Synergistic effects of zinc borate and graphene on enhanced thermal stability and antimicrobial properties of poly(methyl methacrylate)

The use of graphene nanoplatelets (GnP) as reinforcing material for thermoplastic polymer matrices, polymethyl methacrylate (PMMA) and zinc borate (ZnB), as an antimicrobial and fire-retardant agent was studied. PMMA-ZnB and PMMA-GnP-ZnB (ZG) composite films were fabricated with different ZnB concentrations (2.5, 5, 10 wt%) by solvent casting method using acetone. The effect of additives on the antimicrobial activity, thermal and mechanical properties, and surface morphologies of the composites were investigated. Antimicrobial surface activity tests were conducted against seven microorganisms, including bacterial and fungal species. An improvement in antimicrobial activity by up to 99.99% with increasing ZnB content was observed. Thermal stability was increased with increasing concentration of ZnB and a combination of ZnB and GnP additions. 10% ZG-based composites increased the % char residue value of PMMA from 0.5% to 9.3%. The incorporation of the ZnB and GnP into the PMMA matrix resulted in an increase in the calculated limiting oxygen index (LOI). 10% and 50% weight loss temperature increased by 11.7 degrees C and 3.7 degrees C, respectively, for 10% ZG composites. The Young's modulus of the composites increased with increasing ZnB and a combination of ZnB and GnP loading (increasing by 16% to 2033 MPa with the addition of 10 wt% ZG). The commercial application for this study would be in high touch and piano black automotive interior, construction, and medical applications.

Automated summary

This study investigated the use of graphene nanoplatelets (GnP) as reinforcing material for thermoplastic polymer matrices, as well as an antimicrobial and fire-retardant agent. Different PMMA-ZnB and PMMA-GnP-ZnB composite films were fabricated with different concentrations of ZnB, and the effects on antimicrobial activity, thermal and mechanical properties, and surface morphologies were studied.