Evaluation of neat resins based on methacrylates modified with methacryl‐POSS, as potential organic–Inorganic hybrids for formulating dental restoratives

Abstract

Three series of neat resins, based on methacrylates or dimethacrylates modified with 1‐[3‐(methacryl)propyl]‐3,5,7,9,11,13,15‐heptacyclopentylpentacyclo[9.5.113,­9.15,15.17,13]octasiloxane (Methacryl‐POSS or POSS‐MA), were evaluated. Incorporation of POSS‐MA into the polymeric matrix was accomplished in three ways: (a) resins series I was formulated with one‐pot copolymerization of a bis‐GMA/diluent monomer with POSS‐MA; (b) the copolymer of 2‐hydroxylethyl methacrylate (HEMA) and POSS‐MA, with a weight ratio of 1 : 1, was first made, then the copolymer hydroxyl groups were converted into methacrylate groups to get a macromer; finally the macromer was copolymerized with bis‐GMA/diluents to formulate the second series of neat resins; (c) copolymer of POSS‐MA and t‐butyl methacrylate (t‐BMA) or 2‐ethylhexyl methacrylate (EHMA) were first made, then they were combined with a mixture of bis‐GMA and the corresponding diluent to make the third kind of neat resins. The amount of POSS incorporated into the neat resin matrix was controlled at 5, 10 and 15 wt%. Incorporating only 5 wt% substantially reduced the shrinkage of the prepared neat resins. The percentage of methacrylate‐functionalized POSS monomer in the bis‐GMA/diluent base, was compared to neat resins prepared without the POSS. The mechanical properties of neat resin having POSS were improved for approaches (b) and (c), but remained at the same level as the neat resins without POSS for approach (a). The results show that miscibility between the POSS component and the matrix, especially the diluent, plays a very important role in the improvement of the properties of the formulated thermosets. Copyright © 2001 John Wiley & Sons, Ltd.

Physics and Chemistry of Sol-Gel Nanocomposites Formation

“…It is assumed that siloxane network is so hard that it even does not change at this temperature. Nevertheless, pore size is expectable and comparable with domain sizes of a polymer in the initial hybrid, which confirms its dendrimer structure [77]. If the first group of monomers for producing nanocomposites by sol-gel synthesis includes compounds tending to opening of a multiple bond, the second one no less widely spread, includes polymerization transformations of compositions like (RO) 3 M-X-A, in which X is a connecting bridge (organic spacer), and A-group is able to be subjected to opening of the cycle, polymerization (polycondensation) or coupling reaction [28].…”

“…4.6). These products are promising as potential alternative for usage in dental prosthetics, because the materials based on multi-methacrylates have low shrinking deformation 4 [77]. Really, including of just 5 wt% of POSS-MA almost restores shrinking of standard materials.…”

A Nanocage for Nanomedicine: Polyhedral Oligomeric Silsesquioxane (POSS)

“…Their work indicated that synthesising POSS-containing macromonomers enabled the improved overall dispersibility of POSS when reacted with dental monomers. [96,97] Methacrylated and octaphenyl-POSS moieties have been reacted with HEMA (2-hydroxyethylmethacrylate), BisGMA (bis-phenol A-glycidyldimethacrylate), and TEGDMA (tetraethylglycidylmethacrylate)-based restorative fillers, and Dodiuk-Kenig et al compared the effect of the two different terminal functional groups on POSS by investigating the thermal, mechanical, and physical properties. They found that acrylated POSS resulted in a 5 8C increase in T g , a 7% increase in compressive strength, an increase in bond shear strength (36%), and a decrease in polymer shrinkage by 28%, while incorporation of octaphenyl-POSS decreased the compressive strength by 20%, the bond shear strength by 49%, and polymer shrinkage by 67%.…”

“…Moreover, an increased T g and oxygen permeability have been demonstrated when POSS derivatives are incorporated into polymer matrices. [94,96,97] In a study by Culbertson et al three different methods of incorporating a mono-methacrylated POSS into dental composites were studied as follows: 1) by manufacturing POSS-containing macromonomers, and copolymerization with dental monomers, 2) by using a one step polymerisation of POSS with dental monomers, and 3) by developing a POSS co-polymer followed by in situ polymerisation with dental monomers. The results demonstrated that reacting methacrylate POSS into known dental polymeric formulations significantly decreased polymer shrinkage, although a slight reduction in mechanical properties was observed, especially at loadings greater than 10 wt.-%.…”

“…Therefore, taking advantage of the aforementioned properties and its rigidity, POSS can be used as a potential candidate in reducing the shrinkage of dental composite materials based on multi-methacrylate functional groups, as well as improving their biocompatibility confirmed by metabolic and mutagenic studies. [47,96] In a further study investigating novel dental restorative composites, methacryl-functionalized POSS (POSS-MA) was used to replace Bis-GMA. The mechanical properties, shrinkage rate, and degree of double bond conversion of the methacrylates by photo-polymerization were investigated.…”