Enhancing the crystallization and orientation of electrospinning poly (lactic acid) (PLLA) by combining with additives
- 478 Downloads
PLLA is a thermoplastic biopolymer and can be used in industrial applications for medical and filtration applications. The brittleness of PLLA is attributed to slow crystallization rates and its glass transition temperature (Tg) is high (60 °C); for this reason, its applications are limited. The orientation, morphology, and crystal structure of the electrospun fibers was investigated by SEM, POM, DSC, FTIR, XRD, and SAXS. Combining with additives leads to a large decrease of fiber diameter, viscosity, and changes of fiber morphology and crystal structure compared to pure PLLA. DSC showed that the Tg of PLLA decreased about 15 °C and there was no change in relaxation enthalpy by the addition of plasticizer. FT-IR indicate a strong interaction between PLLA and additives; a new band appears in the PLLA blend at 1,756 cm−1 at room temperature as a crystalline band without any annealing. In addition, WAXD indicated that the intensities of the two peaks at (200/110) and (203) increased for the blend at room temperature without any annealing in comparison with PLLA; this means that PHB crystallizes in the amorphous region of PLLA. The POM experiments agree with the results from DSC, FTIR, and WAXS measurements, confirming that adding PHB results in an increase in the number of nuclei with much smaller spherulites and enhances the crystallization behavior of this material, thereby improving its potential for applications.
KeywordsPHB PLLA Biopolymer blends Electrospinning Nano fibers
The author thanks SABIC company for petrochemicals (Research & Consulting Center) and Institute of Scientific Research for supporting this project (grant number: 43005001).
- 2.Ramakrishna S, Kazutoshi F, Teo WE, Lim TC, Ma Z (2005) An introduction to nanofibers. World Scientific Co., Pte. Ltd., SingaporeGoogle Scholar
- 3.Reneker DH, Fong H (2006) Polymeric nanofibers. In: ACS symposium series 918.Washington, DC: American Chemical SocietyGoogle Scholar
- 4.Fong H, Reneker DH (2000) Electrospinning and the formation of nanofibers. In: Salem DR (ed) Structure formation in polymeric fibers. Hanser, Munich, pp 225–289Google Scholar
- 6.Formhals A (1934) Process and apparatus for preparing artificial threads, US patent 1975504Google Scholar
- 9.Chen J, Chang GY, Chen JK (2008) Colloids and Surfaces A: Physicochemical and Engineering Aspects. 313–314: 183–188. Electrospun collagen/chitosan nanofibrous membrane as wound dressingGoogle Scholar
- 15.El-Hadi AM (2011) The Effect of Annealing Treatments on Spherulitic Morphology and Physical Ageing on Glass Transition of Poly Lactic Acid (PLLA). Mater Sci Appl 2:439–5Google Scholar
- 18.Bognitzki M, Czado W, Frese, T A (2001) Schaper, Hellwig M, Steinhart M, Greiner A, Wendorff JH, Nanostructured fibers via electrospinning, Adv Mater 13 :70–2Google Scholar
- 35.Furukawa T, Sato H, Murakami R, Zhang J, Duan YX, Noda I, Ochiai S, Ozaki Y (2005) Structure, Dispersibility, and Crystallinity of Poly (hydroxybutyrate)/ Poly (L-lactic acid) Blends Studied by FT-IR Microspectroscopy and Differential Scanning Calorimetry. Macromolecules 38:6445–6454CrossRefGoogle Scholar