146 ISSN 1229-9197 (print version) ISSN 1875-0052 (electronic version) Fibers and Polymers 2015, Vol.16, No.1, 146-152 Fibre-matrix Adhesion and Properties Evaluation of Sisal Polymer Composite Ruhi Haque*, Mohini Saxena, S. C. Shit 1 , and P. Asokan CSIR-Advanced Materials and Processes Research Institute, Bhopal 462064, India 1 Central Institute of Plastics Engineering and Technology, Ahmedabad 382445, India (Received November 26, 2013; Revised June 25, 2014; Accepted August 2, 2014) Abstract: Fibre matrix adhesions of sisal fibre with polymer were evaluated in terms of physico-chemical and mechanical properties. Effects of acetylation, acrylation, silanization, alkalization, and permanganate treatment on physical and chemical parameters as well as mechanical parameters such as tensile and impact behavior were investigated. Physical properties like density, moisture absorption, water absorption, void content and chemical properties like percentage of lignin, cellulose, and hemicelluloses were determined. From the findings, it was concluded that treatments such as acetylation, acrylation, and silanization can increase interfacial strength, wetting, and compatibility between fibre and matrix, leading to increase composite tensile strength. Acetylated sisal fibre and its polymer composites showed the highest tensile strength, less water absorption, and the acrylated sisal fibre composites showed the highest impact strength (46900 J/m ). Keywords: Fibres, Interfacial strength, Mechanical properties Introduction The performance and properties of composite materials depend on the characteristics of the individual components and their interfacial compatibility. The use of polymers with fillers like short natural fibre reinforcement has grown rapidly due to their good processability, ability to recycle, non abrasive nature, less environmental pollution, com- bustibility, light weight, high stiffness, high strength, biodegradability and improved physico-mechanical properties. Among different natural fibres, utilization of sisal as reinforcing agent is increase day to day. Sisal fibre is a cellulose reinforced lignin composite material with high tensile strength and modulus, makes it suitable for reinforcement in composites for various applications [1-3]. The electron micrograph of cross section of sisal fibre (bundle of fibrils) is shown in Figure 1 which shows that each individual fibre cell is made up of four main parts, namely the primary cell wall, the thick secondary wall, the tertiary wall and the lumen. The tensile properties of sisal fiber are not uniform along its length, i.e. stronger and stiffer at midspan and have moderate properties at tip. Almost 70 % of the fibres have a tensile strength in the range 200 to 400 MPa, tensile modulus in the range of 9-40 GPa and elongation at break (%) in the range 2-14 [1-6]. Mechanical properties of sisal with other natural fibres are summarized in Table 1. But due to the low interfacial adhesion between fibre and polymer matrix in composite, attracts researchers to optimize the interface of fibres [7]. Several mechanisms of activation of fibre i.e. highly cross linked structure formation, elimination of weak boundary layers, formation of tough or flexible layer, improvement in wetting between polymer and fibre etc were outlined. Rong et al. [8] optimized that alkalinized, acetylated, cyanoethylated; silanized sisal shows significantly improve adhesion as filler in epoxy composite. Ferreira et al. [9] characterized benzoylated sisal fibre and found many morphological changes such as the losses of the parenchyma cells, the defibrillation of the technical fibres into ultimate fibres, the micro fibrillation of the ultimate fibres, benzyl incorporation, overall mass gain etc. Valadez-Gonzalez et al . [10] concluded that the alkali treatment increases number of possible reaction site by increasing surface roughness. In respect to thermal behavior, Joseph et al. [11-13]. observed that urethane derivative of polypropylene glycol, maleic anhydride modified polypropylene and KMnO 4 modified sisal exhibited an increased crystallization temperature and crystallinity Bismarck et al. [14] obtained increase performance of grafted sisal which confirms that more accessibility of surface functional groups resulted in lower zeta potential. Li et al. [15] found that permanganate and DCP-treated sisal fibre *Corresponding author: ruhi_haq2003@yahoo.com Figure 1. Cross section of sisal fibre. DOI 10.1007/s12221-015-0146-2