Influence of h-BN fillers on mechanical and tribological properties of PP/PA6 blend

2021

ILT

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Purpose The mechanical and tribological properties of polymers and polymer composites vary with different environmental conditions. This paper aims to review the influence of humidity/water conditions on various polymers and polymer composites' mechanical properties and tribological behaviors. Design/methodology/approach The influence of humidity and water absorption on mechanical and tribological properties of various polymers, fillers and composites has been discussed in this paper. Tensile strength, modulus, yield strength, impact strength, COF and wear rates of polymer composites are compared for different environmental conditions. The interaction between the water molecules and hydrophobic polymers is also represented. Findings Pure polymer matrices show somewhat mixed behavior in humid environments. Absorbed moisture generally plasticizes the epoxies and polyamides and lowers the tensile strength, yield strength and modulus. Wear rates of PVC generally decrease in humid environments, while for polyamides, it increases. Fillers like graphite and boron-based compounds exhibit low COF, while MoS2 particulate fillers exhibit higher COF at high humidity and water conditions. The mechanical properties of fiber-reinforced polymer composites tend to decrease as the rate of humidity increases while the wear rates of fiber-reinforced polymer composites show somewhat mixed behavior. Particulate fillers like metals and advanced ceramics reinforced polymer composites exhibit low COF and wear rates as the rate of humidity increases. Originality/value The mechanical and tribological properties of polymers and polymer composites vary with the humidity value present in the environment. In dry conditions, wear loss is determined by the hardness of the contacting surfaces, which may not effectively work for high humid environments. The tribological performance of composite constituents, i.e. matrix and fillers in humid environments, defines the overall performance of polymer composite in said environments.

Section: Particle Reinforced Polymer Composites and Hybrid Compositesmentioning

confidence: 99%

The effect of environmental humidity/water absorption on tribo-mechanical performance of polymers and polymer composites – a review

2021

ILT

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“…Two-dimensional micro and nano particulate fillers such as graphite, molybdenum disulfide, hexagonal boron nitride and boron oxide are remarkably effective in improving some of the mechanical and tribological properties in dry conditions while embedded in any polymer matrices (Friedrich, 2018; Aldousiri et al , 2013; Bajpai et al , 2020; Mistry and Randhawa, 2020; Randhawa and Patel, 2020a, 2020b, 2020c; Randhawa and Patel, 2021; Vyas and Randhawa, 2021). To investigate the same in high humidity, the PA6/boric-oxide composites are immersed in water for many days before testing in this research.…”

Section: Introductionmentioning

confidence: 99%

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

2021

PRT

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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.

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

2021

PRT

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Purpose This paper aims to investigate the tribological performance, i.e. abrasion resistance, friction coefficient and wear rates, of self-lubricated water conditioned polyamide6/boric oxide composites. Design/methodology/approach Polyamide6 and polyamide6/boric oxide self-lubricated composites were immersed in water for 15 days to analyze the effect of water conditioning on friction, wear and abrasion resistance. Tribological testing on pin-on-disc tribometer and abrasion resistance testing on TABER abrader were performed to see the friction coefficient and wear rates of materials. The scanning electron microscopy (SEM) characterizations were performed to analyze the wear tracks. Findings Tribological testing results revealed the loss in abrasive resistance, but there was an improvement in frictional coefficient and wear rates with steel after water absorption. The SEM images clearly show less depth of wear tracks in water-conditioned materials than dry ones. Water conditioning was found supportive in the formation of smooth lubricating transfer film on steel disc during the tribological testing. Originality/value The tribological behaviour of polymer composites is different in dry and in high humidity or water conditions. Experiments were performed to investigate B2O3 solid lubricant filler effectiveness on tribological behaviour of water-conditioned polyamide composites. Bonding between polyamide6 and water molecules plus the formation of orthoboric acid was found advantageous in decreasing the friction coefficient and wear rates of composites.