Structural and Performance Optimization of Environmentally Friendly Phenolic Resin/Polyvinyl Alcohol/Pure Terephthalic Acid/Silicone Carbide (PF/PVA/PTA/SiC) Porous Composite Grinding Wheels Prepared via Freeze-Drying Methodology

The traditional preparation of polyvinyl alcohol (PVA) grinding wheels typically involves hazardous chemicals such as formaldehyde and hydrochloric acid, posing significant health risks to operators and contributing to environmental pollution. In this study, we utilized the freeze-drying method to fabricate PVA grinding wheels, optimizing both the manufacturing process and the structure of the porous composite materials. The results demonstrate that phenolic resin (PF) participates in constructing a hydrogen-bonded network with PVA and pure terephthalic acid (PTA), which synergistically enhances the esterification efficiency between PTA and PVA. Furthermore, the incorporation of PTA as a crosslinking agent led to a more concentrated pore distribution, reducing the average pore size while enhancing mechanical strength. The freeze-drying duration of 42 h and 10% solid content of the PVA solution yields the favorable comprehensive porosity and mechanical performance of the grinding wheel with a unique bimodal pore structure and porosity exceeding 50%. The maximum grinding ratio was achieved at 0.81, while the surface roughness (Sa) was 0.308 μm. The freeze-drying approach significantly enhances pore uniformity and adjustability, producing grinding wheels with superior mechanical properties and performance consistency. This study presents a novel and environmentally friendly alternative to traditional PVA grinding wheel fabrication methods.