Gypsum polymer composites 2008
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Gypsum polymer composites 2008

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A research work done by Dr. Hesham El-Maghraby, hf_elmaghraby@yahoo.com

A research work done by Dr. Hesham El-Maghraby, hf_elmaghraby@yahoo.com

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Gypsum polymer composites 2008 Gypsum polymer composites 2008 Presentation Transcript

  • A Study on Constitution and Properties of Gypsum-Polymer Composites Author: Hesham Abdel Rehim, MSc. Supervisor: Assoc. Prof., RNDr. Ondrej Gedeon, Ph.D.
    • Gypsum is considered as one of the most common non-metallic minerals.
    • It consists of calcium sulphate dihydrate (CaSO 4 .2H 2 O).
    • It occurs in various forms such as Selenite, Alabaster, Satin spar, Rock gypsum and Gypsite.
    • It is the mother rock for different chemical industries and various applications.
    • When pure it contains 32.5 wt. % Lime (CaO), 46.6 wt. % sulphur trioxide (SO 3 ) and 20.9 wt. % water.
    • It is one of the softest mineral, with a hardness of 2.0 on the Mohs’ scale of hardness (Phillips and Griffin1981).
    Introduction
  • Dehydration: CaSO 4 .2H 2 O + Energy -> CaSO 4 .½H 2 O + 1½ H 2 O CaSO 4 .½H 2 O + Energy ->  -CaSO 4 + ½H 2 O Gypsum Technology Rehydration: CaSO 4 .½ H 2 O+ 1½H 2 O -> CaSO 4 .2H 2 O + Energy
    • Wall Lining
    • Roof Lining
    • Floors
    • Partitions
    • Ceilings
    Living with gypsum ...
    • The study aimed at the investigation of the effect of using three different vinyl-based polymers on
    • The mechanical properties of the formed composites.
    • The microstructure of the formed composites.
    • Preliminary bioactivity of the formed composites.
    Aim of the work
  • Vinyl-based polymers PVA P(VA-co-VAc-co-It) P(VC-co-VAc-co-VA) [ CH 2 CH ] n OH CH 2 COOH [ CH 2 CH ] x [ CH 2 CH ] y [ CH 2 C ] z OH COOCH 3 COOH [ CH 2 CH ] x [ CH 2 CH ] y [ CH 2 CH ] z Cl COOCH 3 OH
  • 1. Assessment of the starting materials (Plaster & polymers). 2. Formation of different polymer/plaster composites. 3. Measuring of the mechanical properties. 4. Correlation with the microstructure. 5. Studying of the bioactivity of gypsum and gypsum- polymer composites. Experimental Work
    • H 2 O and CO 2 were determined by weight loss at 240 and 1000 o C respectively.
    XRF data of the tested plaster Physicomechanical properties of the tested plaster Trace 2.05 16.99 39.18 0.93 40.41 8.96 x10 3 0.43 Mol % Trace 1.54 5.28 53.55 0.64 38.53 0.02 0.44 Wt. % NaCl *CO 2 *H 2 O SO 3 MgO CaO R 2 O 3 SiO 2 Type 8.7±02 6.7±02 4.3±02 18.2±2 17.7±3 8.5±09 30’00” 26’30” 7 days 3 days one day 7 days 3 days one day Final Initial 46 Bending Strength (MPa) CompressiveStrength (MPa) Mechanical Properties Setting Time (min) Normal Consistency (%)
  • PVA/plaster composites Mechanical properties --- --- --- 19.5 ± 0.7 16.1 ± 0.3 7.6 ± 0.3 4.0 --- --- --- 22.0 ± 0.6 17.5 ± 0.4 8.6 ± 0.6 3.0 11.9 ± 0.4 10.4 ± 0.2 4.1 ± 0.1 22.8 ± 0.7 19.6 ± 1.2 9.2 ± 0.6 2.0 14.5 ± 0.2 13.1 ± 0.2 4.9 ± 0.1 28.5 ± 0.1 28.4 ± 0.4 12.9 ± 0.4 1.0 11.3 ± 0.2 10.8 ± 0.2 4.5 ± 0.1 25.0 ± 0.3 23.2 ± 1.0 10.9 ± 0.5 0.5 --- --- --- 22.2 ± 0.7 18.7 ± 0.8 10.8 ± 0.6 0.25 8.7 ± 0.2 6.7 ± 0.2 2.3 ± 0.2 18.2 ± 0.2 17.7 ± 0.2 8.5 ± 0.2 0.00 7 Days 3 Days One Day 7 Days 3 Days One Day Bending Strength (MPa) Compressive Strength (MPa) Polymer/plaster wt. %
  • PVA/plaster composites 1- Compressive strength with aging time 2- Compressive strength with polymer concentration
  • PVA/plaster composites Microstructure
  • P(VA-co-VAc-co-It)/plaster composites Mechanical properties --- --- --- 19.1 ± 0.11 17.9 ± 0.07 8.0 ± 0.05 2.0 --- --- --- 20.9 ± 0.06 19.9 ± 0.08 9.1 ± 0.05 1.6 8.7 ± 0.11 6.7 ± 0.06 2.9 ± 0.09 21.4 ± 0.11 20.4 ± 0.13 9.3 ± 0.06 1.4 9.2 ± 0.08 7.1 ± 0.05 3.1 ± 0.09 23.2 ± 0.25 23.1 ± 0.00 10.4 ± 0.07 1.2 8.6 ± 0.11 6.4 ± 0.08 2.4 ± 0.05 22.3 ± 0.11 21.6 ± 0.09 10.1 ± 0.06 1.0 --- --- --- 21.7 ± 0.05 20.7 ± 0.11 9.9 ± 0.07 0.8 --- --- --- 21.5 ± 0.09 20.2 ± 0.05 9.5 ± 0.16 0.6 --- --- --- 20.8 ± 0.08 19.9 ± 0.15 9.2 ± 0.11 0.4 --- --- --- 19.7 ± 0.10 19.2 ± 0.14 8.8 ± 0.05 0.2 8.7 ± 0.23 6.7 ± 0.19 2.3 ± 0.16 18.2 ± 0.16 17.7 ± 0.18 8.5 ± 0.21 0.0 7 Days 3 Days One Day 7 Days 3 Days One Day Bending Strength (MPa) Compressive Strength (MPa) Polymer wt. %
  • P(VA-co-VAc-co-It)/plaster composites 1- Compressive strength with aging time 2- Compressive strength with polymer concentration
  • P(VA-co-VAc-co-It)/plaster composites Microstructure Neat plaster 2.0 wt. % 1.2 wt. %
  • P(VC-co-VAc-co-VA)/plaster composites Mechanical properties --- --- --- 17.7 ± 0.09 17.3 ± 0.12 8.3 ± 0.06 8.0 6.8 ± 0.07 6.4 ± 0.12 2.9 ± 0.05 17.9 ± 0.05 17.8 ± 0.13 9.9 ± 0.08 6.0 8.9 ± 0.13 8.0 ± 0.19 2.9 ± 0.09 21.0 ± 0.16 19.9 ± 0.08 13.2 ± 0.05 4.0 8.1 ± 0.07 7.8 ± 0.11 2.6 ± 0.05 20.1 ± 0.06 19.2 ± 0.08 12.6 ± 0.09 3.0 --- --- --- 19.3 ± 0.05 18.8 ± 0.07 12.1 ± 0.06 2.0 --- --- --- 18.9 ± 0.08 18.0 ± 0.05 11.0 ± 0.12 1.0 8.7 ± 0.23 6.7 ± 0.19 2.3 ± 0.16 18.2 ± 0.16 17.7 ± 0.18 8.5 ± 0.21 0.0 7 Days 3 Days One Day 7 Days 3 Days One Day Bending Strength (MPa) Compressive Strength (MPa) Polymer wt. %
  • 1- Compressive strength with aging time P(VC-co-VAc-co-VA)/plaster composites 2- Compressive strength with polymer concentration
  • Microstructure P(VC-co-VAc-co-VA)/plaster composites 1 wt. % 2 wt. % 3 wt. % 8 wt. % 4 wt. % 6 wt. %
  • Microstructure P(VC-co-VAc-co-VA)/plaster composites
  • X- Ray diffraction P(VC-co-VAc-co-VA)/plaster composites 1 wt. % 8 wt. % (a) (b)
  • Neat plaster PVA/plaster 1.0 wt. % P(VA- co -VAc- co -It)/plaster 1.2 wt. % P(VC- co -VAc- co -VA)/plaster 4.0 wt. % 28.5 MPa (56 %) 23.2 MPa (27 %) 21.0 MPa (15 %) 18.2 MPa
  • Bioactivity of Gypsum and Gypsum-Polymer Composites Ca and P concentrations
  • Bioactivity of Gypsum and Gypsum-Polymer Composites Variations in the pH of SBF solutions
  • Bioactivity of Gypsum and Gypsum-Polymer Composites Neat plaster Gypsum after treatment in SBF followed by 1.5 SBF for a week (Low Magnification) Gypsum after treatment in SBF followed by 1.5 SBF for a week ( High Magnification ) Energy-dispersive x-ray analysis of the spot marked by X in micrograph (c).
    • Phase compositions of gypsum and gypsum-polymer composite solids after immersion in SBF and 1.5 SBF solutions for a week in each.
    Bioactivity of Gypsum and Gypsum-Polymer Composites
    • Scanning electron micrographs of gypsum composites containing a) polymer I, b) polymer II and c) polymer III after immersion in SBF for one week.
    Bioactivity of Gypsum and Gypsum-Polymer Composites
    • Scanning electron micrographs of gypsum composites containing a) polymer I, b) polymer II and c) polymer III after immersion in SBF for one week, followed by 1.5 SBF for one week.
    Bioactivity of Gypsum and Gypsum-Polymer Composites
    • SEM micrographs of a) Apatite spherolites grown on a gypsum/polymer II composite, and b) Detailed
    • ultrastructure of a spherolite grown on gypsum/polymer III composite.
    Bioactivity of Gypsum and Gypsum-Polymer Composites
    • The purity of the tested gypsum plaster sample was calculated to be around 96 % CaSO 4 .½H 2 O with small amount of siliceous materials and carbonates. The carbonates were calculated to be 1.34 % of MgCO 3 and 1.9 % of CaCO 3 .
    • The investigated gypsum plaster sample blended 46 % water and gave long setting time (30 min) with moderate mechanical properties, 8.7 and 18.2 MPa for bending and compressive strengths respectively.
    • PVA/plaster composites showed a 56% increase in the compressive strength achieving 28.5 MPa with the addition of only 1.0 % by weight of PVA.
    • The influence of addition of P(VA- co -VAc- co -It) to plaster at a slightly higher concentration; 1.2 wt. % showed a maximum compressive strength of 23.2 MPa, which is 27% higher than that of polymer-free gypsum.
    Conclusions
    • P(VC- co -VAc- co -VA)/plaster composites achieved a compressive strength value of 21.0 MPa, which is 15% higher than that of polymer-free gypsum (when the polymer added in 4.0 wt. %).
    • Findings showed a correlation between the polymer solubility as well as its chemical structure with its effect on the mechanical properties of the produced composites.
    • Selected gypsum-polymer composites with the highest mechanical properties were further evaluated for their preliminary bioactivity. SEM micrographs of the SBF-treated composites revealed the formation of bone-like apatite deposits on the composite surfaces as well as inside the open pores. Water insoluble copolymer P(VC- co -VAc- co -VA) showed the greatest extent of apatite coating.
  • - Onderj Gedeon Doc.RNDr., Ph.D. - Ale š Helebrant Doc. Ing., CSc. - Jana Andertová Ing., CSc. - Jan Macháček Ing., Ph.D. - Dana Rohanová Dr. Ing. Acknowledgement
  • Thank you for your attention