Evaluation of properties of bast fiber extracted from Calotropis (Millkweed) by a new decorticator machine and manual methods

• Calotropis fiber quality in new decorticated method was compared to manual method.
• Significant difference was not in the cell morphology between two extracted methods.
• The tensile properties of fiber were improved by mechanical decortication.
• The length of fiber bundle at decorticated method was in the range of 15–80 cm.

The majority of plant fibers which are being considered as reinforcements for polymeric composite are bast fibers. Calotropis bast fiber is one of these types that has been extracted manually up to now. The objective of this study was to investigate the effect of new decorticator machine on some properties of extracted fiber and compare with separated fibers manually. The mentioned decorticator machine was able to extract bast fiber without shattering stems and flowing latex. Some studied properties were morphological characterize, tensile properties (tensile strength, Young’s modulus and strain) and density of fiber. The results indicated that machinery extraction method had no significant effect on the fiber morphology. This means that the decorticator machine did not cause serious mechanical damage on the morphology of fiber, instead the cell length increased in decorticated bast fiber. Also a significant increase (P ≤ 0.01) was observed in the bundle lengths for fibers decorticated by the machine. Regarding tensile strength, the decorticated bast fibers show highest tensile strength (350.73 MPa) in comparison with the strength of extracted fibers manually (254.56 MPa). Also, it is shown that there is no significant difference between densities in two extraction methods.