γ Irradiation effects on optical,thermal, and mechanical properties of polysulfone/MWCNT nanocomposites in argon atmosphere

Polymer‐based composites find use in many nuclear and space application for their ease of fabrication, tailor made properties and light weight. Certain polymers like PTFE, unfilled polyesters and polyamides are prone to degradation in presence of high energy radiation while polymers like epoxies, polyimides, and poly‐ether ether ketone have good stability to ionizing radiation. Incorporation of fillers like carbon nanotubes (CNTs) is likely to improve the radiation resistance of the polymers. In this work, polysulfone (PSU)‐based nanocomposites were fabricated using multiwalled carbon nanotube (MWCNT) by solution mixing process. The morphology of the PSU/ MWCNT nanocomposites films were studied using Field Emission Scanning Electron Microscopy (FESEM). The prepared films were subjected to γ radiation in an argon environment (to avoid the effect of air/oxygen). Different techniques were used to understand the radiation‐induced changes. Gel Permeation Chromatography (GPC) traces of neat PSU before and after exposure to radiation shows a decrease in molecular weight. Infrared spectroscopy shows changes in chemical structure. Differential Scanning Calorimetry (DSC) thermograms reveal dose‐related changes. For neat PSU, a decrease in T_g was observed with increase in dose. For PSU/ MWCNT nanocomposites, the increase in MWCNT content and dose (up to 1.5 MGy) increased the T_g. Thermo Gravimetric Analysis (TGA) showed a marginal decrease in thermal stability for pristine PSU as well as PSU/MWCNT nanocomposites with irradiation. Tensile strength increased with increasing MWCNT content but decreased with dose. Elongation at break decreased with MWCNT content as well as radiation dose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42017.