Synthesis of polymerizable poly(alkenoic acid)s via reversible addition fragmentation transfer polymerization for dental applications

The novel polymerizable poly(alkenoic acid)s 1a–1c (expected = 2500, 5000, and 10,000 g/mol) were synthesized in three steps starting from tert‐butyl acrylate. A RAFT polymerization using 2,2‐(thiocarbonylbis(sulfanediyl))bis(2‐methylpropanoic acid) 4 as a chain transfer agent, followed by a Mitsunobu esterification and a deprotection of the tert‐butyl ester groups with trifluoroacetic acid, provided the desired acidic polymers in moderate to good yields. The synthesized polymers were characterized by ¹H NMR spectroscopy and by gel permeation chromatography. The number‐average molecular weights measured for 1a–1c were in good agreement with the expected values. Self‐etch adhesives (SEAs) based on poly(alkenoic acid)s 1a–1c were formulated in order to investigate their adhesive properties. The addition of 1a–1c to a SEA formulation containing 10‐methacryloyloxydecyl dihydrogen phosphate resulted in a strong increase of the shear bond strength (SBS) of a dimethacrylate‐based composite to dentin. No significant influence of the polymer molecular weight on the dentin and enamel SBS was observed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1814–1821