Mechanical and thermal properties of epoxy polymethyl methacrylate blends synthesized in supercritical carbon dioxide

A series of epoxy/polymethyl methacrylate (E /PMMA) blends was synthesized through impregnation polymerization of methyl methacrylate at concentrations ranging (0-1.5 phr) into diglycidyl ether of bisphenol-A (0.1 mol) in presence of 2,2-azobisisobutyronitrile (2 x 10-2 mol) at 3000 psi, (60-90 +/- 1) deg C for 3 h in supercritical carbon dioxide, followed by curing of treated epoxy with triethylene tetramine (10 phr) at (40 +/- 1) deg C. The progress of all such impregnation polymerization reactions was monitored rheoviscometrically. Formation of E /PMMA blends was ascertained through of PMMA mass uptake (%) into epoxy, UVvis and FTIR spectra, and TEM. With PMMA mass uptake (%), compression strength and resistance against wear of E/PMMA blends were increased with simultaneous decrease in their Rockwell hardness (R scale), charpy impact, and tensile strength, respectively. All E /PMMA blends have shown nonuniform photoelastic behavior at applied load ranging 4-20 kgf and significant stability against thermooxidation with Tg/Tm and char yield (%) ranging 0.53-0.59, 29.31-31.66, respectively.