Effects of Ultrasonic Treatment on Hydrophilicity and Thermal Stability of Silk

摘要

Silk is an important natural protein polymer with unique biological and chemical properties. Ultrasonic technology is recently considered as an efficient energy supply for silk wet processing as well as for polymer modification. This study investigates changes in silk hydrophilicity and thermal properties with ultrasonic treatment at different frequencies and for different time durations. Hydrophilicity reflected by moisture absorption and wicking performance of the fabric is measured and analyzed by scanning electron microscopy and energy dispersive spectroscopy. Thermal properties are investigated by differential scanning calorimeter, thermogravimetric analysis, and derivative thermogravimetric analysis. It is found an improvement in both hydrophilicity and thermal stability of silk after ultrasonic treatment, especially under a lowered frequency and/or under a prolonged treatment time. This is attributed to the realignment of the macro-molecules as a result of intensive heat and pressure generated from acoustic cavitation during ultrasonic treatment.