Thermal oxidation of polyethylene and polypropylene: Effects of chemical structure and reaction conditions on the oxidation process

Iring, M.; Tüdős, F.

doi:10.1016/0079-6700(90)90029-z

Cited by 111 publications

(42 citation statements)

References 15 publications

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“…The changes in bonding structure observed in Figure 9 are consistent with the established mechanisms for LDPE [43] and PET [44].…”

Section: Chemical Characterizationsupporting

confidence: 74%

Optical and chemical effects governing femtosecond laser-induced structure formation on polymer surfaces

Assaf¹,

Kietzig²

2018

Materials Today Communications

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With the emergence of femtosecond technology, laser machining has recently led to the creation of novel porous structures on polymers. However, the mechanism behind their formation is yet to be understood. In this study, the dependence of femtosecond laser-induced surface structure on processing parameters is established at two distinct wavelengths (800 nm and 275 nm) for six different polymer films: LDPE, PC, PET, PLA, PMMA, and PTFE. All of the observed structures are then optically and chemically characterized as a first step towards elucidating their formation mechanism. The threshold fluence at operating conditions was determined to be the main parameter affecting porosity formation during machining. Furthermore, for transparent films, a transition from multiphoton to linear absorption is observed to occur at 800 nm but not at 275 nm. This shift in optical properties was determined to be a major contributor to incubation effects.These observations are also in agreement with UV/VIS analysis as measurements show that polymers with a cut-off wavelength lower than that of the laser beam undergo a shift in absorption behavior. Finally, some polymers experience a continuous darkening of their surface with increasing fluence due to an increasing degree of photo-oxidation.

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“…The changes in bonding structure observed in Figure 9 are consistent with the established mechanisms for LDPE [43] and PET [44].…”

Section: Chemical Characterizationsupporting

confidence: 74%

Optical and chemical effects governing femtosecond laser-induced structure formation on polymer surfaces

Assaf¹,

Kietzig²

2018

Materials Today Communications

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“…PP has three carbon atoms in the chain where radicals can form namely, at primary (methyl group), secondary (in the chain, not attached to methyl group) and/or tertiary position (in the chain to which the methyl group is attached). Iring and Tudos (1990) suggested that the primary alkyl radical may be formed due to the oxidation of the tertiary carbon 46 . In this study the PPv showed low IK values, and peaks around 1720-1730 and 1640 cm -1 were no longer detected after burial, given the biodegradation process.…”

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confidence: 99%

Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment

et al. 2011

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Polymers are vastly employed for numerous purposes in different industrial segments and generate soaring quantities of discarding in the environment. This research analyzed the degradability/biodegradability of polypropylene films (PP) and Bioriented polypropylene (BOPP) polymers after 11 months interred in the São Giácomo landfill in Caxias do Sul. Comparing the buried PP film to a sample of virgin PP, two peaks of degrading activity appeared at the TG curve as well as structure modification typified by occurrence of new absorption bands at FTIR, which can be credited to changes in crystallinity. Thermal analysis carried out on the buried PP and BOPP showed decreases in the percentage of crystallinity due to chain scission. The major reduction was observed in the PP, since its crystallinity is a consequence of polymerization instead of chain orientation processes, as in BOPP. Cracks and erosion of the polymer surface were detected in both PP and BOPP, indicating degrading processes by microorganisms.

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“…This "morphology" hypothesis seems plausible given the theoretical development of diffusion and oxidation models in semi-crystalline polymers. 42,44,57 As in any semicrystalline polymer, diffusion of oxygen in polyethylene takes place in the amorphous regions. Consequently, the flow of an ideal gas through polyethylene is analogous to the fluid flow through porous media.…”

Section: Discussionmentioning

confidence: 99%

Evolution of morphology in UHMWPE following accelerated aging: The effect of heating rates

Kurtz

Pruitt

Crane

et al. 1999

J. Biomed. Mater. Res.

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Accelerated aging methods are used to evaluate the oxidative stability of UHMWPE components for total joint replacements. In this study, we traced the evolution of the crystalline morphology during accelerated thermal aging of UHMWPE in air with the intent of explaining previous, counterintuitive heating rate effects. GUR4150HP extruded rod stock material was machined into miniature (0.5 mm thick) specimens that were either gamma irradiated in air or in nitrogen (27 +/- 3 kGy) or left unirradiated (control). Accelerated aging in an air furnace (at 80 degrees C, atmospheric pressure) was performed on half of the test samples at a heating rate of 0.1 degrees C/min and at 5 degrees C/min for the remaining half. Although the initial heating rate, as measured by changes in density, did influence the absolute degradation rate by up to 214%, the heating rate effect did not appear to influence the relative ranking of UHMWPE in terms of its oxidative stability. The heating rate effect is more consistent with a kinetic mechanism of the oxidation process than it is with a previously hypothesized diffusion mechanism. UHMWPE morphology, as characterized using a transmission electron microscope (TEM), demonstrated considerable rearrangement of the crystalline regions as a result of the accelerated aging. The stacking of the lamellae observed after accelerated aging was not consistent with the morphology of naturally aged UHMWPE components. The observed differences in crystalline morphology likely result from the enhanced mobility of the polymer chains due to thermal aging and may be analogous to an annealing process.

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Thermal oxidation of polyethylene and polypropylene: Effects of chemical structure and reaction conditions on the oxidation process

Cited by 111 publications

References 15 publications

Optical and chemical effects governing femtosecond laser-induced structure formation on polymer surfaces

Optical and chemical effects governing femtosecond laser-induced structure formation on polymer surfaces

Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment

Evolution of morphology in UHMWPE following accelerated aging: The effect of heating rates

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