Impact of graphite particle surface modification on the strengthening of cross-linked polyvinyl alcohol composites: A comprehensive investigation
Pawan K. Agrawal, Pragya Sharma, Akarsh Verma, Vinay Kumar Singh, Arun Kumar Chaudhary, Sakshi Chauhan
Abstract
To reduce the hydrophilicity of polyvinyl alcohol (PVA), various methods are employed. Acid cross-linking is one technique, but it decreases the polymer's strength. To address this, different reinforcements are utilized to enhance the polymer's strength while mitigating the side effects of acid cross-linking. The present research intends to improve the physical, mechanical, and thermal properties of PVA by cross-linking it with fumaric acid and reinforcing it with modified graphite particles. The particles were prepared through oxidative acidic treatment and added in different weight proportions (0.5, 1, 1.5, and 2 wt.%) to the PVA matrix. Water absorption (WA) tests were conducted to affirm the formation of cross-linked bonds, and Fourier transform-infrared spectroscopy was employed to confirm the oxidation of the graphite particles with acid. The composites were examined using scanning electron microscopy, which revealed a robust interfacial adhesion between the modified graphite and cross-linked PVA, resulting in better mechanical characteristics. The highest ultimate tensile strength was observed when using 1.5 wt.% of modified graphite particle reinforcement, resulting in a 31% increase in comparison to pure cross-linked PVA. Moreover, the thermal stability increased from 358°C (PVA alone) to 375°C (composite with 2 wt.% treated graphite particles). Dynamic mechanical analysis revealed an increase in glass transition temperature from 68.2°C to 72.9°C, and activation energy from 604.84 to 1028.21 kJ mol −1 (neat PVA to composite with 1.5 wt.% modified particles). The damping coefficient of the cross-linked composite was 0.257, making it suitable for acoustic damping applications like speakers.