described. Mechanisms to explain the action of stain blockers are discussed. 相似文献
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Vibration welding of dissimilar nylons is a promising technique for assembling complex components made of different polymers. The effects of pressure and meltdown on the tensile strength of nylon 6 (PA 6) to nylon 66 (PA 66) vibration welds were determined in this study using an experimental design and three weld geometries. Weld strengths were generally improved by increasing meltdown and decreasing weld pressure. The weld strength was also shown to vary with the position of the lower melting material for T‐welds. Using differential scanning calorimentry and fracture surface analyses, it is concluded that for all geometries, higher weld strengths can be achieved when both materials are melted. Polym. Eng. Sci. 44:760–771, 2004. © 2004 Society of Plastics Engineers. 相似文献
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采用种子半连续乳液聚合的方法合成了苯丙乳液,采用傅里叶红外光谱(FTIR)、差示扫描量热法(DSC)等分析手段研究了聚合物的分子结构。FTIR和DSC表明,两种单体参与共聚反应,且没有均聚物的产生,共聚物的Tg约为36.42℃,明显高于理论值,显示了内交联作用的存在;该苯丙乳液的平均粒径为141.1 nm,且具有很好的单分散性。 相似文献
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以SEBS(氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物)和SEBS-g-MAH(马来酸酐接枝SEBS)为基体树脂、白油为增塑剂、滑石粉为填料和环氧树脂(EP)为改性剂,利用双螺杆挤出机共混挤出包覆料;然后以玻璃纤维增强尼龙6为被包覆料,采用二次注塑法将包覆料包覆在尼龙板上。通过单因素试验法优选出制备包覆料的较佳工艺条件。结果表明:当w(SEBS)=100%、w(SEBS-g-MAH)=30%、w(白油)=100%和w(滑石粉)=100%时,包覆料具有粘接力强、硬度适中、流动性较好和价格适宜等特点,并且EP的引入使包覆料的粘接机制发生了变化。 相似文献
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Narendiran Vitchuli Quan Shi Joshua Nowak Marian McCord Mohamed Bourham Xiangwu Zhang 《应用聚合物科学杂志》2010,116(4):2181-2187
Electrospun nylon 6 fiber mats were deposited on woven 50/50 nylon/cotton fabric with the motive of making them into protective material against submicron‐level aerosol chemical and biological threats. Polymer solution concentration, electrospinning voltage, and deposition areal densities were varied to establish the relationships of processing‐structure‐filtration efficiency of electrospun fiber mats. A high barrier efficiency of greater than 99.5% was achieved on electrospun fiber mats without sacrificing air permeability and pressure drop. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Interpretive nonlinear viscoelasticity: Dynamic properties of nylon 6, nylon 66, and nylon 12 fibers
Nonlinear response of nylon 6, nylon 66, and nylon 12 fibers to sinusoidal straining under relatively large strain amplitude is analyzed in terms of the changes in properties during the straining, i.e., the change in modulus, change in internal friction and change in structure which involves energy release or absorption in straining. Modulus generally increases with strain but it decreases with increase of strain amplitude, the effect of strain amplitude being largest with nylon 6 and smallest with nylon 66. Mechanical loss increase with the increase of strain amplitudes in nonlinear manner, and the magnitude of change is largest with nylon 66 and smallest with nylon 6. During the extension phase, structural change occurring in nylon 6 is predominantly an increase in order or orientation while that with nylon 66 is crack opening or cavitation. Various aspects of the experiments and analysis of the data are described in detail. 相似文献
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The impact failure of blends of nylon 6,6 and low density polyethylene grafted with maleic anhydride (PEgMA) is discussed in terms of fracture morphology, composition, and particle adhesion and dispersion. Basic criteria for effective impact modification of these materials are developed. A numerical model for estimating the extent of shear banding resulting from shear stress field overlap between neighboring impact modifier particles is presented. 相似文献
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Kazuhiko Hashimoto Mie Sudo Kazumi Ohta Takayuki Sugimura Hiroyuki Yamada Takayuki Aoki 《应用聚合物科学杂志》2002,86(9):2307-2311
The nylon4 portion in the blend films composed of nylon4 and nylon6 was degraded and completely disappeared within 4 months in two kinds of composted soils gathered from different university farms as well as pure nylon4 film reported previously, while the nylon6 portion remained even after the burial test for 15 months. Nylon4 powder was also degraded to carbon dioxide in the degradation test in an activated sludge obtained from a sewage disposal institution in Kogakuin University. Three species of microoganisms (i.e., ascomytous fungi) were isolated through the inoculation from the nylon4 film partially degraded in the soil on a medium containing nylon4 powder as a carbon source. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2307–2311, 2002 相似文献
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A polarised μ-FTIR study on a model system for nylon 6 6: implications for the nylon Brill structure
Polarised transmission FTIR microscopy studies (μ-FTIR) have been performed on a monodisperse 3-amide oligomer. The oligomer is a model compound for nylon 6 6; it has essentially the same room temperature crystal structure, and it undergoes the same high temperature transition, the Brill transition, prior to melting. However, the oligoamide forms extended chain, rather than chain-folded, crystals, and so crystals are produced that are essentially 100% crystalline, and of μm–mm size. Consequently, this material is ideally suited for polarised μ-FTIR single crystal studies. The thermal polarised FTIR behaviour of this material provides definitive proof that the Brill transition does not involve major rearrangement of hydrogen bonds, since the strong parallel polarisation of both the NH stretch and amide I bands are retained right up to melting. Quantitative infrared dichroism measurements indicate that a maximum of 5° rotation of the N–H bonds about the extended chain axis occurs prior to melting. These results strongly suggests that the equivalent Brill transition in nylon 6 6 also proceeds without significant hydrogen bond rearrangement. In addition we have investigated the behaviour of designated ‘Brill’, ‘crystalline’, ‘amorphous’ and ‘fold’ bands that are present in our spectra. 相似文献
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Crystalline nylon 66 was modified by blending with both an amorphous nylon and a rubbermodified amorphous nylon. The ternary blends exhibit a 50–100-fold decrease in fatigue crack propagation rates, even at rubber concentrations of only 1 or 2%. These same blends do not necessarily exhibit improved impact strength and the examination of a variety of alloys and blends demonstrates that fatigue and impact fracture mechanisms are distinctly different. The fracture surface morphologies indicate that the basic fatigue fracture mechanism of craze coalescence for nylon 66 is not changed by alloying. However, the presence of the rubbery phase leads to cavitation and ductile drawing that retard the craze breakdown and coalescence processes without evidence of crack tip blunting. Surprisingly, the addition of rubber-modified nylon 66 to a nylon 66 matrix does not impart as great an improvement in fatigue resistance as does the miscible amorphous nylon. Also, alloys having improved impact strength are observed to exhibit inferior fatigue resistance. These results demonstrate that the excellent fatigue resistance of crystalline polymers can be improved even further by judicious selection of alloying ingredients optimized specifically for fatigue fracture. © 1994 John Wiley & Sons, Inc. 相似文献
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The elastomer toughening of PA66/PA6 nanocomposites prepared from the organic modified montmorillonite (OMMT) was examined as a means of balancing stiffness/strength versus toughness/ductility. Several different formulations varying in OMMT content were made by mixing of PA6 and OMMT as a master‐batch and then blending it with PA66 and different elastomers in a twin screw extruder. In this sequence, the OMMT layers were well exfoliated in the nylon alloy matrix. The introduction of silicate layers with PA6 induced the appearance of the γ crystal phase in the nanocomposites, which is unstable and seldom appears in PA66 at room temperature and it further affected the morphology and dispersion of rubber phase resulting in much smaller rubber particles. The incorporation of POE‐g‐MA particles toughened the nanocomposites markedly, but the tensile modulus and strength were both reduced. Conversely, the use of OMMT increased the modulus but decreased the fracture toughness. The nanocomposites exhibited balanced stiffness and toughness. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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F. Chavarria 《Polymer》2004,45(25):8501-8515
Nylon 6 and nylon 6,6 organoclay nanocomposites were prepared by melt processing using a twin screw extruder. The effects of polyamide type and processing temperature on the mechanical properties and the morphology of the nanocomposites were examined. Mechanical properties, transmission electron microscopy (TEM), wide-angle X-ray diffraction (WAXD), percentage crystallinity and isothermal thermo-gravimetric analysis (TGA) data are reported. A particle analysis was performed to quantitatively characterize the morphology; these results are later employed in modeling the modulus of these materials using composite theory. No significant difference was observed in the mechanical properties and morphology of PA-6 nanocomposites processed at two different temperatures. PA-6 nanocomposites had superior mechanical properties than those made from PA-66. The tensile strength of PA-66 nanocomposites deviated from linearity at high levels of MMT. WAXD and TEM results show that the PA-6 nanocomposites are better exfoliated than the PA-66 nanocomposites, which exhibit a mixture of intercalated and exfoliated structures. Mechanical properties were consistent with the morphology. DSC reveals a higher percentage of crystallinity in the PA-66 samples. Isothermal TGA shows only a 5% difference in the degradation of the organic modifier on the organoclay processed at 240 °C versus 270 °C. Particle analysis shows a higher average particle length and thickness, and a lower average particle density and aspect ratio in nanocomposites based on PA-66 versus PA-6. The Halpin-Tsai and Mori-Tanaka composite theories predict satisfactorily the behavior of the PA-6 nanocomposites, while the PA-66 nanocomposites were predicted acceptably up to a certain volume fraction where the non-linear behavior takes effect. All the results indicate that there is a lower degree of exfoliation in the nanocomposites produced with a PA-66 matrix apparently stemming from the chemical differences between PA-6 and PA-66. 相似文献