Si_3N_4增强LLDPE复合塑料的热导率

Applying Agari Theory to Raising Thermal Conductivity of Si_3N_4 Reinforced LLDPE Composites

用粉末混合法制备了导热型氮化硅(Si3N4)增强线性低密度聚乙烯(LLDPE)塑料,研究了聚乙烯内部填料含量、分散状态、LLDPE颗粒大小对体系热导率影响。研究结果表明Si3N4粒子在LLDPE基体中形成了有效的网状导热通路;提高填料用量,体系热导率升高,30 wt.%填料时体系热导率达1.42 W/(m.K),是基体热导率的7倍。Agari Y模型分析表明填料在大颗粒LLDPE基体中形成导热通路的能力高于小粒径聚乙烯体系。此外,使用Al2O3短纤维和Si3N4混杂填料能获得更高热导率。

Aim. We contracted to raise thermal conductivity of SigN4 reinforced LLDPE （linear low-density polyethylene） composites and applied the Agari theory to achieving it. In the full paper, we explain in some detail our experimental research and discuss the experimental results ; in this abstract, we just add some pertinent remarks to listing the two topics of explanation and discussion. The first topic is： experimental work. In this topic we prepare the LLDPE composites with the powder-mixing method. The second topic is. results and their discussion. Its three subtopics are： the effect of filler content on the thermal conductivity of LLDPE composites （subtopic 2.1）, the effect of particle size of the LLDPE on its thermal conductivity （subtopic 2.2） and the thermal conductivity of Si3N4/Al2O3/LLDPE composites （subtopic 2. 3）. In subtopic 2.1, we point out that the thermal conductivity of LLDPE composites increases with increasing filler content and reaches 1.42 W/m · K when the filler content is 30 wt. %, nearly seven times that of the LLDPE without filler. In subtopic 2.2, we use Fig. 3 in the full paper to show that the LLDPE composites of large particle size have higher thermal conductivity than those of small particle size. This is because LLDPE composites of large particle size can help filler particles to form effective thermal conductive networks of Si3N4 particles. In subtopic 2.3, we find that, as Fig. 4 shows, the joint use of Si3N4 particle filler and Al2O3 short-fiber filler results in a higher thermal conductivity than using Si3N4 filler alone owing to the synergetic effects of two fillers.