title: Development of methacrylate/silorane hybrid monomer system: Relationship between photopolymerization behavior and dynamic mechanical properties.
abstract: Resin chemistries for dental composite are evolving as noted by the introduction of silorane-based composites in 2007. This shift in the landscape from methacrylate-based composites has fueled the quest for versatile methacrylate-silorane adhesives. The objective of this study was to evaluate the polymerization behavior and structure/property relationships of methacrylate-silorane hybrid systems. Amine compound ethyl-4-(dimethylamino) benzoate (EDMAB) or silane compound tris(trimethylsilyl) silane (TTMSS) was selected as coinitiators. The mechanical properties of the copolymer were improved significantly at low concentrations (15, 25, or 35 wt %) of silorane when EDMAB was used as coinitiator. The rubbery moduli of these experimental copolymers were increased by up to 260%, compared with that of the control (30.8 ± 1.9 MPa). Visible phase separation appeared in these formulations if the silorane concentrations in the formulations were 50-75 wt %. The use of TTMSS as coinitiator decreased the phase separation, but there was a concomitant decrease in mechanical properties. In the neat methacrylate formulations, the maximum rates of free-radical polymerization with EDMAB or TTMSS were 0.28 or 0.06 s(-1) , respectively. In the neat silorane resin, the maximum rates of cationic ring-opening polymerization with EDMAB or TTMSS were 0.056 or 0.087 s(-1) , respectively. The phase separation phenomenon may be attributed to differences in the rates of free-radical polymerization of methacrylates and cationic ring-opening polymerization of silorane. In the hybrid systems, free-radical polymerization initiated with EDMAB led to higher crosslink density and better mechanical properties under dry/wet conditions. These beneficial effects were, however, associated with an increase in heterogeneity in the network structure. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 841-852, 2016.
authors.affiliation: Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045.
authors.forename: Linyong
authors.identifier: 0000-0003-1691-9583
authors.initials: L
authors.lastname: Song
authors.affiliation: Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ye
authors.affiliation: Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045.
authors.forename: Xueping
authors.initials: X
authors.lastname: Ge
authors.affiliation: Department of Mechanical Engineering, University of Kansas, Lawrence, Kansas, 66045.
authors.forename: Viraj
authors.initials: V
authors.lastname: Singh
authors.affiliation: Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045.|Department of Civil Engineering, University of Kansas, Lawrence, Kansas, 66045.
authors.forename: Anil
authors.initials: A
authors.lastname: Misra
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kansas, MRB, Lawrence, Kansas, 66047.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Laurence
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, Kansas, 66045.
authors.forename: Cindy L
authors.initials: CL
authors.lastname: Berrie
authors.affiliation: Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045.|Department of Mechanical Engineering, University of Kansas, Lawrence, Kansas, 66045.
authors.forename: Paulette
authors.initials: P
authors.lastname: Spencer
mesh_terms: D008689:Methacrylates / Q000737:chemistry*; D008956:Models, Chemical; D055668:Photochemical Processes; D062047:Silorane Resins / Q000737:chemistry*
chemical_list: D008689:Methacrylates; D062047:Silorane Resins; C008384:methacrylic acid
keywords: dental polymers; heterogeneous polymers; phase separation; photopolymerization; ring-opening polymerization