In Situ Kinetics Study of the Accelerated Aging of Poly(ethylene oxide) Using PhotoDSC

Fraïsse, Frédéric; Morlat‐Thérias, Sandrine; Gardette, Jean‐Luc; Nédélec, Jean-Marie; Baba, Mohamed

doi:10.1021/jp061669g

Cited by 18 publications

(13 citation statements)

References 18 publications

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“…As can be seen in Figure 5, comparing the decrease of G due to the photo-ageing or to the thermo-ageing at the same temperature (60°C), the light exposure causes also a drastic and fast fall in the crystallization rate. This observed sensitivity of the crystallization rate to irradiation and heating confirms our previous results [14] obtained by a non-isothermal crystallization procedure. During the step of irradiation or The mechanism given in reference [11] recalls that formates are formed with chain scission whereas the formation of esters does not involve the cleavage of the macromolecular backbone.…”

Section: Discussionsupporting

confidence: 91%

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Isothermal crystallization kinetics of in situ photo and thermo aged poly(ethylene oxide) using photoDSC

Fraïsse

Nédélec

Grolier

et al. 2007

Phys. Chem. Chem. Phys.

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Isothermal crystallization of a high molecular weight PEO (Mw=4,000,000) has been investigated using photoDSC. Combining light irradiation, heating and DSC analysis, photoDSC demonstrates good capability to follow the in situ photo- and thermo-ageing of semi-crystalline polymers. Isothermal crystallization of PEO was performed at 55 degrees C. After ageing at different temperatures ranging from 0 to 90 degrees C and for various periods of time, the kinetics of this crystallization was found following the Avrami theory. Avrami exponent, n, was found between 0.9 and 1.4 evidencing a one-dimension growth process. It was also found that the isothermal crystallization rate (i.e. reciprocal crystallization half-time) was exposure time, ageing temperature and light intensity dependent which makes this kinetic parameter a good indicator of following and comparing the degradation of the semi-crystalline polymers.

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Section: Discussionsupporting

confidence: 91%

“…The photoDSC device used in this study was already described in (13,14). It combines light irradiation and DSC analysis applied to a single sample using a Hamamatsu light generator equipped with a Lightningcure200 source (Xe/Hg, "medium pressure") and a Metter Toledo DSC 822 e apparatus.…”

Section: Methodsmentioning

confidence: 99%

Isothermal crystallization kinetics of in situ photo and thermo aged poly(ethylene oxide) using photoDSC

Fraïsse

Nédélec

Grolier

et al. 2007

Phys. Chem. Chem. Phys.

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“…As a nontoxic biodegradable soluble polymer, its industrial use in the pharmaceutical field, the packaging industry, or as a lubricant is of considerable importance as well. [1][2][3] Although the degradation of PEO in pyrolysis conditions is well documented, [4][5][6][7][8][9] the natural aging mechanism in thermo- [10][11][12][13][14] and photo-oxidative [14][15][16][17] conditions is not clearly understood.…”

Section: Introductionmentioning

confidence: 99%

Degradation of PEO in the Solid State: A Theoretical Kinetic Model

Claire

2009

Macromolecules

107

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The quantitative kinetic model presented in this work provides insights of the inner mechanisms that play a key role in the natural oxidative degradation (photoinduced and thermal) of a model polymer, polyethylene oxide (PEO). A set of key reactions is selected from ab initio data, theoretical rate constant calculations, and experimental rate constants. Experimental results, i.e., induction times and quantities of carbonyl end-products, are accurately reproduced by this model. While this study grasps the complexity of the degradation mechanism, results depend mainly on the reactivity of peroxy radicals and that of hydroperoxide groups. Three pathways are available to the peroxy species, i.e., intermolecular and γ-intramolecular H-abstraction reactions, and the termination reaction. The competition between these processes is the driving force of the degradation mechanism. Moreover, in thermo-oxidative conditions, the relative quantities of esters and formates depend strongly on four competitive hydroperoxide decomposition channels, i.e., the unimolecular, bimolecular, induced decomposition by hydroxyl radicals and the hydroperoxide H-abstraction reaction. Many of the reactions investigated here participate also in polymer synthesis, pyrolysis or other degradation processes. Moreover, the simple structure of the model polymer in this work is representative of a wide range of polymer systems.

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“…[25][26][27] Changing the structure of PEO with irradiation, producing macromolecules with radical end and recombination with cleavage of polymer chains, opens new perspective in application of this polymer. [28][29][30] Due its outstanding thermal, electrical and mechanical properties graphene sheets are used in a wide range of applications such as electric devices, solar cells and, as in our study, as reinforcement in composite films. [31][32][33][34][35][36] New perspective of graphene structure could be incorporation in polymer blend systems.…”

Section: Introductionmentioning

confidence: 84%

Keratin–polyethylene oxide bio-nanocomposites reinforced with ultrasonically functionalized graphene

et al. 2015

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address: Dusica B. Stojanovic duca@tmf.bg.ac.rs † Footnotes relaƟng to the Ɵtle and/or authors should appear here. Electronic Supplementary Information (ESI) available: Results of DSC analysis of ultrasonic treatment of PEO films. Nanoindentation measurements of composite films and keratin-PEO blend with different content ratio. Discussion of FTIR spectra of composite films. FESEM images of composite films. Optical images of keratin-PEO blend with different content ratio. SeePolyethylene oxide (PEO) functionalized graphene (f-G) was prepared by ultrasonication of pristine graphene in PEO aqueous solution. Feasible sonication protocol of PEO degradation and graphene functionalization enabled fabrication of solvent casted nanocomposites. Additionally, the steps to form new bio-nanocomposite films have been described, taking the advantage of the combination of graphene, PEO and keratin fibers from poultry feather waste, to design the aforementioned bio-nanocomposite films, which allow extraordinary properties that would have promising applications as eventual packaging materials and enable bio-waste keratin to be converted to added-value material. Compared to neat PEO, addition of only 0.3 wt.% f-G provided increase of 92 % of storage modulus. These findings are similar to the nanoindentation results, which yielded the increases for reduced modulus of same composition for about 92 %. Nanoindentation testing shows that the incorporation of 0.3 wt.% f-G increased reduces modulus and hardness of keratin-PEO blend for about 155 and 99 %, respectively.

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In Situ Kinetics Study of the Accelerated Aging of Poly(ethylene oxide) Using PhotoDSC

Cited by 18 publications

References 18 publications

Isothermal crystallization kinetics of in situ photo and thermo aged poly(ethylene oxide) using photoDSC

Isothermal crystallization kinetics of in situ photo and thermo aged poly(ethylene oxide) using photoDSC

Degradation of PEO in the Solid State: A Theoretical Kinetic Model

Keratin–polyethylene oxide bio-nanocomposites reinforced with ultrasonically functionalized graphene

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