Ozonisation et modifications morphologiques et physicochimiques de fibres de polypropylene

Oueslati, R.; Catoire, B.

doi:10.1016/0014-3057(91)90114-4

Cited by 11 publications

(9 citation statements)

References 6 publications

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“…It is probably related to carboxyl groups formed by ozonation of alkyl groups of the PDMS. However, after four hours of ozone exposition is it observed a reduction of this band, meaning a removal of C=O bonds to form silicon oxide as described in literature 14 . It is import to accentuate that no modifications were observed in bands relative to the Si-O-Si (865 cm -1 ) or to -CH 3 in the bond Si-CH 3 (785 cm -1 ).…”

Section: Infrared Analysis Of the Polymerssupporting

confidence: 51%

“…Appearance of a band in 1708 cm -1 , region of ketone carboxyl groups (C=O), also reflects changes occurring in the polymer structure. Although Cataldo 12 had observed that materials with single bonds showed great resistance to ozone attack, in the present work two polymeric materials, PP and PDMS, have suffered break of the single bonds due to ozone attack at high concentrations used, as observed in the literature [13][14][15] . Similar modifications were also observed for PDMS membranes (Figure 5b), moreover for prolonged exposition to ozone it was observed changes in the spectral region 2990-2855 cm -1 and 1485-1415 cm -1 of alkyl groups (-CH 3 ) from long chain with stretching vibration (symmetric and asymmetric) and asymmetric bending vibration, respectively 32 .…”

Section: Infrared Analysis Of the Polymersmentioning

confidence: 51%

“…Nevertheless, some authors proposed a simple mechanism of initiation and propagation for ozone attack of single bonds structures where various groups, as carboxyl, ketone, etc., are created with elevated ozone concentrations [13][14][15] . Goto et al 16 evaluated the chemical reactivity between ozone and different polymers through material thickness reduction.…”

Section: Introductionmentioning

confidence: 99%

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Polymeric Materials for Membrane Contactor Devices Applied to Water Treatment by Ozonation

2015

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Section: Infrared Analysis Of the Polymerssupporting

confidence: 51%

Section: Infrared Analysis Of the Polymersmentioning

confidence: 51%

Section: Introductionmentioning

confidence: 99%

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Polymeric Materials for Membrane Contactor Devices Applied to Water Treatment by Ozonation

2015

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“…after which propagation follows, leading to a rapid oxidation following the scheme Certain increases in the whiteness degree and certain reductions of the yellowing index, as seen in Figure 2 [9] indicate that mostly chromophore-based groups are created at a much higher level of ozonization (carboxyl, keto, cyclic, etc. ), which means that the positive effects of whiteness degree intensification, mentioned before, are surely lost under such circumstances.…”

Section: Resultsmentioning

confidence: 95%

Influence of Ozone as an Air Pollutant on Polypropylene Fiber Properties

Pezelj

Čunko

2000

Textile Research Journal

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Ever increasing ozone concentrations in the earth's atmosphere polluted by photochemical smog raise the question of possible ageing of fibers in such an environment. This paper investigates polypropylene fibers characterized by pronounced ageing in the natural environment under the impact of sunlight. Fibers are exposed to ozone for varying times and temperatures in a concentration range that can be expected in a heavily polluted urban industrial environment. Changes in the level of chemical composition and molecular configuration are investigated, together with morphological characteristics and end-use properties. Results indicate that, even under relatively mild ozone conditions, hydroperoxide groups are created, morphological surface changes occur, fibers become more brittle and lose strength, and the isotacticity of the configuration is pronounced, but there are some rather positive effects as well. I The investigation described in this paper is primarily aimed at determining the possibly detrimental influence of ozone on polypropylene (PP) fibers. These fibers are highly sensitive to atmospheric factors, especially ultraviolet rays [3, 4, 11 ], so the question arises whether (and if so, how much) the increased amount of ozone in the troposphere influences the problem of PP fiber ageing in atmospheric conditions. The literature on the subject indicates a lack of research on this topic, especially where fibers, as a specific form of the material, are concerned.Oueslati et al. have made some interesting investigations of the impact of ozone on chemical and morphological changes in PP fibers [8, 9, 101, which were exposed to ozone concentrations of -4.5 x 106 pphm, a very intensive treatment. This amount of ozone is a few thousand times higher than the average concentrations in polluted environments registered for a number of years in various parts of the world (Los Angeles, California; Arkon, Germany; Basel, Switzerland; Sydney, Australia). All the concentrations registered were in the range between 1.5 and 4 pphm [ 12], while occasional peaks of pollution reached-115 pphm (Los Angeles) or -75 pphm (Zurich). Using IR-and ESR spectroscopy, the authors investigated chemical changes in PP macromolecules [9, 10], and with electronic microscopy, they showed what this level of &dquo;ozonization&dquo; does to the core/sheath structure of PP fibers [8]. Similar morphological changes were also observed by Catoire et al.[2] at somewhat milder, but still highly intensive, ozone treatments (3.1 x 105 pphm).The literature does not offer proof of the impact of ozone on other relevant physicomechanical properties of the fibers, which is important for assessing ageing during use in real conditions of air pollution with ozone. For this reason, our investigation deals with ozone concentrations slightly higher than peak values in polluted urban environments. We focus on end-use properties, but we also consider other relevant properties for a complete overview of the problem.. MethodologyAll the tests involved undyed PP filaments...

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“…These mechanisms can be contrasted with those described for thermal oxidation [18], chemical oxidation [19], ozonization [20][21][22], UV [23][24][25], ion beam [26], and 1 [27][28][29][30][31][32] irradiation of PP, where tertiary hydrogen abstraction is proposed.…”

mentioning

confidence: 99%

Reactivity of a polypropylene surface modified in a nitrogen plasma

Poncin-Epaillard

Chevet

Brosse

1994

Journal of Adhesion Science and Technology

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Reactivity of a polypropylene surface modified in a nitrogen plasmaAbstract-The modification of a polypropylene surface in a nitrogen plasma is studied in terms of degradation, crosslinking, functionalization, and activation (radical site creation.) The most important reactions are functionalization through primary amine formation and radical creation through methyl-group elimination. Degradation and crosslinking are competitive and the latter is more important when the plasma conditions (exposure time, discharge power) are severe. Exomethylenic bonds (CH2=C) are formed preferentially over crosslinking reactions. Chemical titrations are described for radical and amine concentrations on the polypropylene surface.

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Ozonisation et modifications morphologiques et physicochimiques de fibres de polypropylene

Cited by 11 publications

References 6 publications

Polymeric Materials for Membrane Contactor Devices Applied to Water Treatment by Ozonation

Polymeric Materials for Membrane Contactor Devices Applied to Water Treatment by Ozonation

Influence of Ozone as an Air Pollutant on Polypropylene Fiber Properties

Reactivity of a polypropylene surface modified in a nitrogen plasma

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