Modification of Gypsum Products (Part II): The Effect of Drying Methods on The Compressive Strength and Surface Hardness of Modified Gypsum Products

• Main Authors: Nadira A. Hatim (Author), Isam K. Al-Khayat (Author), Mohammed A Abdulla (Author)
• Format: Book
• Published: University of Mosul, College of Dentistry, 2009-08-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.33899/rden.2009.9107; 1812-1217; 1998-0345
• Keywords: gypsum products; additives; microwave drying.; Dentistry; RK1-715
• Source: Al-Rafidain Dental Journal, Vol 9, Iss 2, Pp 162-167 (2009)

Aims: Studying the effect of microwave drying on the physical and mechanical properties of modifiedIraqi plaster and modified Plaster of Paris in comparison with open air drying method. Materials andmethods: Two types of gypsum products were used in this study (Iraqi plaster, Plaster of Paris) withthe combined additives (gum arabic 0.5%, calcium oxide 0.75%, and ferric oxide 0.2%) that incorporatedwithin the two gypsum products. Physical and mechanical properties of the experimental gypsumproducts have been evaluated by measuring the compressive strength, surface hardness, and surfaceroughness. Mean, standard deviation, analysis of variance (ANOVA), and Duncan's multiple rangestatistical test were used to analyze the data. Results: ANOVA analysis showed that there was a significantdifference in the compressive strength, surface hardness, and surface roughness between Iraqiplaster (I.P) and Plaster of Paris (P.O.P) with or without additives. Conclusions: At two hours timeinterval microwave oven drying, Iraqi plaster and Plaster of Paris samples were stronger than air driedsamples; and microwave oven at 10 minutes for 800 Watt not only increased the strength of gypsumproducts samples, but also save time.