Highly hydrophilic and porous sintered body made of thermoplastic polyacrylonitrile resin

A highly hydrophilic and porous sintered body having open-cellular pores and substantially precluded from further curing and treatment with an alkali, consisting essentially of a polypyridine ring structure represented by the following formula of:

• ##STR7## wherein n is an integer, which is obtained by sintering a pulverized copolymer of 1 to 5000 microns in diameter made from acrylonitrile, a conjugated diene monomer and an .alpha.,.beta.-unsaturated olefinic carboxylic ester represented by the following formula of ##STR8## wherein R.sub.1 is hydrogen, a lower alkyl group having 1 to 4 carbon atoms or a halogen;
• and R.sub.2 is an alkyl group having 1 to 6 carbon atoms, said pulverized copolymer being thermoplastic before sintering, and said sintering being effected at 200.degree. C. to 300.degree. C. for 10 to 30 minutes under a pressure of from ambient pressure to 1000 kg/cm.sup.2, wherein said sintered body has a porosity of 10 to 50%, a Shore hardness of 70 to 98 degrees and a hydrophilic degree of 1 to 10 minutes.