Journal of the Faculty of Engineering and Architecture of Gazi University 38:1 (2023) 435-449 Preparation of shape-stabilized composite phase change materials containing n- nonadecane with modified kaolinite clay-doped poly(styrene-co-divinyl benzene) matrix and determination of their properties Sena Bayram 1 , Hatice Hande Mert 1 * , Mehmet Selçuk Mert 2 1 Department of Chemical Engineering, Engineering Faculty, Yalova University, 77200, Yalova, Türkiye 2 Department of Energy Systems Engineering, Engineering Faculty, Yalova University,77200, Yalova, Türkiye Highlights: Graphical/Tabular Abstract  Synthesis of porous support materials by emulsion templating method  Preparation of shape- stabilized composite phase change materials  Determination of energy storage capacity for thermal energy storage applications Phase change materials (PCMs) are functional materials that allow thermal energy to be stored as latent heat and can be used in a wide range of thermal energy storage applications with their high latent heat storage capacities. In this study, emulsion-templated porous polymers containing modified aluminum silicate-based nanoparticles to be used in thermal energy storage systems were prepared and the materials obtained were used as support material for the preparation of shape-stabilized phase change materials. The morphological, thermal and chemical characterization of n-nonadecane based shape-stabilized composite phase change materials containing modified kaolinite clay-doped were performed (Figure A) and according to the analysis results obtained, the application potentials of these materials were evaluated. Figure A. Morphological and thermal characterizations of shape-stabilized composite PCMs Purpose: It was aimed in this work to control the volume change by integrating the paraffin-based phase change material into polymer composite support material, which is not suitable for using in direct heating / cooling applications in building materials due to the leakage problem during phase change process. The shape- stabilized composite phase change materials have been produced that can contribute to the provision of thermal comfort in buildings by adding to the building materials. Theory and Methods: Kaolinite clay was modified with cationic agent. Porous polymer support materials were synthesized by high internal phase emulsion polymerization method in the presence of modified kaolinite. N-nonadecane based shape-stabilized composite phase change materials were produced by one-step impregnation method. Results: According to analysis results, the pore morphologies of polymer composite support materials improved with the increase of modified kaolinite nanoparticles, and the composite containing 1% filler had the highest thermal stability and specific surface area. Also, shape-stabilized composite PCMs produced by using porous composites as support materials showed a remarkable thermal energy storage capacity (up to 141.7 J / g) for thermal energy storage applications and leak-proof property. Conclusion: The produced composite PCMs have the potential to be used especially in smart building applications, as they do not have leakage and volume change problems, have high thermal stability and energy storage capacity. Keywords:  Phase change materials  porous polymers  emulsion templating  n-nonadecane  kaolinite Article Info: Research Article Received: 13.07.2021 Accepted: 11.02.2022 DOI: 10.17341/gazimmfd.970716 Acknowledgement: The authors would like to thank Yalova University Scientific Research Projects Coordination Unit (Project Number: 2020/YL/0010) for providing master's thesis project support in the realization of this study. Correspondence: Author: Hatice Hande Mert e-mail: hndmert@yalova.edu.tr phone: +90 226 815 5397