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Photoactive films obtained from methacrylo-urethanes tannic acid-based with potential usage as coating materials: analytic and kinetic studies

Authors
Journal
Progress in Organic Coatings
0300-9440
Publisher
Elsevier
Publication Date
Volume
37
Identifiers
DOI: 10.1016/s0300-9440(99)00050-8
Keywords
  • Synthesis
  • Kinetics
  • Uv-Curing
  • Acrylo-Urethanes
  • Films
  • Tannic Acid
Disciplines
  • Chemistry
  • Earth Science
  • Physics

Abstract

Abstract New UV-curable urethane functionalized precursors were synthesized from methacrylic derivatives of tannic acid (TA) ( m-digallic acid), using tolylene 2,4-diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) as major reagents. These products were obtained through two different procedures: two-step and one-step synthetic routes. Thus, Hypermonomers I and II were obtained. Hypermonomer I was prepared via convergent synthesis of two precursors, i.e. tannic acid methacrylate (Monomer I A) and TDI–HEMA adduct (Monomer I B) in a 1 : 1 molar ratio (Route I). On the other hand, Hypermonomer II was obtained in a one-step procedure; the coupling reaction between tannic acid and TDI (Monomer II A) was followed by HEMA addition, in a molar ratio TA–TDI–HEMA 1 : 3 : 3 (Route II). To begin with, kinetic and thermodynamic parameters were defined by means of differential photocalorimetry (DPC) to evaluate the following parameters: enthalpy (Δ H), peak maximum (PM), percent of monomer reacted at peak maximum (RPM %), induction time (IT), order of the initiation reaction ( m), and rate constant ( k). The hypermonomers were thermally and photochemically polymerized into films, and the resulting films were characterized by infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance spectroscopy ( 1H NMR), and thermogravimetric analysis (TGA–DTG). From all these studies, it is clear that the films obtained from Hypermonomer II (Route II) yield compounds of higher crosslinking extent than films from Hypermonomer I (Route I) readily and effectively.

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