Abstract The thermal properties of bio-based phase change material (PCM) microcapsules and their separate components, core and shell, were investigated considering the influence of used thermal enhancer. As a core, bio-based PCM, capric acid (CA), was used. Biodegradable material, such as polylactic acid (PLA), was used as a shell. To improve the thermal conductivity of PLA/CA microcapsules, the multiwall carbon nanotubes (MWCNTs) were used as a thermal enhancer. Composites of PCM with different concentrations of MWCNT as well as composites of PLA with these carbon compounds were prepared and investigated to assess how MWCNT influences the thermal conductivity of the core and the shell. The heat storage and release capacity, as well as the phase change temperatures of CA/MWCNT composites and manufactured PCM microcapsules, were determined using differential scanning calorimetry. To evaluate the thermal conductivity of prepared composites and to compare it with the conductivity of pure materials (without MWCNT), their thermal resistance was measured using the guarded-hotplate test method. To obtain the supplementary information and to assess the dynamic behavior of used PCM during the temperature changes, another technique, such as monitoring of a cold/hot plate with an IR camera, was used. The results of these measurements showed that introduced MWCNT increases the thermal conductivity of PCM used for the core and the conductivity of films prepared from PLA. Consequently, with reference to the results obtained, it could be stated that the introduction of MWCNT into PLA/CA microcapsules improved the thermal properties of these microcapsules. However, it was determined that too large concentration of MWCNT reduces an enthalpy of melting and crystallization of tested PCM and PCM microcapsules. Therefore, during the investigation, an optimal concentration of MWCNT additives has been determined.

中文翻译：

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用于纺织品应用的生物基微胶囊的热性能增强

摘要 考虑到所用热增强剂的影响，研究了生物基相变材料 (PCM) 微胶囊及其独立组分核壳的热性能。作为核心，使用了基于生物的 PCM，癸酸 (CA)。可生物降解的材料，如聚乳酸 (PLA)，被用作外壳。为了提高 PLA/CA 微胶囊的热导率，多壁碳纳米管 (MWCNT) 被用作热增强剂。制备并研究了具有不同浓度 MWCNT 的 PCM 复合材料以及 PLA 与这些碳化合物的复合材料，以评估 MWCNT 如何影响核和壳的热导率。CA/MWCNT 复合材料和制造的 PCM 微胶囊的储热和释放能力，以及相变温度，用差示扫描量热法测定。为了评估制备的复合材料的热导率并将其与纯材料（无 MWCNT）的热导率进行比较，使用防护加热板测试方法测量了它们的热阻。为了获得补充信息并评估所用 PCM 在温度变化期间的动态行为，使用了另一种技术，例如使用 IR 摄像机监控冷/热板。这些测量的结果表明，引入的 MWCNT 增加了用于核心的 PCM 的热导率和由 PLA 制备的薄膜的热导率。因此，参考获得的结果，可以说将 MWCNT 引入 PLA/CA 微胶囊改善了这些微胶囊的热性能。然而，已确定太大浓度的 MWCNT 会降低所测试的 PCM 和 PCM 微胶囊的熔化和结晶焓。因此，在研究过程中，已经确定了 MWCNT 添加剂的最佳浓度。