ADHESIVE PROPERTIES OF CARBOХҮМЕТНҮYLATED CASSAVA STARCH

Cassava starch was carboxymethylated to different degrees of substitution by treating the alkalized starch with different amounts of sodium monochloroacetate. From the carboxymethylated cassava starch materials, adhesives were produced, which were used to bond wood substrates. The adhesive strength of bonded wood substrates was determined using a tensometer. The effects of degree of substitution, solids content, pH and relative humility (RH) on adhesive strength were investigated. The variation of adhesive strength with degree of substitution (r2= 0.999) and solids content (r2= 0.98) obeyed a third and fourth order polynomial, respectively, while it was second order with pH (r²= 1). The result showed that the adhesive property decreased with increasing relative humidity. The high water dispersibility of carboxymethylated cassava starch would permit its use at high solids content for enhanced adhesive properties.