No abstract

Fly ash particles are usually spherical and based on their chemical composition; they are categorized into two classes: C and F. This study compares the microstructural, mechanical and thermal properties of extruded rigid PVC foam composites reinforced with class C and class F fly ash. The mechanical properties: such as tensile and flexural strength of composites containing class C fly ash were superior to the composites containing class F fly ash particles. Composites containing 6 phr class C fly ash showed a 24% improvement in the tensile strength in comparison to a mere 0.5% increase in composites reinforced with class F fly ash. Similarly, the addition of 6 phr of class F fly ash to the PVC foam matrix resulted in a 5.74% decrease in the flexural strength, while incorporating the same amount of class C fly ash led to a 95% increase in flexural strength. The impact strength of the composites decreased as the amount of either type of fly ash increased in the composites indicating that fly ash particles improve the rigidity of the PVC foam composites. No significant changes were observed in the thermal properties of the composites containing either type of fly ash particles. However, the thermo-mechanical properties measured by DMA indicated a steep increase in the viscoelastic properties of composites reinforced with class C flyash. The microstructural properties studied by Scanning Electron Microscopy (SEM) confirmed that fly ash particles were mechanically interlocked in the PVC matrix with good interfacial interaction with the matrix. However, particle agglomeration and debonding was observed in composites reinforced with higher amounts of fly ash.

In this study, the effect of particle size of fly ash (FA) on the interfacial interaction between the filler particles and the polymer matrix is investigated. Structural and physical characterization of FA with different particle sizes show that its chemical composition is highly dependent on the particle size. The mechanical, dynamicmechanical, structural, and microstructural properties of the composites are evaluated. Interfacial interaction between FA particles and the polymer matrix is assessed experimentally using a nanoindenter and numerically using two different models developed by Pukanszky and Kubat. The composites reinforced with smaller particles exhibit better mechanical, viscoelastic, and microstructural properties. Structural and interfacial studies show that, although the characterized amount of silicon oxide in the small particles is lower than the large particles, the concentration of -OH group in SiO 2 is particle-size and surface-area dependent. Therefore, smaller particle inclusions result in better interfacial interaction and improved properties. This observation is consistent with the numerically estimated interfacial interaction. J. VINYL ADDIT. TECHNOL., 00:000-000,

In this study, the effect of reinforcements' shape and type on the mechanical, thermal, and morphological properties of polyvinyl chloride (PVC) foam composites is investigated. For this purpose, three different fillers, longitudinal structure glass fiber, flaky structure mica, and spherical structure fly ash, were selected to prepare PVC foam composites with 0-20 wt% loading. The tensile strength in both 10 wt% reinforced mica and glass fiber composites improved slightly, while it decreased with the addition of 10 wt% fly ash. Flexural strength reached its maximum in mica and fly ash-filled composites at 10 wt% loading. Meanwhile, flexural strength exhibited higher saturation levels of longitudinal glass fibers due to their penetration within the foam cells. Charpy impact strength measurements showed a decreasing trend with increasing the filler content; however, the rate of reduction was the lowest in PVC/glass fiber foam composites. The effect of filler type and geometry on thermal and dynamic mechanical properties of PVC foam composites was studied using thermogravimetric analyzer and dynamic mechanical analysis, respectively. First decomposition temperature of PVC composites dropped slightly with the addition of fillers, where glass fiber-reinforced foam composites exhibited the lowest rate of reduction. The second decomposition step of PVC foam composites shifted toward higher temperatures with increasing the filler content. Fly ash was found to be more effective in improving the second decomposition temperature. The dynamic modulus of mica and glass fiber-reinforced composites showed an increasing trend below and above glass transition temperature, up to 10 wt% loading, while the storage modulus in fly ash-reinforced composites increased with increasing the filler content at a constant rate. Morphological studies revealed that mica flakes with a paralleled structure within cell walls and glass fibers Downloaded from with a penetrated structure within the cell bubbles exhibited higher agglomeration compared to fly ash composites.

Cenosphere fly ash is a byproduct of coal combustion processes of power plants. It is composed of hollow, hard shelled, minute spheres, which are made up of silica, iron, and alumina. In this study, cenosphere fly ash is incorporated into rigid PVC foam to improve thermal and mechanical properties of their composites. Microstructural, physical, mechanical, and thermal properties of rigid PVC foam extruded with different loadings of cenosphere fly ash (6, 12, 18phr) are characterized. The measured density of the extruded PVC foam composites increased with cenosphere content, indicating a hindrance to the foaming process. Tensile and flexural mechanical properties improved at higher cenosphere content, while the impact strength decreased at initial loading of 6 phr of cenosphere particles and remained steady at higher loadings. Thermal characterization of the extruded samples showed that glass transition temperature remained almost unaffected, while TGA analysis revealed no change in the initial degradation temperature and significant improvement in the final degradation temperature. Thermo-mechanical properties measured by DMA revealed a remarkable improvement in the viscoelastic properties of the composites reinforced with cenosphere particles. SEM analysis of the composites microstructure confirmed that the cenosphere particles were mechanically interlocked with good interfacial interaction in the PVC matrix.