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Abstract. This study investigates the acoustic properties of polymer foam composites (FC) filled with natural fiber. The FC were produced based on crosslinking of polyol, with flexible isocyanates and wood filler. The percentages of wood filler loading are 10, 15, and 20 wt% ratio of polyol. The FC also has a thickness of 10, 20 and 30 mm. The acoustic properties of the FC were determined by using Impedance Tube test, Optical Microscope (OM) and Mettler Toledo Density Kit test. The results revealed that FC20 with 30 mm in thickness gives the highest sound absorption coefficient (α) with 0.970 and 0.999, at low and high frequency respectively. FC20 also shows smallest pores structures size with 134.86 µm and biggest density with 868.5 kg/m 3 which helps in absorbing sound. In this study, FC with different percentage loading of wood filler and different foam thickness shows the ability to contribute the absorption coefficient of polymeric foam at different frequency levels. Lastly, this type of FC is suitable for any type of sound absorption applications material.

This study focused on fabrication of polyurethane (PU) foams and its composites based on hydroxylated bioepoxy (B) and petroleum based synthetic epoxy (E), crosslinker and wood fillers. The fabrication of foams: B and E with different wood filler size such as flake (L) and powder (P) on different composition ratios of 5%, 10%, 15% and 20%.  The fabrication techniques used in this research are open moulding technique. The physical properties such as morphological pore structure and its homogeneity of wood filler distribution in foam polymer composites were measured. The effect of different size of wood filler loading in PU foam composites were analyzed and discussed in detail such as gelling time, main pore size, interconnected pore and struts thickness. The operatory conditions of in-situ PU foams synthesis were optimized using a design of experiment (DOE). The correlations between factors (X1, X2, X3) and the responses (Y1, Y2, Y3, Y4) for B, E as well as BL, BF, EL or EF foams were further analyzed using Minitab software.

In this paper, polymer foam composites (FC) have been developed based on polyol mixed flexible crosslinker and fibre filler of Meranti Merah. 10 mm, 20 mm and 30 mm thickness of foam polymer and its composites have been use in this study. The percentage loading of wood fibre of 5%, 10%, 15% and 20% added with polymer foam is namely as polymer foam (PP) and its composites of PP5, PP10, PP15 and PP20. The sound absorption coefficient (α) and pore structure of the foam samples have been measure by using Impedance Tube test and Scanning Electron Microscopy (SEM). UV Weatherometer is used to examine the durability and weatherproof of its composite. The results show that the highest thickness of the highest percentage fiber filler (Pp2030) gives higher sound absorption coefficient (α). 0.9922 and 0.99889 which contributed from low and high frequency absorption level respectively. The smallest pores size structure was observed with highest filler loading of PP20. The higher the thickness and the higher the percentage loading of wood filler gives smaller pore structure, consequently, increased the sound absorption coefficient level. Meanwhile, the stability of polymer foam composites is high due to unchanged pore structures morphology with prolonged ultra violet exposure.