Surface Modification of Cellulose with Silanes for Adhesive Application: Review

There has been an increasing interest in research on using bio-renewable polymers as a replacement to traditional synthetic polymers based on petroleum resources for adhesive applications. Cellulose, which is the most abundant biopolymer finds application as a reinforcing agent in conventional adhesives. However, natural polymer cellulose suffers from a few drawbacks like poor water resistance, low mechanical strength, and compatibility within the hydrophobic matrix. For emerging as sustainable alternatives for synthetic polymers, cellulose and its derivatives must have comparable physical, chemical, thermal, and mechanical properties to those of synthetic polymers. To achieve this, cellulose has been chemically modified as it has free hydroxyl groups which act as a site for modification. Among various techniques used crosslinking and silane modification have shown better properties. Various silanes have been identified and used for modifying both micro-cellulose and nano-cellulose, by the formation of covalent bonds. Silanes have the ability to react with the low number of free hydroxyl groups present in the cellulose surfaces, therefore promotes surface modification. Hence referring to the increase in the research works related to the silane modification of cellulose and its applicability focusing on wood adhesives, the main aim of this review paper is to summarize various works relating to this field.