Water diffusion in carbon fiber reinforced polyamide 6 composites: Experimental, theoretical, and numerical approaches

Abstract

Diffusion of moisture through composites is one of the main environmental causes of their deterioration and loss of service life. This paper deals with water diffusion in the unidirectional continuous carbon fiber reinforced polyamide 6 composites by experimental measurement, theoretical analysis, and numerical simulation. Immersion experiment is respectively conducted in distilled water at 25°C, 70°C, and 95°C for the pure polyamide 6 resin and the carbon fiber/polyamide 6 composite. Then, the theoretical Fickian and Langmuir models are employed to fit the gravimetric data of the specimens. Subsequently, water diffusion in the composite is also simulated using finite element method. Moreover, to capture the real distribution of fibers in the matrix, the random algorithm is developed to generate the computational composite models with randomly dispersed fibers. Finally, the comparison between the experimental, theoretical, and numerical results is made to assess the applicability of theoretical models and the influences of fiber distribution and interphase on the effective water diffusion coefficient of composite.

Effect Mechanism and Simulation of Voids on Hygrothermal Performances of Composites

“…PA6 matrix can absorb about 10 wt% water [ 22 ], and the absorbed water has deleterious effects on the mechanical performances of PA6-based composites [ 23 , 24 , 25 ]. It is necessary to understand the combined impact of hygrothermal aging and voids defects on the water absorption properties and mechanical performances for PA6-based composites.…”

The Integral Utilization of Date Palm Waste to Produce Plastic Composites

“…However, compounds without a coupling agent and a low fiber content tend to have a slope of 1. A value close to 1 of the slope of the absorption mechanism means that water diffusion is faster than the moderation route [ 75 ]. Therefore that compounds with a coupling agent and low date palm waste contents approach a Fickian diffusion mechanism.…”

Polymer Processing and Surfaces

“…In oxidation and hydrolysis reactions, aldehyde and carboxyl groups were formed and the resulted carbonyl group generated in the cellulose chains influenced its color appearance [61,62]. Formation of furan type compounds in thermal degradation of carbohydrates was also a responsible factor for the color changes in cellulose due to high temperature [63,64].…”

“…The interfacial interaction could restrain the mobility of PA6 chains and weaken the hydrogen bonding interactions between the polymer chains, hindering the formation α-phase crystals. [7,8,44,63], the PA6 hydrothermal stability can be studied at different ageing temperatures, e.g., at room temperature or close to water boiling point (~70-90 • C). It is generally accepted that temperature acts like an activator of eater diffusion within the polymer matrix [64].…”