Optimization of pullulan fiber processing parameters via the Forcespinning method

Abstract In this study PL fibers were used to analyze the influences of two key parameters in the optimization process aimed at maximizing fiber yield using the centrifugal spinning technique called Forcespinning ® . The optimization process was conducted focusing on rotational velocity (rpm) and precursor polymer concentration. These variables were then correlated with both fiber yield and diameter. Rheological analysis of the precursor polymeric solutions was performed to examine the relationships between fiber production parameters and solution viscosities ( η ) as well as storage ( G′ ) and loss ( G″ ) moduli. Fiber yields were analyzed at intervals from 2,000 to 10,000 rpm. In terms of morphological properties, most fibers exhibited diameters ranging from 0.2 to 1.2 μm, with a gradual decrease observed as the rpm increased, which aligns with expectations. The 18.2 wt% pullulan solution demonstrated an optimal balance of high fiber production yield (60–67 %), low production rpm (4,000), and low viscosity (1,415 cp), facilitating the production process compared with the other systems. Additionally, thermal characterization analysis revealed that the fibers absorbed solvents in the range of 10–11 % by weight, with thermal stability exceeding 270 °C in a nitrogen atmosphere. This optimization study is a processing platform for future research on pullulan-based fibers.