Effect of magnesium hydroxide as a multifunctional additive on high solar reflectance, thermal emissivity, and flame retardancy properties of PP/SEBS/oil composites

Magnesium hydroxide (Mg(OH)(2)) as a traditional environmentally friendly flame-retardant is widely used in polymer matrix to fabricate engineering materials. Cooling performance is important for engineering materials and can be characterized by solar reflectance and emissivity. However, solar reflectance and emissivity of Mg(OH)(2)are rarely reported. In this work, cooling properties of Mg(OH)(2)were investigated and the samples were prepared by blending a series weight ratios of Mg(OH)(2)with polymer elastomer matrix (styrene-ethylene-butylene-styrene copolymer [SEBS], polypropylene [PP], and processing oil). With the introduction of 150 phr Mg(OH)(2), the solar reflectance enhanced to 47.23%, which is 31.19% higher than the polymer matrix. Simultaneously, the cooling effect of 15 degrees C can be obtained in comparison with the polymer matrix and emissivity enhanced to 0.86. Meanwhile, an introduction of 150 phr Mg(OH)(2)increased the limit oxygen index from 17 to 26 and vertical burning test (UL-94) attained to V-0 rating. Thermal behaviors indicate that the composites exist multiple phase structure, where the glass transition temperature of SEBS is -55 degrees C and melt temperature of PP is 153 degrees C. The results show the composites can be used from -30 degrees C to 80 degrees C and satisfy the outdoor use conditions.