Effect of ethyl-α-hydroxymethylacrylate on selected properties of copolymers and ACP resin composites

Abstract

There is an increased interest in the development of bioactive polymeric dental composites and related materials that have potential for mineralized tissue regeneration and preservation. This study explores how the substitution of ethyl alpha-hydroxymethylacryate (EHMA) for 2-hydroxyethyl methacrylate (HEMA) in photo-activated 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA) and Bis-GMA/tri(ethylene glycol) dimethacrylate (TEGDMA) resins affected selected physicochemical properties of the polymers and their amorphous calcium phosphate (ACP) composites. Rate of polymerization and the degree of conversion (DC) of polymers {EHMA (E), HEMA (H), Bis-GMA/EHMA (BE), Bis-GMA/HEMA (BH), Bis-GMA/TEGDMA/EHMA (BTE) and Bis-GMA/TEGDMA/HEMA (BTH)} were assessed by photo-differential scanning calorimetry and Fourier-Transform Infrared (FTIR) spectroscopy. ACP/BTE and ACP/BTH composites were evaluated for DC, biaxial flexure strength (BFS), water sorption (WS) and mineral ion release. Mid-FTIR and near-IR measurements revealed the following order of decreasing DC: [E, H polymers (97.0%)] > [BE copolymer (89.9%)] > [BH copolymer (86.2%)] > [BTE, BTH copolymers (85.5%)] > [ACP/BTH composite (82.6%)] > [ACP/BTE composite (79.3%)]. Compared to HEMA, EHMA did not adversely affect the BFS of its copolymers and/or ACP composites. Lower WS of BTE copolymers and composites (28% and 14%, respectively, compared to the BTH copolymers and composites) only marginal reduced the ion release from ACP/BTE composites compared to ACP/BTH composites. More hydrophobic ACP composites with acceptable ion-releasing properties were developed by substituting the less hydrophilic EHMA for HEMA.

Tuning photo-catalytic activities of TiO2 nanoparticles using dimethacrylate resins

“…The DC of resin and composite specimens was determined using near infrared spectroscopy (NIR) [26-28]. NIR spectra were acquired before photo cure and at 24 h post cure.…”

Self-adhesive resin cements - chemistry, properties and clinical considerations

“…It also contains a bulky hydrophobic substituent as its ester substituent and thereby can be expected to provide reasonable overall stability in acidic media. In comparison with methacrylate monomers, some restriction in reactivity may be encountered for the more sterically encumbered vinyl group of this type, but overall, their polymerisation behaviour is fairly similar to and compatible with methacrylate monomers (29).…”

Influence of hydrophobic monomers on secondary nucleation of hydroxyl-functionalized latexes

“…Unlike carboxylic functionalized monomers, HEMA does not dissociate under emulsion polymerization conditions, therefore its behavior is not pH dependent as is the case with acrylic (AA) or methacrylic acid (MAA) . The water solubility and latex swellability of HEMA is driven by hydrogen bonding forces . Additionally, limited water solubility of poly‐HEMA‐rich oligomers was found to induce formation of secondary particles through homogeneous nucleation mechanism .…”

“…9,11 The water solubility and latex swellability of HEMA is driven by hydrogen bonding forces. 12 Additionally, limited water solubility of poly-HEMA-rich oligomers was found to induce formation of secondary particles through homogeneous nucleation mechanism. 6,10,13 According to the Hansen and Ugelstad theory 14 oligomer agglomeration and new particle population are going to occur when oligomer hydrophilicity will prevent entry in existing primary particles.…”