Dissolution Kinetics of R-Glass Fibres: Influence of Water Acidity, Temperature, and Stress Corrosion

Andrey Krauklis,Maris Klavins,Ilze Kalnina,Abedin Gagani,Andreas Echtermeyer,Kristine Vegere

doi:10.3390/fib7030022

Abstract

Glass fibres slowly degrade due to dissolution when exposed to water. Such environmental aging results in the deterioration of the mechanical properties. In structural offshore and marine applications, as well as in the wind energy sector, R-glass fibre composites are continuously exposed to water and humid environments for decades, with a typical design lifetime being around 25 years or more. During this lifetime, these materials are affected by various temperatures, acidity levels, and mechanical loads. A Dissolving Cylinder Zero-Order Kinetic (DCZOK) model was able to explain the long-term dissolution of R-glass fibres, considering the influence of the pH, temperature, and stress corrosion. The effects of these environmental conditions on the dissolution rate constants and activation energies of dissolution were obtained. Experimentally, dissolution was measured using High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). For stress corrosion, a custom rig was designed and used. The temperature showed an Arrhenius-type influence on the kinetics, increasing the rate of dissolution exponentially with increasing temperature. In comparison with neutral conditions, basic and acidic aqueous environments showed an increase in the dissolution rates, affecting the lifetime of glass fibres negatively. External loads also increased glass dissolution rates due to stress corrosion. The model was able to capture all of these effects.

Highlights

Glass fibres (GFs) are the most common fibrous reinforcement material used in fibre-reinforced composites [1]
Glass fibre-reinforced composites (GFRPs) are continuously exposed to water and humid environments for decades, with a typical design lifetime being around 25 years or more [8]
From the measured cumulative concentration data of the ions released during the dissolution of glass, the dissolution rate constants were obtained using non-linear regression for Si (K0I Si and K0I SiI )

Summary

Introduction

Glass fibres (GFs) are the most common fibrous reinforcement material used in fibre-reinforced composites (fibre-reinforced polymers; FRPs) [1]. Glass fibre-reinforced composites (GFRPs) are often used in structural applications in marine and offshore industries, as well as in the wind energy sector [4,5,6,7,8,9,10,11] In these applications, GFRPs are continuously exposed to water and humid environments for decades, with a typical design lifetime being around 25 years or more [8]. GFRPs are continuously exposed to water and humid environments for decades, with a typical design lifetime being around 25 years or more [8] When exposed to such environments, hydrolytic degradation of the glass material occurs [12,13], leading to a reduction of the mechanical strength and the initiation of corrosion-induced defects in fibres and composites [14]. Aqueous environments clearly have a negative effect on the Fibers 2019, 7, 22; doi:10.3390/fib7030022 www.mdpi.com/journal/fibers

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