Physical and Sound Absorption Properties of Spent Tea Leaf Fiber Filled Polyurethane Foam Composite

Abstract

Spent tea leaves (STL) from tea producing factories can be considered as new resources for sound absorbing polyurethane (PU) matrix composite materials because STL are rich in polyphenols (tannins) which cause high durability, high resistance to fungal and termites, and high resistance to fire. The research aims to study the physical characteristics of STL and the effect of dispersion morphology of STL on the sound absorption properties of polyurethane foam composites by varying filler loading. Three grades of STL fibers either as received or granulated are used in this study, namely BM-FAE and SWBHE derived from the stalk while FIBER-FAE derived from the leaves of the tea plant. The PU/STL composites are fabricated through open molding method with a fiber loading of 16 wt. %. The fabricated composites are then subjected to physical and sound absorption testing as well as microscopic observations to analyze the distribution of filler in composite. The study shows that as-received FIBER-FAE spent tea leaves provide the best sound absorption coefficient and for composites using granulated fibers from any grade have lower sound absorption coefficient. These results show that a novel kind of sound absorption materials with the recycling of waste materials can be obtained for the solution of noise and environmental pollution.