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Open AccessArticle

The Influence of Low Shear Microbore Extrusion on the Properties of High Molecular Weight Poly(l-Lactic Acid) for Medical Tubing Applications

1
Materials Research Institute, Athlone Institute of Technology, Dublin Road, Bunnavally, Athlone and Co., Westmeath, Ireland
2
Faculty of Engineering and Informatics, Athlone Institute of Technology, Dublin Road, Bunnavally, Athlone, Co., Westmeath, Ireland
*
Author to whom correspondence should be addressed.
Polymers 2019, 11(4), 710; https://doi.org/10.3390/polym11040710
Received: 28 January 2019 / Revised: 8 April 2019 / Accepted: 10 April 2019 / Published: 18 April 2019
(This article belongs to the Special Issue Biopolymers and Biobased Polymers: Chemistry and Engineering)
Biodegradable polymers play a crucial role in the medical device field, with a broad range of applications such as suturing, drug delivery, tissue engineering, scaffolding, orthopaedics, and fixation devices. Poly-l-lactic acid (PLLA) is one of the most commonly used and investigated biodegradable polymers. The objective of this study was to determine the influence low shear microbore extrusion exerts on the properties of high molecular weight PLLA for medical tubing applications. Results showed that even at low shear rates there was a considerable reduction in molecular weight (Mn = 7–18%) during processing, with a further loss (Mn 11%) associated with resin drying. An increase in melt residence time from ~4 mins to ~6 mins, translated into a 12% greater reduction in molecular weight. The degradation mechanism was determined to be thermal and resulted in a ~22-fold increase in residual monomer. The differences in molecular weight between both batches had no effect on the materials thermal or morphological properties. However, it did affect its mechanical properties, with a significant impact on tensile strength and modulus. Interestingly there was no effect on the elongational proprieties of the tubing. There was also an observed temperature-dependence of mechanical properties below the glass transition temperature. View Full-Text
Keywords: Bioabsorbable polymers; poly-l-lactic acid; microbore extrusion; low shear; residence time; molecular weight; residual monomer; crystallinity Bioabsorbable polymers; poly-l-lactic acid; microbore extrusion; low shear; residence time; molecular weight; residual monomer; crystallinity
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MDPI and ACS Style

Dillon, B.; Doran, P.; Fuenmayor, E.; Healy, A.V.; Gately, N.M.; Major, I.; Lyons, J.G. The Influence of Low Shear Microbore Extrusion on the Properties of High Molecular Weight Poly(l-Lactic Acid) for Medical Tubing Applications. Polymers 2019, 11, 710.

AMA Style

Dillon B, Doran P, Fuenmayor E, Healy AV, Gately NM, Major I, Lyons JG. The Influence of Low Shear Microbore Extrusion on the Properties of High Molecular Weight Poly(l-Lactic Acid) for Medical Tubing Applications. Polymers. 2019; 11(4):710.

Chicago/Turabian Style

Dillon, Brian; Doran, Patrick; Fuenmayor, Evert; Healy, Andrew V.; Gately, Noel M.; Major, Ian; Lyons, John G. 2019. "The Influence of Low Shear Microbore Extrusion on the Properties of High Molecular Weight Poly(l-Lactic Acid) for Medical Tubing Applications" Polymers 11, no. 4: 710.

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