Multi-component analysis of low-density polyethylene oxidative degradation

Salvalaggio, Mario; Bagatin, Roberto; Fornaroli, Marco; Fanutti, Sergio; Palmery, Stefano; Battistel, Ezio

doi:10.1016/j.polymdegradstab.2006.03.024

Cited by 59 publications

(59 citation statements)

References 21 publications

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“…The second and the fourth order derivatives IR spectra were obtained using the SavitzkyeGolay algorithm (9-point smoothing). Visual inspection of the curve fitting and the second and fourth order derivatives are used to identify the existence and position of any sub-absorbances from the possible oxidation products [13]. IR spectra shoulders with corresponding negative second order and positive fourth order derivatives are chosen as the absorbances of the specific oxidation products.…”

Section: Mathematical Curve-fittingmentioning

confidence: 99%

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Identification of carbonyl species of weathered LDPE films by curve fitting and derivative analysis of IR spectra

Yagoubi¹,

Abdelhafidi²,

Sebaa³

et al. 2015

Polymer Testing

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a b s t r a c tWe describe the examination of the weathering degradation of LDPE (low density polyethylene -locally produced B24/2 and imported LDPE 2100T), supplied by two different manufacturers and processed into films for greenhouse coverings, over several months in a sub-Saharan region of Algeria. The three IR regions most affected by weathering degradation are 800e1100 cm À1 , 1680e1800 cm À1 and 3300e3600 cm À1 . The IR spectral region most affected by the aging process is the carbonyl region. Curve fitting combined with derivative spectroscopy revealed that the composite carbonyl band encompasses more than 10 different oxidation products. The most significant among these in terms of absorbance are carboxylic acids, ketones, aldehydes and esters. The oxidation kinetics with respect to the type of LDPE film shows that B24/2 LDPE undergoes less oxidization than LDPE 2100 T. Calculating the concentrations of different carbonyl species compared to their respective absorbances indicates that the aldehydes are the predominant component of the final compound, rather than the carboxylic acids.

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Section: Mathematical Curve-fittingmentioning

confidence: 99%

“…A quantitative estimation of the carbonyl species using this method for an aged sample has rarely been reported in the literature [13]. Moreover, this treatment has permitted the quantification of different carbonyl species and has allowed their progress during aging to be followed.…”

Section: Introductionmentioning

confidence: 99%

Identification of carbonyl species of weathered LDPE films by curve fitting and derivative analysis of IR spectra

Yagoubi¹,

Abdelhafidi²,

Sebaa³

et al. 2015

Polymer Testing

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“…In fact, models have been developed describing thermal degradation as obtained by FTIR spectroscopy [Gugumus (1996b); Salvalaggio et al (2006)]. In this context, differential scanning calorimetry (DSC) has been applied to obtain the heat of fusion and the melting points [Holmstr€ om and S€ orvik (1978); Volke-Sep ulveda et al (1999)], and gel permeation chromatography (GPC) to identify the variations in structure and molecular weight distribution (MWD) [Holmstr€ om and S€ orvik (1978); Iring et al (1980); Kumar et al (2002)].…”

Section: Introductionmentioning

confidence: 99%

Increase of long-chain branching by thermo-oxidative treatment of LDPE: Chromatographic, spectroscopic, and rheological evidence

Rolón-Garrido¹,

Zatloukal²,

Wagner³

2013

Journal of Rheology

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SynopsisLow-density polyethylene was thermo-oxidatively degraded at 170 C, i.e., degraded in the presence of air, by a one thermal cycle (1C) treatment during times between 30 and 90 min, and by a two thermal cycles (2C) treatment, i.e., after storage at room temperature, an already previously degraded sample was further degraded during times between 15 and 45 min. Characterization methods include gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, as well as linear and nonlinear rheology. A reduction of molar mass was detected for all degraded samples by GPC, as well as an increase of the high molar mass fraction of the 1C sample degraded for the longest time. Intrinsic viscosity measurements indicate also a reduction of molar mass with increasing degradation times for both 1C and 2C samples. Thermo-oxidation is confirmed for 1C and 2C samples by analyzing specific indices in FTIR. Linear viscoelasticity seems to be in general only marginally affected by thermo-oxidative exposure, while the enhanced strain-hardening effect observed in uniaxial extension experiments presents a clear evidence for an increased long-chain branching (LCB) content in both 1C and 2C samples. Elongational viscosity data were analyzed by the molecular stress function (MSF) model as well as the Wagner-I model, and for both models, quantitative description of the experimental data for all samples was achieved by fit of only one nonlinear model parameter. Time-deformation separability was confirmed for all samples degraded, 1C as well as 2C, for cumulative degradation times of up to 90 min. The characterization by GPC was confronted with the characterization obtained from nonlinear rheology. It can be stated that elongational rheology is a powerful method to detect structural a) Author to whom correspondence should be addressed; electronic mail: victor.h.rolongarrido@tu-berlin.de

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“…According to the mechanism proposed in Scheme 1, aldehydes and vinyls can be produced either by chain scission in the close vicinity of a macro-alkoxy (a) or by a  scission of a ketone via the NII process. The ketone itself comes from a cage reaction between the macro-alkoxy and a hydroxyl radical [18], [24][25][26], [30]. This ketone can be transformed into a keto radical and a macroradical via the N I process which is known to be possible when solar energy or temperature are relatively high.…”

Section: Discussionmentioning

confidence: 99%

“…This makes necessary to refine the spectra analysis by means of mathematical data processing [18][19].…”

Section: Introductionmentioning

confidence: 99%

Sun radiation and temperature impact at different periods of the year on the photooxidation of polyethylene films

Abdelhafidi¹,

Chabira²,

Yagoubi³

et al. 2017

IJHT

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Analysis of the IR spectra of weathered films exposed at different periods of the year reveals that, the main regions of the IR spectrum affected by solar irradiation and temperature variation are the complex carbonyls and unsaturations composite absorption bands. Their respective kinetics vary in different manner according to the period at which the exposure is started. Curve fitting has been performed to refine the analysis of the IR spectra and to identify all the chemical species constituting the complex absorption bands. The analysis of the results let appears that whatever the exposure period of the year is, it does not affect the type of developing products, but it has strong effect on their kinetic rate of formation. The warm season is the more effective in terms of carbonyl formation and crystallinity index. This indicates that the Norrish type I (NI) process is very important in this season and it adds to the Norrish type II (NII) process. Both contribute to the carbonyl and vinyl groups formation via chain scission reactions; however the NII process is active during all the period of the year.

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Multi-component analysis of low-density polyethylene oxidative degradation

Cited by 59 publications

References 21 publications

Identification of carbonyl species of weathered LDPE films by curve fitting and derivative analysis of IR spectra

Identification of carbonyl species of weathered LDPE films by curve fitting and derivative analysis of IR spectra

Increase of long-chain branching by thermo-oxidative treatment of LDPE: Chromatographic, spectroscopic, and rheological evidence

Sun radiation and temperature impact at different periods of the year on the photooxidation of polyethylene films

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