Mohammed Fahim

Tribology of natural fiber polymer composites

Natural fibers and their composites Introduction to tribology of polymer composites Sisal reinforced polymer composites Jute reinforced polymer composites Cotton reinforced polymer composites Bamboo reinforced polymer composites Wood reinforced polymer composites.

1 - Natural fibers and their composites

This chapter gives an introduction to the types of vegetable fibers that can be extracted from different parts of plants and to their sources. These fibers, extracted from plants such as sisal, cotton, jute, bamboo, wood, etc., are popularly known as natural (plant) fibers. They are biodegradable and, following surface treatments, they develop mechanical properties close to those of synthetic fibers. By virtue of this, they form an important class of fibrous reinforcements for fiber reinforced polymer composites. These composites, in turn, enable the development of tribological components having excellent wear, friction and lubrication properties which find numerous applications in industry, particularly in the automotive sector.

Role of polymeric matrices in improving wear resistance of irradiated FRP composites

The present paper reports the effect of different resin matrices on the abrasive wear behaviour of woven fabric composites based on them. Three different resin systems and a common glass fibre reinforcement were used in the present study. It was found that polymer composites based on the epoxy resin system show maximum wear resistance. This has been attributed to the fact that fibre-matrix interfacial bonding is very strong between the glass fibres and epoxide resin. The bonding resists composite failure and improves on irradiation.

4 - Jute reinforced polymer composites

This chapter deals with the structural, thermal and mechanical characterization of jute fibers extracted from the plants Corchorus capsularis and Corchorus olitorius. The strength properties of jute fiber and its compatibility with polymers are excellent. Consequently, a spectrum of composites including jute-epoxy, jute-polyester, jute-phenol formaldehyde and jute-polypropylene, etc. have been developed and have found uses such as low cost housing elements, silos for grain storage and small fishing boats. Surface treatment of jute fibers and use of coupling agents strongly influence the tribological properties of jute fiber reinforced polymer composites. The chapter discusses the important issues related to the tribological behavior of jute-polymer composites, particularly for anti-friction bearing applications.

2 - Introduction to tribology of polymer composites

This chapter gives a brief introduction to the interdisciplinary subject of tribology which is a relatively new subject dealing with the interface between two or more bodies in relative motion such as in gears, bearings, piston–cylinder assembly, gyroscopes, etc. In broader terms tribology, derived from the Greek word tribos which means rubbing, deals with the subject of friction, wear, lubrication and related phenomena. Tribological characterization of a material, determining its wear and friction coefficient and lubrication properties at different operating parameters such as load, sliding distance, sliding velocity, temperature, etc., assumes paramount significance with regard to developing economically viable and energy efficient tribo-materials.

5 - Cotton reinforced polymer composites

Cotton grows around the seeds of the cotton plant which belongs to the genus Gossypium. This chapter discusses the utility of cotton as reinforcement in polymer composites for automotive applications. Polymer composites based on plant fibers are extensively used for thermo-acoustic insulation, and such insulating materials are mainly based on cotton fibers. The chapter deals with the structural, thermal and mechanical characterization of cotton fibers and polymer composites based on them. Cotton as a reinforcement influences the tribological properties of cotton polymer composites in different wear modes. The material acts as a lubricant in wear related situations. These issues are discussed in detail in this chapter.

6 – Bamboo reinforced polymer composites

This chapter deals with the thermal, structural and mechanical characterization of bamboo subjected to various chemical treatments. Bamboo has a unique structure which resembles that of a unidirectional fiber reinforced composite with many nodes along its length. The mechanical and tribological characterization of bamboo and bamboo powder/fiber reinforced polymer composites is strongly influenced by the orientation of bamboo along the test direction. The tribological properties of bamboo are also influenced by the vascular bundles, their orientation and their content. These issues and their influence on the resultant tribological properties of bamboo in various wear modes are discussed in this chapter.

7 - Wood reinforced polymer composites

This chapter deals with the structural, thermal, mechanical and tribological characterization of wood flour/fiber reinforced polymer composites (WPCs). These composites are composed of wood fibers from recovered sawdust reinforced in polymeric matrices, and they can be moulded into intricate shapes. They are environmentally-friendly and require less maintenance. By virtue of these properties their potential applications such as in tribo-composites are being explored. The issues related to the tribological behavior of WPCs are the prime focus of this chapter and are discussed at length. In addition, the tribological properties of wood and the effect of its orientation with respect to test direction in different wear modes are also discussed.

3 - Sisal reinforced polymer composites

This chapter deals with the structural, thermal and mechanical characterization of sisal fibers extracted from the plant Agave sisalana. The surfaces of these fibers are modified using different chemical and physical treatments in order to obtain a strong interface between fibers and the polymeric matrices while developing a composite. The coupling agents used for fibers and polymer matrix strongly influence the tribological properties of the resulting composite. Sisal fiber reinforced polymer composites such as sisal-epoxy, sisal-polyester, sisal-phenolic, sisal-polyethylene, etc. possessgood mechanical as well as tribological properties. Sisal fibers also serve as a very useful ingredient offering desired properties in friction composites.

Modelling the effect of artificial weathering on abrasive wear behaviour of glass-polyester composites

Moisture absorption degrades interfacial strength and induces expansional strains in fibre-polymer composites. These strains subsequently affect the abrasive wear behaviour of composites subjected to boiling water treatment. A wear model is suggested, which quantitatively estimates the wear performance of boiling-water-treated glass-polyester composites. The theoretical model is in concurrence with experimental results.