为了提升相变大胶囊导热性能,拓展相变材料应用范围,通过将石墨烯与海藻酸钠、相变微胶囊共混,并由钙离子交联后制得石墨烯改性相变大胶囊。通过拉曼光谱、扫描电镜表征石墨烯改性相变大胶囊组分及微观结构,通过差式扫描量热仪分析其相变储能性能,并比较了石墨烯改性后样品导热系数的变化。结果表明:石墨烯改性相变大胶囊是由海藻酸钠凝胶连接成簇相变微胶囊,并由石墨烯穿插其中。制备的石墨烯改性相变大胶囊包覆率为58.8%～63.6%,相变潜热为112.5～121.7J/g范围内,石墨烯的添加对相变大胶囊包覆率、相变潜热及相变温度影响不显著。经过石墨烯改性后的相变大胶囊导热系数显著提升,但随着石墨烯添加量的增加其导热系数提升效果降低。所制石墨烯改性相变大胶囊在不显著改变其相变储热性能的同时提升了导热性能,提高了相变大胶囊的换热效率,为进一步开发高性能相变储能发泡材料提供了技术支持。
In order to improve the thermal conductivity of phase change macrocapsules and expand the application range of phase change materials,a graphene(rGO) modified phase change macrocapsule was prepared by blending graphene,phase change microcapsules and sodium alginate gel.The Raman spectrum and scanning electron microscope (SEM) were used to characterizing the component and micromorphology of the prepared macrocapsules,and also discussed the thermal storage and thermal conduction performances.The results indicated that the prepared macrocapsules were composed of phase change microcapsules and sodium alginate gel,and the rGO interspersed in the sodium alginate gel.The encapsulation rate of prepared macrocapsules was 58.8%～63.6%,the phase change latent heat was 112.5～121.7J/g.It can be observed that the thermal storage performance of macrocapsules was insignificantly affected by the blending of rGO.More importantly,the thermal conduction obviously increased with the increase of rGO content,although the improvement effect was degenerative.Thus,the prepared macrocapsules improved the thermal conduction of macrocapsules while the thermal storage performance was stable.The prepared macrocapsules will optimize thermal exchange efficiency of phase change materials,and provided a technical base for the development of phase change foam.
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