Interpenetrating Polymer Network

Purpose. This study examined the interface between acrylic resin polymer teeth and denture base polymers.Material and methods. An autopolymerized denture base polymer was cured either at 30° C, 50° C, or 70° C, and a heat-cured denture base polymer was cured at 100° C in contact with acrylic resin polymer teeth. The specimens were ground wet and polished to a thickness of 0.21 mm for the examination of the interface with a light microscope. The surface of the specimens was then treated with the solvent tetrahydrofuran, and the specimens were examined with a scanning electron microscope (SEM).Results. As a result of grinding, the inner parts of the beads at the interface of the teeth were exposed to the denture base polymer. The inner part in these polymer beads of the polymer teeth swelled to a depth of 3 μm when the autopolymerized polymer was cured at 30° C. When cured at 70° C, the thickness of the swelled layer was 21 μm (p < 0.001). Microscopically, the interface between the heat-cured denture base polymer and the polymer teeth appeared diffuse in the region of the interpenetrating polymer networks (IPN) and the matrix. The IPN appeared as a separate zone in the outer parts of the beads of the teeth, both with the light microscope and with the SEM.Conclusions. The results suggest that by increasing the polymerization temperature, the monomers of the denture base polymers diffused more effectively into acrylic resin polymer teeth. This increases the bond strength between the polymer teeth and the denture base polymer. (J Prosthet Dent 1997;78:194-99.)

A new semi-Interpenetrating Polymer Network (semi-IPN) based on polyvinyl alcohol–glutaraldehyde/polyaniline was synthesized and characterized by spectroscopic analysis in the UV–Visible–Infrared region and by scanning electron microscopy (SEM). The semi-IPNs exhibit good mechanical properties, characteristic of polyvinyl alcohol–glutaraldehyde polymer network, and excellent optical properties. The UV–Visible results show that the optical properties of the semi-IPNs are characteristic only of polyaniline polymer,

A series of interpenetrating polymer networks (IPNs), based on a polyurethane (PU) and polydimethylsiloxane, has been synthesized and characterized by means of DSC, TEM, TGA, 1H-NMR and IR spectroscopies, and other techniques. The homo-networks have been characterized by swelling in n-hexane and chloroform. The IPNs are obtained by combination of a PU based of the castor oil and 2,4-toluene diisocyanate (TDI) with different amounts of polydimethylsiloxane-α,ω-diol (PDMS). These materials have interesting individual physical properties, but some IPNs exhibited superior properties than either of the separate networks. For interesting results, it was used as compatibilizer the polydimethylsiloxane graft polyalkylene oxide. All the IPNs exhibited phase separation and maximum extent at the point of phase inversion.

Diamine amic acids were synthesized by reacting aromatic diamines with 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in dimethylacetamide and were characterized by melting points, elemental analyses, IR, 1H-NMR and HPLC. Poly(amide–amic acid)s were prepared by low temperature solution polycondensation of diamine amic acids with isophthaloyl chloride in dimethylacetamide. Poly(amide–imide)s with alternate (amide–amide) and (imide–imide) sequences were obtained by cycloimidization of poly(amide–amic acid)s with Et3N–Ac2O mixture in dimethylacetamide solution. They were characterized by solubilities, inherent viscosities, IR and 1H-NMR. Thermal properties of the polymers were measured by differential scanning calorimetry and thermogravimetric analyses.

A series of interpenetrated polymer networks (IPNs) in which the first component is a porous poly(ethyl methacrylate) (PEMA) hydrophobic network and the second one is a poly(2-hydroxyethyl acrylate) (PHEA) hydrophilic network were synthesized. Equilibrium sorption isotherms can be reduced to a single master curve for all the IPNs when the water absorbed is expressed per gram of PHEA in them. The equilibrium water sorption in immersion is always much smaller than that of pure PHEA. This feature is due to the confining effect of the stiff PEMA matrix. The plasticizing effect of the absorbed water on the PHEA phase was characterized using thermally stimulated depolarization currents, dynamic-mechanical analysis and dielectric relaxation spectroscopy. The results show that the shift of the main relaxation peak towards lower temperatures is unaffected by the presence of the PEMA matrix, and only depends on the water content per gram of PHEA in the IPN.