Studies on production and analysis of hemp nanofibers by electrospinning method

In this thesis, fibers reduced to nano dimensions were obtained from hemp fiber, hemp seed and hemp stem by using electrospinning method, which is one of the most effective methods in polymer-based nanofiber production compared to traditional fiber production methods. For nanofiber synthesis, a solution of PAN (polyacrylonitrile) in DMF (N,N-dimethylformamide) was prepared. First of all, PAN polymer fiber was produced in the electrospinning mechanism with this solution. Then, hemp stem, fiber and seed were mechanically pulverized by ball milling technique. The obtained hemp powders were produced using electrospinning technique by adding PAN polymer hemp stem, hemp fiber and hemp seed nanofibers to the PAN polymer solution. Since the optimization parameters of the electrospinning process (such as syringe diameter, collection distance, voltage, spray rate and collection time) involve precise control of many variables, the electrospinning process for each (hemp stem with PAN polymer, hemp fiber and hemp seed); voltage, distance and accumulation time were changed. The produced nanofibers were observed to have diameters ranging from 30 to several hundred nanometers. The morphology of the nanofibers was determined and characterized using scanning electron microscopy (SEM). In addition, UV-Vis-NIR spectroscopic technique was used to determine the absorption spectrum. With FTIR, the chemical structure was tried to be clarified and the presence of functional groups in its composition was examined. It was determined that there are PAN and hemp peaks in the structure of nanofibers. Thermogravimetric Analysis (TGA) was carried out in the temperature range from 20 to 800 oC to determine the thermal durability of nanofibers produced from PAN polymer hemp stem and PAN. As a result, the TGA spectrum of hemp stem with 6 % PAN polymer and PAN was obtained, with a deposition time of 15 minutes, respectively. It shows a weight loss of 40% at 300 oC for PAN nanofibers alone, while there is a 20 % weight loss at 314 oC for hemp stem nanofibers. Both PAN and PAN:hemp stem nanofibers were observed to slowly lose weight after the initial sharp decline and almost completely disintegrated at 800 oC.