Enhanced mechanical, rheological and processing properties of PMMA nanocomposites with propylene carbonate-modified ZrO2 nanoparticles

Surface-modified zirconia (PCmZrO 2 ) nanoparticles were prepared by mixing propylene carbonate (PC) with nano-ZrO 2 in methanol at PC/ZrO 2 weight ratios ranging from 5 to 40 wt%. PMMA/ZrO 2 and PMMA/PCmZrO 2 polymer nanocomposites were then fabricated via melt blending in a Haake Rheomix Lab mixer at 210 °C for 6 min (in which ZrO 2 content was fixed at 2.5 wt% for all samples). Melt flow index measurements showed that the processability of the nanocomposites increased with increasing PC/ZrO 2 ratio (or PC content). Notably, raising the PC/ZrO 2 ratio from 0 to 40 wt% improved both the elastic modulus and elongation at break of the PMMA/ZrO 2 nanocomposite. The elongation at break increased from 5.1 to 6.6%, while the elastic modulus rose from 1587 MPa to a plateau value of around 1611 MPa. The bending strength of the nanocomposites reached a maximum of 113 MPa at a PC/ZrO 2 ratio of 20 wt%. DSC analysis indicated that the glass transition temperature (T g ) of PMMA/ZrO 2 remained nearly unchanged after PC modification of ZrO 2 . In contrast, DMTA revealed a slight increase in T g for PMMA/PCmZrO 2 nanocomposites (115 °C) compared with the PMMA/ZrO 2 sample (112 °C), suggesting restricted molecular mobility due to interfacial interactions. FESEM observations confirmed that PC modification led to a more uniform dispersion of nano-ZrO 2 in the PMMA matrix. Overall, surface modification of nano-ZrO 2 with 20 wt% of PC/ZrO 2 significantly enhanced the mechanical performance and processability of PMMA/ZrO 2 nanocomposites, while also providing a slight improvement in their thermal properties. Graphical abstract Propylene carbonate (PC) surface modification improves the dispersity of ZrO 2 nanoparticles in PMMA, enhancing processability, mechanical, thermal stability and rheological properties of PMMA/ZrO 2 nanocomposite.