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A novel natural adhesive from rice bran

W.H. Wang (Key Laboratory of Bio‐based Material Science and Engineering of Education Ministry, Northeast Forestry University, Harbin, People's Republic of China)
X.Q. Zhang (Key Laboratory of Bio‐based Material Science and Engineering of Education Ministry, Northeast Forestry University, Harbin, People's Republic of China)
X.P. Li (Key Laboratory of Bio‐based Material Science and Engineering of Education Ministry, Northeast Forestry University, Harbin, People's Republic of China)

Pigment & Resin Technology

ISSN: 0369-9420

Article publication date: 4 July 2008

Abstract

Purpose

The purpose of this paper is to investigate a new approach for making a bio‐based adhesive from a new resource, rice bran (RB) adhesive.

Design/methodology/approach

RB solution was prepared and its pHs were adjusted to either 8.5‐9.0 or 10.0‐10.5. The solid content of slurry was controlled at ≈18 per cent and then gelatinised in a water bath shaker at 60°C for 2 h or at 100°C for 1 h. The bonding strength of RB adhesive was determined by testing the strength of three‐layer plywood. A differential scanning calorimeter (DSC) was used for detecting the reaction energy and curing temperature. According to the DSC analysis, hot pressing at three temperatures was performed to select the best bonding conditions. Then, a two level split‐plot design was used to determine the effects of gelatinisation and pH on the bonding strength of RB adhesive. Thus, the formulation of RB adhesive was optimised. In order to improve the water resistance of RB adhesive, toluene diisocyanate (TDI) was used as a cross linking agent.

Findings

In the study reported here, a RB adhesive was developed by alkaline modification. Very high pH was not necessary, when RB adhesive with pH 10.0‐10.5 was gelatinised at 100°C for 1 h, its bonding strength was significantly lower than pH 8.5‐9.0 gelatinised at 60°C for 2 h. Water resistance of RB adhesive improved significantly when TDI was added as a cross linking agent. Compared to pure RB adhesive, the RB‐TDI mixed adhesive started curing at a higher temperature. For RB adhesive curing, 130°C was a suitable hot pressing temperature.

Research limitations/implications

Though the RB adhesive developed had a good bonding strength, its water resistance and dark colour was not satisfactory, which risks discolour of light colour wood. Further study is needed to solve this problem.

Practical implications

The approach provided a bio‐adhesive with good bonding strength, reasonable working life, and without formaldehyde emission. Based on further study, RB adhesive could be considered a promising alternate adhesive in many applications such as paper board bonding and plywood.

Originality/value

It provided a potential way to utilise by‐product of agriculture, RB as industrial raw material. This will do farmers a great favour. Meanwhile, the modified RB adhesive is promising to partly or completely replace urea formaldehyde resin that mainly used in wood industry, avoiding formaldehyde emission and reducing the dependence on petroleum products.

Keywords

Citation

Wang, W.H., Zhang, X.Q. and Li, X.P. (2008), "A novel natural adhesive from rice bran", Pigment & Resin Technology, Vol. 37 No. 4, pp. 229-233. https://doi.org/10.1108/03699420810887861

Publisher

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Emerald Group Publishing Limited

Copyright © 2008, Emerald Group Publishing Limited