ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Enhancement on fireproof performance of construction coatings using calcium sulfate whiskers prepared from wastewater

Hsi-Chi Yang, Tsung-Pin Tsai, and Chien-Te Hsieh

Department of Construction Management, Chung Hua University, Hsinchu, Taiwan

E-mail: hcyangse@yahoo.com

Abstract: This work is dealing with the fireproof performance of gypsum composite painting for fire passive protection in building construction. An efficient microwave-assisted method is adopted to fabricate high-crystalline CaSO₄·2H₂O whiskers from wastewater. The as-prepared CaSO₄·2H₂O whiskers display one-dimensional structure with a high aspect ratio of 40. The thermal resistive behavior of CaSO₄− containing paints is investigated using thermo-gravimetric analyzer, differential scanning calorimetry, and direct flaming test (at 150, 570, and 1100 °C). The addition of CaSO₄·2H₂O whiskers not only improves the anti-flammability but also reduces the ignition temperature of construction painting. This result can be attributed to the fact that the heat transfer through the CaSO₄-containing painting can be alleviated until the endothermic reaction steps [i.e., dehydration of gypsum (CaSO₄·2H₂O) and crystalline phase change of β-hemihydrated plaster] are totally completed. The burned fractions (including pyrogenation and carbonization) on CaSiO₃ substrate are decreasing functions of the content of CaSO₄·2H₂O whiskers, proving that gypsum works as an insulator against heat transfer and flame spreading. Accordingly, the CaSO₄·2H₂O whiskers can be considered as an effective fire retardant additive for improving the fireproof ability of construction coatings.

Keywords: Fireproofing, Flame retardancy, Calcium sulfate whiskers, Wastewater, Construction coating

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-016-0126-z

Chemical Papers 71 (7) 1343–1350 (2017)