IMPROVED BLOOD COMPATIBILITY OF DRAWN POLYAMIDE SHEETS

A series of aliphatic polyamide (nylon) sheets with different draw rat ios were prepared and their blood-contacting properties examined in re lation to the bulk and surface characteristics. Increases in both the molecular orientation and crystallinity were observed with increasing draw ratio. Their surface wettability slightly decreased with draw rat io, indicating less amide linkages at their surfaces by the drawing pr ocess. An increase in contact angle hysteresis by the drawing process is thought to be due to the existence of more amorphous chains at the surfaces. The adsorption of albumin and fibrinogen onto nylon sheets w as significantly reduced with draw ratio, suggesting the formation of well-established crystalline-amorphous microdomain structures at the s urfaces. Blood compatibility of these surfaces was greatly improved wi th draw ratio in terms of a change in cytoplasmic calcium levels in pl atelets contacting these surfaces. Thus, it is suggested that the cont rol of crystalline-amorphous microdomain structures by the drawing pro cess is a feasible approach to improve blood compatibility of commerci ally available semicrystalline polyamides.