Physicochemical Properties of Novel Copolymers of Quaternary Ammonium UDMA Analogues, Bis-GMA, and TEGDMA

This study aimed to elucidate the physicochemical properties of copolymers comprising 40 wt.% bisphenol A glycerolate dimethacrylate (Bis-GMA), 40 wt.% quaternary ammonium urethane-dimethacrylate analogues (QAUDMA-m, where m corresponds to the number of carbon atoms in the N-alkyl substituent), and 20 wt.% triethylene glycol dimethacrylate (TEGDMA) copolymers (BG:QAm:TEGs). The BG:QAm:TEG liquid monomer compositions and reference compositions (40 wt.% Bis-GMA, 40 wt.% urethane-dimethacrylate (UDMA), 20 wt.% TEGDMA (BG:UD:TEG) and 60 wt.% Bis-GMA, 40 wt.% TEGDMA (BG:TEG)) were characterized in terms of their refractive index (RI) and monomer glass transition temperature (Tg(m)) and then photocured. The resulting copolymers were characterized in terms of the polymer glass transition temperature (Tg(p)), experimental polymerization shrinkage (S(e)), water contact angle (WCA), water sorption (WS), and water solubility (SL). The prepared BG:QAm:TEG liquid monomer compositions had RI in the range 1.4997–1.5129, and Tg(m) in the range −52.22 to −42.12 °C. The BG:QAm:TEG copolymers had Tg(p) ranging from 42.21 to 50.81 °C, S(e) ranging from 5.08 to 6.40%, WCA ranging from 81.41 to 99.53°, WS ranging from 25.94 to 68.27 µg/mm(3), and SL ranging from 5.15 to 5.58 µg/mm(3). Almost all of the developed BG:QAm:TEGs fulfilled the requirements for dental materials (except BG:QA8:TEG and BG:QA10:TEG, whose WS values exceeded the 40 µg/mm(3) limit).