Production of Bio-Based Thermal Insulator Using Tapioca Starch and Oryza sativa (Rice) Husk

Abstract

INTRODUCTION

The Philippines allocates 47% of its land for agriculture (Zafar, 2018). Despite the great advantages this sector brings, the abundance of agricultural wastes has become a problem. These wastes are burned, bringing harmful effects to the environment and health of the farmers (Department of Science and Technology, 2006). As a tropical country, the Philippines also experiences high temperature that ranges from 32 to 41 degree Celsius. This falls under extreme caution in the heat index scale of PAGASA (Cabuenas, 2018). With these situations, the study aimed to produce a bio-based thermal insulator to resolve problems on agricultural wastes and high heat index in the country.

METHODS

Rice husk in varying amounts (25, 40, and 50 g) was treated with muriatic acid for an hour. One hundred fifty (150) mL of wood glue, 50 mL of distilled water, and varying amounts of tapioca starch (180, 150, and 120 g) were added. The mixture was stirred, transferred to a mold, and was left to dry. Two wood boxes were made(one installed with a commercial insulator and the other with bio-based insulator). Both insulator underwent the flammability test, water absorption test, and rate of heat transfer test. The preceding processes were done for three trials. Collected data were organized and analyzed using One-Way Analysis of Variance.

RESULTS

The commercial insulator burned the fastest (8.7 s) while Set up B burned the slowest (129.5 s). In terms of water absorption, Set ups B and C had the least amount of absorbed water (0.5 g). On the other hand, Set up A absorbed the highest amount (0.7 g). Bingel and Bown (2009) stated that if a material absorbs water, its strength and durability decreases. The commercial insulator performed best in preventing heat loss. The retained temperature is 51 degree Celsius, followed by Set up C, B, and A. With a level of significance of 0.05, results of One-Way ANOVA show that there is significant difference between the insulators in terms of flammability and no significant difference in terms of water absorption and rate of heat transfer.

DISCUSSIONS

Results show that the produced insulator is comparable to the commercial insulator in terms of water absorption and insulation properties. Meanwhile, in terms of being flame-retardant, the bio-based thermal insulator performed better than the commercial insulator. These imply that varying amounts of rice husk and tapioca starch affect the flame retardant, water absorption, and insulation properties of the bio-based thermal insulator.