Nadendla Srinivasababu, J. Suresh Kumar,

K. Vijaya Kumar Reddy, and Gutta Sambasiva Rao

Contents

8.1 Introduction……………………………………………………………………………………………………. 126

8.2 Materials and Methods……………………………………………………………………………………….. 128

8.2.1 Pure Splitting Method…………………………………………………………………………….. 128

8.2.2 Chemical Treatment……………………………………………………………………………….. 129

8.2.3 Fiber Characterization……………………………………………………………………………… 129

8.2.4 Fabrication and Testing of Composites…………………………………………………………. 130

8.3 Results and Discussion………………………………………………………………………………………. 131

8.3.1 Physical and Mechanical Properties of Fiber……………………………………………………. 131

8.3.2 Fiber Morphology………………………………………………………………………………….. 131

8.3.3 Tensile Properties…………………………………………………………………………………. 133

8.3.4 Flexural Properties…………………………………………………………………………………. 135

8.3.5 Impact Properties…………………………………………………………………………………… 137

8.3.6 Dielectric Properties……………………………………………………………………………….. 138

8.4 Conclusions……………………………………………………………………………………………………. 138

References………………………………………………………………………………………………………….. 139

N. Srinivasababu (*)

Department of Mechanical Engineering, Vignan’s Lara Institute of Technology and Science, Vadlamudi 522 213, Andhra Pradesh, India e-mail: cnjlms22@yahoo. co. in

J. S. Kumar ♦ K. V.K. Reddy

Department of Mechanical Engineering, JNTUH College of Engineering, Hyderabad 500 085, Andhra Pradesh, India

G. S. Rao

Mechanical Engineering Department, V. R. Siddhartha Engineering College, Vijayawada 520 007, Andhra Pradesh, India

K. R. Hakeem et al. (eds.), Biomass and Bioenergy: Processing and Properties,

DOI 10.1007/978-3-319-07641-6_8, © Springer International Publishing Switzerland 2014

Abstract Natural fibers and their composites play a vital role in the fabrication of various components in automobile and structural components because of their supe­rior specific performance. In order to satisfy day-to-day requirements in various sectors, new eco-friendly materials are introduced which are reinforced with renew­able, cheap, and easily available natural fibers. A new leaf fiber, i. e., Indian date leaf (IDL), is introduced in this work and extracted by “pure splitting method” (PSM). Initially, the fiber is characterized for its density and tensile behavior. Surface morphology of the fiber is also examined by using JEOL JSM scanning electron microscope (SEM). Using IDL and IDL CT fibers as reinforcement in the polyester matrix, the composites are fabricated by wet lay-up technique. The fabricated com­posite specimens are tested to determine mechanical and dielectric properties as per ASTM procedures. Chemically treated IDL fiber exhibited 25.69 %, 4.6 % more tensile strength and modulus than untreated ones, and the stress vs. strain curves are drawn for all tested specimens. The specific tensile strength of chemically treated IDL FRP composites is 1.38 times higher than untreated IDL FRP composites whereas specific tensile modulus of IDL FRP composites is 1.04 times higher than treated IDL FRP composites at maximum fiber volume fraction. Chemically treated IDL FRP composites exhibited flexural strength, modulus of 63.47 MPa, 5 GPa under flexural loading, which is higher than untreated FRP composites. IDL FRP composites’ impact strength is 18.94 kJ/m2 at maximum fiber volume fraction. The dielectric strength is clearly decreasing with increase in fiber content, which gives an opportunity for a designer in selecting suitable lightweight material with reasonable insulation. A clear rougher surface at all portions on the surface of chem­ically treated IDL fibers is visualized from SEM image.

Keywords Indian date leaf fiber • Mechanical properties • Dielectric strength • Scanning electron microscopy (SEM)

8.1 Introduction

Natural fibers, the name itself implies that they are created by nature. The renewable nature of fibers and high specific performance when they are reinforced into the matrix invited the attention of several researchers from the past few decades. Several people made numerous efforts for investigating the performance of fiber and its composites under mechanical, thermal, and electrical loadings at various fiber con­tents. Some of the imperative results related to various natural fiber reinforced com­posites using various fibers and matrices have been reviewed and are highlighted. In order to understand the behavior of IDL FRP composites, focus is made to com­pare the obtained results from the present work with the results which are available in literature on leaf fibers like sisal and pineapple polymer composites.

The pineapple fiber length of 6 mm was found to be optimum in pineapple leaf fiber reinforced LDPE composites when the mechanical properties and process ability characteristics were considered (George et al. 1995). Cardanol derivative of toluene diisocyanate-treated sisal fiber reinforced composites had shown best mechanical performance dimensional stability when compared with the composites reinforced with sisal fiber under same aging conditions (Joseph et al. 1995).

Sisal fiber reinforced polystyrene composites had exhibited marginal increase in tensile strength at 10 mm fiber length, and benzoylation-treated sisal fiber rein­forced composites have shown considerable improvement in tensile properties (Manikandan Nair et al. 1996). After conducting the study on pineapple leaf FRP composites, it was found that the mechanical properties were optimum at a fiber length of 30 mm (Uma Devi et al. 1997). With enhancement in fiber volume in matrix, the tensile strength of henequen fiber reinforced HDPE composites decreases for different processing temperatures, whereas the flexural strength and modulus were increased (Herrera-Franco et al. 1997).

An improvement in the mechanical performance of the composites was observed with the reinforcement of wood fiber in LDPE matrix along with titanate coupling agents (Liao et al. 1997). In order to assess the improved mechanical performance of the FRP composites, acetylated coir/oil palm fibers were reinforced in case 1, whereas in case 2, silane/titanate coupling agents were used (Hill and Abdul Khalil 2000). A comparison of mechanical properties was made among the composites reinforced with abaca (short) and glass fiber prepared by melt mixing and injection molding (Mitsuhiro et al. 2002).

An increase in tensile strength and modulus was observed up to an MAPP con­centration of 35 % weight (Luo et al. 2002). The natural rubber composites were reinforced with bamboo fiber, and their mechanical performance was assessed after the silane coupling agents were added (Ismail et al. 2002). Big blue stem fiber reinforced composites had shown higher strength than wood and are comparable (Julson et al. 2004). A new experiment was conducted and composites were made,

i. e., the use of polyester matrix, modified with coupling agent; flame retardant system; and blend of both as matrices and sisal fibers were reinforced to determine their mechanical properties (Fonseca et al. 2004).

Two investigations on flax and jute fiber reinforced composites were made. In the first case, various maleated PP coupling agents were used in agro-fiber PP compos­ites. In the second case, oxidized PE, MAPP, and newly introduced MaPE coupling agents were used in the composites. The tensile and impact behavior of the compos­ites in both the cases were studied (Keener et al. 2004). The effect of hybridization on the mechanical properties of randomly oriented banana/sisal hybrid FRP com­posites was investigated with the reinforcement of banana and sisal fibers at various volume fractions (Idicula et al. 2005). With the enhancement in NaOH concentra­tion, the mass loss in Phormium tenax fibers was investigated. The composites consisting of epoxy matrix and treated and untreated fibers are tested under flexural load (Roger et al. 2007).

The glass, sisal, and coconut fibers reinforced polyester composites were tested for their mechanical properties after they were exposed in salt spray chamber (Nicolai et al. 2008). The resin transfer-molded banana FRP composites had shown maximum tensile, flexural, and impact properties at 40 % fiber content and had fiber of 30 mm in length (Sreekumar et al. 2008) . The soaking time and molarity of

Fig. 8.1 Indian date tree or Indian date palm tree

chemical on the properties of turmeric FRP composites under tensile loading was investigated (Srinivasababu et al. 2010) . The composites manufactured with the reinforcement of vakka and jowar fibers had tested for their mechanical and dielec­tric performance at various fiber volume fractions in the composites (Murali Mohan Rao et al. 2010; Ratna Prasad and Mohana Rao 2011).

Leaf fibers are obtained from mesophyll ofleaves, e. g., sisal, Indian date, etc. In the present work, an attempt is made to introduce a new fiber, IDL. Indian date is called Eetha chettu in Telugu, shown in Fig. 8.1. This belongs to the Arecaceae family, binomially called “Phoenix dactylifera L.” Palm trees are grown extensively in coastal areas, specifically in Gorigapudi village, Guntur Dt., Andhra Pradesh, India. The leaves of the ID palm trees are about 0.5 in. to 1 ft. in length.