PROPERTIES OF POLYETHYLENE MONOFILAMENT: I. TENSILE PROPERTIES AND CREEP RESISTANCE

By spinning and stretching Ziegler process low pressure polyethylene, monofilaments were made and various properties have been determined. The results are as follows: 1) Relationships between tensile properties and stretch ratio have become clear. Young's modulus are 400-800kg/mm2. Maximum loop strength reachs to 14g/d and this value corresponds to the two folds of loop strength of commercial Nylon monofilament. 2) By heat set treatment under tension about 20% of Young's modulus decreases, but thermal shrinkage is much improved. 3) Tensile properties have been determined over the range 0.25-500%/min of extension speed. The dependence on extension speed are higher in polyethylene monofilament than in Nylon and polypropylene. 4) In ductile failure tests of monofilaments made by various stretch ratios, the relations between relative load and log (time to failure) are represented as one straight line. And this line is determined by molecular weight and molecular construction of raw material of each filament. The more molecular weight and side chains there are, the higher the creep resistance. Otherwise, in absolute load tests, the creep resistance of filaments having higher tenacity are higher in case of the same resin. 5) The relative load-creep resistance in twin, rope and cord are much higher by construction effect than in monofilament.