World Journal of Advanced Research and Reviews, 2020, 05(03), 074–080 World Journal of Advanced Research and Reviews e-ISSN: 2581-9615, Cross Ref DOI: 10.30574/wjarr Journal homepage: https://www.wjarr.com  Corresponding author: Kishan Kumar VS Copyright © 2020 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. (R ESEARCH A RTICLE ) Bending strength enhancement of finger joints by inclusion of nanoclay in low concentrations into Urea formaldehyde adhesive Ismita Nautiyal, Zeerak Tamkeen, Khali Dwarika Prasad, Kishan Kumar VS * and Gupta Sachin Forest Products Division, Forest Research Institute, P.O. New Forest, Dehradun-248006. Uttarakhand, India. Publication history: Received on 05 March 2020; revised on 17 March 2020; accepted on 19 March 2020 Article DOI: https://doi.org/10.30574/wjarr.2020.5.3.0062 Abstract Results on the effects of using nanoclay as filler in Urea Formaldehyde (UF) adhesive to finger-joint short pieces of Melia azedarach wood are reported in this paper. Three relatively low (0.5%, 1% and 1.5%) concentrations of nanoclay containing metallic oxides were used in the study. The results are indicative of the fact that all three concentrations were able to effectively enhance the bending strengths by 22% to 58% compared to sections joined using UF with no added nano-filler. A nanoclay concentration of 1% of UF resin powder weight resulted in the highest bending strength of 50.3 N/mm 2 . Comparing with the MoR of clearwood sections reported in literature, the efficiency could be enhanced from 51.7% up to a range of 63% to 81.8% by addition of nanoclay. The addition of nanoclay did not result in any significant changes in the MoE values of the finger jointed sections. The study demonstrates the value addition that can be brought to finger jointed sections of M. azedarach using nanoclay in low concentrations as filler in UF to enhance the bending strength of short pieces without compromising on the stiffness. Keywords: Finger-joint; Melia azedarach; MoE; MoR; Nanoclay; Urea Formaldehyde 1. Introduction The strength of the finger-joint is one of the reasons for its extensive use in timber joinery world-wide. Traditionally, these are considered as a series of scarf joints separated by low-strength butt joints [1]. This technique’s success is due to the fact that end grain to end grain direct contact is reduced by using thin finger tips. The two wood pieces are ultimately in contact through the shorter contact vector [2]. The geometry of the finger profile plays an important role in deciding the strength of the joint since it decides the areas available for adhesive application [3]. Apart from the finger geometry, a suitable adhesive is the most important requirement for good joint strength. This led to a situation wherein most of the research works in finger joints were on the effectiveness of various adhesives for different wood species [4,5]. A large number of adhesives have been found to be successful with different tree species. Mango wood finger jointed with Urea Formaldehyde (UF) adhesive yielded 100% bending strength efficiency [1]. However, finger jointed sections of M. azedarach resulted in less than 50% efficiency in bending strength compared to its unjointed solid wood when a profile with thicker finger tips was used [6]. The performance of UF with Eucalyptus sections was equally unsatisfactory [7]. It thus became imperative that suitable adhesive combinations should be investigated for such hardwood species for obtaining strong finger joints. Nano-fillers possess large surface areas and have high reactivity. This property has been utilised to enhance the physical and mechanical properties of wood composites and reducing emissions from such products [8]. Bardak et al. reported improvement in the bending and tension strengths of the mortise and tenon joints by adding TiO2 and SiO2 nano-fillers in to the Polyvinyl Acetate (PVAc) matrix [9]. Taking a cue from such studies, nanofiller addition to UF was tried successfully to enhance the bending strengths of short sections of Melia azedarach [10,11]