Characterization and properties of plywood bioadhesive derived from cottonseed protein and sawdust cellulose

The development of plant adhesive with good bonding strength, water resistance and thermal stability remains challenging to replace formaldehyde-based adhesive resins that usually release toxic formaldehyde. Herein, an environmentally friendly bioadhesive derived from cottonseed meal waste and cellulose sawdust was successfully prepared, verified by FTIR and X-ray photoelectron spectroscopy detailed analysis. Pretreatment of cottonseed meal and sawdust at mild conditions was made to obtain cottonseed protein, purified and oxidized cellulose. Structure of these treated samples was characterized by particle size distribution, FTIR and wide angle X-ray diffraction. When adding 15% of the oxidized cellulose into cottonseed protein, the dry bonding strength of the resulting adhesive reached 2.4 MPa on average; and the highest wet bonding strength of 1.1 MPa was found when 10% dialdehyde starch was used. The improvements of bonding strength as well as thermal stability of the prepared oxidized cellulose/cottonseed protein adhesives are largely ascribed to the formation of strong chemical bonds and their mechanical interlocking with plywood substrates. Both protein-oxidized cellulose and protein-oxidized starch cross-linking networks are formed in the adhesive system, combining tightly the adhesive components. The biodegradable adhesive fabricated in work provides a new approach for the development of all-biomass derived adhesives with properties comparable to the state-of-the-art protein derived bioadhesives, thus holding great potential as an alternative to formaldehyde-based resins in wood board and indoor panel bonding industries. [GRAPHICS] .

Automated summary

An environmentally friendly bioadhesive derived from cottonseed meal waste and cellulose sawdust was successfully prepared in this study. It exhibited good bonding strength and thermal stability. The improvements in bonding strength and thermal stability were attributed to the strong chemical bonds and mechanical interlocking formed between the adhesive and the plywood substrates.