Using hyperbranched oligomer functionalized glass fillers to reduce shrinkage stress

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 1H-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 – 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.

Radical Thiol‐yne Chemistry on Diphenylacetylene: Selective and Quantitative Addition Enabling the Synthesis of Hyperbranched Poly(vinyl sulfide)s

“…Since then, it has been the subject of intensive research, especially for the efficient functionalization of polymeric materials . To this point, TYC has been successfully applied to the modification of polymers, peptides, proteins, materials, and surfaces but also as a synthetic method to prepare small molecules, monomers, polymers, and materials . This interest was initially driven by the successful application of thiol‐ene chemistry in a variety of polymer and materials science areas coupled with the novel ability to add two thiols per alkyne unit to form a 1,2‐dithioether .…”

Synthesis of fluorinated dimethacrylate monomer and its application in preparing Bis-GMA free dental resin

“…In order to improve properties of methacrylate based dental restorative materials, many studies involved reducing polymerization shrinkage (Ye et al, 2012(Ye et al, , 2014He et al, 2013), improving mechanical properties (Pereira et al, 2005;Yamazaki and Kurata, 2011), decreasing water sorption and solubility (Kim and Chung, 2003;, and endowing antibacterial activity (He et al, , 2012(He et al, , 2015Liang et al, 2013 have been taken, and most of them focused on using synthesized dimethacrylate monomers to prepare new dental resin.…”

The Potential of Functionalized Ceramic Particles in Coatings for Improved Scratch Resistance

“…Alumina has successfully been used as reinforcement for organic coatings with improved scratch resistance in a number of previous studies, for example, when added to Nylon-11 [15], melamine films [18] or PTFE [19]. A further improvement in the scratch resistance can be obtained through the strengthening of the polymer/particle interface [4], which will improve the dispersion state of the particles within the polymer matrix [20] and reduce the stresses associated with polymerization shrinkage [21] among others. Silane coupling agents are commonly used for functionalization, along with amines, carboxilates, phosphonates, etc., [22] as they can act as chemical bridges between the particle and the polymer.…”