Lifetime estimation of glass reinforced epoxy pipes in acidic and alkaline environment using accelerated test methodology

Abstract

Accelerated ageing test methodology is valid and widely accepted procedure for estimating the lifetime of isotropic homogeneous polymeric materials. However for non-isotropic and heterogeneous polymeric compounds such as glass reinforced epoxy (GRE) pipes, accelerated ageing test methodology has not been much investigated. Various standards such as ASTM D 3681, ASTM D 5365 are being used to estimate the lifetime of GRE pipes using regression analysis which is time consuming, and requires large number of test specimens and fixtures specific to pipe dimensions. Accelerated ageing test methodology can be a viable method for estimating the lifetime. The research on accelerated test methodology as a vital tool to determine the lifetime of GRE pipes has been limited. The major concern for using accelerated ageing test methodology is primarily due to the degradation kinetics of the anisotropic composite materials which may not be governed by the Arrhenius principle. The present study on the estimation of lifetime of GRE pipes in extreme acidic and alkaline medium reveals that degradation of the composite pipe follows the Arrhenius principle and the degradation mechanism can be described by first order reaction kinetics. The degradation rate, the temperature dependence of the degradation rate and lifetime of the glass reinforced epoxy pipes in extreme acidic and alkaline medium as found in the current study are presented here, along with the morphological study of aged and un-aged GRE pipes.