title: Synthesis and characterization of POSS-(PAA)8 star copolymers and GICs for dental applications.
abstract: OBJECTIVE
  To investigate the application of a new type of multiarm polymer resins in the formulation of Glass Ionic Cements.
  
  
  METHODS
  A series of star copolymers of t-butyl acrylate has been prepared by ATRP using a multiarm POSS-Br8 initiator. The resulting POSS-co-t-butyl acrylate star copolymers with eight arms were subsequently hydrolysed by trifluoroacetic acid to produce the corresponding POSS-co-acrylic acid star copolymers. All of the copolymers have been characterized by (1)H and (13)C NMR and FTIR spectroscopies and TGA/DSC. The as-prepared star copolymers were mixed with the glass powder from Fuji IX GP to produce the GIC samples for compression testing.
  
  
  RESULTS
  The new type of multiarm polymer resins have been shown to have narrow molecular weight distributions and thermal properties of the acrylic acid copolymers are similar to that of poly(acrylic acid), with a two stage degradation profile involving transitions at ≈140°C and 250°C, corresponding to anhydride formation and loss of carbon dioxide, respectively. In aqueous solution the POSS-co-acrylic acid copolymers form aggregates with ≈33nm dimensions. When aqueous solutions of POSS-(PAA)8 are mixed with a glass powder, a rigid glass ionomer cement, GIC, is formed with a maximum compressive stress significantly greater than that for a linear PAA GIC of a comparable polymer molecular weight.
  
  
  CONCLUSIONS
  Therefore, these POSS-(PAA)8 copolymers demonstrate the potential for the application of well characterized star copolymers in the future development of new GICs as dental materials.
authors.affiliation: Free University of Berlin, Institute of Chemistry and Biochemistry, Takustrasse 3, 14195 Berlin, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Zelmer
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: David K
authors.initials: DK
authors.lastname: Wang
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Imelda
authors.initials: I
authors.lastname: Keen
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia; School of Chemistry and Molecular Biochemistry, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: David J T
authors.initials: DJ
authors.lastname: Hill
authors.affiliation: School of Dentistry, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Anne L
authors.initials: AL
authors.lastname: Symons
authors.affiliation: School of Dentistry, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Laurence J
authors.initials: LJ
authors.lastname: Walsh
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia; Petroleum Research Centre, Kuwait Institute for Scientific Research (KISR), PO Box 24885, Safat 13109, Kuwait. Electronic address: f.rasoul@uq.edu.au.
authors.forename: Firas
authors.initials: F
authors.lastname: Rasoul
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D000180:Acrylic Resins / Q000737:chemistry; D019245:Compressive Strength; D005899:Glass Ionomer Cements / Q000138:chemical synthesis / Q000737:chemistry*; D006244:Hardness; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D011208:Powders / Q000737:chemistry; D013718:Tensile Strength
chemical_list: D000179:Acrylates; D000180:Acrylic Resins; D005899:Glass Ionomer Cements; C000610393:POSS-PCU polymer; D011108:Polymers; D011208:Powders; C110713:fuji IX; C006903:carbopol 940; C522411:tert-butyl acrylate
keywords: ATRP; GIC; Multiarm-POSS; Polyacrylic acid