1,4-Pentadien-3-one-1,5-bis(p-hydroxyphenyl) (PBHP) was prepared by reacting p-hydroxybenzaldehyde and acetone in the presence of an acid catalyst. 1,4Pentadiene-3-one-1-p-hydroxyphenyl-5-p-phenyl methacrylate (PHPPMA) monomer was prepared by reacting PBHP dissolved in ethyl methyl ketone (EMK) with methacryloyl chloride in the presence of triethylamine. A free-radical solution polymerization technique was used for synthesizing homo- and copolymers of different feed compositions of PHPPMA and ethyl acrylate (EA) in EMK as a solvent with benzoyl peroxide as a free-radical initiator at 70 +/- 1 degreesC. All the polymers were characterized with IR and H-1 NMR techniques. The compositions of the copolymers were determined with the H-1 NMR technique. The copolymer reactivity ratios were evolved with Kelen-Tudos (EA = 1.25 and PHPPMA = 0.09) and extended Kelen-Tudos (EA = 1.30 and PHPPMA = 0.09) methods. Q (0.48) and e (1.68) values for the new monomer (PHPPMA) were calculated with the Alfrey-Price method. UV absorption spectra for poly(PHPPMA) showed two absorption bands at 302 and 315 nm. The photocrosslinking properties of the polymer samples were examined with the solvent method. Thermal analyses of the polymers were performed with the thermogravimetric-differential thermogravimetric technique. First, the decomposition temperatures started for poly(PHPPMA), copoly(EA-PHPPMA) (62:38), and copoly(EA-PHPPMA) (41:59) were at 350, 4 10, and 417 degreesC, respectively. A gel permeation chromatographic method was used for determining the polymer molecular weights (weight-average molecular weight: 2.67 x 10(4) and number-average molecular weight: 1.41 x 10(4)) and polydispersity index (1.89). The solubility of the monomer and the copolymers occurred at 30 degreesC with solvents having different polarities. (C) 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1632-1640, 2003.