Ultrasound Assisted Synthesis of Starch Nanocrystals and It’s Applications withPolyurethane for Packaging Film
Vikas S. Hakke, Uday Bagale, Sami Boufi, G. Uday Bhaskar Babu, Shirish H. Sonawane
Abstract
Starch nanocrystals (SNC) were prepared from maize starch using ultrasound assisted acid hydrolysis. The process takes less time for the generation of SNC, which is advantageous over conventional acid hydrolysis. The synthesized SNC were characterized using X-ray diffraction, dynamic light scattering, zeta potential and transmission electron microscopy (TEM). Particle size and TEM data show that the particles were near to 150 nm, with oval morphology. The SNC with higher surface charge are obtained with this innovative approach as compared to conventional acid hydrolysis. Because of high surface charge and oval like morphology, the SNC performed well in reinforcing a polyurethane film. The rise in crystallinity by 16% was observed due to ultrasound cavitation. At the lower concentration of SNC in nanocomposite film, dynamic mechanical analysis demonstrated meaningful increment in mechanical properties of polyurethane nanocomposite film. The decrease in chain slippage over the glass transition temperature was observed because of the SNC reinforcement in polyurethane dispersion. Compared to the conventional acid hydrolysis, the present approach for the synthesis of starch nanocrystals is much faster and easier.