不同聚烯烃包覆石蜡的定形相变材料性能比较研究

Research on different polyolefin encapsulating paraffin as form-stable phase change materials

用乙烯-辛烯共聚物(POE)、乙烯-醋酸乙烯共聚物(EVA)取代高密度聚乙烯(HDPE)作为包覆材料,石蜡作为相变材料,通过热熔法制备了60%石蜡含量的定形相变材料(FSPCM),以此来提高定形相变材料的稳定性。用高温老化试验,恒温水浴试验和温度循环试验研究了定形相变材料的稳定性能。试验结果表明,POE/石蜡定形相变材料和EVA/石蜡定形相变材料的质量损失率远小于HDPE/石蜡定形相变材料的质量损失率。利用DSC研究了定形相变材料、石蜡及相应的基体树脂的热性能,并以此计算定形相变材料中实际的石蜡含量。结果表明,当设计含量为60%时,POE/石蜡定形相变材料和EVA/石蜡定形相变材料的实际石蜡含量为49.75%和58.49%,而HDPE/石蜡定形相变材料的仅为42.78%。这一结果与HDPE/石蜡定形相变材料样品在平板硫化机制备过程中发现有较多石蜡流出相一致。

Ethylene/octane copolymer（POE） and ethylene/vinyl acetate copolymer（EVA） were used to improve the stability of form-stable phase change material（FSPCM） instead of HDPE.The stability of FSPCM was investigated via high temperature aging test,constant temperature water bath test and temperature cycle test.The heat capacity of paraffin,FSPCM and relevant matrix were obtained respectively by the technique of differential scanning calorimetry（DSC）,in order to calculate the actual content of paraffin.The results showed that the weight loss rate of the FSPCM based POE and EVA were greatly less than the rate of the FSPCM based HDPE in three tests.The DSC test indicated that the actual paraffin content of the FSPCM with the design value（60%） in prescription was 49.75% based POE,58.49% based EVA,but 42.78% based HDPE.The results accorded with the phenomenon that more paraffin effused out of the HDPE/paraffin FSPCM than others FSPCM when it was processed in press vulcanize.