Processing by electrospinning method and characterization of poly(lactic acid) and poly(lactic acid)-based composite nanofibers

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2022-6

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Aşcı, Emine Ümran

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Electrospinning method is a versatile, cost-effective and viable technique to produce nanofibers with high ratios of surface area to the volume. The ability to obtain characteristics of the nanofibers via electrospinning, i.e., small pore size, high porosity and surface area/volume ratio, are some of the significant reasons why this method has eventually become a widespread technique for developing continuous and long fibers with nanometer-scale diameters. Furthermore, these advantages enable the produced nanofibers to be a class of nanomaterials suitable for various applications in industry and academic research. In this study, it is aimed to optimize the electrospinning process parameters (i.e., solution feed rate, tip-to-collector distance and applied voltage) and solution properties by changing the solvent ratio and solution concentration for the neat polylactic acid (PLA) nanofiber production. Furthermore, the effect of polyethylene glycol (PEG) and halloysite nanotubes (HNTs) addition on the performance of nanofibers was also investigated by generating PLA/PEG and PLA/HNT nanofibers. Also, the influence of solution preparation methods on properties of PLA/PEG/HNT nanofibers were studied. All the prepared mats were characterized in terms of their morphology, thermal and mechanical properties. In addition, water contact angle measurements were performed on the generated nanofibrous mats. The obtained results indicated that 13 wt.% of polymer solution concentration, 1 ml/h of feed rate, 20 cm of tip-to-collector distance, 20 kV of applied voltage and 80/20 v/v chloroform (CHL)/dimethylformamide (DMF) solvent ratio were the optimum parameter values for the electrospinning of neat PLA. Moreover, inclusion of 15 wt.% PEG and 0.5 wt.% HNT resulted in enhanced mechanical properties of the nanofibrous PLA/PEG and PLA/HNT mats, respectively. The results revealed that the tensile strength value of PLA/PEG and PLA/HNT nanofibers increased by 80% and 13%, respectively compared to the neat PLA nanofibrous mat at the optimum conditions. Also, degree of crystallinity was found to be 38% and 22% for PLA/PEG and PLA/HNT mats, respectively while it was calculated as 15% for the neat PLA sample. For the electrospinning of PLA/PEG/HNT nanofibers, the solution preparation method in which suspension of HNTs was sonicated for 30 mins before adding PLA and PEG to the solution and magnetically stirred for 4 hours, led to enhanced performance of the nanofibers. The tensile test results indicated that the tensile strength and tensile modulus increased by 95% and 27% for PLA/PEG/HNT samples, respectively compared to neat PLA nanofibers. The decomposition temperature of the nanofibrous mats did not significantly change with the parameters of the study.

Subject Keywords

Composite nanofibers, Electrospinning, Polylactic acid, Polyethylene glycol, Halloysite nanotubes

URI

https://hdl.handle.net/11511/98110

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

E. Ü. Aşcı, “Processing by electrospinning method and characterization of poly(lactic acid) and poly(lactic acid)-based composite nanofibers,” M.S. - Master of Science, Middle East Technical University, 2022.