Novel bioengineering functional terpolymers were synthesized by complex-radical terpolymerization of N-isopropylacrylamide (NIPA), 3,4-dihydro-2H-pyran (DHP) and maleic anhydride (MA) with alpha,alpha'-azoisobisbutyronitrile (AIBN) as a radical initiator in 1,4-dioxane at 65 degrees C under nitrogen atmosphere. Structure compositions and composition-property relationships of terpolymers, and the monomer reactivity ratios were investigated by H-1 (C-13) NMR spectroscopy, DSC and TGA thermal analysis. The monomer reactivity ratios were determined by modified methods of Jaacks and Kelen-Tudos using H-1-NMR analysis data: r(1) = 1.14 and r(2) = 0.06 (by H-1-NMR) and r(1) = 1.07 and r(2) = 0.04 (by N analysis) for NIPA (M-1) and MA ... DHP (M-2) monomer-monomer complex pair. An alpha,omega-hydroxy-methoxy-polyethylene oxide branched derivative was synthesized by grafting (esterification) of anhydride units of the terpolymer. Investigation into the factors affecting the antitumor activity revealed that terpolymers containing a combination of H-bonded ionizable amide and carboxylic groups exhibited higher antitumor activity, towards SCLC cancer cells. (c) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4285-4295, 2010