| abstract |
Solid, ultrafine porous polymer articles and processes of producing such polymer articles are described wherein a solid body of a crystalline thermoplastic polymer exhibiting at least 70 percent crystallinity or blends of such crystalline thermoplastic polymers and thermoplastic polymers exhibiting up to 65 percent crystallinity where the latter polymer is present in an amount up to 50 weight percent of the crystalline polymer is heated at a temperature of at least in its melting temperature range, a benzoate salt is incorporated therein forming a composite body, the composite body is shaped at a temperature in the range of the initial heating temperature of the polymer, the shaped composite body is cooled to room temperature forming a solid composite body, and the salt is dissolved from the solid composite body leaving the polymer as an ultrafine porous article. |