Sliding Wear Characteristics of Biodegradable Nanocomposites of Cellulose Acetate Phthalate and Chitosan Reinforced with Functionalized Nanoclay

Abstract

Cellulose and chitosan are two of the most abundant naturally occurring substances which are being increasingly used for developing biodegradable polymer composites given the current environmental concerns. In this report, the wear performance of nanocomposites of cellulose acetate phthalate (CAP) and chitosan reinforced with surface functionalized nanoclay (NC) is studied using a pin-on-disc (PoD) tester. The earlier basic material characterization of these nanocomposites has shown improvement in mechanical and thermal properties with the addition of NC, with a kind of optimum behaviour at around 6% NC addition. In the present study, with nanocomposite pin sliding on the steel disc, for lower loads (5 N and 10 N), the wear coefficient K was observed to be in the range 2.9 x 0⁻⁵ − 2.7 x 10⁻⁴ mm³.m⁻¹.N⁻¹ and for higher load of 30 N, it was in the higher range (2.7 x 10⁻⁴ − 6.9 x 10⁻³ mm³.m⁻¹.N⁻¹). In this adhesive wear mode, as expected from the earlier study, the wear coefficient was minimum for the composite with 6% NC for all the three load conditions used. On the other hand, in the abrasive wear case, with the pin sliding on SiC abrasive paper covered disc, a different trend was seen with the reference 0% nanoclay sample showing less wear (5.25 x 10⁻³ mm³.m⁻¹.N⁻¹) than 6% NC containing sample. An attempt is made to understand this difference in the wear behaviour bringing in the heterogeneous nature of the test material and the dispersed nature of the reinforcing nanoclay.

Keywords:

• Cellulose acetate phthalate
• Chitosan
• Nanoclay
• Wear and friction properties
• Biodegradable nanocomposite