Dynamic viscoelastic properties of photo-activated composite resins containing short glass fibres

Abstract

The dynamic shear modulus in torsion (G'), water absorption, thermal expansion and residual monomer of the reinforced materials produced by adding four short glass fibres (19 microm in mean diameter and 86.1--763 microm in mean length) and one spherical E glass (11.1 microm in mean diameter) were examined and discussed in comparison with those of the materials without filler. G' of short fibre reinforced composites increased with fibre length and reached a maximum value near 382 microm for a dry specimen and near 156 microm for a wet one. In addition, the coefficient of thermal expansion of the fibre reinforced composites and the amount of residual monomer decreased considerably compared with those of composites containing spherical glass. There was no significant difference in water absorption between the fibre reinforced composites and the composites containing spherical glass. Therefore, it was concluded that the reinforcement method of adding short glass fibres is favourable for improving the viscoelastic properties of the materials.

Physical and mechanical properties of PMMA resins containing γ‐methacryloxypropyltrimethoxysilane

“…The mixing ratio and curing conditions are shown in Table 1. After heat curing, the test specimens were removed from the mould and reheated at 110 °C for 5 h to eliminate residual stresses (11). Then, the test specimens were stored in air (dry) or water (wet) at 37 ± 0·5 °C for 28 days.…”

“…Dynamic shear modulus ( G ′) and loss tangent (tan δ ) were measured using dry test specimens (30 × 8 × 0·5 mm) and a torsion pendulum viscoelastometer (TPA‐10)***, as explained in our previous report in detail (11). The distance between the upper and lower specimen holders was 15 mm and an angle of twist (0·5–1·0°) was applied to the test specimen.…”

Effects of Glass Fiber Layering on the Flexural Strength of Microfill and Hybrid Composites

“…Continuous parallel unidirectional fibers are used to reinforce the connection between pontic and crown in a fixed partial denture, and woven fibers are indicated to reinforce the crown 16,18,20,21–23 . Reinforcement of resin composite with randomly oriented short glass fibers was also used for improving the mechanical properties of the material 24,25 …”