Fugen Daver

Influence of surface texturing on scratch/mar visibility for polymeric materials: a review

Surface texturing has long played a vital role in determining both the look and feel of modern consumer goods. Recently, texture patterns have also shown to be an effective method for enhancing the scratch resistance of polymeric surfaces, which are more sensitive to scratch damage due to their relatively low strengths and stiffness. This paper examines the emerging studies of scratch-resistant surface textures and analyses the key principles and challenges faced by texture design and the assessment of scratch resistance. The analysis of scratch resistance is broken into three key sections: (1) the influence of the base material on deformation characteristics, (2) the influence of surface texturing on scratch damage and visibility, and (3) the influence of human vision and the capacity of textures to obscure scratch damage. The complex interactions between these three facets highlight the wealth of opportunities for further study in this area, and the need for improved methods for quantifying scratch resistance for these materials. This paper also presents experimental results to demonstrate the variation in scratch damage and texture effects.

Creep and Recovery Behaviour of Polyolefin-Rubber Nanocomposites Developed for Additive Manufacturing

Nanocomposite application in automotive engineering materials is subject to continual stress fields together with recovery periods, under extremes of temperature variations. The aim is to prepare and characterize polyolefin-rubber nanocomposites developed for additive manufacturing in terms of their time-dependent deformation behaviour as revealed in creep-recovery experiments. The composites consisted of linear low density polyethylene and functionalized rubber particles. Maleic anhydride compatibilizer grafted to polyethylene was used to enhance adhesion between the polyethylene and rubber; and multi-walled carbon nanotubes were introduced to impart electrical conductivity. Various compositions of nanocomposites were tested under constant stress in creep and recovery. A four-element mechanistic Burger model was employed to model the creep phase of the composites, while a Weibull distribution function was employed to model the recovery phase of the composites. Finite element analysis using Abaqus enabled numerical modelling of the creep phase of the composites. Both analytical and numerical solutions were found to be consistent with the experimental results. Creep and recovery were dependent on: (i) composite composition; (ii) compatibilizers content; (iii) carbon nanotubes that formed a percolation network.

Cellulose fibre-cellulose acetate hybrid composites with nanosilica

Abstract Biocomposites incorporating cellulose fibres, a renewable resource, have high modulus and strength and flexibility suitable for structural applications. Solution casting, ultrasonication, and compression moulding methods were used to prepare the specimens. Results show that plasticiser indeed improved the flexibility of the composite and adding fillers further enhanced the performance of the composite.

Bio-composites based on cellulose acetate and kenaf fibers: Processing and properties

Research on bio-composites is important because of its positive environmental impact. In this study, bio-composites based on plasticised cellulose acetate and kenaf fibers were prepared by solution casting and compression moulding methods. The fibers were chemically treated to remove lignin, hemicellulose and impurities. Mechanical, morphological and thermal properties of the bio-composites were studied. Introduction of chopped kenaf fibers increased the storage modulus. The flexural storage modulus of the composite was affected with the introduction of moisture. Moisture behaved similar to the effect of plasticiser, it reduced the modulus.

Assessing environmental impact of textile supply chain using life cycle assessment methodology

Abstract The environmental impact of textile supply chain of selected cotton, wool and polyester apparels consumed in Australia was accessed in this study using life cycle assessment methodology. The environmental impact category, climate change was used for this assessment. Climate change is related to the emissions of greenhouse gases to the atmosphere and the reference unit of climate change impact category is kg CO2 equivalent. The environmental impact of these apparels was then scaled up based on their total consumption in Australia in 2015. The results highlight the differences in environmental impact between the three apparels. This study demonstrates that the main contributor to climate change is the consumer use stage for cotton and polyester apparel whereas wool apparel production process contributes more impact than consumer use stage. Energy use is the main factor of environmental impact. Sensitivity analysis was carried out based on the different parameters used to develop baseline model, such as change of transport from airfreight to sea freight; change of transport distance, change of consumer laundering behaviour. Around 10% CO2 equivalent emission can be reduced from base case by reducing washing machine energy up to 40%. A high efficient washing machine and full load machine wash can save energy and reduce carbon emission.

Characterization of nanocomposite filaments developed for additive manufacturing

The study aims to characterize innovative filaments in the form of polyolefin-rubber nanocomposites developed for additive manufacturing. Polyolefin-rubber filaments were consisted of linear low density polyethylene and de-vulcanised, activated rubber. A compatibilizer in the form of maleic anhydride grafted polyethylene was used to enhance adhesion between the two phases. Multi-walled carbon nanotubes were introduced for electrical conductivity. Various compositions of filament material were tested for mechanical properties, electrical conductivity and time-dependent deformation behavior as demonstrated in creep-recovery experiments. A four element model of Maxwell and Voigt-Kelvin was employed to analyze the creep behavior of the nanocomposites. Results were discussed in terms of the effect of (i) carbon nanotubes, (ii) compatibilizers and (iii) composition of each nanocomposites.

Modeling the elastic modulus of HDPE in terms of stress-dependent thermally activated rate process

If a three-element mechanical model incorporating a stress-dependent thermally activated rate process is used to predict the instantaneous and anelastic components of elastic modulus of high density polyethylene, it is suggested that the measured elastic modulus determines the anelastic response rather than an instantaneous response and, furthermore, it is related to an interlamellar shear rather than a slip process in the crystalline region.