相变膨胀珍珠岩制备工艺及相变控温砂浆性能

Preparation of Phase Change Expanded Perlite and Its Temperature Control Performance

摘要:

根据低共熔相变点理论计算结果，制备月桂酸肉豆蔻酸二元低共熔脂肪酸相变材料，以膨胀珍珠岩为无机载体，采用高温真空浸渍法制备相变骨料，并对其进行包裹，确定最佳包裹材料及掺量.通过场发射扫描电镜观测相变骨料切割截面，脂肪酸经吸附进入多孔颗粒内部，并黏附于珍珠岩孔隙内壁，经石蜡包裹后脂肪酸相变材料较稳定地处于石蜡与膨胀珍珠岩内壁包围的孔空间内.利用相变骨料制备相变控温砂浆，测试其物理力学性能及热性能.结果表明：相变珍珠岩砂浆板物理力学性能达到建筑保温砂浆标准要求，且具有较好的控温效果，随着脂肪酸掺量的增加，有效热量值降低越多，温度延时越长，降温幅度越大.

Abstract:

The aim of this paper is to prepare dual low communion fatty acids phase change materials (PCM) with lauric acid (LA) and myristic acid (MA), according to the calculation results of low eutectic phase transition point theory. Using the vacuum absorption method, a eutectic mixture of lauric acid and myristic acid was incorporated with expanded perlite (EP), and the phase change aggregates were encapsulated with appropriate encapsulations. The cross section of phase change aggregate was observed using field emission scanning electron microscopy (SEM). It was discovered that the fatty acids were absorbed into the porous particle inside and adhered to the wall of perlite pore, and the fatty acids steadily existed in the space encircled by paraffin and expanded perlite inside wall. The LA MA eutectic mixture as PCM was confined in the porous EP by a mass fraction of 200%, and it demonstrated that paraffin was effective to encapsulate the LA MA/EP composite aggregates by a mass fraction of 60%, with less than 3% mass loss after the thermal cycle test, and just 4% mass loss after being soaked into the alkali solution. More PCMs can lead to a decrease of effective heat value, a longer temperature delay and a greater cooling extent. The physical and mechanical performances of the PCMs based mortar board can meet the requirements of the standards of building insulation mortar.