Evaluation of commercial polycarbonate optical properties after QUV-A radiation—the role of humidity in photodegradation

Tjandraatmadja, Grace; Burn, Lachlan; Jollands, Margaret

doi:10.1016/s0141-3910(02)00179-9

Cited by 76 publications

(53 citation statements)

References 15 publications

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“…13). There are two major mechanisms that are responsible for the aggravated photo-degradation of polymer in the presence of absorbed moisture: (i) the water molecules enhance the photo-oxidative reactions due to the increased OH -and H + ions [22]; and (ii) the water molecules can be located on the free volume sites between polymer molecules, improving the mobility of free radicals within the surface layer, thus accelerating photo-oxidation [23].…”

Section: Combined Effects Of Moisture and Uv Exposurementioning

confidence: 99%

Environmental degradation of epoxy–organoclay nanocomposites due to UV exposure. Part I: Photo-degradation

Woo

Chen

Zhu

et al. 2007

Composites Science and Technology

147

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The environmental degradation mechanisms of epoxy-organoclay nanocomposites due to accelerated UV and moisture exposure are studied. Various characterisation tools, including FTIR, SEM, XRD and XRF analyses, were used to evaluate the effects of clay content on the progressive changes in chemical element, topography and colour of the nanocomposite. It is found that microcracks started to appear on both the neat epoxy and nanocomposite surface after about 300 h of UV exposure. The nanocomposite exhibited thicker and shallower cracks with a less degree of discoloration than the neat epoxy due to the diffusion barrier characteristics of organoclay with high aspect ratio. The presence of transition metal ions along with low-molecular-weight organic modifiers in organoclay, however, accelerated the degradation of polymer, counterbalancing the above ameliorating barrier properties of clay. FTIR analysis indicated that photo-degradation generated carbonyl groups by chain scission and the rate was slightly higher for the nanocomposites than for the neat epoxy. While moisture further accelerated the photo-degradation process through the enhanced mobility of free radicals and ions, the organoclay could limit the deteriorating effect of moisture, resulting in much better overall resistance to photo-degradation in the presence of moisture for the nanocomposite than the neat epoxy.

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Section: Combined Effects Of Moisture and Uv Exposurementioning

confidence: 99%

Environmental degradation of epoxy–organoclay nanocomposites due to UV exposure. Part I: Photo-degradation

Woo

Chen

Zhu

et al. 2007

Composites Science and Technology

147

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“…Apesar dos mecanismos de fotodegradação da maioria dos polímeros serem bem estabelecidos, o comportamento das blendas poliméricas frente à radiação UV ainda é um campo a ser explorado. Alguns tipos de polímeros, como o polietileno, polipropileno, poliestireno e poli(tereftalato de etileno), foram extensivamente estudados ao longo dos anos, e os mecanismos de fotodegradação e fotoestabilização, bem como os fatores que controlam a cinética do processo e mudanças nas propriedades do produto estão razoavelmente bem estabelecidos [7][8][9][10][11][12][13][14] . Enquanto isso, no caso de blendas poliméricas, poucos estudos na área de fotodegradação podem ser encontrados na literatura [15][16][17][18] .…”

Section: Introductionunclassified

Estudo do efeito do tipo de polipropileno na fotodegradação da blenda polipropileno/poliestireno de alto impacto

et al. 2012

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Resumo: Este trabalho visa avaliar a influência do tipo de polipropileno no comportamento da blenda polipropileno/poliestireno de alto impacto (PP/HIPS) quando exposta à radiação UV. Foram usados uma resina virgem de PP (PPv) e outra reprocessada (PPrep). Inicialmente, avaliou-se o comportamento individual dos componentes da blenda, HIPS, PPv e PPrep, quando submetidos à radiação UV por até 15 semanas de exposição. As técnicas de caracterização utilizadas para monitorar o desempenho tanto das resinas individualmente quanto das blendas submetidas à radiação UV foram: propriedades mecânicas (tração e impacto), medidas de índice de fluidez (MFI), análise térmica (DSC), espectroscopia no infravermelho (FTIR) e microscopia eletrônica de varredura (MEV). A partir dos resultados com essas técnicas verificou-se que o PPv foi a resina mais afetada pela radiação e consequentemente as blendas preparadas com esse PP também foram mais sensíveis à fotodegradação do que as demais. Em termos de fotoestabilização este resultado mostra-se interessante, já que as blendas PP/HIPS preparadas com uma resina previamente degradada necessitariam de menores teores de aditivos do que esse mesmo tipo de blenda preparada com resina virgem. Palavras-chave: Polipropileno, poliestireno de alto impacto, blenda, fotodegradação. Influence of the Type of Polypropylene on the Photodegradation of Blends of Polypropylene/High Impact PolystyreneAbstract: The influence from the type of polypropylene on the photodegradation resistance of blends of polypropylene/high impact polystyrene (PP/HIPS) was studied. A virgin polypropylene (PPv) and another sample that suffered prior thermo-mechanical degradation (PPrep) were used. All materials, components of the blends and blends were exposed to UV radiation for up to 15 weeks. They were characterized as a function of time of UV exposure using differential scanning calorimetry (DSC), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The mechanical (tensile and impact) properties and melt flow indexes of the materials were also evaluated. The experimental results revealed that PPv resin and its blends were more sensitive to UV radiation than PPrep and its blends. In terms of photostabilization this finding is very interesting, since PP/HIPS blends prepared with a previously degraded polyolefin would require smaller amounts of additives than the same kind of blends prepared with virgin resin. Keywords: Polypropylene, high impact polystyrene, blend, photodegradation. IntroduçãoO interesse no estudo das blendas poliméricas tem aumentado a cada ano. Um dos grandes motivos para esse crescimento se dá pela vantagem: 1) tecnológica: as blendas possuem a capacidade de combinar as propriedades de diferentes componentes de modo a obter excelentes propriedades mecânicas, térmicas e químicas, e 2) financeira: o custo de desenvolvimento de uma blenda é menor que o custo de desenvolvimento de um novo polímero. Porém o desenvolvimento de um novo material não se restringe apenas a sua obtenção, é preciso tamb...

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“…Following the ageing process by UV irradiation, functional polar groups, such as carboxylic acid (-COOH) and hydroxyl groups (-OH), can be introduced to the surface of PC by photodegradation and thus increase surface polarity, as proven by FTIR and XPS characterization. 21,22 Changes in AS coatings under UV irradiation significantly differed. No significant variation in contact angle was observed, with the remaining at 100…”

Section: Surface Wettability Analysesmentioning

confidence: 97%

“…23,24 FTIR was employed to investigate the surface elemental compositions of the PCs and AS coatings after UV ageing. Figure 4 shows the FTIR spectra of PC in the 400 cm 21 to 4500 cm 21 region after exposure to UV radiation for different durations.…”

Section: Ftir Characterizationmentioning

confidence: 99%

Adhesion failure of antiscratch coatings on polycarbonate under UV irradiation

Zhang

Zhong

2014

J of Applied Polymer Sci

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The adhesion failure of antiscratch (AS) coatings on unmodified and plasma-modified polycarbonate (PC) substrate was studied using both chemical and physical methods while considering the surface and interface changes between coatings and PC under ultraviolet (UV) irradiation. The differences in the wettability and surface elemental compositions of the PC surface (PCs) and AS coatings after UV ageing were evaluated by contact angle and Fourier transform infrared (FTIR) measurements. The nanoindentation technique was employed for the quantitative assessment of the changes in the nanomechanical properties of both PCs and AS coatings under UV irradiation. The adhesion of coating on plasma-modified PC was found to be significantly better than that of unmodified substrates. The hydrophilicity and polarity of PCs covered by AS coatings were significantly increased because of the photodegradation of PCs, whereas silicon coatings remained invariant. Nanoindentation tests revealed an obvious enhancement in stiffness of the coating and exposed PC after ageing. Based on these experiments, we proposed that adhesion failure under UV irradiation may be caused by two reasons: first, the photodegradation that occurred at the PCs covered by AS coatings; and second, the stress induced by the changes in stiffness of both AS and PCs under UV ageing.

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Evaluation of commercial polycarbonate optical properties after QUV-A radiation—the role of humidity in photodegradation

Cited by 76 publications

References 15 publications

Environmental degradation of epoxy–organoclay nanocomposites due to UV exposure. Part I: Photo-degradation

Environmental degradation of epoxy–organoclay nanocomposites due to UV exposure. Part I: Photo-degradation

Estudo do efeito do tipo de polipropileno na fotodegradação da blenda polipropileno/poliestireno de alto impacto

Adhesion failure of antiscratch coatings on polycarbonate under UV irradiation

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