Effect of the crystallinity on the barrier properties of PLA based nanocomposites

J. Trifol, C. Mericer, D. Plackett, C. Sillard, M. Minelli, O. Hassager, A. E. Daugaard, J. Bras, M. Giacinti, P. Szabo

Research output: Contribution to conferencePaperScientificpeer-review

Abstract

Nanocomposites with cellulose nanofibers and/or commercially available nanoclay (Cloisite™ 30B) were prepared and evaluated for use in food packaging. Cellulose nanofibers were extracted from sisal fibers using an optimized three-step chemical protocol. In sequence, the steps were strong alkali treatment, a bleaching process, and finally an acetylation step. Nanocomposite films were prepared by solvent casting using an optimized method for each nanofiller or nanofiller combination. The combination of nanocellulose and nanoclay within a PLA matrix decreased dramatically the oxygen barrier properties (the PLA/CNF/C30B 1% 1% showed a) 63% of decrease on the oxygen transmission rate (OTR and the PLA/CNF/C30B 5% 5% showed a 88%), water barrier properties (the PLA/CNF/C30B 1% 1% showed a 57% of decrease on the water vapour barrier properties WVTR and the PLA/CNF/C30B 5% 5% a 75%), enhanced the thermomechanical properties and crystallization kinetic (the addition of 1% CNF and 1% of C30B reduced the half crystallization time of the PLA from 25 to 5 minutes) without a significant reduction on transparency. It was found that the addition of nanofillers to the matrix was leading to reduced water diffusion than the neat PLA but the nanocomposites with CNF showed also slightly higher water absorption than neat PLA and PLA/C30B. Moreover it was also found that bigger spherulite size leads to a higher decrease on diffusivity but also to slight increase in water sorption, the smaller spherulite size was leading to a reduction in both parameters. Finally the fully crystallized PLA/C30B/CNF 1% 1% nanocomposite showed a 45% of decrease on WVTR if compared with fully crystallized PLA meaning that the presence of both nanofillers even at low load can enhance the barrier properties of PLA.

Original languageEnglish
Publication statusPublished - 2015
MoE publication typeNot Eligible
EventInternational Conference on Composite Materials - Copenhagen, Denmark
Duration: 19 Jul 201524 Jul 2015
Conference number: 20

Conference

ConferenceInternational Conference on Composite Materials
Abbreviated titleICCM
CountryDenmark
CityCopenhagen
Period19/07/201524/07/2015

Keywords

  • Barrier Properties
  • Crystallinity
  • Nanocellulose
  • Nanoclay
  • PLA

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