Effect of maleic anhydride modified MWCNTs on the morphology and dynamic mechanical properties of its PMMA composites

Highlights: · Maleic anhydride that was grafted on MWCNTs can provide additional active species for MMA. · The modification resulted in a better adhesion between the MWCNTs and PMMA. · The dynamic mechanical properties of PMMA composites were improved significantly. · The better properties of MWCNTs composite address the applications regarding MWCNTs. - Abstract: This study successfully grafted multiwalled carbon nanotubes (MWCNTs) with maleic anhydride (Mah-g-MWCNTs) via Friedel-Crafts acylation with the aluminum chloride catalyst (AlCl3), investigated by Raman and TGA analysis. The covalent bonds and carboxylic groups of maleic anhydride provided additional active species, improving adhesion between the MWCNTs and poly(methyl methacrylate) (PMMA). This investigation also studied the morphology and dynamic mechanical properties of pristine MWCNTs (P-MWCNTs) and modified MWCNTs (Mah-g-MWCNTs) reinforced with PMMA. Findings show a homogeneous distribution of MWCNTs throughout the matrix for Mah-g-MWCNTs/PMMA composites, as revealed by transmission electron microscope (TEM). The addition of both MWCNTs influenced the molecular arrangement of the PMMA matrix and also increased the dynamic mechanical properties of MWCNTs/PMMA composites. Glass transition temperature (Tg) and storage moduli (E') of the Mah-g-MWCNTs/PMMA composites increased significantly comparing with P-MWCNTs/PMMA composites, attributed to improved interfacial adhesion between the reinforcement and the matrix. DMA studies revealed that adding 4.76 wt% Mah-g-MWCNTs into PMMA generates a 184% enhancement in the storage modulus and a 19 deg. C increase in Tg. However, adding 4.76 wt% P-MWCNTs into PMMA only generates 108% enhancement in the storage modulus and a 14 deg. C increase in Tg.