The Influence of Solid-State Drawing on Mechanical Properties and Hydrolytic Degradation of Melt-Spun Poly(Lactic Acid) (PLA) Tapes

Fibers

Fang Mai²  Wei Tu¹  Emiliano Bilotti²  Ton Peijs² 

[1] Nanoforce Technology Ltd., Joseph Priestley Building, Queen Mary University of London, Mile End Road, E1 4NS London, UK; E-Mail:;School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, E1 4NS London, UK; E-Mails:

关键词: poly(lactic acid);    fibres;    morphology;    mechanical properties;    degradation;   

DOI  :  10.3390/fib3040523

来源: mdpi

【 摘 要 】

The influence of solid-state drawing on the morphology of melt-spun poly(l-lactic acid) (PLLA) tapes, and the accompanying changes in mechanical and degradation behaviour have been studied. Mechanical properties are found to be strongly dependent on both applied draw ratio and drawing temperature. Moduli of these highly oriented tapes are significantly increased compared to as-extruded tapes at both ambient and elevated temperatures. Interestingly, drawing leads to a significant increase in elongation to break (~3 times) and toughness (~13 times) compared to as-extruded tapes. Structural and morphological characterization indicates strain-induced crystallization as well as an increase in orientation of the crystalline phase at small strains. Upon further stretching, an “overdrawing” regime is observed, with decreased crystalline orientation due to the breakage of existing crystals. For fixed draw ratios, a significant increase in Young’s modulus and tensile strength is observed with increasing drawing temperature, due to a higher crystallinity and orientation obtained for tapes drawn at higher temperatures. FT-IR results indicate no crystal transformation after drawing, with the α-form being observed in all tapes. Hydrolytic degradability of PLLA was significantly reduced by solid-state drawing.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.