Among these, MWNTs typically exist in the form of aggregates ranging from tens to hundreds of nanometers in size due to van der Waals interactions [13; 14; 15; 16; 17; 18; 19]. In this study, PS and PETE were selected as representative examples of radical and condensation polymerization, respectively, and utilized as polymer matrices. In situ polymers incorporating MWNTs as conductive fillers were synthesized, and their structural, thermal, and electrical properties were systematically investigated. This approach is expected to facilitate the broader application of MWNTs in various polymer systems through in situ polymerization in future studies. In this study, PS was selected as a representative polymer due to its excellent processability, low density, and chemical resistance. Its superior electrical insulating properties have led to its widespread use in numerous industrial applications [20; 21; 22]. Its ease of free radical initiation and its high compatibility with various additives also provide flexibility in the design of in situ polymers. PETE is a polymer with a high mechanical strength, heat resistance, and chemical stability, making it well suited for industrial applications that require structural integrity and thermal durability [23; 24]. In particular, the presence of ester linkages within its molecular structure enhances crystallinity and intermolecular cohesion, which, in turn, contributes to improved thermal stability and weather resistance [25]. A prior study reported that the polymerization of polymethyl methacrylate (PMMA) with mixed MWNTs yielded a surface resistivity of approximately \(10^{4}\) Ohm/sq\(\Omega\)/\(\square\), which was insufficient for commercial applications [26]. In this study, efforts were focused on achieving enhanced performance by utilizing high-quality MWNTs and identifying optimized polymerization conditions. This study focused on a multi-component system in which MWNTs, a type of CNT, were introduced prior to polymerization into two distinct polymers: PS, based on radical polymerization, and PETE, based on condensation polymerization. Unlike a simple physical blend of polymers and MWNTs, the MWNTs were incorporated into the polymerization process itself, ensuring their direct integration into the polymer chains. The resulting materials were then quantitatively analyzed to evaluate the differences in their electrical and thermal properties. In particular, the use of an in situ polymerization method enabled the direct incorporation of the MWNTs into the polymer matrix, thereby simplifying the synthesis process. This approach maximized both the dispersion of the nanotubes and interfacial bonding, which was further confirmed by FE-SEM and TEM analyses showing a uniformly distributed MWNT structure. Through this approach, the enhancement in electrical conductivity resulting from MWNT incorporation was systematically evaluated. Furthermore, this study simultaneously achieved the synthesis of a novel conductive polymer composite and the development of an antistatic tray material suitable for semiconductor processing, thereby demonstrating originality compared to previously reported studies. A thermogravimetric analysis (TGA) and DSC were performed to investigate the thermal behavior of the synthesized MWNT/PS and MWNT/PETE materials as a function of the MWNT weight content. Electrical conductivity was evaluated through surface resistivity measurements to confirm the materials' suitability as antistatic materials.