Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Long-term properties and migration of low molecular mass compounds from modified PLLA materials during accelerated ageing
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-7790-8987
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
2012 (English)In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 97, no 6, 914-920 p.Article in journal (Refereed) Published
Abstract [en]

The durability of polylactide during accelerated ageing and the entire degradation process were significantly altered by different low molecular mass additives and stereocomplexation. The samples were aged in air at 60°C and 90°C and the degradation process was followed by monitoring mass loss, molar mass, presence and formation of low molecular mass compounds, changes in surface structure and thermal properties. Stereocomplexation increased the long-term durability of polylactide materials. Mass loss and molar mass changes also indicated that addition of TiO 2 nanoparticles had a stabilizing effect at higher temperature and during longer exposure times. Interestingly addition of linear lactic acid oligomers resulted in lower mass loss compared to materials containing cyclic lactide oligomers. This is interpreted as a result of stronger interactions between the linear oligomers and PLLA chains, resulting in slower migration rate, which was also shown by ESI-MS analysis. However, the linear oligomer additives accelerated the molar mass decrease, probably due to the catalytic effect of the end groups. The stereocomplex displayed the greatest resistance towards degradation, a consequence of strong secondary interactions.

Place, publisher, year, edition, pages
2012. Vol. 97, no 6, 914-920 p.
Keyword [en]
Degradation, Degradation products, ESI-MS, Polylactide, Stereocomplex
National Category
Chemical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-96177DOI: 10.1016/j.polymdegradstab.2012.03.028ISI: 000304641300011Scopus ID: 2-s2.0-84860358383OAI: oai:DiVA.org:kth-96177DiVA: diva2:532337
Note
QC 20120611Available from: 2012-06-11 Created: 2012-05-31 Last updated: 2017-12-07Bibliographically approved
In thesis
1. Controlling Polylactide Degradation through Stereocomplexation and Lactic Acid Based Additives
Open this publication in new window or tab >>Controlling Polylactide Degradation through Stereocomplexation and Lactic Acid Based Additives
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The successful use of degradable materials in new applications depends on our ability to control the degradation process. A number of aspects need to be evaluated including degradation rate, the onset of degradation and the nature, formation and release of degradation products. In this study, the possibility of tuning the properties and degradation of polylactide (PLA) through stereocomplexation between the L- and D-enantiomers of PLA was investigated. The influence of the oligo(D-lactic acid) architecture on the stereocomplexation and subsequent degradation rate was evaluated. The dependence of stereocomplex formation on the structure of the side-group and the effect of oligo(L-lactide) additives on hydrolytic degradation and thermal aging were also investigated. One advantage of these additives is that no foreign migrants are introduced into the degradation product pattern. This reduces the risk of a harmful impact on the environment. The degradation process was monitored through analyses of the remaining material and the released degradation products. Depending on the modification, both increased and decreased degradation rates could be obtained. Resistance against degradation was increased by stereocomplexation, which is explained by the strong interactions between the complementary L- and D- chain structures. On the other hand, even though the mass loss was low, larger amounts of short hydroxy acids were released from the stereocomplex materials, resulting in a faster decrease in the pH. This can be explained by an increase in the amount of intermolecular stereocomplex crystallites resulting in a large number of tie-chains connecting the crystallites. These chains are more exposed to hydrolysis, and hence short degradation products are released. The architecture of the added oligo(D-lactic acid) had a considerable impact on material properties such as crystallinity and degradation. Acidic end-groups increased the degradation rate, while alcoholic end-groups had the opposite effect. The addition of hydrophilic linear oligo(L-lactide) to poly(L-lactide) (PLLA) resulted in a rapid migration of additives from the material during hydrolytic aging and a faster loss of mass and molar mass than from a material containing cyclic analogues. During thermal aging, however, the opposite effect was observed as the linear oligo(L-lactide) additives interacted more strongly with PLLA, which resulted in smaller mass loss. Stereocomplexation was also revealed to take place between oligomers of the two enantiomers of the lactic acid-like monomer α-hydroxyisovaleric acid.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. 53 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2013:14
Keyword
Polylactide, stereocomplex, plasticizer, degradation, degradation products, ESI-MS
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-120120 (URN)978-91-7501-687-0 (ISBN)
Public defence
2013-04-26, K2, Teknikringen 28, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20130403

Available from: 2013-04-03 Created: 2013-03-28 Last updated: 2013-04-03Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Hakkarainen, Minna

Search in DiVA

By author/editor
Regnell Andersson, SofiaHakkarainen, MinnaAlbertsson, Ann-Christine
By organisation
Fibre and Polymer Technology
In the same journal
Polymer degradation and stability
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 128 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf