Silk has high performance and super properties such as good luster

hangle and moderate moisture absorption

meanwhile it is prone to crease and yellowing and has low color fastness．So scientific researchers have been exploring new silk materials since 1980s．At present

the methods to modify silk focus on chemical ways of grafting

crosslinking and sericin fixation．In this work physical treatment of silk was investigated for improving its dyeing behavior and wear performance by using steam explosion at different pressure in a self-made maehine．The molecular configuration and morphology of the treated silk specimens were studied by means of electron micmscopy

infrared spectroscopy

x-ray diffraction and thermal analysis．It was found that the β-configuration of moleeules remained unchanged after steam explosion of the silk specimens

while the surface morphology and degree of crystallization of silks changed a lot．The binding force of micmfibrils became weaker．the specific surface area was enlarged and crystallinity decreased Experimental results also indicated that the solubilitv of silk in aqueous solutions of calcium chloride and ethanol was enhanced

and the reactive ability of the silks was improved．It was concluded that the steam explosion technique

as a physical method without pollution

can be used in pretreatment of silks.