Reinforced poly (butylene succinate)/ethyl succinyl chloride cellulose nanocrystal composite fiber: a stretching induced orientation study

To prepare poly (butylene succinate) (PBS)/cellulose nanocrystals (CNCs) with high performance and investigate the relationship between microstructure and properties, in this work, CNCs were firstly treated with ethyl succinyl chloride to improve their interfacial compatibility with PBS. Then melt spun processing was adopted to obtain PBS/CNC fibers, which were followed by heat stretching to further improve the orientation and mechanical properties of as-spun PBS fibers. The effects of modification of CNCs on chemical structure, their wettability as well as dispersion, thermal properties and mechanical properties were systematically investigated for the composite fibers. The dispersion, alignment of the CNCs and crystalline thermal behavior, and PBS chain orientation in the composite fibers were significantly influenced by the stretching treatment. The possible formation of multidimensional oriented superstructure including regularly arranged PBS shish kebab crystals, modified CNCs and oriented PBS chains has been suggested via SEM and SAXS in the composite fibers prepared at the high draw ratio. Significant improvement in tensile strength has been realized at the high draw ratio due to the enhanced orientation and dispersion of CNCs as well as the formation of multidimensional oriented superstructure.