Dynamic-mechanical analysis of the photo-degradation of long glass fibre reinforced polypropylene: Mechanical properties' changes

Larena, A.; Ochoa, S. Jiménez de; Domínguez, F. Martín

doi:10.1016/j.polymdegradstab.2005.05.034

Cited by 21 publications

(15 citation statements)

References 20 publications

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“…It was found that photo-oxidation only leads to slight changes in the DSC thermogram of pure PP. The DSC curve shape is qualitatively not modified, however it is slightly shifted towards lower temperatures [37,[57][58][59][60]. In consequence, the melting temperature and the maximum lamellar thickness of pure PP tend to slightly decrease during photo-oxidation (Table 1).…”

Section: Morphological Changesmentioning

confidence: 95%

“…Furthermore, a slight increase of the original crystalline content is also observed for pure PP during exposure to UV radiation (Table 1). It is well evidenced that the crystalline content of polypropylene increases at the beginning of oxidation [35][36][37]57,59,60,[63][64][65]. This phenomenon has been explained as due to chain scission, which initially is the major driving force of the oxidative process, and leads to increasing segment mobility and chain arrangements, favouring further crystallisation [58].…”

Section: Morphological Changesmentioning

confidence: 98%

“…Basically, UV-irradiation leads to a multimodal and more heterogeneous DSC curve [37,[57][58][59]66]. Regardless of the additive content, as the exposure time increases, there is a shape transition in which the maximum shifts to the lowest temperature contribution, while the original high temperature contribution vanishes.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Regardless of the additive content, as the exposure time increases, there is a shape transition in which the maximum shifts to the lowest temperature contribution, while the original high temperature contribution vanishes. These morphological changes lead to a significant drop of the melting temperature [37,57,59,62] that occurs concurrently with a considerable decrease of the maximum lamellar thickness of these photo-oxidized PP samples, suggesting that as photooxidation proceeds, crystals are progressively becoming thinner (Table 1). Furthermore, this evidences that the crystalline phase, despite its lower permeability to oxygen, is also affected by the photo-oxidation process.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Contat‐Rodrigo

2013

Polymer Degradation and Stability

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The oxo-degradation process of polypropylene (PP) samples containing different concentrations (4% and 10% w/w) of pro-oxidant/pro-degradant additive Envirocare TM AG1000C was investigated under accelerated test conditions. Samples were initially exposed to UV radiation for 300 hours. The tendency to biodegradation in soil medium of these UV-aged samples was then indirectly assessed by an indirect method for a period of 6 months. The entire degradation process of these materials was first examined by monitoring changes in their morphological properties (melting temperature, maximum lamellar thickness and crystallinity) with the aging time, by Differential Scanning Calorimetry (DSC). Then, changes in the thermal properties (onset temperature and maximum decomposition temperature) of these materials with the aging time were analysed by Thermogravimetric Analysis (TGA). Furthermore, the kinetics of the thermal decomposition of these PP samples with pro-oxidant/prodegradant was also studied during the oxo-degradation process, by means of the Chang differential method. During exposure to UV radiation, the more significant changes in the morphological and thermal properties that were detected in PP samples containing M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTpro-oxidant/pro-degradant additive compared to pure PP, clearly suggest a higher level of oxidation in these samples, confirming the effectiveness of this pro-oxidant/prodegradant additive in promoting the abiotic oxidation of polypropylene during UVirradiation. Moreover, the level of oxidation observed in UV-aged samples seems to be dependent on the additive load.On the other hand, during incubation in soil medium, changes in the morphological and thermal properties of previously photo-oxidized PP samples with pro-oxidant/prodegradant were detected that indirectly support a certain progress of oxidation, indicating that previous abiotic oxidation can promote further degradation of the polypropylene matrix by soil microorganisms. In general, both morphological and thermal properties exhibit a non-linear dependency with the incubation time in soil, supporting the idea that biodegradation is a complex process that occurs in different stages. Furthermore, the extent of the changes in these properties during soil incubation was found to be proportional to the pro-oxidant/pro-degradant load and the previous photo-oxidation level.

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Section: Morphological Changesmentioning

confidence: 95%

Section: Morphological Changesmentioning

confidence: 98%

Section: Accepted Manuscriptmentioning

confidence: 99%

Section: Accepted Manuscriptmentioning

confidence: 99%

See 2 more Smart Citations

Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Contat‐Rodrigo

2013

Polymer Degradation and Stability

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“…For the nanocomposites with 3 and 5wt% clay contents, the reductions were relatively moderate, 15.5 % and 10.6 % respectively. The reduction in failure strain is common for all polymers after UV exposure [12][13][14]. Neat polymers without reinforcements tend to be more severely embrittled with ultimate elongation decreasing at a much higher rate than those with rigid fillers.…”

Section: Residual Tensile Properties After Uv Exposurementioning

confidence: 99%

Environmental degradation of epoxy-organoclay nanocomposites due to UV exposure: Part II residual mechanical properties

Woo

Zhu

Leung

et al. 2008

Composites Science and Technology

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The residual mechanical properties of epoxy-organoclay nanocomposites after moisture and UV exposure have been evaluated. The flexural modulus decreased after moisture saturation, with much less extent for the nanocomposite than the neat epoxy. The tensile failure strain was significantly reduced with UV exposure time due to the embrittlement effect, and the addition of organoclay mitigated the failure strain reduction. The elastic modulus varied little with UV exposure time regardless of organoclay, because the modulus was determined by the core material which was unaffected by UV exposure. The microhardness and the modulus of the surface material determined from nanoindentation tests increased after UV exposure, with less extent in the nanocomposite than the neat epoxy due to the thinner embrittled top layer for the nanocomposite. All these observations confirmed the beneficial effects of organoclay in improving the barrier characteristics against UV exposure.

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Natural Aging Effects in HMS-Polypropylene Synthesized by Gamma Radiation in Acetylene Atmosphere

Oliani¹,

Komatsu²,

Lugão³

et al. 2016

TMS 2016: 145^thAnnual Meeting &Amp; Exhibition: Supplemental Proceedings

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Dynamic-mechanical analysis of the photo-degradation of long glass fibre reinforced polypropylene: Mechanical properties' changes

Cited by 21 publications

References 20 publications

Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Thermal characterization of the oxo-degradation of polypropylene containing a pro-oxidant/pro-degradant additive

Environmental degradation of epoxy-organoclay nanocomposites due to UV exposure: Part II residual mechanical properties

Natural Aging Effects in HMS-Polypropylene Synthesized by Gamma Radiation in Acetylene Atmosphere

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