Enhancing Thermal and Mechanical Properties of Polybenzoxazine Composites through Methyl Substitution and Organoclay Incorporation

Malathi Devi et al.,

Polybenzoxazine | Thermal

Vol: 11; Iss. 6; Jun 25 | ISSN: 2454-5422

This study investigates the synthesis and characterization of polybenzoxazine (PBZ) composites derived from methylamine, bisphenol-A, and formaldehyde, focusing on the effects of methyl substitution and the incorporation of organoclay (montmorillonite) on their thermal and mechanical properties. Polybenzoxazine is a promising thermosetting phenolic resin known for its excellent properties, including low shrinkage, high char yield, and mechanical strength. However, challenges such as brittleness and low processability limit its applications. To address these issues, methylamine was utilized as a precursor to lower the polymerization temperature and reduce volatile emissions during curing. The synthesis involved the ring-opening polymerization of the methylamine-derived monomer, followed by the preparation of organoclay-loaded composites. The resulting materials were characterized using Fourier Transform Infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and thermogravimetric analysis (TGA). FTIR analysis confirmed the successful formation of the benzoxazine structure, while FESEM images revealed uniform dispersion of the organoclay within the polymer matrix, which is crucial for enhancing mechanical properties. Mechanical characterization through Rockwell hardness tests indicated that the pristine PBZ exhibited a low hardness value of 11. In contrast, the incorporation of functionalized organoclay significantly improved hardness, with the optimal composite achieving a Rockwell Hardness Number (RHN) of 83. TGA results demonstrated that the thermal stability of the composites was markedly enhanced, with residual mass percentages of 40-49% at 600°C, indicating their suitability for high-temperature applications. Overall, this research highlights the potential of methyl-substituted polybenzoxazine composites as high-performance materials, offering improved thermal stability and mechanical strength. The findings suggest avenues for further exploration in optimizing synthesis processes and expanding the functional applications of these advanced composites in various industries, including aerospace and automotive sectors.

S.Malathi Devi, Department of Chemistry, Mepco Schlenk Engineering College, Sivakasi, Tamilnadu, India