Influence of crystal polymorphism on mechanical and barrier properties of poly(l-lactic acid)

Cocca, Mariacristina; Lorenzo, Maria Laura Di; Malinconico, Mario; Frezza, Vincenzo

doi:10.1016/j.eurpolymj.2011.02.009

Cited by 251 publications

(234 citation statements)

References 61 publications

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“…Increase of intensity with increasing crystallization temperature was seen for the (0 1 5), (2 0 7) and (0 1 8) plane reflections. We concluded for a change of crystalline form from a 0 to a with increasing temperature for both PLA stereochemistries, which is in accordance with current literature [13,33]. Taking together information on crystalline form and crystallinity degree, data show that the maximum crystallinity degree obtained in a 0 -form was 40% in the case of PLLA and 35% in the case of PDLLA (Table 1).…”

Section: Pla Sample Morphologysupporting

confidence: 78%

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Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties

Guinault¹,

Sollogoub²,

Ducruet³

et al. 2012

European Polymer Journal

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible.This is an author-deposited version published in: http://sam.ensam.eu Handle ID: .http://hdl.handle.net/10985/10118 To cite this version :A GUINAULT, C SOLLOGOUB, Violette DUCRUET, Sandra DOMENEK -Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties -European Polymer Journal -Vol. 48, p.779-788 -2012 Any correspondence concerning this service should be sent to the repository The helium and oxygen gas barrier properties of poly(lactide) were investigated as a function of stereochemistry and crystallinity degree. Poly(L-lactide) and poly(D,L-lactide) films were obtained by extrusion and thermally cold crystallized in either a 0 -or a-crystalline form with increasing crystallinity degree. Annealing of the films at low temperatures yielded to a 0 -crystals as well as the creation of a rigid amorphous fraction in the amorphous phase. Unexpectedly, the quantity of the rigid amorphous fraction was highest in poly(L-lactide) crystallized under a 0 -form. Unexpectedly, the gas permeability increased with increasing quantity of a 0 -crystals in poly(L-lactide) and remained constant with increasing quantity of a 0 -crystals in poly(D,L-lactide). A gain in gas barrier properties was obtained upon crystallization at higher temperatures yielding a-crystals. The analysis of the oxygen transport parameters, in particular the diffusion and the solubility coefficient showed that the diffusion was accelerated upon crystallization, while the solubility coefficient decreased in an expected manner which led to conclude that it remained constant in the amorphous phase. The acceleration of the diffusion seems to be correlated to the occurrence of the rigid amorphous fraction, which holds larger free volume. To conclude, for optimization of poly(lactide) gas barrier properties by focussing on the decrease of the diffusion coefficient it can be suggested to work with poly(D,L-lactide) and to aim a crystallization in a-form avoiding the formation of a rigid amorphous fraction.

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Section: Pla Sample Morphologysupporting

confidence: 78%

“…2 and the observed crystalline form is summarized in Table 1. As shown by Cocca et al [33], the crystalline structure of PLLA which depends on the crystallization temperature can be determined with the help of the characteristic reflexion ( Fig. 2a and c).…”

Section: Pla Sample Morphologymentioning

confidence: 99%

Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties

Guinault¹,

Sollogoub²,

Ducruet³

et al. 2012

European Polymer Journal

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“…4. Upon the second scanning, the melting peaks of all the compositions show two endothermic peaks attributed to the two types of crystalline phases in PLA compositions (, and ') [9], [11] which became more pronounced when the plasticizer is added. The first peak corresponds to the melting of thinner crystals and the second peak is attributed to the melting of more stable crystals.…”

Section: Resultsmentioning

confidence: 99%

“…In good accordance also the coldcrystallization of PLA in the second heating was at 108 °C in pure and 85 °C in PLA/206 3NL. Besides, the presence of the nucleating agent which is already formed during the cooling process caused heterogeneous nucleation to overcome the free energy barrier; and thus inducing higher and faster nucleation [10], [11]. Therefore, all of these components promote crystallinity while they provide a lower cold crystallization temperature.…”

Section: Resultsmentioning

confidence: 99%

Thermal Properties of Plasticized Poly (Lactic Acid) (PLA) Containing Nucleating Agent

Fehri¹,

Cinelli²,

Coltelli³

et al. 2016

IJCEA

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Abstract-The present research reports the investigation of the role of an oligomeric polyadipate plasticizer (206 3NL), and a nucleating agent aromatic sulfonate derivative (LAK301) on thermal behaviours of poly-lactic acid (PLA) evaluated through differential scanning calorimetry (DSC) measurements in order to investigate the separated effect due to the addition of plasticizer and nucleating agent on the thermal behavior of PLA respectively. Binary and ternary systems containing PLA/206 3NL/LAK301 have been developed. All samples have been prepared by melt-blending. The results of the present study show that LAK301 acts as a very efficient nucleating agent by increasing crystallinity percentage from 5.6% in pure PLA to 12% in PLA/LAK301 5%wt/206 3NL, and that (206 3NL) is a compatible plasticizer for PLA as the glass temperature drops down from 59.4 °C in pure PLA to 38.9 °C in blends of PLA-NL 15 wt%. Also the approach of investigating the compatibility in ternary system where the plasticizer and nucleating agent have a synergic effect on thermal properties as well on crystallinity and glass transition temperature of PLA were addressed. In fact in ternary blends of PLA/LAK301/206 3NL with 5 wt% of LAK301 the glass transition temperature was reduced to 30.3 °C and PLA crystallinity increased to 39 wt%.

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“…Another study by Cocca et al 15 has reported water vapour permeability of poly(l-lactide) with crystallinity varying between 33% and 45%. There was found to be a constant value of permeability from 33% to 39% crystallinity but a sudden drop at 39%-40%, which was attributed to a different ratio of crystalline polymorphs in the structure.…”

Section: Introductionmentioning

confidence: 99%

Water vapour permeability of poly(lactic acid): Crystallinity and the tortuous path model

Zhang

Thomas

2014

Journal of Applied Physics

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Citation: DUAN, Z. and THOMAS, N.L., 2014 The water vapour transmission rates (WVTR) through samples of polylactic acid of different crystallinities have been measured. Three different grades of commercial poly(lactic acid) (PLA) were used with different ratios of L-lactide and D-lactide to give a range of crystallinities from 0% to 50%. Sheets of PLA were prepared by melt compounding followed by compression moulding and annealing at different temperatures and for different times to give the range of crystallinities required. Crystallinity was measured by differential scanning calorimetry and the morphology of the samples was observed under crossed polars in a transmitted light microscope. Water vapour transmission rates through the films were measured at 38 C and at a relative humidity of 90%. It was found that the measured values of WVTR decreased linearly with increasing crystallinity of the PLA from 0% to 50%. The results are discussed in terms of the effect of crystallinity on solubility and shown to fit the "Tortuous Path Model." The model was also successfully used to explain published data on water permeability of polyethylene terephthalate. V C 2014 AIP Publishing LLC.

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Influence of crystal polymorphism on mechanical and barrier properties of poly(l-lactic acid)

Cited by 251 publications

References 61 publications

Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties

Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties

Thermal Properties of Plasticized Poly (Lactic Acid) (PLA) Containing Nucleating Agent

Water vapour permeability of poly(lactic acid): Crystallinity and the tortuous path model

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