PREPARATION AND CHARACTERIZATION OF POLYURETHANES BASED ON A SERIES OF FLUORINATED DIOLS

This research is part of an effort directed toward obtaining polymers with minimally adhesive surfaces. Fluorinated polyurethanes based on a series of ethylene-fluoroalkyl-ethylene diols and hexamethylene diiso cyanate were prepared and characterized to include a preliminary evalu ation of surface properties. Polymerization was carried out both in bu lk and in tetrahydrofuran solution. Glass transition temperatures of t he resulting polymers were ca. 20-degrees-C. Average molecular weights , determined by GPC, were in the range M(w) = (12-54) x 10(3). Mechani cal properties were determined using an Instron tester. Young's modulu s ranged from 1 to 56 MPa depending on composition and processing hist ory. High strain-at-break values were observed ranging from ca. 900 to 1800 %. A significant decrease in surface free energy from 31.5 to 25 .5 erg/cm2 was seen with an increase in the fluorocarbon content from 58 to 64 wt %.