WHEREIN R REPRESENTS AN ALKYL GROUP WHAVING FROM 1 TO 18 CARBON ATOMS, R'' REPRESENTS HYDROGEN OR METHYL, R" REPRESENTS HYDROGEN, HYDROXYALKYL OR HYDROXYALKYL CARBALKOXY, AND R$ REPRESENTS HYDROXY, HYDROXYALKYL OR HYDROXYALKYL CARBALKOXY, X REPRESENTS FROM ABOUT 50 TO ABOUT 98 MOLE PERCENT, Y REPRESENTS FROM ABOUT 1 TO ABOUT 40 MOLE PERCENT AND Z REPRESENTS FROM ABOUT 1 TO ABOUT 10 MOLE PERCENT. THE METHOD OF PREPARING THE NOVEL TERPOLYMERS BY COPOLYMERING CINYL CHLORIDE, AN ALKYL VINYL ETHER AND A POLYMERIZABLE HYDROXYLE GROUP-CONTAINING MONOMER IN THE PRESENCE OF A FREE RADICAL CATALYST IS ALSO DISCLOSED.