重载纤维模塑材料热压成型的水分传递过程
发布时间：2018-08-19 11:53
【摘要】：目的探究各工艺因素(热压温度、热压压力、初始含水率、定量)对重载纤维模塑材料水分传递过程的影响,揭示重载纤维模塑材料热压成型的水分传递机理。方法采用隔层设计测得纤维模塑板坯不同位置的水分变化;引入t检验与F检验法检验对称位置水分变化曲线的差异。结果热压过程中,水分在重载纤维模塑板坯中对称分布,水分变化可划分为2个阶段,即快速下降段(Q段)和集中汽化段(L段)。水分梯度主要发生在L段,其水分传递依次满足菲克第一定律的稳态扩散和菲克第二定律的非稳态扩散,扩散速率由表及里逐渐减慢。在Q段与L段,提高热压温度、增大热压压力或减小定量均能加快芯层水分下降速率,初始水分含量对水分下降速率无明显影响。结论热压过程中,重载纤维模塑材料由表及里先后完成干燥。降低初始含水率、提高热压温度、增大热压压力或减小定量均能缩短重载纤维模塑材料的干燥时长。
[Abstract]:Objective to explore the effect of various technological factors (hot pressing temperature, hot pressing pressure, initial moisture content, quantitative) on the moisture transfer process of heavy duty fiber moulding materials, and to reveal the water transfer mechanism of heavy duty fiber moulding materials. Methods the moisture changes in different positions of fiber moulded slabs were measured by the interlayer design, and the difference of the symmetrical position water change curves was tested by t test and F test. Results during hot pressing, water was symmetrically distributed in heavy duty fiber moulded slab, and the variation of water content could be divided into two stages, I. e., fast descending stage (Q section) and concentrated vaporization stage (L section). The moisture gradient mainly occurs in L region, and the water transfer satisfies the steady diffusion of Fick's first law and the unsteady-state diffusion of Fick's second law in turn, and the diffusion rate slows down gradually from the outside to the inside. In the Q and L section, increasing the hot pressing temperature, increasing the hot pressing pressure or decreasing the quantity of water in the core layer can accelerate the decrease rate of water content in the core layer, but the initial moisture content has no obvious effect on the decline rate of water content. Conclusion during hot pressing, the heavy-duty fiber molding materials are dried from outside to inside. Reducing the initial moisture content, increasing the hot pressing temperature, increasing the hot pressing pressure or decreasing the quantitative quantity can shorten the drying time of the heavy duty fiber moulding material.
【作者单位】： 东北林业大学;
【基金】：中央高校基本科研业务费专项(2572016AB69) 国家林业公益性行业科研专项(201304506)
【分类号】：TB484
本文编号：2191579
[Abstract]:Objective to explore the effect of various technological factors (hot pressing temperature, hot pressing pressure, initial moisture content, quantitative) on the moisture transfer process of heavy duty fiber moulding materials, and to reveal the water transfer mechanism of heavy duty fiber moulding materials. Methods the moisture changes in different positions of fiber moulded slabs were measured by the interlayer design, and the difference of the symmetrical position water change curves was tested by t test and F test. Results during hot pressing, water was symmetrically distributed in heavy duty fiber moulded slab, and the variation of water content could be divided into two stages, I. e., fast descending stage (Q section) and concentrated vaporization stage (L section). The moisture gradient mainly occurs in L region, and the water transfer satisfies the steady diffusion of Fick's first law and the unsteady-state diffusion of Fick's second law in turn, and the diffusion rate slows down gradually from the outside to the inside. In the Q and L section, increasing the hot pressing temperature, increasing the hot pressing pressure or decreasing the quantity of water in the core layer can accelerate the decrease rate of water content in the core layer, but the initial moisture content has no obvious effect on the decline rate of water content. Conclusion during hot pressing, the heavy-duty fiber molding materials are dried from outside to inside. Reducing the initial moisture content, increasing the hot pressing temperature, increasing the hot pressing pressure or decreasing the quantitative quantity can shorten the drying time of the heavy duty fiber moulding material.
【作者单位】： 东北林业大学;
【基金】：中央高校基本科研业务费专项(2572016AB69) 国家林业公益性行业科研专项(201304506)
【分类号】：TB484
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