Postgraduate symposium on biocomposite technology 2015, 03 March 2015

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3 Mechanical properties of woven kenaf reinforced Phenolic resin produced using a hot press technique Suhad D. Salman 1,3,*, Z. Leman 1, M.T.H. Sultan 2, M. R. Ishak 2,4 and F. Cardona 2 1 Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, Serdang, Selangor, Malaysia 2 Aerospace Manufacturing Research Centre (AMRC), Level 7, Tower Block, Faculty of Engineering, UPM Serdang, Selangor, Malaysia 3 Materials Engineering Department, Faculty of Engineering, The University of Mustansiriyah, Baghdad, Iraq 4 Laboratory of Bio-Composites Technology, Institute of Tropical Forestry and Forest Products (INTROP), Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia * suhaddawood2007@yahoo.com Abstract Kenaf fiber reinforced composite shows a bright future, among other natural fiber reinforced composites due to its availability and readiness to be used with various manufacturing processes. Unidirectional long fibers or randomly oriented short fiber shapes are the most common type of kenaf fibers that were investigated with either epoxy or polyester resin in previous works. This work evaluates the tensile and flexural properties of plain woven kenaf fabric with Phenolic resin, in order to assess their suitability as lignocellulosic reinforced polymer composites. The hot press manufacturing technique was used to prepare the specimens and eight specimens were prepared for each test, (five replications were adopted). The results show that the plain woven kenaf/phenolic composites possess a good tensile and flexural strength and they are good candidates as reinforcement material in many applications. In addition, the tensile and flexural strength of WKFPH composite were found to be higher than the tensile and flexural strength of woven kenaf/epoxy composite, while the elongation at break exhibited by WKFPH composite was almost same. Keywords: Plain woven kenaf, Phenolic resin, mechanical, natural-based composite. Introduction In the past two decades a number of researchers have sought to use natural fibers with polymer matrix composite (PMC) and received considerable attention both in the literature and industry. Many of the woven natural fabrics are rising as a viable option to glass fiber reinforced composites in industrial applications like packaging, paper making and composite materials with many uses, including as parts in automotive, aircraft, building materials, agriculture, furniture and defense industry application and sport equipments [1]. One of the popular natural fibers is kenaf fiber, which is an annual plant due to its rapid growth, average yield of 1700 kg/ha [2]. Kenaf fibers have the advantage that they are renewable resources, low cost, light, plentiful, non-abrasive, and non-hazardous, therefore they can serve an excellent reinforcing agent for plastics [3]. Kenaf fiber possesses moderately high specific strength and stiffness that could be utilized as reinforcing materials in polymeric resins to make useful structural composite material. Kenaf has been already adopted as automobile parts due to lightweight and good mechanical properties [4]. Woven fabrics are formed in particular by interlacing of fiber bundle (yarns) to form a fabric layer, which offered advantages in terms of good dimensional stability and high packing density. The use of the plain weave technique can add structural strength to the material because it increases both the (1-4)

4 strength and the ability of energy absorption capacity. Whilst articles and even books on the overall properties of natural fiber reinforced composites have been published, the authors have concluded that a specific article on the overall characteristics of plain woven kenaf fiber reinforced Phenolic resin composites, has not yet been published and give value addition to enhance its use. In an experimental study, the tensile and flexural strength of the unidirectional kenaf fiber composites were investigated by Ochi [5] with different fiber content. Experimental results showed that the weight of composites increased linearly up to a fiber content of 50%. Several attempts have been made to study the influence of fiber content on mechanical properties of kenaf bast fiber reinforced thermoplastic polyurethane (TPU) composites with different fiber loadings was investigated by Shekeil et al. [6]. It was concluded that a 30% fiber loading display the best tensile strength, whilst the tensile modulus, thermal stability, hardness, and flexural strength increased with increase of fiber content, but the strain decreased. Even though kenaf fibers have the potential to supplement synthetic fibers in polymer composites, limitations arise with respect to mechanical performance and moisture absorption when natural fibers are used [7]. This study is a part of an ongoing study to achieve the advantages of using kenaf fibers and woven pattern on the tensile and flexural properties in order to draw a brief guideline for future development on using woven kenaf fibers. Materials and Methods In order to study the behavior of woven kenaf fibers with Phenolic resin (WKFPH) on the mechanical properties of composites, tensile and flexural test were carried out. Kenaf fiber is the main fiber that's used in this study and was supplied by ZKK Sdn Bhd, Malaysia. Table 1 shows the properties of plain woven kenaf that used in this study. The composite samples of WKFPH were made with 40% kenaf fiber weight content by using a hot press technique which leads to better fiber-to-resin bonding, as shown in Figure 1. Eight specimens were fabricated for each test, five replications were considered. Table 1: Properties of plain woven kenaf. Characterization Woven kenaf Thickness, t (mm) 2 ± 0.2 Weight (g/m 2 ) 890 Density (g/cm 3 ) 1.2 Warp density (warp/inch) 12 Weft density (weft/inch) 12 Wavelength, λ (mm) 4.2 Inter-yarn fabric porosity (ɛ) Moisture Content (%) Water Uptake (%) Average breaking strength (MPa) Average maximum strain (%) 17.3 (2-4) Figure 1: The composite specimen by using the hot press technique. Mechanical properties of WKFPH Tensile and flexural testing were carried out in the composite laboratory of the Mechanical Department, Universiti Putra Malaysia, according to ASTM D 3039 and ASTM D-790 standard [8, 9], to determine the ultimate tensile strength and ultimate flexural strength of the WKFPH. Tensile specimens were cut to the 250mm 25mm 7mm, rectangular sectional area flat strip and gage length 170mm. The rectangular shape three-point bending specimens were prepared with dimensions of 127mm 12.7mm 7mm. The distance between supports (span length) was calculated as per the

5 standard, with a ratio of 16:1. Both tests were conducted by using a universal testing machine INSTRON 3365 with the capacity of 100 KN, and crosshead speed 2 mm/min with replication 8 times. Results and Discussions Figure 2 (a) shows the tensile strength of WKFPH, the tensile stress curve is shown linearity in the first phase followed by non-linearity up to fracture. Similar trend had been reported in the study done by Khan et al. [10] on the jute fabric reinforced composites. The maximum tensile strength and modulus of WKFPH composite in this study is MPa and MPa, which is found to be higher than the tensile strength of woven kenaf/epoxy composite which were 16.46MPa and MPa [11]. The similar finding was also observed in the flexural strength of WKFPH by using a 3- point flexural test, as shown in Figure 2 (b). It is noted that the flexural stress curve is shown linearity in the first phase followed by non-linearity up to fracture, the staircase region, which lead to the sudden rupture of the specimens. The ultimate flexural strength and flexural modulus were Mpa and respectively. Generally, the increase in tensile strength and modulus of the composites is attributed to differences in the load-distribution properties. The maximum tensile strain was 2.26%, while the maximum flexural strain was 0.14%, because the flexural effect can create an interlocking structure which could result in constraints for the extension of the kenaf fiber along the directions. (a) Fig. 2: (a) Tensile properties of WKFPH of composites, (b) Flexural properties of WKFPH of composites. Conclusions The woven kenaf composite material is fabricated with Phenolic resin (WKFPH) to study the tensile and flexural properties with more emphasis. It was concluded that WKFPH composites possess a good tensile and flexural strength; therefore it is possible to be a good candidate as reinforcement material in many applications. In addition, the tensile and flexural strength of WKFPH composite was found to be higher than the tensile and flexural strength of woven kenaf/epoxy composite, while the elongation at break exhibited by WKFPH composite was almost same. Acknowledgements This work is supported by UPM under GP-IPS/2014/ and GP-IPB grant, The authors would like to express their gratitude and sincere appreciation to the Mechanical and (3-4) (b)

6 Manufacturing Engineering Department and Aerospace Manufacturing Research Centre of the Universiti Putra Malaysia. Our appreciation and gratitude also extend to the Ministry of Higher Education & Scientific Research of Iraq and to the Material Engineering Department- College of Engineering - The University of Mustansiriyah for their scientific assistance and financial support. Reference [1] Y.A. El-Shekeil, S.M. Sapuan, M.W. Algrafi., Effect of fiber loading on mechanical and morphological properties of cocoa pod husk fibers reinforced thermoplastic polyurethane composites. Materials and Design 64, (journal) [2] N. Saba, M. Jawaid, K.R.Hakeem, M.T.Paridah, A.Khalina, O.Y.Alothman., Potential of bioenergy production from industrial kenaf (Hibiscus cannabinus L.) based on Malaysian perspective. Renewable and Sustainable Energy Reviews 42, (journal) [3] Imtiaz Ali, Krishnan Jayaraman, Debes Bhattacharyya, Implications of fiber characteristics and mat densification on permeability, compaction and properties of kenaf fiber panels. Industrial Crops and Products (journal) [4] Qatu MS. Application of kenaf-based natural fiber composites in the automotive industry. In: Proceedings of SAE 2011 world congress and exhibition. Detroit; April, (paper in proceedings) [5] Shinji Ochi., Mechanical properties of kenaf fibers and kenaf/pla composites. Mechanics of Materials 40, (journal) [6] Y.A. El-Shekeil, S.M. Sapuan, M. Jawaid, O.M. Al-Shuja a. Influence of fiber content on mechanical, morphological and thermal properties of kenaf fibers reinforced poly(vinyl chloride)/thermoplastic polyurethane poly-blend composites. Materials and Design 58 (2014) (journal) [7] Sgriccia N, Hawley MC, Misra M. Characterization of natural fiber surfaces and natural fiber composites. Compos Part A: Appl Sci Manuf 2008; 39: (journal) [8] ASTM D :2010. Standard test method for tensile properties of polymer matrix composite materials. (standard) [9] ASTM D 790: Standard test methods for flexural properties of unreinforced and reinforced plastics and electrical insulating materials. (standard) [10] Khan GMA, Terano M, Gafur MA, et al. Studies on the mechanical properties of woven jute fabric reinforced poly(l-lactic acid) composites. J King Saud Univ Eng Sci (journal) [11] R Yahaya, SM Sapuan, M Jawaid, Z Leman and ES Zainudin, (2014). Mechanical performance of woven kenaf-kevlar hybrid composites. Journal of Reinforced Plastics and Composites published online 7 November (journal) (4-4) View publication stats