رسائل ماجيستير
English
2016
Development and characterization of Ultrahigh Molecular Weight Polyethylene(UHMWPE) Nanocomposites for bearing application under water lubriction
Annas Bin Ali, Nesar Merah
كلية الهندسة-جامعة الملك فهد للبترول والمعادن · السعودية
Ultrahigh Molecular weight Polyethylene that has paved ways in applications where high wear resistance is required. It is employed in variety of applications such as gears, pump housings, impellers, biomedical transplants and almost in every industrial sector both in the form of coatings and bulk. The addition of nano fillers like carbon nanotubes and nanoclay contribute significantly in improving the mechanical and wear resistance properties of UHMWPE. Even though lot of work has been done on UHMWPE composites in terms of their mechanical and tribologicalcharacterization, its potential to be used under water lubrication has not been tapped completely. Hence, the objective of the present study is to explore the feasibility of using UHMWPE hybrid nanocomposites under water lubrication using nano clay and carbon nanotubes as reinforcements. The unique idea to use nanoclay along with CNTs in the development of hybrid nanocomposites stems from the fact that nano clay is widely used in reducing the water uptake of polymers and enhancing the mechanical properties. In the first part of the present work, 1.5 wt% of three different organo-modified clays I.30E, I.28E and C-15A were used as reinforcements in UHMWPE. XRD, micro-hardness tests, water uptake tests and most importantly tribological tests have been conducted to evaluate the structural, mechanical and tribological properties of the developed nanoclay reinforced composites. It was observed from the water uptake tests that the addition of all the three types of nanoclays to UHMWPE resulted in reducing the water absorption. However, the addition of C15A and I30E nanoclays to UHMWPE also resulted in improving the tribological properties in terms of lowering the coefficient of friction and increasing the wearresistance. In the second stage, the C15A content was optimized based on its tribologicalperformance using three different clay loadings nanocomposite were developed with fixed clay content of 1.5 wt% while varying CNTs loading from 0.5 wt% to 3 wt %. Structural and morphological characterization using FESEM, XRD and Raman Spectroscopy for hybrid nanocomposites was done along with tribological testing. Optimized hybrid nanocomposite was tested under water lubricated condition along with pristine UHMWPE, C15A/UHMWPE and CNTs/UHMWPE. Hybrid nanocomposites showed highest reduction in wear rate by reducing wear rate by 63% as compared to pristine UHMWPE. Finally hybrid UHMWPE nanocomposites were tested under accelerated life testingUHMWPE and a reduction of about 45% was observed in specific wear rate with slightly increased coefficient of friction due to superior mechanical properties of CNTs.