Preparation and control of surface properties of monodisperse micrometer size beads by dispersion copolymerization of styrene and butyl methacrylate in polar media

Fluorinated emulsifier-free emulsion surface sizing agent (FEE) was prepared by emulsifier-free polymerization of hexafluoro-butyl methacrylate (FA), styrene (St) and so on in the presence of fuorinated random amphiphilic polymers (ASRF) copolymerized by FA, St and acrylatic acid. Effects of ASRF content and treatment temperature on the surface properties of the films were investigated. Effects of ASRF content and oxide starch on the application were also discussed. Additionally, fiber morphologies of the samples were characterized by SEM.The results show that the appropriate increases of ASRF content and treatment temperature are good for the decreases of surface free energies of the films. When the ASRF content and oxide starch content is 5% and less 50% respectively, the FEE and its combination with oxide starch have good sizing performance. After the treatment by FEE, the fiber surface becomes smooth, which provides lower surface free energy of the fibers.

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Effects of erosive challenge on the morphology and surface properties of luting cements

Revista de Odontologia da UNESP ◽

10.1590/1807-2577.022315 ◽

2016 ◽

Vol 45 (2) ◽

pp. 103-109

Author(s):

Brenna Louise Cavalcanti GONDIM ◽

Isabella Cavalcante MEDEIROS ◽

Bruna Palmeira COSTA ◽

Hugo Lemes CARLO ◽

Rogério Lacerda dos SANTOS ◽

...

Keyword(s):

Surface Properties ◽

Zinc Phosphate ◽

Artificial Saliva ◽

Sem Analysis ◽

Resin Matrix ◽

Luting Cements ◽

Porous Surfaces ◽

Before And After ◽

And Control ◽

Scanning Electron

Abstract Introduction Few studies investigated the surface properties of luting cements after erosive challenge. Objective To evaluate the surface roughness (Ra), Vickers hardness (VHN) and morphology of 4 luting cements after erosive challenge. Material and method Twenty specimens of each cement were prepared (4×2mm) and divided into experimental (erosive challenge) and control (artificial saliva) groups (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) and Zinc phosphate (ZnP). The erosive challenge was performed by four daily erosive cycles (90s) in a cola drink and 2 h in artificial saliva over 7 days. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was analyzed by scanning electron microscopy (SEM). ANOVA, Tukey and Student-T tests were used (α=0.05). Result After erosion, all luting cements had increase in Ra values and U200 and ZnP groups had the highest %VHN. After saliva immersion, only U200 and ZnP groups had significant increases in Ra values and there were no significant differences among the groups in %VHN. SEM analysis showed that Ketac and ZnP groups had rough and porous surfaces, and U200 group had higher resin matrix degradation than ARC group. Conclusion Erosive challenge with a cola drink affected the surface properties of all luting cements.

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Effect of Whitening Toothpastes and Brushing on Microhardness of Esthetic Restorative Materials

Journal of Clinical Pediatric Dentistry ◽

10.17796/1053-4625-44.5.2 ◽

2020 ◽

Vol 44 (5) ◽

pp. 296-301

Author(s):

Fouad Salama ◽

Faika Abdelmegid ◽

Lamya Alhomaidhi ◽

Sara Alswayyed ◽

Shatha Alfarraj

Keyword(s):

Surface Properties ◽

Study Design ◽

Distilled Water ◽

Restorative Material ◽

Water Control ◽

Over The Counter ◽

Significant Difference ◽

Restorative Materials ◽

And Control

OBJECTIVE: Whitening toothpastes are widely used. Hence, it is important to understand their effect on the surface properties of restorative materials. To evaluate the effect of three over-the-counter whitening toothpastes and toothbrushing simulation on microhardness of three restorative materials. Study design: Forty cylindrical (10×2mm) specimens were prepared from each restorative material and randomly assigned into four groups/10 each according to the whitening toothpastes used and distilled water (control). All specimens were measured for microhardness (Baseline–T1). The specimens were brushed with a soft brush using an in vitro tooth-brushing simulator with the assigned whitening toothpaste using the same setting for brushing cycles/load for all groups. Specimens were then measured for microhardness (T2) similar to baseline. Results: The highest (mean±SD) microhardness after application of the whitening toothpastes and brushing was recorded for Intense White and Filtek Z250 XT (127.6±1.8), followed by Optic White and Fuji ll LC (73.9±0.9) and Optic White and Photac Fill (72.7±1.3). There was statistically significant difference for microhardness between pre- and post-application of the whitening toothpastes and brushing for all tested restorative materials (P=0.0001). The microhardness of Filtek Z250XT with 3D White post-application of the whitening toothpastes and brushing was lowest compared to other toothpastes and control (P=0.0001). Conclusion: Microhardness increased after application of the whitening toothpastes and toothbrushing simulation for all combination of tested restorative materials and whitening toothpastes. The microhardness of FIiltek Z250XT with 3D White post-application of the whitening toothpastes and brushing was lowest compared to other toothpastes and control.

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