Ductile-brittle transition behaviour of PLA/o-MMT films during the physical aging process

Ll, M.; Santana, Oliverio J.; Cailloux, Jonathan; Urquiza, Edgar Adrian Franco; Rodríguez, Celestino; Belzunce, F. J.; Martínez, Alejandro Rosillo

doi:10.3144/expresspolymlett.2015.20

Cited by 17 publications

(26 citation statements)

References 33 publications

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“…For further loading, these voids grew with extensive fibrillation (shear yielding) which gives rise to the distortion and coalescence of the holes with ridge formation. Similar observations have been reported in the literature [48,49].…”

Section: Evaluation Of the Clay Interactions By Pukanszky's B Factorsupporting

confidence: 92%

Mechanical and Barrier Properties Enhancement in Film Extruded Bio‐Polyamides With Modified Nanoclay

et al. 2018

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The plastics industry is increasingly oriented towards the use of bio‐based polymers replacing the fossil‐based ones. Bio‐based polyamides (PAs) in the film packaging application are not still used and need enhancement to overcome some drawbacks. In this scenario, fully (PA10.10) and partially (PA6.10) bio‐based PAs were extruded in a laboratory sheet‐casting machine. The materials used to obtain films were previously melt blended with modified clay in a twin‐screw extruder. The resulting films were morphologically investigated through the scanning electron microscope. The magnifications show agglomerated particles and the packed layers are preferentially aligned in the extrusion machine direction. X‐rays confirm that 5 wt% of clay content is difficult to exfoliate in such matrices. The crystallinity was studied by using X‐ray diffraction (XRD) and differential scanning calorimetry. The XRD results show coexisting α and γ phases in the PA6.10 while the presence of only γ in the PA10.10. The presence of clay platelets constrains the crystallites formation, especially in the more polar PA6.10, resulting in changes in the type and the amount of crystals. The mechanical analysis data showed that 5 wt% of clay induced significant improvement in Young's modulus (+68 and + 14%), a slight increase in the tensile yield stress (+21 and + 5%) and only a surprisingly small decrease in the deformation at break (−15 and −24%) for PA10.10 and PA6.10, respectively. Furthermore, the addition of clay gave the best oxygen barrier properties reaching a value of 1.8 ± 0.2 cm3 × mm/m2 × day × atm comparable to a commercial PA6 film used in the packaging field. POLYM. COMPOS., 40:2617–2628, 2019. © 2018 Society of Plastics Engineers

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Section: Evaluation Of the Clay Interactions By Pukanszky's B Factorsupporting

confidence: 92%

Mechanical and Barrier Properties Enhancement in Film Extruded Bio‐Polyamides With Modified Nanoclay

et al. 2018

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“…Tsuji and Sawada also observed the strong enthalpy relaxation and found that physical ageing increased both the glass transition temperature and the enthalpy of the glass transition, but did not increase the crystallinity. Also, the ageing behaviour of plasticised PLLA, PLLA blends and composites have been shown to broadly exhibit the same trends as those observed for pure PLLA.…”

Section: Introductionmentioning

confidence: 54%

Rejuvenation of PLLA: Effect of plastic deformation and orientation on physical ageing in poly(l-lactic acid) films

Ghazaryan

Schaller

Feldman

et al. 2016

J. Polym. Sci. Part B: Polym. Phys.

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Poly(L-lactic acid) (PLLA) is a bio-degradable polyester which exhibits brittle behaviour due to relatively fast physical ageing of the amorphous phase. This work describes the effects of thermal rejuvenation and molecular orientation of the amorphous phase on this physical ageing process. Uniaxial compression testing showed that physical ageing of the amorphous phase increases the yield stress and the associated strain softening response, both contributing to the observed embrittlement of PLLA in tension. Molecular orientation at constant crystallinity was applied by uniaxial and biaxial plastic deformation just above the glass transition temperature, up to plastic strains of 200% to avoid strain-induced crystallisation. Using stress-relaxation experiments combined with tensile testing, both as a function of ageing time, it is shown that both uniaxial and biaxial plastic deformation in excess of 150% plastic strain, decelerates and possibly prohibits the physical ageing process. The oriented monofilaments and films have improved mechanical properties such as stiffness, strength and strain-to-break, which were not affected by physical ageing during the whole testing period (40 days). In addition, plastic deformation to higher draw ratios and/or higher temperatures strongly enhanced crystallinity and resulted in PLLA monofilaments and films that also exhibited tough behaviour, not affected by physical ageing.

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“…28,29 The accompanied decrease in the molecular mobility was attributed to a configurational rearrangement of chain segments from a totally disordered configuration for unaged materials to locally ordered ones for aged samples below T g . This phenomenon is commonly called physical ageing process, which is the principal factor responsible for the advanced PLA brittleness.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

“…This phenomenon is commonly called physical ageing process, which is the principal factor responsible for the advanced PLA brittleness. 28,29 The accompanied decrease in the molecular mobility was attributed to a configurational rearrangement of chain segments from a totally disordered configuration for unaged materials to locally ordered ones for aged samples below T g . 30 Under the experimental conditions used, results suggest that the addition of silica nanofillers did not seem to hamper these restricted molecular motions, which lead to the ductile-brittle transition.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

PLA/SiO₂ composites: Influence of the filler modifications on the morphology, crystallization behavior, and mechanical properties

Hakim

Cailloux

Santana

et al. 2017

J of Applied Polymer Sci

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Films of an architecturally modified poly(lactic acid) (PLA REx ) with three different types of fumed silica nanofillers (SiO 2 ) were processed through reactive extrusion-calendering in a pilot plant. The effects of the SiO 2 type on both the dispersion and the crystallization behavior under dynamic and isothermal conditions are investigated using transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The mechanical properties are assessed by tensile testing. TEM micrographs showed that the improved chemical affinity of both surface-treated SiO 2 toward PLA REx end groups did not improve particle dispersion. DSC results revealed that untreated SiO 2 nucleated PLA REx more efficiently than both surface-modified silicas. The activation energy for the isothermal crystallization process, as determined by an Arrhenius method, suggests that addition of untreated SiO 2 enhances the crystallization rate of PLA REx . However, it seems that the tensile behavior remained unchanged whether silicas were added or not. V C 2017Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45367.

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Ductile-brittle transition behaviour of PLA/o-MMT films during the physical aging process

Cited by 17 publications

References 33 publications

Mechanical and Barrier Properties Enhancement in Film Extruded Bio‐Polyamides With Modified Nanoclay

Mechanical and Barrier Properties Enhancement in Film Extruded Bio‐Polyamides With Modified Nanoclay

Rejuvenation of PLLA: Effect of plastic deformation and orientation on physical ageing in poly(l-lactic acid) films

PLA/SiO₂ composites: Influence of the filler modifications on the morphology, crystallization behavior, and mechanical properties

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Ductile-brittle transition behaviour of PLA/o-MMT films during the physical aging process

Cited by 17 publications

References 33 publications

Mechanical and Barrier Properties Enhancement in Film Extruded Bio‐Polyamides With Modified Nanoclay

Mechanical and Barrier Properties Enhancement in Film Extruded Bio‐Polyamides With Modified Nanoclay

Rejuvenation of PLLA: Effect of plastic deformation and orientation on physical ageing in poly(l-lactic acid) films

PLA/SiO2 composites: Influence of the filler modifications on the morphology, crystallization behavior, and mechanical properties

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PLA/SiO₂ composites: Influence of the filler modifications on the morphology, crystallization behavior, and mechanical properties