Understanding the water uptake in F-161 glass-epoxy composites using the techniques of luminescence spectroscopy and FT-NIR

Abstract

This paper investigates the application of the luminescence spectroscopy technique in steady-state to study the moisture influence in glass fiber/epoxy prepreg and their laminates. The studies were monitored by intrinsic luminescence comparing the results with gravimetric analysis and near infrared with Fourier transform. Samples are cured and submitted to humidity controlled at 60 and 80 °C until 90 days. It is verified that the decrease in the maximum emission of the samples is directly related to the material moisture content. However, for very short periods, there is an increase in the relative intensity and blue shift of the emission band for all samples treated at 60 °C, which is related to an increase of the rigidity of the polymeric matrix. The results in this paper have a great significance because it brings a wide discussion on the interaction of water in epoxy composites materials.

Experimental assessment of the improved properties during aging of flax/glass hybrid composite laminates for marine applications

“…By assuming such trend, potentially future water absorption parameters could be argued by interpolation approach also for other stacking sequences of glass/flax laminates giving an advance not needing to make experiments for each new combination. The values reported in Figure are in agreement with those reported in the literature . Alvarez et al .…”

Hygrothermal effects on mode II interlaminar fracture toughness of co‐bonded and secondary bonded composites joints

“…Eventually, several chains become linked together into a network of infinite molecular weight with a substantial increase in crosslink density, a better compaction of polymeric chain and decreasing the voids between the polymeric chains . The established parameters of temperature and pressure used to set up the autoclave equipment to accelerate the curing process in polymeric composites also contributed to the compaction and decreasing of voids and the free volume between the polymeric chains increasing the difficulty of water ingress into the matrix .…”

An Assessment of the Effect of Progressive Water Absorption on the Interlaminar Strength of Unidirectional Carbon/Epoxy Composites Using Acoustic Emission

“…Free water is transported into a polymer via microcracks, whereas bound water is dispersed in the polymer matrix and attaches to the polymer’s polar groups [ 20 ]. Knowledge of the mechanisms that drive moisture absorption, as well as the influence of dimensions, temperature, and relative humidity, is important when the long-term properties of the composite are of interest [ 21 ]. It is crucial to understand the three common methods of moisture absorption by polymeric composite materials, namely the diffusion process, capillary actions, and the transport of water molecules.…”

“…The study of the interaction of polymers with water at the molecular level is very important because water intake determines a material’s mechanical properties at the macroscopic level [ 21 ] and any moisture absorption by polymeric composite materials can result in permanent damage to the matrix and interface [ 19 , 26 ]. This ingress of water molecules is significant if the polymer-based structure is immersed in water, salt, or alkaline-based solutions because this leads to a reduction in stiffness, strength, and the resin’s glass transition temperature (Tg) due to plasticisation effects [ 2 , 7 , 10 , 11 , 12 , 13 ].…”