Disentangled high or ultrahigh molecular weight polyethylene ((U)HMWPE) being produced with a Ziegler-Natta catalyst, characterized by (i) a factor for the normalized elastic modulus G′0/G′P of less than 0.95 determined in a dynamic time sweep measurement at 180° C. with constant strain of 0.5% at fixed frequency of 10 rad/s for at least 3600 s, whereby G′0 is the elastic shear modulus measured at t0 directly after melting the sample and G′p is the maximum plateau modulus.