Water absorption behavior of functionalized graphene reinforced PVA based composite crosslinked using citric acid

Abstract

Graphene is a versatile 2-D atomic carbon nanomaterial having a unique combination of thermal/electrical conductivity and high surface area along with impressive mechanical properties which makes it attractive in the field of composites. Poly vinyl alcohol (PVA) is a well-known synthetic biodegradable polymer. One of the draw backs of PVA that restricts its use is hydrophilicity due to the presence of hydroxyl group in its structure hence, water absorption is an important criterion while experimenting with PVA. The water absorption test reveals information about the adhesion action between the particles and matrix in the interface region. Higher the adhesion, lower will be water absorption. We used ASTM D5229 standards to perform water absorption test where we use a gravimetric test method that monitors change over time of moisture content by measuring the total mass change of a sample that is exposed to a specified environment. Present work studies the water absorption behaviour of crosslinked PVA based composite reinforced with different weight percentage of functionalized graphene. For this test samples of size 20 × 10 mm2 of different compositions are first dried in the microwave oven at 60 °C for 2 h and corresponding weight of each sample are measured and then samples are dipped in the distilled water at ambient temperature for 24 hrs, after that removed from water and wiped with tissue paper and weighed again. Present work also compares the water absorption behaviour for different weight percentage of functionalized graphene. We found that the rate of water absorption is extremely rapid for the first 20–40 min followed by slight reduction in rate of water absorption for next 50–60 min and after 80–100 min rate of water absorption becomes almost steady. As we increase the wt.% of functionalized graphene the percentage of water absorbed also increases for the particular time interval.