Format

Send to:

Choose Destination
See comment in PubMed Commons below
Dent Mater. 2012 Sep;28(9):1004-11. doi: 10.1016/j.dental.2012.05.003. Epub 2012 Jun 18.

Using hyperbranched oligomer functionalized glass fillers to reduce shrinkage stress.

Author information

  • 1Department of Chemical & Biological Engineering, University of Colorado, Boulder, 80309, United States. sheng.ye@colorado.edu

Abstract

OBJECTIVE:

Fillers are widely utilized to enhance the mechanical properties of polymer resins. However, polymerization stress has the potential to increase due to the higher elastic modulus achieved upon filler addition. Here, we demonstrate a hyperbranched oligomer functionalized glass filler UV curable resin composite which is able to reduce the shrinkage stress without sacrificing mechanical properties.

METHODS:

A 16-functional alkene-terminated hyperbranched oligomer is synthesized by thiol-acrylate and thiol-yne reactions and the product structure is analyzed by (1)H NMR, mass spectroscopy, and gel permeation chromatography. Surface functionalization of the glass filler is measured by thermogravimetric analysis. Reaction kinetics, mechanical properties and shrinkage stress are studied via Fourier transform infrared spectroscopy, dynamic mechanical analysis and a tensometer, respectively.

RESULTS:

Silica nanoparticles are functionalized with a flexible 16-functional alkene-terminated hyperbranched oligomer which is synthesized by multistage thiol-ene/yne reactions. 93% of the particle surface was covered by this oligomer and an interfacial layer ranging from 0.7 nm to 4.5 nm thickness is generated. A composite system with these functionalized silica nanoparticles incorporated into the thiol-yne-methacrylate resin demonstrates 30% reduction of shrinkage stress (from 0.9 MPa to 0.6 MPa) without sacrificing the modulus (3100 ± 300 MPa) or glass transition temperature (62 ± 3°C). Moreover, the shrinkage stress of the composite system builds up at much later stages of the polymerization as compared to the control system.

SIGNIFICANCE:

Due to the capability of reducing shrinkage stress without sacrificing mechanical properties, this composite system will be a great candidate for dental composite applications.

Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

PMID:
22717296
[PubMed - indexed for MEDLINE]
PMCID:
PMC3410741
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science Icon for PubMed Central
    Loading ...
    Write to the Help Desk