Effect of Humid Ageing on the Durability of Functionalized CNT Embedded GFRP Composite

Abstract

Glass fiber reinforced polymer (GE) composite is considered as an alternative material for naval and aerospace applications due to its greater advantages over conventional materials. The long term exposure of GE composite to high humidity/temperature environment degrades its mechanical performance due to the influence of absorbed moisture in the interfacial area of matrix and reinforcement. The degradation of mechanical properties can be minimised by the incorporation of suitable nano-fillers into the GE matrix. The objective of present investigation lies in the evaluation of effects of addition of carbon nanotubes (in pristine as well as oxidized form) into GE composites. The characterization of as-received CNTs was done by TEM and FTIR. In the present study GE, 0.1 wt.% pristine CNT embedded GE (PCNT-GE) composite and 0.1 wt.% Oxidized CNT embedded GE (OCNT-GE) composites were prepared. All these composites were subjected to different humidity conditions (15 ºC -90% RH and 50 ºC -90% RH). Moisture uptake was monitored by gravimetric tests at different time intervals. Flexural test, dynamic mechanical analysis (DMA) and creep tests were done to assess/evaluate the mechanical properties of the composites. The experimental creep test results were modelled with the analytical modelling (Burger’ model). A comparison has been done between the results of unconditioned samples and conditioned samples to evaluate the extent of degradation of properties. The addition of 0.1% OCNT and 0.1% PCNT in the matrix increases the flexural strength and modulus by 15.88% and 17.6% for OCNT-GE 4.76% and 10.3% for PCNT-GE over GE composite. Also, The addition of 0.1% OCNT in the matrix decrease the creep and creep rate by 13.578% and 36.737% at 40 MPa and 50 ºC and 13.62% and 23.755% at 40 MPa and 80ºC than GE composite respectively. This signifies that incorporation of oxidised CNT to the composite has significant impact on the mechanical properties composite.