Polymer Photodegradation

Rabek, Jan F.

doi:10.1007/978-94-011-1274-1

Cited by 352 publications

(153 citation statements)

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“…where C is carbonyl index of the exposed sample, C is carbonyl index of the sample before degradation [25], c is area of the carbonyl band, ref is area of the reference band (2,019 cm −1 ).…”

Section: Assessment Of the Oxo-degradable Ldpe Degradationmentioning

confidence: 99%

“…Consequently, for next assessments, the films were extracted from the UV chamber at 300 h, that is, before the enhancement of the hydroperoxide band. The proliferation of the hydroperoxide group was established as the degradation limit before the extreme material fragmentation and reticulation occur [25,26].…”

Section: Qualitative Assessmentmentioning

confidence: 99%

“…These results indicate the degradation level of each blend during the reprocessing. Additionally, it was found that the 20 wt.% blend degrades in the first reprocessing which means that the molecular weight decreases due to polymer chains breakage [25,32].…”

Section: Study Of the Degraded Material/ldpe Blends Reprocessingmentioning

confidence: 99%

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Effect of the Prodegradant-Additive Plastics Incorporated on the Polyethylene Recycling

Aldás

Paladines

Valle

et al. 2018

International Journal of Polymer Science

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The effect of degraded plastic with prodegradants on the polyethylene properties was studied. First, the mixture of low-density polyethylene (LDPE) with 5 wt.% prodegradant (oxo-degradable) additive was prepared by melt processing using a mixer chamber. Then, the degradation of the mixtures was evaluated by exposing the oxo-degradable LDPE in a Xenon arc chamber for 300 hours. The degraded material was characterized by infrared spectroscopy (FTIR) assessing the carbonyl index and the hydroperoxide band. Then, different percentages of degraded material (1, 5, 10, 20, and 50 wt.%) were incorporated into the neat LDPE. Mechanical and rheological tests were carried out to evaluate the recycling process of these blends. Also, the feasibility of the blends reprocessing was determined by analysing the melt flow index for each heating process and shear stress applied. It was evidenced that the increment of the content of the degraded material in the neat LDPE decreased the mechanical strength and the processability of blends due to the imminent thermal degradation. All the test results showed that the incorporation of degraded material causes a considerable reduction in the matrix properties during the reprocessing. Nevertheless, at low concentrations, the properties of the oxo-degradable LDPE-LDPE blends were found to be similar to the neat LDPE.

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Section: Assessment Of the Oxo-degradable Ldpe Degradationmentioning

confidence: 99%

Section: Qualitative Assessmentmentioning

confidence: 99%

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Effect of the Prodegradant-Additive Plastics Incorporated on the Polyethylene Recycling

Aldás

Paladines

Valle

et al. 2018

International Journal of Polymer Science

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“…This is a mature and complex subject, covered in monographs [23][24][25][26] and journals such as Progress in Organic Coatings, Polymer Testing, and Polymer Degradation and Stability. An additional interesting reference is the United Nations' assessment [27] of effects of increased UV exposure on building materials due to a decrease in ozone levels in the upper atmosphere.…”

Section: Photodegradation Of Polymeric and Other Organic Materialsmentioning

confidence: 99%

Weathering of roofing materials – An overview

Berdahl

Akbari

Levinson

et al. 2008

Construction and Building Materials

233

121

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An overview of several aspects of the weathering of roofing materials is presented. Degradation of materials initiated by ultraviolet radiation is discussed for plastics used in roofing, as well as wood and asphalt. Elevated temperatures accelerate many deleterious chemical reactions and hasten diffusion of material components. Effects of moisture include decay of wood, acceleration of corrosion of metals, staining of clay, and freezethaw damage. Soiling of roofing materials causes objectionable stains and reduces the solar reflectance of reflective materials. (Soiling of non-reflective materials can also increase solar reflectance.) Soiling can be attributed to biological growth (e.g., cyanobacteria, fungi, algae), deposits of organic and mineral particles, and to the accumulation of flyash, hydrocarbons and soot from combustion.

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“…Os polímeros em geral quando expostos a radiação ultravioleta do sol desencadeiam uma série de reações químicas que juntamente com os efeitos fotofísicos, fotoquímicos da radiação solar, oxidativos do oxigênio atmosférico, hidrolíticos da água e de temperatura fazem com que ocorra a degradação do polímero [1,2] . A fotodegradação pode causar alterações no comprimento das cadeias do polímero, nas propriedades mecânicas, propriedades de barreira, mudança de coloração, surgimento de fissuras e fraturas, perda de brilho entre outras.…”

Section: Introductionunclassified

Influência de estabilizantes na degradação foto-oxidativa de filmes de compósitos de SWy-1/poli(óxido de etileno)

2015

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ResumoCompósitos de poli(óxido de etileno) (PEO) com argila montmorilonita SWy-1 e estabilizantes (2-hidroxibenzofenona e tinuvin 770) foram preparados pelo método de intercalação em solução. Os filmes obtidos foram expostos a irradiação UV, e os produtos da fotodegradação foram monitorados por FTIR (Fourier Transform Infrared Spectroscopy, ou Espectroscopia no infravermelho por transformada de Fourier) e SEC (Size Exclusion Chromatography, ou cromatografia de exclusão por tamanho). O PEO puro apresentou maior coeficiente de degradação, k d, comparado com as demais amostras. O sistema que apresentou o menor valor para o coeficiente de degradação (k d = 1,9×10-6 mol g -1 h -1 ) foi o compósito de PEO/5%SWy-1 com 0,25% de tinuvin 770. Nesse caso, a estabilização da matriz de PEO pode ser atribuída à argila juntamente com o tinuvin 770. A argila dispersa e absorve a irradiação UV, e o tinuvin age como estabilizante do tipo HALS (do inglês hindered amine light stabilizer, ou estabilizantes à luz tipo aminas impedidas). Palavras-chave: poli(óxido de etileno), montmorilonita, fotoestabilizantes, degradação foto-oxidativa. AbstractPoly(ethylene oxide) (PEO) with SWy-1 montmorillonite and stabilizers (2-hydroxybenzophenone and tinuvin 770) composites were prepared by intercalation in solution method. The films of the composites were exposed to UV irradiation. The photodegradation products were monitored by FTIR (Fourier Transform Infrared Spectroscopy) and SEC (Size Exclusion Chromatography) method. The PEO pure showed higher degradation rate coefficients, k d , compared to the others samples. The system that showed the lowest value for the degradation rate coefficients (k d = 1.9×10 -6 mol g -1 h -1 ) was the PEO/SWy-1 5% composite with 0.25% of tinuvin 770. In this case, the stabilization of the PEO matrix can be attributed to clay associated with tinuvin 770. The clay scatters and absorbs UV irradiation and tinuvin acts as a stabilizer of the HALS (hindered amine light stabilizers) kind.

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Polymer Photodegradation

Cited by 352 publications

References 0 publications

Effect of the Prodegradant-Additive Plastics Incorporated on the Polyethylene Recycling

Effect of the Prodegradant-Additive Plastics Incorporated on the Polyethylene Recycling

Weathering of roofing materials – An overview

Influência de estabilizantes na degradação foto-oxidativa de filmes de compósitos de SWy-1/poli(óxido de etileno)

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