Dataset Information

Accelerated weathering parameters for some aromatic engineering thermoplastics. Part 2: Polycarbonate copolymers, polyarylate and ABS.

ABSTRACT: Understanding the responses of materials to environmental variables is essential for performing meaningful accelerated weathering and service life prediction. Samples of polycarbonate-b-resorcinol polyarylate copolymer (RPA), poly(acrylonitrile-co-butadiene-co-styrene) (ABS), and two polycarbonate copolymers with silicone or aliphatic diacids were exposed in the NIST (National Institute of Standards and Technology) SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) to determine the effects of ultraviolet intensity (UV irradiance), temperature, relative humidity (RH), and UV wavelength on yellowing and gloss loss and were compared to other aromatic polymers. All showed proportional response to irradiance (i.e., reciprocity) except ABS, which deviated notably at elevated temperatures. The activation energy for ABS yellowing was higher than other aromatic polymers (31 kJ mol^-1 ± 2 kJ mol^-1) while RPA had a slightly negative activation energy (-5 kJ mol^-1 ± 3 kJ mol^-1), reflecting differences in their photodegradation mechanisms. These two polymers also exhibited faster degradation when the RH was ? 10 % compared to ? 50 % RH. Wavelength effects varied among the polymers. The results indicate that predictive accelerated weathering should be performed with UV sources that accurately reproduce sunlight, at temperatures as close as possible to use conditions, and with RH > 10 %.

SUBMITTER: Pickett JE

PROVIDER: S-EPMC7860088 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Accelerated weathering parameters for some aromatic engineering thermoplastics. Part 2: Polycarbonate copolymers, polyarylate and ABS.

Pickett James E JE Kuvshinnikova Olga O Sung Li-Piin LP Ermi Brett D BD

Polymer degradation and stability 20190101

Understanding the responses of materials to environmental variables is essential for performing meaningful accelerated weathering and service life prediction. Samples of polycarbonate-b-resorcinol polyarylate copolymer (RPA), poly(acrylonitrile-co-butadiene-co-styrene) (ABS), and two polycarbonate copolymers with silicone or aliphatic diacids were exposed in the NIST (National Institute of Standards and Technology) SPHERE (Simulated Photodegradation via High Energy Radiant E ...[more]

PMID: 33551517

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Project description:The incorporation of thermoplastics with pigments imparts diverse aesthetic qualities and properties to colored thermoplastic products. The selection of pigment type and content, along with specific processing conditions, plays a pivotal role in influencing color properties and overall product performance. This study focuses on optimizing these parameters to ensure the desired color quality and product functionality. Two types of polypropylene copolymer (PPCP) with different melt flow rates (MFRs) and acrylonitrile butadiene styrene (ABS) were compounded with ultramarine blue pigment masterbatch (MB) in concentrations ranging from 1 to 5 wt.% using a twin-screw extruder. The compounding process was conducted at a constant screw speed of 200 rpm and a die temperature of 210 °C. The effects of screw speed and die temperature were investigated at a constant MB of 3 wt.%. Colored samples were fabricated by injection molding. Microscopic analysis revealed a well-dispersed pigment within the PPCP matrix when using the MB. Rheological properties, assessed through the power law index, confirmed effective pigment dispersion, facilitated by shear thinning behavior and controlled shear rate via the manipulation of screw speed and die temperature. The effects of masterbatch contents and processing conditions on color spaces were evaluated using CIELAB and CIELCH, with one-way ANOVA employed to identify statistical significance. Higher opacity in high-MFR PPCP and ABS resulted in increased lightness and color strength, surpassing low-MFR PPCP by 15-40% at equivalent MB contents. Masterbatch content emerged as a significant factor influencing the color spaces of all colored thermoplastics. Further analysis, including Fisher pairwise comparisons of one-way ANOVA, revealed that screw speed influenced the redness and hue of low-MFR PPCP, whereas die temperature affected the lightness and hue of high-MFR PPCP and ABS. Interestingly, the blueness and chroma of colored thermoplastics were minimally affected by both screw speed and die temperature. Notably, regardless of processing conditions, the flexural properties of colored thermoplastics remained comparable to the neat polymer when incorporated with ultramarine blue pigment masterbatch.

Dataset Information

Accelerated weathering parameters for some aromatic engineering thermoplastics. Part 2: Polycarbonate copolymers, polyarylate and ABS.

Publications

Accelerated weathering parameters for some aromatic engineering thermoplastics. Part 2: Polycarbonate copolymers, polyarylate and ABS.

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