Abstract:The present work studied the hydrolysis of pea starch by isoamylase, and the hydrolyzed product was applied in glass fibre sizing. Results indicated that the isoamylase hydrolyzed pea starch by pitting and splitting. The aggregation behavior of the starch particles was affected by hydrolysis, which was manifested in the fluctuation of particle size, XRD intensity and viscosity. When the hydrolysis temperature was 50 oC, the surface tension of the hydrolyzed starch suspension could be reduced to 40 mN/m, which is close to the critical surface tension of glass fibre (30 mN/m). By breaking the starch granules with isoamylase, more hydroxyl groups of the starch molecules would be exposed. Therefore, the hydrolyzed product could easily spread over the surface of glass fibre, and conglutinated to glass surface firmly. Using the hydrolyzed product as sizing agent, the glass fibre-forming process was accomplished smoothly. Uniform protective film formed on the surface of glass fibre. The average breaking force of the 68 tex glass fibre was 25.0 N.