A Study of Acoustic Properties of Coconut Coir and Vermiculite Composite as Noise Insulation in Vehicles

Coconut coir and vermiculite composite is a promising front on the research on natural fiber sound insulation panels. Vermiculite particles are introduced in the matrix to prop up the pores in the coconut coir fibers thus allowing for sound energy to be dissipate as it passes through the pores. Since the composite can be compressed considerably while still maintaining the pores, the acoustic performance can rival that of conventional noise insulation materials but with added value of sustainability and possible cost savings. By using a mix of 7:2:1 ratio of coconut coir fibers to vermiculite particles to PVA binder in weight percentages, an improvement of 18.7% can be seen with the acoustic absorption coefficient with respect to the control sample. The 8:1:1 variations also sees an improvement of over 16% but in both cases, chopped fibers were used with an average length of 60mm. In the long fibers specimens, only 8% improvement was seen with the 8:1:1 variation and the 7:2:1 variation was only marginally better than the former.