Synthesis and characterization of surface modified CNT reinforced PVA nanocomposite films

Abstract

Polymers have been ruling the packaging market for decades because of their versatility, lightness, availability, strength, easy manufacturability, and low cost. Overusing non-biodegradable plastics in food packaging has become a major environmental issue. To overcome this, biopolymers can be a suitable alternative. Polyvinyl alcohol (PVA), a synthetic biopolymer, well known for its nontoxic, hydrophilic, chemical resistance, and excellent film-forming characteristics. It has been widely used for medicine cachets, controlled drug delivery systems, and surgery yarns. However, due to their poor mechanical, thermal, and barrier characteristics, biopolymers' usage as food packaging is limited. Carbon nanotube (CNT) reinforced nanocomposites have received attention for their exceptional mechanical, thermal, and electrical properties. However, a major difficulty in the synthesis of CNT-reinforced nanocomposites is the nanotube agglomeration. Poor dispersion and less interfacial bonding between reinforcements and matrix limit its advantages. To improve this, acidic functionalization has shown some major improvements. Although acid treatment is effective, strong acid, treatment timing, and sonication power can lead to nanotube damage. In this study, multiwalled carbon nanotubes (MWCNTs) have been treated with acid and polydopamine. PVA/ pristine CNT nanocomposite films were fabricated with different amounts of MWCNTs (0 wt.%, 0.5 wt.%, 1.0 wt.%, 1.5 wt.%, and 2.0 wt.%). These samples went through characterization for the optimization of CNTs’ concentration in PVA matrix. Then the optimized amount of treated MWCNTs were used to fabricate PVA/CNT nanocomposite films. The mechanical, optical, and antibacterial characteristics of the resultant composite films were investigated for their possible use for food packaging. It’s been found that the polydopamine treatment of MWCNTs provide better dispersion in the PVA matrix. Besides, the thermal and mechanical properties of the PVA/polydopamine treated MWCNT nanocomposite films has been enhanced in comparison to that of pure PVA, PVA/pristine MWCNT and PVA/acid treated MWCNT nanocomposite films. Moreover, the resultant film also shows good antibacterial activity.