Soundproofing properties of open- cell microcellular polyurethane foam containing styrene-grafted polyester polyol

Abstract

Both soundproofing and mechanical strength present significant challenges in the context of sound-insulating materials. Herein, to take advantage of higher intermolecular interactions of ester groups, a soundproofing open-cell Microcellular Polyurethane Foam (MPUF) was developed using polymer-grafted polyester polyol (POP) and saturated polyester polyol. The POP was synthesized by grafting polystyrene on unsaturated polyester polyol (UNPES) in a saturated polyester polyol media. The amount of styrene monomer and UNPES were changed and the POP with optimum properties was selected. The successful synthesis of POP was approved by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), and gel permeation chromatography (GPC). The spherical morphology of selected POP with a diameter of about 500 nm was confirmed by scanning electron microscopy (SEM) and dynamic light scattering (DLS) analysis. MPUFs containing different amounts of POP (10, 30, 50, and 100 %) as polyester polyol parts were prepared. It was found that mechanical properties including tensile strength: 3500 KPa, elongation at break%: 350% and soundproofing properties with acoustic activity of 0.72 were obtained when the POP content of the MPUF was fixed at 30%. The cell-opening behavior of POP in polyester-based MPUF was studied using SEM. It was found that the average of the open cells’ size and their population were increased as the POP content increased. Such MPUFs can be effective in successful mechanical and acoustic damping in the automotive industry.