Abstract: Fibrils prepared by a differential temperature precipitation process of the type described in U.S. Pat. No. 4,013,751 are refined in isopropanol at a subambient temperature not higher than about 10.degree. C., and subsequently are treated with an aqueous solution of polyvinyl alcohol to sorb at least 1.0 weight % of polyvinyl alcohol on the fibrils. The treated fibrils, as compared with fibrils prepared by prior art processes disperse more readily in aqueous media and provide water-laid sheets having greater strength. The fibrils preferably are prepared from an olefin polymer having a weight average molecular weight of at least one (1) million.