| abstract |
Polymer compositions having a first and second portion selected from polypropylenes, polyethylenes, propylene-ethylene copolymers and mixtures thereof having enhanced crystallization properties and a method for producing the same are disclosed. Antioxidant is mixed with the first portion, 0.01 to 1.25 wt %, of the composition which is then irradiated to a dosage of 5-30 Mrads of ionizing radiation in air to induce cross linking. The irradiated first portion is then blended with the non-irradiated second portion. The cross-linked polymer is believed to provide nucleation sites for the initiation of crystallization, thereby enhancing crystallization of the polymer as evidenced by elevated DSC freeze points. Crystallization of the polyolefin is enhanced without any detrimental effects on hexane or xylene extractability of the polymer and without degrading the composition to any appreciable extent. |