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.

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To explore new VLC oligomers exhibiting low shrinkage, low water sorption, and improved mechanical properties, a family of multi-methacrylates, based on poly(isopropylidenedipheno1) resin (BPA), was synthesized, characterized, and evaluated. The BPA resin, having an average of eight phenolic hydroxyl groups per molecule, was treated with ethylene carbonate and the resultant product esterified at four different grafted levels, using methacryloyl chloride. Structures of these EEBPA oligomers, were confirmed by FT-IR and 13C NMR. The EEBPA oligomer/TEGDMA (50/50, w/w) blends were combined with 0.5 wt% camphoroquinone(CQ) and 1 .O wt% N,N-dimethylaminoethyl methacrylate (DMAEM). The control was BisGMA/TEGDMA (50/50, w/w) blends having the same levels of CQ/DMAEM. Differential photocalorimetry (DPC) and differential scanning calorimetry (DSC) showed the multi-methacrylate/TEGDMA (neat resin) blends have polymerization characteristics comparable to the BisGMA/TEGDMA control. These multi-functional oligomers have lower polymerization shrinkage and lower uptake of water and other liquids. In addition, two experimental oligomers EEBPA #2 2405 Copyright 0 1997 by Marcel Dekker, Inc. Downloaded by [TOBB Ekonomi Ve Teknoloji] at 00:09 20 December 2014 2406 CULBERTSON, WAN, AND TONG and #3 have higher compressive strength than the BisGMA and comparable diametral tensile strength to the BisGMA control.These results suggest that the new type of multi-functional methacrylate oligomers (EEBPA) have potential application in formulating dental composites with improved properties.

Two novel trimethacrylates, i.e., 1,1,1-tri-[4-(methacryloxyethoxy)phenyl] ethane (TMPE) and 1,1,1-tri-[4-(2-methyl-2-methacryloxyethoxy)phenyl]ethane (TMMPE), have been synthesized by reacting methacryloyl chloride with the corresponding hydroxyl intermediates. Both trimethacrylate monomers, having a low viscosity of 11.5 and 13.1 Pa.S, respectively, were blended with TEGDMA at three different weight ratios, i.e., 90=10, 70=30, and 50=50. The mixtures were made visible light-curable (VLC) by the addition of camphorquinone (0.5 wt%) and N,N-dimethylaminoethyl methacrylate (1.0 wt%). In addition to evaluation as cured neat resins, VLC formulations with 70% by wt. of silanated microfiller were also prepared and evaluated. The control in both cases was a VLC formulation of BisGMA=TEGDMA (70=30 and 50=50 wt=wt). These new, formulated resins have both improved physical properties and higher double bond conversion than the BisGMA control, as well as decreased linear polymerization shrinkage (LPS). The neat resin having 70=30 (wt=wt) ratio of TMPE=TEGDMA (T7T3, Table 2) exhibited a compressive strength (CS) of 496 (AE51) MPa compared to the 70=30 (wt=wt) ratio of BisGMA=-TEGDMA control having 425(AE27) MPa. A filled resin having a 90=10 (wt=wt) ratio of TMPE=TEGDMA exhibited a flexural strength (FS) of 122.6(AE 23) MPa, compared with a similar filled BisGMA=TEGDMA (70=30, wt=wt) resin exhibiting 112.7(AE 19) MPa. These and other results suggest that these new trimethacrylates have potential application in formulating dental composites with improved performance.

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