reliable and efficient etching method used to characterize the morphology of nylon-6
i.e. CCl3COOH solution
was established. It was the first time that the crystal morphology of monomer casting nylon-6 and its modified samples was directly observed by means of SEM. Their spherulites of tens micron were three-dimensionally clear. The crystalline structure of modified MC nylons can be successfully studied by means of the physical or chemical effect of CCl3COOH and its solvent on the modifying agents.