Tear strength theory of semicrystalline polymers

摘要

AbstractA theroretical model describing how the tear strenght of semicrystalline polymers depends upon the interaction of the crystalline and amorphous phases is presented. It is based upon the “freevolume“ theory and a “Hooke's law ‐lattice energy” treatment. The strengthTMis hypothesized to be partitioned between the crystallineQcand amorphousQaphases. ThereforeTM∝︁Qc.Qa,TM=To.Qc.Qa, whereQc=NKTE/bY2and e−v/vf=G/Goτ. Proof of this theory is obtained by measuring the oxygen transmission rates of 11 polyethylene film samples varying in tear strenght. Good agreement exists betweenTM(experimental) andTM(theroetical) for 9 of the polyethylene samples. The other 2 Samples differ from the theory by factor of 2. One explantion of this departure is the τ