Fabrication of bamboo fibre reinforced polymer matrix composites.
Bamboo is peffrennial plant having its origin in Indiansub-continent, its scientific name and its classification is given below in table 1. There are about 75 genres of bamboo and 1500 species of bamboo. The structure of a bamboo visualised as below by Liese  is shown below in Figure 1.
[FIGURE 1 OMITTED]
Composite materials can be classified based on the matrix material used and the type of reinforcement used. Based on the matrix material used, composite can be broadly classified into Ceramic matrix composites, metal matrix composites and polymer matrix composites. Each type of composites have their own advantages and applications. Based on the type of reinforcement used, a composite material is classified into fibre reinforced composites in which the fibre used for reinforcement may be unidirectionally aligned or it may be dispersed in whisker form in the matrix, and particle reinforced composites in which a metal or oxide or nitride or carbide material is dispersed in the matrix medium to improve certain properties as shown in figure 2.  Some commonly used fibres are glass fibres, carbon fibres, and metallic fibres also can be used. A fibre reinforced polymer (FRP) is a composite material in which the matrix is a polymer which is reinforced with high-strength fibres like glass, aramid and carbon. Common thermoplastic resin matrix materials are polypropylene, polyethylene, and poly vinyl chloride
[FIGURE 2 OMITTED]
Because of environmental concern and health hazards, instead of metallic and non-organic fibres, bio degradable organic bio fibres are used to a large extent in composite materials that are used for various industrial applications like automobile parts (doors and body panels) and in sound damping applications.
For our work the resin selected was thermosetting Epoxy resin. The properties of this resin are shown in table 1. On comparing these properties as well as the cost among various resins including Polyester resin and Vinyl ester resin, epoxy resins have lower density, higher elastic modulus and tensile strength but the major disadvantage is that the impact strength which is less than other polymer material.
Similarly the reinforcement material was selected as bamboo fibre. In the table 2, based on literature survey conducted the physical properties of various fibre materials are listed along with references. Among the materials considered for making the reinforcement, the concentration was on bio fibres so E glass and S glass fibres were not eligible. Of all other materials, bamboo has least density and the young's modulus of 36 GPa was the highest compared to Cotton (12.6 GPa), Jute (26.5 Gpa), flax (27.6 GPa), Sisal (22 GPa) and Coir (6 MPa). It also exhibits considerable tensile strength of 441 MPa. Also the bamboo fibres are often referred as natural glass fibres because of its high specific strength (strength to weight ratio) but they are brittle in nature. So the fibres are to be drawn carefully.
a) Bamboo fibre:
Bamboo can be effectively used as a reinforcement material because, the cellulose fibres are arranged in such a way that they are along the length of bamboo. This arrangement provides maximum tensile strength and rigidity along the direction.
According to K Okubo et. Al, bamboo tree has large number of vascular bundles and xylem. Each vascular bundle contains four sheaths of fibres of diameter 20 [micro]m, two vessels and some sieve tubes and they are surrounded by Xylem. .
Bamboo is basically made up of cellulose which accounts for 60%, hemi cellulose and lignin which accounts for about 32%.  Figure 2 shows the cross section of bamboo fibre and the enlarged SEM view of a single bundle is shown in figure 2 (b) where the sheaths of fibres and vessels and tubes are clearly visible.
b) Matrix material:
[FIGURE 3 OMITTED]
B. Chemical Treatments:
Bio fibres which are used to reinforce thermosetting as well as thermoplastic materials are subjected to chemical treatment to obtain various required characteristics which are desirable in many ways. One of the most commonly used chemical treatment process is mercerisation which is also known as alkaline treatment. This process disturbs the hydrogen bond in network structure which increases the surface roughness which will result in better mechanical interlocking between the fibre and matrix material. This process also removes a little amount of lignin, wax and oils that cover the external surface of the fibre cell wall and also depolymerizes cellulose which exposes the crystallites.  Also this process increases the amorphous cellulose by decreasing the crystalline cellulose as showed by studies done by Morrisionet. Al.,  Garcia et. Al., . Another major effect of this process is the increase in amount of cellulose being exposed. As per the work of Valdez et al., this increase in amount of cellulose increases the number of sites where reaction between the matrix and fibre can occur. 
[FIBER] - OH + NaOH [right arrow] [FIBER] - 0 - Na + [H.sub.2]O
From the above equation put forward by Agarwal et. Al., it is clear that on adding aqueous sodium hydroxide to the natural fibre, the ionisation of hydroxyl group found in fibre to alkoxide group is achieved.  Another major effect of this process is improvement of mechanical strength (both fibre strength and stiffness). As per the studies of Van de Weyenberg et al.  improvement of tensile properties to a level of 30% was observed.
Jaco et al.,  and Mishra et al., studies show that maximum tensile strength is achieved at room temperature when the NaOH solution concentration is 4 - 5% as more amount of alkali will damage the bamboo fibre and result in excess removal of lignin.
b) Acetylation of Natural Fibres:
Acetylation process involves plasticization of cellulosic natural fibre by esterification process. In this process acetyl functional group (C[H.sub.3]COO-) is introduced into an organic compound. On doing this process acetic acid (C[H.sub.3]COOH) is produced as a by-product and this product must be removed.
This chemical treatment process involves the substitution of polymer hydroxyl groups with acetic anhydride (CH3-C(=O)-O-C(=O)-CH3) which makes the fibres hydrophobic or inactive to water. The reaction involved in this process according to Hill ASC et al.,  is as follows
Fiber - OH + C[H.sub.3] - C (= 0) - 0 - C(= O) - C[H.sub.3] [right arrow] Fiber - OCOC[H.sub.3] + C[H.sub.3]COO
This process increases the dimensional stability and reduces the water affinity of the natural fibre. [17,18,19,20].
As observed by Nair et al.  Another major improvement because of this process on the fibre with respect to bonding between the fibre and matrix is that the surface roughness increases many levels and becomes very rough thereby providing better mechanical interlocking with the matrix material and also further increase in mechanical properties of natural bio fibres were observed because of better thermal stability and improved fibre matrix interactions.
c) Benzoylation Treatment:
As per the research work of Joseph et al.,  this treatment process involves the treatment of fibre With Benzoyl chloride and NaOH solution which results in increase of hydrophobic nature of the fibre. The reaction of this treatment is shown in this equation as Fibre - OH + Na OH ->Fibre - [O.sup.-] [Na.sup.+] + [H.sub.2]O
Based on previous works carried out this process results in improved thermal stability of composites compared to untreated fibres.
C. Preparation Of Composites:
There are several methods used for the preparation of composites. Some of them are as follows:
1. Hand Lay Up Process
2. Spray Up Process
3. Vaccum bagging Process
4. Pre Preg Process and others
Here by we are using Hand Lay Up process.
a) Hand Lay Up Technique:
The fiber plies are cut to size from the bamboo fiber. The appropriate numbers of fibre plies are taken (two for each) and weighed. The epoxy resin and hardeners are weighed and mixed using glass rod in a bowl Carefully without air bubbles as they may cause failure in matrix material.
The subsequent fabrication process consist of first putting a releasing film on the mould surface. Next a polymer coating is applied on the sheets. Then fiber ply of one ply is put and proper rolling has to be done. Then resin is again applied, next to it fiber ply of another fiber ply is put and rolled. The Rolling is done using cylindrical mild steel rod. This procedure is repeated until required alternating fiber layer has been laid. On the top of the last ply a polymer coating is done which serves to ensure a good surface finish. Finally a releasing sheet is put on the top; a light rolling is carried out. Then a 20 kgf weight is to be applied on the composite . It has to be left for 72 hrs to allow sufficient time for curing and subsequent hardening
[FIGURE 4 OMITTED]
Preparation Of Frp:
To prepare the bio FRC, first the bamboo fibres were extracted from bamboo plant.
The process involves immersing the fibres in 2% NaOH solution for a period of 24 hours at 2000C which degummed and defibrillated the bamboo fibres. This resulted in increase of tensile strength up to 25% of untreated bamboo fibres using prescribed test method .
The fibres after mercerization are subjected to acetylation process, in which they are treated with glacial acetic acid and acetic anhydride containing two drops of sulphuric acid which are obtained form M/S Royal Scientific for a period of 2 hours. The bamboo fibres surface roughness increased which results in better mechanical interlocking between the araldite matrix and fibre.
Next the fibres arepre-treated with alkaline to activate the hydroxyl group of cellulose and lignin in fibre and then it is suspended in 10% NaOH and benzoyl chloride solution for 20 minutes. After this treatment it was soaked in [C.sub.2][H.sub.5]OH for an hour to remove the benzoyl chloride and then washed with water and dried for 48 Hours at room temperature. This removed the lignin.
E. Fabrication Of Frp Composite Laminate:
Initially any moisture content in bamboo fiber were removed by heating it in furnace at 1250C for an hour. The araldite AW106 resin are mixed with 10% by weight of hardener HV 953 IN which are obtained from M/s Royal Scientific, Trichy, Tamilnadu, after removal of air bubbles. The fibres were soaked in this mixture and left for drying for 24 hours which resulted in formation of a composite lamina which had a dimension of 15cm x 1 cm x 1cm (LXBXW) shown in fig 5. The formed lamina is checked by non-destructive testing methods for internal defects at M/s G.B. Engg. Enterprises, Pudukudi, Trichy and they are found to be free of major defects (voids more than 1mm). As bamboo has minimum strength across the fibres, multi-layered composites of different fibre orientations, with a view to improving strength in all directions, have been developed. The composite laminate is constructed by cutting the plate and arranging the unidirectional fibre plate in required direction and applying the resin hardener mixture between individual laminas.
[FIGURE 5 OMITTED]
Scope For Future Work:
1. Hardness of the composite lamina is to be tested using brinell and Rockwell hardness.
2. Tensile test is to be done on the lamina to determined the tensile properties.
3. Drilling is to be done as different laminae can be joined together using holes drill and various defects that may occur during drilling process.
[1.] Avtar singh saroya, Vishvendra Meena, Study Of Mechanical Properties of Hybrid Natural Fibre Composite.
[2.] Wambua, P., J. Ivens and I. Verpoest, 2003. Natural Fibres: Can They Replace Glass in Fibre Reinforced Plastics, Composites Science and Technology, 63: 1259-1264.
[3.] Ahmad, I., A. Baharum and I. Abdullah, 2006. Effect of Extrusion Rate and Fibre Loading on Mechanical Properties of TwaronFibre-thermoplastic Natural Rubber (TPNR) composites, Journal of Reinforced Plastics and Composites, 25: 957-965.
[4.] NabiSaheb, D. and J.P. Jog, 1999. Natural Fibre Polymer Composites: A Review, Advanced in Polymer Technology, 18: 351-363.
[5.] Holbery, J and D. Houston, 2006. Natural-Fibre-Reinforced Polymer Composites in Automotive Applications, 58(11): 80-86.
[6.] Hajnalka, H., I. Racz and R.D. Anandjiwala, 2008. Development of HEMP Fibre Reinforced Polypropylene Composites, Journal of Thermoplastic Composite Materials, 21: 165-174.
[7.] Okubo, K. et al., 2004. Development of bamboo-based polymer composites and their mechanical properties Composites: Part A 35: 377-383.
[8.] Jain, S., R. Kumar, U.C. Jindal, 1992. Mechanical behaviour of bamboo and bamboo composite. J Mater Sci., 27: 4598-604.
[9.] van de Velde K., P. Kiekens, 2001. Polym Test 20:885
[10.] Agrawal, R., N.S. Saxena, K.B. Sharma, S. Thomas, M.S. Sreekala, 2000. Mater SciEng: A 277: 77.
[11.] Morrison III W.H., D.D. Archibald, H.S.S. Sharma, D.E. Akin, 2000. Ind Crops Prod, 12: 39.
[12.] Garcia-Jaldon, C., D. Dupeyre, M.R. Vignon, 1998. Biomass Bioenergy, 14: 251.
[13.] Valadez-Gonzalez, A., J.M. Cervantes-Uc, R. Olayo, P.J. Herrera- Franco, 1999. Compos B: Eng. 30: 309.
[14.] van de Weyenberg, I., J. Ivens, A. De Coster, B. Kino, E. Baetens, I. Vepoes, 2003. Compos SciTechnol, 63: 1241.
[15.] Jacob, M., S. Thomas, K.T. Varughese, 2004. Compos SciTechnol, 64: 955.
[16.] Mishra, S., A.K. Mohanty, L.T. Drzal, M. Misra, S. Parija, S.K. Nayak, S.S. Tipathy, 2003. Compos SciTechnol, 63: 1377.
[17.] Hill, A.S.C., H.P.S. Abdul Khalil, M.D. Hale, 1998. Ind Crops Prod, 8(1): 53.
[18.] Paul, A., K. Joseph, S. Thomas, 1997. Compos SciTechnol., 57(1): 67.
[19.] Rong, M.Z., M.Q. Zhang, Y. Liu, G.C. Yang, H.M. Zeng, 2001. Compos SciTechnol., 61: 1437.
[20.] Sreekala MS, Thomas S (2003). Compos SciTechnol., 63(6): 861.
[21.] Manikandan Nair, K.C., S. Thomas, G. Groeninckx, 2001. Compos Sci Technol., 61(16): 2519.
[22.] Joseph, K., L.H.C. Mattoso, R.D. Toledo, S. Thomas, L.H. de Carvalho, L. Pothen, S. Kala, B. James, 2000. Frollini E, Lea'o AL, Mattoso LHC, Sa~n Carlos (eds) Natural polymers and agrofibres composites. Embrapa, USP-IQSC, UNESP, Brazil
[23.] NeleDefoirdt et al., 2010. Assessment of the tensile properties of coir, bamboo and jute fibre, Composites: Part A 41: 588-595.
[24.] LIESE, W., 1986. "Recent Research on Bamboo", Proceedings of the International Bamboo Workshop, Hangzhon, People's Republic of China, p: 196.
[25.] Peters, S.T., 1998. Handbook of Composites, 2nd ed., Chapman & Hall.
[26.] ASTM. 2010. Standard test method for tensile properties of yarns by the single-strand method. ASTM D2256. Philadelphia, PA: ASTM
(1) R. Manikandan, (1) T.R. Manimaran, W. Roopesh Babu, (2) M. SAMUEL M. Tech.
(1) Department of Mechanical Engineering, Indra Ganesan College of Engineering, Trichy-12, Tamil Nadu, India.
(2) Assistant Professor, Indra Ganesan College of Engineering, Trichy-12, Tamil Nadu, India.
Received 25 February 2016; Accepted 10 April 2016; Available 15 April 2016
Address For Correspondence:
R. Manikandan, Department of Mechanical Engineering, Indra Ganesan College of Engineering, T richy-12, T amil Nadu, India.
Table 1: Bamboo Nomenclature Group Angiosperm Order Monocotyledon Family Poaceae Subfamilies (i) Arundinoideae, (ii) Pooideae, (iii) Chloridodeae, Panicoideae, and (iv) Bambusoideae. Table 2: Properties of Epoxy Resin (Matrix) Density Elastic Tensile Compressive Elongation g/[cm.sup.3] modulus strength strength GPa MPa MPa % 1.1 - 1.4 3 - 6 35 - 100 100 - 200 1-6 Density Cure Water Impact g/[cm.sup.3] shrinkage absorption strength % 24h@20[degrees]C J/m 1.1 - 1.4 1-2 0.1 - 0.4 0.3 Table 3: Properties of fibre materials. Fibre Density Elongation Tensile strength g/[cm.sup.3] % MPa Cotton 1.5 - 1.6 7.0 - 8.0 400 Flax 1.5 2.7-3.2 500-1500 Hemp 1.47 2 - 4 690 Kenaf 1.45 1.6 930 Sisal 1.5 2.0 - 2.5 511 - 635 Coir 1.2 30 593 E - glass 2.5 0.5 2000 - 3500 S - glass 2.5 2.8 4570 Bamboo 0.8 1.3 441 Fibre Elastic Modulus Reference GPa Cotton 5.5 - 12.6 2,3 Flax 27.6 4 Hemp 70 4 Kenaf 53 4 Sisal 9.4 - 22 5 Coir 4 - 6 6 E - glass 70 6 S - glass 86 6 Bamboo 36 7
|Printer friendly Cite/link Email Feedback|
|Author:||Manikandan, R.; Manimaran, T.R.; Babu, W. Roopesh; Samuel, M.|
|Publication:||Advances in Natural and Applied Sciences|
|Date:||Apr 1, 2016|
|Previous Article:||Experimental study on performance and emission characteristics of a direct injection compression ignition engine with Fe3O4 nanoparticles.|
|Next Article:||Performance analysis of palmprint pattern recognition techniques.|