Systematic studies on polyacrylates containing side‐chain hydrogen bonding units: Significant effects of the pendant functions on thermal behaviors and solubility of polymers

Abstract

The synthesis of polyacrylates containing various pendant hydrogen bonding or non‐hydrogen bonding functions and the effects of side‐chain functions on their physical properties are described. The polyacrylates possessing urea, urethane, N‐substituted urea, or carbonate groups are prepared by the free radical polymerization of acrylate monomers possessing the corresponding functional groups. The presence of stronger hydrogen bonding interactions both in bulk and solutions of a highly polar solvent such as dimethyl sulfoxide (DMSO) is supported by the infrared (IR) spectra, whereas the urethane‐based polyacrylate does not exhibit the interaction in the solution. The presence of the stronger hydrogen bonding interactions of the urea unit is discussed by the IR and nuclear magnetic resonance spectra and the density functional theory calculations of the corresponding model compounds. The solubility in organic solvents and the glass transition temperature (Tg) of polymers are also dependent on the structure of the pendant groups. Polar aprotic solvents such as DMSO can only dissolve the urea‐based polyacrylate, while the other polymers are soluble in a much wider range of solvents such as tetrahydrofuran. The urea‐based polyacrylate shows the highest Tg among the polymers studied owing to the presence of plural hydrogen bonding sites in the urea groups.