Effect of thermal and hygrothermal aging on the plane stress fracture toughness of poly(ethylene terephthalate) sheets

Bárány, Tamás; Földes, Enikő; Czigány, Tibor

doi:10.3144/expresspolymlett.2007.28

Cited by 30 publications

(14 citation statements)

References 16 publications

(25 reference statements)

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“…Nevertheless, there are few works describing the effect of physical aging on the fracture behaviour of PLA using Fracture Mechanics approaches. It has been shown that the EWF methodology is a useful tool to investigate the effect of physical aging on PET and Glycol-modified Poly (ethylene terephthalate) (PETG) films [14][15][16]. In the case of PLA, which has faster physical aging than PET and PETG, the EWF analysis can only be successfully applied in the non-aged material.…”

Section: Introductionmentioning

confidence: 99%

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

Ll¹,

Santana²,

Cailloux³

et al. 2015

Express Polym. Lett.

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Abstract. The ductile-brittle transition behaviour of organo modified montmorillonite-based Poly(lactic acid) films (PLA/o-MMT) was analysed using the Essential Work of Fracture (EWF) methodology, Small Punch Tests (SPT) and Enthalpy relaxation analysis. While the EWF methodology could only be applied successfully to de-aged samples, small punch test (SPT) was revealed as more effective for a mechanical characterization during the transient behaviour from ductile to brittle. According to differential scanning calorimetry (DSC) results, physical aging at 30°C of PLA/o-MMT samples exhibited slower enthalpy relaxation kinetics as compared to the pristine polymer. Although all samples exhibited an equivalent thermodynamic state after being stored one week at 30°C, significant differences were observed in the mechanical performances. These changes could be attributed to the toughening mechanisms promoted by o-MMT.

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Section: Introductionmentioning

confidence: 99%

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

Ll¹,

Santana²,

Cailloux³

et al. 2015

Express Polym. Lett.

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“…The sudden cooling freezes this less ordered structural state and hampers a chain reorganization such as the one caused by aging during slow cooling. Even though physical aging on toughness behaviour of polymers has been little investigated using fracture mechanics approaches, the essential work of fracture method (EWF) has been reported as a successful technique to follow the effect of physical aging on polymer films [12][13][14][15][16]. The aim of this work consists in the application of a de-aging thermal treatment to two commercial grades of PLA with different D-lactic monomer fractions and studying their fracture behavior applying the EWF method.…”

mentioning

confidence: 99%

Fracture behavior of quenched poly(lactic acid)

Gámez‐Pérez¹,

Infante²,

Urquiza³

et al. 2011

Express Polym. Lett.

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The effect of a quenching treatment applied on heated cast sheet extruded films of two poly(lactic acid) (PLA)\ud commercial grades, with different optical purities, was studied. The thermal and mechanical properties of the films, as well\ud as their fracture behavior, were assessed by differential scanning calorimetry (DSC), tensile tests, and the essential work of\ud fracture (EWF) approach. The heating-quenching treatment causes a de-aging effect with an increase in the free volume of\ud polymer chains evidenced by a decrease in the glass transition temperature (Tg) and a decrease in the tensile stiffness and\ud yield stress. As a result, there is an abrupt increase in ductility, finding a dramatic change in the fracture behavior, from brittle\ud to ductile. The use of digital image correlation (DIC) of the strain field analysis during fracture testing has allowed relating\ud the decrease on the yield stress promoted by quenching with the crack propagation kinetics. The use of the EWF method\ud to characterize the fracture toughness of PLA has allowed to measure this enhancement on toughness, finding that the specific\ud essential work of fracture (we) and the plastic term (!wp) parameters increased 120% and 1200%, respectively, after\ud the quenching process.Peer ReviewedPostprint (published version

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“…Except for a ligament length equal to 8 mm, all the sample dimensions are in the validity domain of the EWF method, as analyzed in the literature [11,14,16,32]. The specimens were drawn using a Zwick machine at 2 mm min −1 , a crosshead speed currently used in recent work (e.g., [27,29]). They were tested in the controlled laboratory conditions: temperature 23°C, relative humidity 50%.…”

Section: Mechanical Testingmentioning

confidence: 99%

“…Many polymers have been characterized by this technique: polyethylene [14][15][16], polypropylene [17,18], polyamide 6 [19] and 6-6 [14,16], poly(ethylene terephthalate) and copolymers [16,[20][21][22][23][24][25][26][27][28][29], poly(ethylene naphthalate) [30,31], polycarbonate [32], etc. The EWF method is able to detect environment effects, such as hygrothermal aging in hygroscopic polymers like poly (ethylene terephthalate) [27,29]. The essential work of fracture is also sensitive to morphological parameters, such as cristallinity [16,21] or molecular orientation [25,32].…”

Section: Introductionmentioning

confidence: 99%

Relationships between processing conditions and mechanical properties of PA12 tubes. The EWF approach

et al. 2009

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International audienceIn polyamide 12 (PA12) tube extrusion, calibration is the key step of the process that affects the subsequent mechanical properties. In previous work it has been shown that according to the calibration conditions, a very oriented skin layer may be created, which has been correlated to an important decrease of elongation at break. In this paper, we present new results showing a good correlation between molecular orientation and fracture toughness, as evaluated by the EWF (Essential Work of Fracture) approach. They concern notched specimens and confirm the results obtained in classical tensile testing. The specific essential work of fracture is very sensitive to the orientation generated in the skin region by appropriate processing conditions: it decreases from the external to the inner regions of the tube, and increases with skin orientation

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Effect of thermal and hygrothermal aging on the plane stress fracture toughness of poly(ethylene terephthalate) sheets

Cited by 30 publications

References 16 publications

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

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

Fracture behavior of quenched poly(lactic acid)

Relationships between processing conditions and mechanical properties of PA12 tubes. The EWF approach

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