Effects of carbon nanotube/polymer interfacial bonding on the long-term creep performance of nanophased glass fiber/epoxy composites

This article is focused on prediction of the long-term creep performance of glass fiber/epoxy (GE) composites reinforced with pristine carbon nanotube (CNT) and functionalized carbon nanotube (FCNT). 0.1 wt% of CNT and FCNT are added to GE composites to fabricate CNT-GE and FCNT-GE composite laminates, respectively. Flexural tests were carried out at room temperature (RT) and 120 degrees C to assess the effect of environment temperature on the flexural properties of the aforesaid materials. FCNT-GE showed highest improvement in flexural properties at RT followed by CNT-GE composite and control GE composite, due to better stress transfer with strong chemical interfacial bonding. By using accelerated deformation at elevated temperature and time-temperature superposition principle, long-term creep behavior of GE, CNT-GE, and FCNT-GE composites at various reference temperatures (30 degrees C, 60 degrees C, 90 degrees C, and 110 degrees C) has been anticipated. Positive reinforcement efficiency is noted up to similar to 10(10.5) and similar to 10(12.5) years for CNT-GE and FCNT-GE, respectively at reference temperature of 30 degrees C, following which it neutralized and moderately became negative. However, at higher temperature this time period is reduced abruptly due to unfavorable thermal stress generation at the CNT/polymer interface. Evaluation of thermomechanical properties were also carried out using dynamic mechanical analysis. Differential scanning calorimetry was used to investigate the variation in glass transition temperature due to CNT/FCNT addition to GE composite. Fractographic study was also carried out to know the mode of failure for CNT-GE and FCNT-GE composite flexural tested at room temperature.