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介绍天然胶乳手套的起源和发展以及天然胶乳检查手套、外科手套、织物浸渍防护手套、家用手套、工业手套的用途、规格、特点和表面形式,指出因天然胶乳手套存在安全性能和使用性能的不足,促进了合成胶乳手套和人造胶乳手套的发展。丁腈胶乳检查手套因技术进步和成本降低成为天然胶乳检查手套的主要竞争者;低蛋白无粉天然胶乳外科手套、氯丁胶乳外科手套和聚异戊二烯胶乳外科手套成为对天然胶乳过敏症医护人员的选择;在非医疗领域,合成胶乳手套和人造胶乳手套适用于特殊领域的防护需求。 相似文献
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天然胶乳的电子束辐照硫化 总被引:1,自引:0,他引:1
使用低能量电子加速器电子束有利于降低天然胶乳的辐照硫化成本,但存在射线穿透力低的缺点,而采用转鼓方式,其电子束能量利用率要高于容器型辐照方式,且具有实用价值。 相似文献
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天然胶乳以及用成膜法将其制成的聚合物 ,具有某些合成材料无法比拟的宝贵性能 ,其中包括全顺式聚异戊二烯提供的物理性能。但是这种材料也有某些缺点。例如 ,用作压敏粘合剂时 ,如果干燥后聚合物受热 (如在激光打印机中 ) ,有时会失去粘合性能。此外 ,由于蛋白质过敏问题 ,使得天然胶乳在外科手术手套和避孕套中的应用越来越受到限制。本文提出了解决这些问题的方法。天然胶乳被用作一种人造聚合物进行第二步游离基乳聚的种子。在进行此种聚合时 ,必须注意或是通过确保可代替蛋白质的聚合物组分接枝到胶乳粒子外部 ,或是通过确保能改善聚合… 相似文献
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B. G. Osborne 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1986,36(8):364-366
Near infrared reflectance spectroscopy (NIR) is a rapid (50s) and non-destructive method of analysis of a wide variety of solid, semi-solid and liquid samples. Since no sample preparation is required for many sample types, particularly powders, NIR is an ideal technique for process control. The use of NIR to monitor the protein content of flour in order to optimise the milling conditions and the composition of the grist is described. Control of the blending of flours or supplementation with wheat gluten to achieve a composite flour of a given protein content is proposed. 相似文献
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Sulfur prevulcanization of natural rubber latex was conducted at 60, 70, 80, and 90°C for different periods. The extent of crosslinking was assessed. Tensile properties, water absorption, leaching, and stress-relaxation characteristics of the films were also evaluated. The volume fraction of rubber (Vr), which is a measure of crosslink density of the films, showed a maximum when prevulcanization was conducted at 80°C for 2 h or at 90°C for 1 h. At lower temperatures, the rate of reaction was slow. At each temperature, tensile strength and elongation at break decreased when the prevulcanization time increased, whereas the modulus increased up to a maximum crosslinking and thereafter decreased. Water absorption and leaching were more rapid in prevulcanized film than in postvulcanized film. The rate of stress relaxation slightly increased as the extent of prevulcanization increased. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1913–1920, 1997 相似文献
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The air‐aging process at 120°C and the thermooxidative degradation of peroxide prevulcanized natural rubber latex (PPVL) film were studied with FTIR and thermal gravity (TG) and differential thermal gravity (DTG) analysis, respectively. The result of FTIR shows that the ? OH and ? COOH absorption of the rubber molecules at IR spectrum 3600–3200 cm?1, the ? C?O absorption at 1708 cm?1, and the ? C? OH absorption of alcohol at 1105 and 1060 cm?1 increased continuously with extension of the aging time, but the ? CH3 absorption of saturated hydrocarbon at 2966 and 2868 cm?1, the ? CH3 absorption at 1447 and 1378 cm?1, and the C?C absorption at 835 cm?1 decreased gradually. The result of TG‐DTG shows that the thermal degradation reaction of PPVL film in air atmosphere is a two‐stage reaction. The reaction order (n) of the first stage of thermooxidation reaction is 1.5; the activation energy of reaction (E) increases linearly with the increment of the heating rate, and the apparent activation energy (E0) is 191.6 kJ mol?1. The temperature at 5% weight loss (T0.05), the temperature at maximum rate of weight loss (Tp), and the temperature at final weight loss (Tf) in the first stage of degradation reaction move toward the high temperature side as the heating rate quickened. The weight loss rate increases significantly with increment of heating rate; the correlation between the weight loss rate (αp) of DTG peak and the heating rate is not obvious. The weight loss rate in the first stage (αf1) rises as the heating rate increases. The final weight loss rate in second stage (αf2) has no reference to heating rate; the weight loss rate of the rubber film is 99.9% at that time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3196–3200, 2004 相似文献
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Hydrogenation is an important method of chemical modification, which improves the physical, chemical, and thermal properties of diene‐based elastomers. Natural rubber latex (NRL) could be hydrogenated to a strictly alternating ethylene–propylene copolymer using diimide generated in an in situ system. The diimide generated using the in situ technique for hydrogenation of NRL was accomplished by thermolysis of p‐toluenesulfonyl hydrazide (TSH). A molar ratio of TSH to double bonds equal to 2 : 1 was found to be the optimum ratio to provide a high percentage of hydrogenation. 95% Degree of saturation of NRL was achieved in o‐xylene. Hydrogenated products are characterized by FTIR and NMR spectroscopy. The thermal stability of hydrogenated rubber was improved as shown from the results of thermogravimetric analysis. From the differential scanning calorimetry measurement, the glass transition temperature of the hydrogenated product did not appear to change. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2885–2895, 2007 相似文献
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Using ultrafine calcium carbonate to reinforce natural rubber latex film, the effect of its content on latex properties such as surface tension, viscosity, mechanical stability, and heat stability and the physical properties of latex film before and after aging such as tear strength, modulus, and tensile strength were investigated. The results showed that the surface tension of natural rubber latex reinforced by ultrafine calcium carbonate only changed slightly; when the content of calcium carbonate was less than 20%, the change of viscosity was not obvious, but when the content was greater than 20%, the viscosity significantly lowered. Ultrafine calcium carbonate could effectively improve the tear strength, tensile strength, and modulus of the natural rubber latex film. The modulus increased with the increment of the calcium carbonate. When the content of calcium carbonate was less than 15%, the tear strength and tensile strength increased with the increments of calcium carbonate, but when the content was greater than 15%, the above‐mentioned properties decreased with the increment of calcium carbonate. By comprehensive consideration, the best reinforcing effect was obtained at a content of 15% ultrafine calcium carbonate. The particle diameters of calcium carbonate and their distribution in the calcium carbonate emulsion and in the rubber film were analyzed with SEM and a laser particle size tester, which showed that the distribution of calcium carbonate in the latex film was even and that it could effectively reinforce natural rubber latex film. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 982–985, 2003 相似文献
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