The Relationship Between Properties Of Single Bamboo Fibers And Preparation Methods

The bamboo fiber is primary constitute of bamboo and its physical and mechanical properties are important for the utilization. And the properties of single fibers are related with the preparation methods. With single fiber as a link, establishing suitable preparation technology in bamboo fiber industry will be the main direction for future development.Based on the former research, the fibre morphology, chemical constitution, surface wettability, mechanical properties of fibers isolated by HNO₃ + KClO₃, NaClO, H₂O₂ + HAc, NaOH, sulfate method, tweezers and fibers from sulfate pulp and chemical and mechanical pulp (CMP) were studyed. Meanwhile, studied the contact angle of fibers isolated by different methods and of different types. Also how the temperature and humidity affect the contact angle of different fibers was researched.The conclusions are summarized as follows:1. Differnt methods affect properties of single fiers(1) The maceration time in the HNO₃ + KClO₃ is shortest, and some fibers have a hollow, whose elongation is also the smallest one (1.84%). MOE of fibers isolated by NaClO is biggest, 41.99 GPa. Fibers isolated by H₂O₂+HAc, without a hollow, have the highest tensile strength (1776 MPa). MOE of fibers macerated by NaOH is lowest (19.6 GPa). The morphology and hollow of fibers isolated by sulfate method are similar with that of fibers isolated by H₂O₂ + HAc, and its mechanical property is good as well. The fibers from sulfate pulp has no hollow and its tensile strength and MOE are low, however, its elongation is high. The tensile strength of fibers from CMP is lower (519 MPa) than all other fibers, but its elongation is the highest (4.58%). Some fibers isolated by tweezers has fractures on the surface and its MOE and elongation is high, but tensile strength is low;(2) All the methods scarcely affect the cellulosice, but HNO₃ + KClO₃, H₂O₂ + HAc and sulfate method remove almost all of the lignin, and NaClO remove most, however, NaOH, sulfate method and CMP contain much lignin. NaClO, NaOH and sulfate method make all the hemicelluloses degraded, and CMP and sulfate pulp also contain little hemicelluloses, nevertheless, HNO₃ + KClO₃ and H₂O₂ + HAc just degrade part of hemicelluloses. Meanwhile, methods do not has significant effect on the contact angle of fibers.2. The function of ultrasonic treatment(1) Ultrasonic can shorten the maceration time, and ultrasonic make the cross section area, hollow area and cell wall area decrease except that of fibers isolated by HNO₃ + KClO₃. However, ultrasonic hardly affect the chemical constitution and ultrasonic can make the contact angle lower;(2) With the ultrasonic treatment, the tensile strength of fibers macerated by NaClO and H₂O₂ + HAc decrease significantly. Nevertheless, ultrasonic makes all the elongation become into the same level.3. Facors for testing the contact angle of single fibers(1) Both temperature and related humidity affect the contact angle of natural fibers, and humidity influences more. Temperature affects contact angle of regenerated cellulose fibers scarcely, but humidity influences it significantly, however, temperature affects that of synthetic fibers a little and humidity almost has no effect on it;(2) Methods hardly affect contact angles, but fiber types affect contact angles more. And the contact angle of ramie fibers is smaller than that of bamboo/jute/kender fibers.