Affiliation:
1. Queen Mary University of London
2. The University of Manchester
3. The University of Hong Kong
4. University of Turku
Abstract
Abstract
Purpose To compare and contrast mechanical properties of experimental alkali-resistant (AR) glass fibre-reinforced composites (FRCs) silanised with one of three functional trialkoxy silanes: 3-methacryloxypropyltrimethoxysilane (3-MPS), 8-methacryloxypropyltrimethoxysilane (8-MOS) and 3-acryloxypropyltrimethoxysilane (3-APS). The experimental AR-FRCs were silanised with or without plasma pretreatment.
Materials and methods Continuous unidirectional AR-glass fibres (ARcoteX® 5326 2400tex, Owen Corning) were cleaned ultrasonically, treated either with or without cold plasma (Piezobrush® PZ2, Relyon Plasma, Germany), then silanised by immersion for 10 min in activated, hydrolysed silane solution containing either 3-MPS, 8-MOS or 3-APS. The fibre bundles were next air-dried (24 h), and dried in vacuum oven (80 °C, 5 kPa, 2 h), producing 6 types of silanised AR-glass fibres.
Next, silanised AR-glass fibres were laminated with a resin matrix, bis-GMA:TEGDMA at 60:40 wt%, CQ at 0.7 wt%, DMAEMA at 0.7 wt%) for 10 min and paired randomly in rovings of two in stainless steel moulds (2 mm × 2 mm × 25 mm) to prepare an AR-FRC beam specimen (n = 16). All specimens were light-cured from the top and bottom directions for 60 s (Elipar S10, 3M ESPE). Half of the samples (n = 8) underwent accelerated artificial ageing by immersion in boiling water (100°C, 16 h). Finally, 12 experimental AR-FRC groups were produced.
All specimens were subjected to the three-point bending test with the upper surface (facing curing light) towards the cross-head. After testing, fibres, silanised and non-silanised, were inspected under scanning electron microscopy (SU1510, Hitachi, Tokyo, Japan).
Statistical analysis was performed with three-way ANOVA and the Tukey post hoc test at α = 0.05.
Results The flexural modulus, flexural strength and fracture work of the materials were significantly affected by silane type (p < 0.05) and artificial ageing (p < 0.001). Plasma treatment on AR-glass fibres significantly reduces flexural modulus of FRC (p<0.001) and slows the plasticising effect of artificial ageing on FRC.
Conclusion Long chain silanes impart higher flexural strength and lower flexural modulus to AR-FRCs. While artificial ageing halves flexural strength and plasticises them, plasma surface pre-treatment of AR-glass fibres before silanisation reduces the plasticising effect.
Publisher
Research Square Platform LLC