**1. Introduction**

Bamboo is a natural biomaterial and consists of vascular bundles (cellulose fibers). The vascular bundles are composed of many right-handed spiral phloem fibers at a certain spiral angle. Lakkad and Patel [1] investigated the mechanical properties of bamboo specimen, such as, Young's modulus, tensile strength, compressive strength, and interlaminar shear along

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fibers and the tensile strength across fibers. Bamboo has higher specific tensile strength than glass-reinforced plastic (GRP) and mild steel with chopped strand mat and woven roving, and comparable specific modulus with mild steel and GRP. Godbole and Lakkad [2] studied the influences of water absorption on mechanical performances of bamboo. The tensile strength, compressive strength, tensile modulus, and interlaminar shear of bamboo specimen reduced after soaking or boiling in distilled water. Li et al. [3] designed a double-fold spiral bionic composite model imitating the characteristic structure of bamboo. The tensile strength of carbon fiber reinforced tin composites processed by the bionic model was higher by 40% than that of unidirectional carbon fiber reinforced ones.

more biological fiber reinforced composite materials have been used as tribological ones. Dimensions and orientation of fibers in friction materials are important factors affecting its tribological properties. Such natural biomaterials with composite structures as bamboo provide clues and ideas for designs of friction materials, for example, antifriction materials and wear-resistant materials. The excellent structure of bamboo fiber was investigated by Paramesaran and Liese [24]. Bamboo fibers were used as one of the components in friction materials because of their low density and excellent mechanical properties in comparison to that of glass fibers [25–27]. Meanwhile, the bamboo fiber is a kind of plant fiber with cellulose structure and vascular bundles consisting of the fiber bundle and sclerenchyma sheaths.

In the present study, sliding wear behavior of bamboo (*Phyllostachys pubescens*) against a gray iron (HT200) was investigated in the cases of dry friction. The wear volume of bamboo was a function of the sliding velocity, the normal load, and the relative orientation of bamboo fibers with respect to the friction surface. Moreover, the mechanical and physical properties of the bamboo fibers were studied. Comparative studies were performed to investigate the effects of bamboo fiber content on the friction performances of friction materials. The tribological property of the friction materials was evaluated and discussed at the test temperature of 100–350°C. The wear surface morphologies and the wear mechanism of bamboo fiber reinforced friction materials (BFRFMs) were analyzed using scanning electron

Bamboo specimens of dimensions 14 × 10 × 8 mm were cut from the air-dry bamboo (*P. pubescens*). Three types of specimens were prepared. The friction surface was normal to the cellulose fiber orientation for the N-type, and parallel to both the cellulose fiber orientation and the


Sliding wear properties of bamboo specimens were studied on a block-on-ring machine. The counterfaces were made of a gray iron (HT200) and had a diameter of 40 mm. The normal loads were from 30 to 120 N and the sliding velocity was set as 0.42 and 0.84 m s−1, respectively; the total sliding distance was about 504 m and the surrounding temperature was about 23°C during all these tests. Worn morphologies of bamboo specimens and gray iron rings and

Bamboos possess the excellent wear properties, and in present paper, bamboo fibers are selected as the reinforced fibers. The fresh bamboo (*Phyllostachys heterocycla*) was first cut into pieces after removing the outer and inner surface materials. The bamboo pieces were



Bamboo Wear and Its Application in Friction Material http://dx.doi.org/10.5772/intechopen.69893 89


microscopy (SEM).

**2.1. Bamboo wear experiments**

**2. Experimental materials and methods**

outside surface of bamboo stem for the PS

fiber orientation with the sliding direction.

0.5 mm beneath the natural surface for the P<sup>S</sup>

wear debris were examined by SEM and stereoscopy.

**2.2. Preparation of bamboo fiber specimens**

Yakou and Sakamoto [4] investigated abrasive performances of bamboo specimen with carborundum paper as the counterface. They indicated that the abrasive wear rate of the inner layer was higher than that of the outside surface layer for bamboo specimens of normal- and parallel-oriented cellulose fibers relative to the friction surface. Tong et al. [5] evaluated the abrasive wear properties of bamboo specimens by using quartz sand particles as abrasive material. The results showed that the abrasion resistance of bamboo specimen was decided by the relative orientation of the cellulose fibers with respect to the friction surface and by the size of abrasive particles. The abrasive wear rate increased with the increase of size of abrasive particles. Specimens with the normal orientation of cellulose fibers to the friction surface presented better abrasion resistance than those with the parallel orientation; the inner layer had lower abrasion resistance than the outside layer; and the cellulose fibers had better resistance than the matrix tissue. The dry sliding wear behavior of bamboo was studied in order to obtain some useful information for designs of friction materials.

On the other hand, friction materials are the key parts of automobiles brake systems, and many studies have been investigated to improve brake properties in order to adapt the people's requirement for security and rapid development of automobile [6]. To acquire comfortable and dependable brake properties of the automobiles, braking friction materials usually contain more than 10 different components. The components are normally classified as reinforced fibers, binders, property modifiers, and fillers. Each component plays an important role for brake performance under different braking conditions. Many studies investigated the effect of different components on brake performance [7, 8]. A related review on frontiers of fundamental tribological research emphasized the concern over the environmental protection, for instance, biodegradability in the development of tribo-materials [9].

Asbestos fibers, which have been widely used in braking friction materials, are harmful to human health and environment; they have been forbidden to be used for manufacturing friction materials. Therefore, substitutes of the asbestos fibers, such as steel fibers, Al<sup>2</sup> O3 fibers, carbon fibers, glass fibers, aramid fibers, copper fibers, and their hybrid fibers [10–12] have been studied and selected. Moreover, many study results showed that these fibers have excellent properties for friction materials; however, there are many shortcomings (such as weak combination strength, high cost, and high noise) to be resolved when these fibers are applied in friction materials.

Many researches have focused on the utilization of biological fibers with the function of protecting environment, such as betel nut fibers [13], cotton fibers [14, 15], jute fibers [16–18], kenaf and ramie fibers [19], sisal and flax fibers [20–22], and sugarcane fibers [23]. More and more biological fiber reinforced composite materials have been used as tribological ones. Dimensions and orientation of fibers in friction materials are important factors affecting its tribological properties. Such natural biomaterials with composite structures as bamboo provide clues and ideas for designs of friction materials, for example, antifriction materials and wear-resistant materials. The excellent structure of bamboo fiber was investigated by Paramesaran and Liese [24]. Bamboo fibers were used as one of the components in friction materials because of their low density and excellent mechanical properties in comparison to that of glass fibers [25–27]. Meanwhile, the bamboo fiber is a kind of plant fiber with cellulose structure and vascular bundles consisting of the fiber bundle and sclerenchyma sheaths.

In the present study, sliding wear behavior of bamboo (*Phyllostachys pubescens*) against a gray iron (HT200) was investigated in the cases of dry friction. The wear volume of bamboo was a function of the sliding velocity, the normal load, and the relative orientation of bamboo fibers with respect to the friction surface. Moreover, the mechanical and physical properties of the bamboo fibers were studied. Comparative studies were performed to investigate the effects of bamboo fiber content on the friction performances of friction materials. The tribological property of the friction materials was evaluated and discussed at the test temperature of 100–350°C. The wear surface morphologies and the wear mechanism of bamboo fiber reinforced friction materials (BFRFMs) were analyzed using scanning electron microscopy (SEM).
