多孔凝胶基碳纳米定形相变材料的制备与表征

Preparation and Characterization of Superporous Hydrogel/Carbon Nano Form-stable Phase Change Materials

为提高定形相变材料(PCM)基材的负载能力,以丙烯酸和丙烯酰胺为单体,采用泡沫聚合法,通过优化工艺参数制备出超大多孔水凝胶(SPH);并以SPH为基材,水为PCM,碳纳米材料〔氧化石墨烯(GO)和碳纳米管(CNTs)〕为添加剂,制备了两种多孔凝胶基碳纳米PCM(GO-H2O/SPH和CNTs-H2O/SPH)。对SPH和PCM的性能进行了表征。结果表明,通过优化工艺制备的SPH内部孔径在100~500μm,负载PCM的质量分数最高达95.7%。相变潜热从纯PCM的352.3 J/g下降到CNTs-H2O/SPH的337.1 J/g,仅下降4.3%。但SPH的加入使PCM的导热系数降低42.1%。加入GO和CNTs可提高PCM的导热系数及吸收和释放热能的速率。当GO和CNTs含量(以GO-H2O和CNTs-H2O质量为基准,下同)为0.200%时,与不含碳纳米材料的PCM相比,导热系数分别提高了91.5%和86.0%。PCM有良好的热循环稳定性,可循环使用。

In order to improve the load capacity of the substrate of form-stable phase change materials(PCM), superporous hydrogels(SPH) were prepared by a foam polymerization method using acrylic acid and acrylamide as monomer.And then two kinds of superporous hydrogel/carbon nano form-stable phase change materials(GO-H2 O/SPH and CNTs-H2 O/SPH) were prepared by using SPH as substrate, water as PCM and carbon nanomaterials, graphene oxide(GO) and carbon nanotubes(CNTs) as additives. The properties of SPH and form-stable PCMs were characterized. The results showed that the internal pore size of SPH was 100~500 μm. The mass fraction of load PCM was up to 95.7%. The phase change enthalpy decreased from 352.3 J/g of pure PCM to 337.1 J/g of CNTs-H2 O/SPH, which decreased by only 4.3%. However, the addition of SPH reduced the thermal conductivity of PCM by 42.1%. Adding GO and CNTs could increase the thermal conductivity and the rates of thermal charging and discharging of form-stable PCMs. When the dosage of GO and CNTs were 0.200%(based on the mass of GO-H2 O and CNTs-H2 O, the same below), the thermal conductivity of the prepared form-stable PCMs increased by 91.5% and 86.0%, respectively, compared with the form-stable PCM without carbon nanomaterials. The form-stable PCMs had good thermal cycle stability and could be recycled.