Crystallinity and oxygen transport properties of PET bottle walls

Liu, R. Y. F.; Hu, Yanfeng; Schiraldi, David A.; Hiltner, A.; Baer, E.

doi:10.1002/app.20905

Cited by 77 publications

(50 citation statements)

References 25 publications

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“…They attribute the dedensification to increased constraints on the amorphous phase macromolecular chains due to their attachment to crystallites. This effect causes the glass transition to shift to higher temperatures [40], which is also observed in our case and in the case of Drieskens' publication for PLA. In the case of PLA the shift of the T g was attributed to the confinement of the MAF, though [21][22][23][24], as the RAF is not able to relax in the region of the glass transition.…”

Section: Gas Barrier Propertiessupporting

confidence: 85%

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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

100

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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: Gas Barrier Propertiessupporting

confidence: 85%

“…In the case of poly(ethylene terephthalate) (PET), permeability decrease with increasing crystallinity only relies on the drop of D and a rise of S what has been evidenced by several authors [38][39][40]. The effect was explained by dedensification of the amorphous phase, which increases oxygen solubility.…”

Section: Gas Barrier Propertiesmentioning

confidence: 92%

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

Guinault¹,

Sollogoub²,

Ducruet³

et al. 2012

European Polymer Journal

100

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“…Analogous phenomena occur in PET, and the competing effects of simultaneous orientation and crystallization are manifest in the blown bottle wall. 59 The dedensification of the amorphous phase can be discussed in terms of the temperature-volume relationship in Figure 5. 58 As the polymer is cooled from the melt, unconstrained amorphous chains contract along the equilibrium liquid line to the glass transition and then along the solid line to 25°C.…”

Section: Crystalline Polyesters Oxygen Solubility and Glassy Amorphoumentioning

confidence: 99%

Oxygen transport as a solid‐state structure probe for polymeric materials: A review

Hiltner

Liu

et al. 2005

J Polym Sci B Polym Phys

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ABSTRACT:In the quest to elucidate the solid-state structures of polymers, insight into the amorphous phase is particularly elusive. Although the permeability of small molecules is often measured as an important performance property, numerous researchers have found that a deeper analysis of the transport characteristics provides insight into polymer morphology, especially if used in combination with more usual characterization techniques. The transport of small gas molecules senses the permeable amorphous structure and probes the nature of the free volume. In recent years, our interest in the gas barrier of polyesters has resulted in an unusual opportunity to investigate the nature of the free volume in the polymer glassy state. This effort has been aided by access to aromatic polyesters with designed variations in their chemical structure. This review focuses on oxygen transport, supplemented with other methods of physical analysis, as a probe of the excess-hole free volume. The review addresses the profound effects of orientation and crystallization on the free volume of the glassy state. The discussion also presents a simple odel for the gas permeability of the isotropic glass based on lattice concepts and tests more sophisticated models for the gas permeability of semicrystalline polymers. The final section addresses other opportunities for fruitful applications of oxygen transport as a solid-state structure probe.

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“…32 A second hypothesis might be the de-densification of the amorphous phase which counteracts the decrease of the quantity of permeable amorphous phase due to crystallization. Dedensification of the amorphous phase in PET has been shown by Liu et al 36 to be responsible for the higher oxygen permeability of bottle walls processed under conditions of higher thermal exposure, although the treatment led to an increase in the volume fraction of impermeable crystals. A decrease in the permeable amorphous phase density causing an increase of gas permeability through heat-set PET was also shown by Qureshi et al 37 It has been shown for poly(L-lactic acid) (PLLA), in comparison to PET, that there is an important decoupling between crystalline and surrounding amorphous phase.…”

Section: Gas Barrier Propertiesmentioning

confidence: 99%

Barrier properties of poly(lactic acid) and its morphological changes induced by aroma compound sorption

Colomines

Ducruet

Courgneau

et al. 2010

Polymer International

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properties of poly(lactic acid) and its morphological changes induced by aroma compound sorption. Polymer International, Wiley, 2010Wiley, , 59 (6), pp.818-826. 10.1002Wiley, /pi.2793 Barrier properties of poly(lactic acid) and its morphological changes induced by aroma compound sorption Gael Colomines, a Violette Ducruet, b Cécile Courgneau, b Alain Guinault a and Sandra Domenek b * The barrier properties of poly(lactic acid) (PLA) play a key role in food packaging applications. For their optimization, the influence of crystallinity on the barrier properties of PLA and the interaction of PLA with the aroma compound ethyl acetate were investigated. PLA film samples with various crystallinities were fabricated by flat die extrusion and thermocompression and compared to PLA Biophan  . The degree of crystallinity had no effect on the oxygen permeability. However, an increase of crystallinity caused a decrease in ethyl acetate sorption. The sorption isotherm of ethyl acetate obtained using microgravimetry showed a steep increase with increasing aroma activity, a form which is consistent with a plasticization effect. This behaviour was verified using differential scanning calorimetry and dynamic mechanical analysis. Sorption caused a marked decrease in the glass transition temperature well below room temperature to approximately 0• C. Furthermore, PLA underwent a solvent-induced crystallization when equilibrated in ethyl acetate atmosphere at an activity of 0.5. The results obtained show the importance of considering possible interactions between polymer and foodstuff during the optimization step of polymeric materials for food packaging applications.

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Crystallinity and oxygen transport properties of PET bottle walls

Cited by 77 publications

References 25 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

Oxygen transport as a solid‐state structure probe for polymeric materials: A review

Barrier properties of poly(lactic acid) and its morphological changes induced by aroma compound sorption

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