title: Strength retention behavior of oriented PLLA, 96L/4D PLA, and 80L/20D,L PLA.
abstract: The strength retention characteristics of oriented semicrystalline polylactides were monitored during hydrolytic degradation in vitro. The effects of the polymer type, the material's initial inherent viscosity (iv), the sample diameter and the residual monomer content on strength retention were analyzed. The analyzed polylactides had similar, but not identical, strength retention characteristics. It was concluded that a higher degree of initial crystallinity was a major variable determining the earlier and more profound strength loss of PLLA than 96L/4D PLA and 80L/20 D,L PLA. Samples with a higher initial iv were found to have a longer strength retention time than lower iv samples. Size-dependency was observed, as the strength retention time was shorter for the smaller diameter samples. This size-dependency was caused by faster iv decay. The amount of residual monomer content had a remarkable impact on strength retention. Neither the sample diameter, initial iv or residual monomer content were found to have an effect on the iv range in which there was a rapid decline in strength properties. Therefore, it was concluded that the inherent viscosity and/or molecular weight of oriented PLLA, 96L/4D PLA and 80L/20 D,L PLA is a major variable determining the strength retention of these materials.
authors.affiliation: BioMediTech; Tampere, Finland; Department of Electronics and Communications Engineering; Tampere University of Technology; Tampere, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Huttunen
authors.affiliation: BioMediTech; Tampere, Finland; Department of Electronics and Communications Engineering; Tampere University of Technology; Tampere, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Kellomäki
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D019245:Compressive Strength; D006868:Hydrolysis; D019344:Lactic Acid / Q000737:chemistry*; D008422:Materials Testing; D008968:Molecular Conformation; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical; D013718:Tensile Strength; D014783:Viscosity
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)
keywords: degradation; polylactide; strength retention
references.citation: J Mater Sci Mater Med. 1999 Jan;10(1):1-8
references.pmid: 15347988
references.citation: J Biomed Mater Res. 2002;63(6):752-9
references.pmid: 12418020
references.citation: Biomaterials. 1993;14(4):291-8
references.pmid: 8476999
references.citation: Biomaterials. 2011 Apr;32(12):3166-77
references.pmid: 21315446
references.citation: J Biomater Sci Polym Ed. 1994;5(6):591-606
references.pmid: 8086385
references.citation: J Mater Sci Mater Med. 2008 May;19(5):2063-70
references.pmid: 17968505
references.citation: J Biomed Mater Res. 1989 Oct;23(10):1115-30
references.pmid: 2808460
references.citation: J Biomed Mater Res. 1999;48(3):342-53
references.pmid: 10398040
references.citation: Biomaterials. 1995 Mar;16(4):305-11
references.pmid: 7772670
references.citation: J Mater Sci Mater Med. 2013 May;24(5):1131-44
references.pmid: 23471499
references.citation: J Mech Behav Biomed Mater. 2011 Oct;4(7):1283-90
references.pmid: 21783137
references.citation: J Biomed Mater Res B Appl Biomater. 2006 Feb;76(2):403-11
references.pmid: 16184534
references.citation: J Biomed Mater Res B Appl Biomater. 2007 Aug;82(2):325-33
references.pmid: 17238162