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首页> 外文会议>Automotive Fuel Containment Conference 2000 May 26, 2000 Birmingham, UK >The Processing and Peformance of Materials in Multi-Layer, Low Emission Automotive Fuel Lines
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The Processing and Peformance of Materials in Multi-Layer, Low Emission Automotive Fuel Lines

机译：多层低排放汽车燃油管线中的材料加工和性能

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This work presents the rheological properties and mechanical performance upon exposure to a standard test fuel of polymer materials recommended for the manufacture of low permeation automotive fuel line systems. These high performance tubing systems are co-extruded structures and therefore the melt viscosities of the various polymers entering the co-extrusion forming die must be similar in order to avoid flow instabilities in the different layers and so maintain asymmetry of the various layers in the final product. The rheological data shows that all the polymers investigated in this study exhibit grossly dissimilar viscosities at similar shear rates and temperature. In order to match viscosities of the polymer melts at the lower shear rates associated with extrusion ie 10 sec~(-1) to 100 sec~(-1) , changes in the melt temperature by up to 20℃ are required. The activation energy calculated from the rheological data shows that the viscosities of the various fluoropolymer barrier materials are far less sensitive to changes in temperature than the nylon outer layer and tie layer materials. Superimposed rheograms, i.e., Figure 8, of viscosities of the Hills system were used successfully to determine optimum processing conditions for triple layer tube extrusion. With regard to exposure to fuel C it has been shown that relatively high adsorption occurs. Values of up to 4.5% weight gain were recorded for some of the impact modified nylons. The results also show significant deterioration in mechanical properties for some of the impact modified nylons. The barrier materials PVdF and PBT were also investigated and reported in this paper. The results also indicate that there is only slight deterioration in overall mechanical performance after immersion of these materials at room temperature in Fuel C. The tie layer materials studied showed slight deterioration in mechanical performance after immersion in Fuel C. Although the recorded weight gain over the 42 day period of immersion was in the region of 3%. Dynamic Mechanical Thermal Analysis of the materials showed a significant decrease in Tg of up to 28℃ for the Nylon materials Vestamid X7293 and LX 9002. This depression in Tg was found to be related to the extent of uptake of Fuel C, thus indicating that it had a plasticising effect on the supermolecular structure and the mechanical performance of the materials.
机译：这项工作介绍了在推荐用于制造低渗透性汽车燃料管线系统的聚合物材料的标准测试燃料下的流变性能和机械性能。这些高性能的管道系统是共挤结构，因此进入共挤成型模具的各种聚合物的熔体粘度必须相似，以避免不同层的流动不稳定性，从而在最终阶段保持各个层的不对称性。产品。流变数据表明，在这项研究中研究的所有聚合物在相似的剪切速率和温度下均表现出完全不同的粘度。为了使聚合物熔体的粘度在与挤出相关的较低剪切速率下（即10 sec〜（-1）到100 sec〜（-1））相匹配，要求熔体温度变化最多20℃。根据流变数据计算出的活化能表明，各种含氟聚合物阻隔材料的粘度对温度变化的敏感性远低于尼龙外层和粘结层材料。 Hills系统粘度的叠加流变图（即图8）已成功用于确定三层管挤出的最佳加工条件。关于暴露于燃料C，已经表明发生了相对高的吸附。对于某些抗冲改性尼龙，记录的增重值高达4.5％。结果还表明，某些抗冲改性尼龙的机械性能明显下降。本文还对阻隔材料PVdF和PBT进行了研究和报道。结果还表明，将这些材料在室温下浸入燃料C中后，总体机械性能仅略有下降。研究的粘结层材料在浸入燃料C后显示出机械性能略有下降。浸泡42天的时间在3％左右。材料的动态机械热分析表明，尼龙材料Vestamid X7293和LX 9002的Tg最高降低了28℃。Tg的降低与燃料C的吸收程度有关，因此表明它对超分子结构和材料的机械性能具有增塑作用。

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