Investigation on the thermal degradation, moisture absorption characteristics and antibacterial behavior of natural insulation materials

The demand for natural insulation materials is increasing with special attention to the use of such materials for exploiting renewable energy. Natural insulation materials tremendously influence the sustainability development and energy efficiency enhancement in the buildings. Natural fibers from animal’s origin absorb great amount of moisture on exposed to the environment which significantly affects the performance and thermal insulation properties. The thermal degradation of such material strongly influences the accidental burning characteristics, an important selection criteria for building materials. In the present study, three different kind of natural insulation materials namely sheep wool, goat wool and horse mane have been characterized in terms of moisture absorption, thermal degradation and morphology using thermogravimetric analysis (TGA), differential scanning calorimetry techniques, and scanning electron microscopy, respectively. In addition, antibacterial behavioral study has been also carried out for untreated raw wool and treated wool (copper nitrate). These properties are vital for a holistic evaluation of the insulation material. Moisture absorption results indicate that the sheep wool and goat wool absorb less moisture content as compared to horse mane. Unlike this horse mane shows great stability than goat wool and sheep wool in the temperature range not exceeding 470?°C. TGA data indicate 50% mass loss (T_50%) at 306?°C, 322?°C and 318?°C for sheep wool, goat wool and horse mane, respectively. In addition the tests show that the content of fire retardant elements like nitrogen and sulphur is more in horse mane as compared to sheep wool and goat wool. The treated wool samples showed excellent antibacterial properties as compared to untreated wool samples.