Interfacial strength and mechanical properties of biocomposites based on ramie fibers and poly(butylene succinate)

In this work, a single ramie fiber was firstly treated with various surface modification agents including alkali, silane, maleic anhydride and acetic anhydride. Then single fiber fragmentation was carried out to evaluate the interfacial interaction between the fiber and poly(butylene succinate) (PBS) matrix by means of interfacial shear strength (IFSS). The highest IFSS was found for the fiber treated with alkali. In this simple way, alkali was easily selected as a good surface modification agent for the preparation of PBS/ramie fibers biocomposites. In order to verify that the single fiber fragmentation is an effective method for the selection of a good surface modification agent, the interfacial interaction and mechanical properties of the prepared PBS/alkali treated ramie fibers composites were investigated. It was found that alkali treated ramie fibers could be well dispersed and had better interfacial adhesion with the matrix than untreated fibers, as indicated by scanning electron microscope (SEM) observation and dynamic mechanical analysis (DMA). The tensile strength and modulus of PBS were greatly increased by adding the alkali treated fibers, while only a slight increase of tensile strength and modulus was observed for those compounded with untreated fibers. These results indicate that alkali is indeed a good coupling agent for the improvement of the interfacial strength of the composites, which is well consistent with that obtained via the IFSS measurement. Therefore, single fiber fragmentation test can be used as an effective and simple method to evaluate the surface modification and interfacial enhancement as well.