Mechanical properties of surface-treated ramie fiber fabric/epoxy resin composite fabricated by vacuum-assisted resin infusion molding with hot compaction

The optimization of composite manufacturing process is an important means for improving mechanical properties of natural fiber composites. In this paper, ramie fiber fabrics were, respectively, modified by NaOH, KMnO₄, and ammonium polyphosphate flame retardant, and then ramie fabric/epoxy resin composite laminates were prepared using vacuum-assisted resin infusion molding. In order to increase ramie fiber content in composite, vacuum pressure compaction and hot compaction with high pressure and temperature were, respectively, used to compress the fabric stack before molding. The effects of precompaction process on fiber compaction and mechanical properties of ramie fiber yarns and composites were studied. The comparison with the ramie fiber fabric without surface treatment was also done. It is found that surface-treated ramie fiber fabric has lower compressibility than the untreated one. Moreover, hot compaction with suitable conditions is effective in increasing fiber content and mechanical properties of all studied ramie fabric composites.