石墨对改性挤塑聚苯乙烯泡沫板导热性能的影响

Influence of graphite on thermal conductivity of modified extruded polystyrene foam board

随着JC/T 2627—2021《建筑绝热用石墨改性挤塑聚苯乙烯泡沫板(GXPS)》行业标准的发布,石墨挤塑板由于较低的导热系数获得市场的青睐。采用扫描电子显微镜对石墨、石墨聚苯乙烯板、石墨挤塑板的微观形貌、泡孔尺寸进行观察,讨论了石墨掺杂量与导热系数的关系,分析了石墨挤塑板导热系数降低的原因。结果表明:石墨粒径分布在0.03~0.05mm范围,呈不规则片状结构,片状结构可以吸收和反射辐射传热的粒子;石墨掺杂量为3%(质量分数)时,石墨挤塑板导热系数最低;添加石墨后石墨挤塑板泡孔尺寸变小,增加了泡孔的比表面积,发泡气体的扩散变得缓慢;石墨挤塑板的微观形貌和石墨聚苯乙烯板基本相同,两者导热系数降低的原理相似。

With the release of the industry standard of JC/T 2627—2021“Graphite Modified Extruded Polystyrene Foam Board(GXPS)for Building Insulation”,graphite extruded polystyrene board is favored by the market due to its low thermal conductivity.The microscopic morphology and cell size of graphite,graphite polystyrene plate and graphite extruded plate were observed by scanning electron microscope,the relationship between graphite doping content and thermal conductivity was discussed,and the reduction of thermal conductivity of graphite extruded plate was analyzed.The results show that the particle size distribution of graphite is in the range of 0.03~0.05 mm,and it has an irregular flake structure.The flake structure can absorb and reflect the particles of radiation heat transfer;when the doping content of graphite is 3%,the thermal conductivity of the graphite extruded board is the lowest.After adding graphite,the cell size of the graphite extruded board becomes smaller,the specific surface area of the cell is increased,and the diffusion of the foaming gas becomes slow;the microscopic morphology of the graphite extruded board is basically the same as that of the graphite polystyrene,and the two conduct heat.The principle of coefficient reduction is similar.