Influence of moisture/water absorption on mechanical and thermal properties of polyamide6/boric oxide composites

Abstract

Purpose This paper aims to investigate the mechanical and thermal behavior, i.e. tensile strength, hardness, impact strength and glass transition temperatures of water-treated polyamide6/boric oxide (PA) composites. Design/methodology/approach The PA6 and PA6/boric oxide composites were exposed to an open environment and immersed in water for 15 days to analyze the effect of environmental humidity and frequent water immersion conditions on the composite’s mechanical and thermal properties. The tensile strength, elastic modulus, hardness and impact strength of materials were measured to identify the mechanical properties. The scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) characterizations were used to see the effect of humidity/water absorption on microstructure, crystallinity and glass transition temperatures. Findings The testing results revealed the loss in strength, elastic modulus and hardness, while the impact resistance was improved after exposure of materials to humidity/water. SEM images clearly show the formation of voids and XRD graphs revealed the loss in crystallinity after water immersion. The DSC plots of water immersed materials revealed the loss of glass transition temperatures up to 15°C. Originality/value The mechanical and thermal behavior of PA composites varies according to the surrounding atmosphere. Experiments were performed to investigate the influence of water treatment on the PA6/B2O3 composite’s mechanical and thermal properties. Water treatment resulted in the bonding between PA and water molecules, which generated voids in the materials. These voids generations are found the main reason for the low strength and hardness of water-treated materials.

Influence of Dispersion and Orientation on Polyamide-6 Cellulose Nanocomposites Manufactured through Liquid-Assisted Extrusion

“…The degree of crystallinity of PA6/0.5NC (28%) is higher than that of PA6 (21%), as listed in Table S1 in the Supplementary Information . The addition of PEG/NC had a small effect on crystallinity (25%), explained by the similar polarities of PEG and PA6, which decreased the degree of crystallinity [ 29 ]. The PA6 shows two melting endotherms, T m1 at ~205 °C and T m2 at 218 °C, as illustrated in Figure S3 .…”

Tribological performance of self-lubricated polyamide6/boric oxide composites after water conditioning

“…After injection moulding, the tribological test specimens were immersed in distilled water for 15 days. The analysis of water absorption was carried out according to the ASTM D 570 standard (Randhawa and Patel, 2021a, 2021b, 2021c).…”

“…Generally, the developed traditional solid lubricants were in the form of metals, ceramics and polymer matrix composites (Findik, 2014). Solid lubricant fillers like graphite, MoS 2 , h-BN and B 2 O 3 are remarkably effective in reducing COF and wear rates in dry conditions while embedded in any polymer matrices (Randhawa and Patel, 2020a, 2020b, 2020c; Mistry and Randhawa, 2020; Randhawa and Patel, 2021a, 2021b, 2021c; Friedrich, 2018; Aldousiri et al , 2013; Vyas and Randhawa, 2021). But the results are not the same in high humidity or tested after water conditioning.…”

Study on microstructure and tribological properties of hierarchical 3D braid applicable in heavy operating tribology conditions

“…Furthermore, due to metal sensitivity to aquatic corrosion, typical metallic materials are inappropriate for water lubrication 2 . For tribo‐engineering materials recently, polymer composites have received much interest and have been widely employed because of their attractive qualities, such as low density, strong chemical resistance, and good water‐lubrication adaption 3 …”