A Basic Study on Material Selection Process from Waste Polymers Utilizing Unsteady Heat Conduction

本课题通过实验研究了聚合物颗粒与受热固体表面之间的粘着现象，从而对多种聚合物材料混合而成的废聚合物，利用不稳定热传导和聚合物与受热表面之间的粘着现象进行选材过程的基本认识。得到的结果总结如下：(1)研究了不同种类高分子材料在加热固体表面的粘附现象。结果表明，当被加热表面的初始温度超过一定温度（起热温度）时，聚合物与被加热表面之间的粘附现象就会变得明显，并且起热温度几乎对应于玻璃化转变温度或聚合物材料的熔体温度，因此不同类型的聚合物之间存在差异。这意味着各种材料的废聚合物可以利用粘着现象在每种材料中分离。(2)一般情况下，废聚合物表面可能有污垢或油漆。实验考察了污垢和涂料对粘接现象的影响。结果清楚地表明，聚合物颗粒表面的污垢导致粘着起始温度略有升高，但聚合物颗粒的粘着特性几乎不受污垢的影响。相反，涂料对聚合物颗粒的粘附特性有显著影响。粘起温度介于基材和涂料的粘起温度之间。(3)测量了不同聚合物材料和不同受热表面初始温度下聚合物颗粒与受热表面接触点处的界面温度。结果表明，在聚合物与受热表面黏附明显的情况下，界面温度略高于聚合物材料的玻璃化转变温度/熔融温度；这一结果表明，聚合物材料的粘着不仅受聚合物“软化”的支配，而且受接触点周围聚合物变形导致的接触面积扩大的支配。(4)详细测量了高分子材料在粘接起始温度前后的流变性能。结果表明，当聚合物的损耗正切值超过1时，聚合物与受热表面之间的黏附现象明显，在此条件下，存储/损耗模量约为10^6 Pa，且与聚合物材料的种类无关。少

In this research project, sticking phenomenon occurring between a polymer particle and a heated solid surface has been experimentally investigated, in order to obtain basic understandings about the material selection process from waste polymers, which are the mixture of various kinds of polymer materials, utilizing unsteady heat conduction and the sticking phenomenon occurring between the polymer and the heated surface. Obtained results are summarized as follows :(1) Sticking phenomenon of polymer particles occurring on a heated solid surface was investigated for various kinds of polymer materials. As the results, it was shown that the sticking between a polymer and a heated surface becomes evident when the initial temperature of heated surface exceeds a certain temperature (an onset temperature), and that the onset temperatures almost correspond to the glass-transition temperature or the melt temperature of polymeric materials and therefore differ for different kind of polymers. This … More means that the waste polymer of various kinds of materials may be separated in each material by utilizing the sticking phenomenon.(2) In general, waste polymer may have dirt or paint on its surface. Effects of the dirt or paint on the sticking phenomenon were experimentally examined. The results clearly showed that the dirt on the surface of polymer particles results in a slight rise of the sticking onset temperature, but that the sticking characteristics of polymer particles are hardly influenced by the dirt. To the contrary, paint on the polymer particles markedly affects the sticking characteristics. The sticking onset temperature becomes the middle of those for the base polymer and for the paint material.(3) The interface temperature at the contact point between a polymer particle and a heated surface was measured for various polymer materials and for various initial temperature of the heated surface. The results showed that, under the condition that the sticking between a polymer and a heated surface becomes evident, the interface temperature is a little bit higher than the glass-transition temperature/melt temperature of the polymer material. This results suggests that the sticking of polymeric materials is dominated not only by the "softening" of the polymer, but also by the enlargement of contact area due to deformation of polymer around the contact point.(4) Rheological properties of polymeric materials were measured around the sticking onset temperature in detail. It was shown that the sticking between a polymer and a heated surface becomes evident when the loss tangent of the polymer exceeds unity, and that under the condition the values of storage/loss moduli are about 10^6 Pa and are independent on the kind of polymer materials. Less