Fluidized bed combustion fly ash as filler in composite polyurethane materials

Area of Science:

• Materials Science
• Polymer Engineering
• Waste Valorization

Background:

• Fly ash (FA) is an industrial waste with potential applications in polymer composites.
• Fluidized bed combustion (FBC) FA is underutilized in polyurethane (PUR) foam technology.
• Understanding FBC FA's impact on PUR foam properties is crucial for material development.

Purpose of the Study:

• To investigate the effect of FBC FA as an additive on the properties of rigid PUR foams.
• To analyze the microstructural, mechanical, thermal, and chemical changes in PUR foams with varying FBC FA content.
• To evaluate the potential of FBC FA as a reinforcing filler in PUR composites.

Main Methods:

• Composite rigid PUR foams were prepared with 5, 10, 15, and 20 wt% FBC FA using hand mixing and casting.
• Microscopic analysis (SEM) was used to examine foam morphology and FA distribution.
• Fourier Transform Infrared (FTIR) spectroscopy and X-ray Diffraction (XRD) analyzed chemical composition and bonding.
• Mechanical properties (tensile strength, etc.) and thermal stability were evaluated.

Main Results:

• FBC FA was uniformly distributed in the PUR matrix, acting as nucleation sites and reducing cell size.
• No chemical bonding occurred between FBC FA and the PUR matrix, confirmed by FTIR and XRD.
• Mechanical performance improved with FA content up to 10 wt%, indicating interfacial interactions.
• FA addition reduced carbon content and calorific value but enhanced thermal stability due to a barrier effect.

Conclusions:

• FBC FA can be effectively incorporated into rigid PUR foams, improving mechanical properties and thermal stability.
• The optimal FBC FA content for enhanced mechanical performance is around 10 wt%.
• FBC FA acts as a physical filler and nucleation agent, offering a sustainable route for waste utilization in polymer foams.