SYNTHESIS AND PROPERTIES OF POLYMER MODIFIED FLY ASH BASED POROUS COMPOSITES

In this research, polyvinyl alcohol/cellulose composite porous materials with high content of fly ash were prepared. The preparation process of the composite was simple, without requirement of high-temperature or high-pressure conditions. The characterization of the fly ash composites was analyzed via XRF, XRD, FT-IR, SEM, and mercury porosimetry. The effects of the mixture ratio of raw materials and drying temperature on the properties of the samples were explored. It was found that PVA could effectively increase the unconfined compressive strength of the composites, and cellulose was useful to improve the porous structure of the composites. The pore structure of the composites mainly came from the bubble polymerization in the process of water evaporation. The drying temperature was an essential factor that had influence on the pore structure, when the samples were prepared under the condition without external pressure. When the content of fly ash was 80%, polyvinyl alcohol was 10 wt% and cellulose was 10 wt%, the composite had good properties in porosity, pore structure, compressive strength, water absorption and water retention capacity. The comprehensive performance of the fly ash-based materials could be further developed by improving the internal porous structure and activation of the chemical functional groups. Further research needs to be conducted, to make the hydrophilic fly ash composites with certain compressive strength and provide good alternative for the utilization of fly ash.