scholarly journals Correlation of a Temperate UV-Weathering Cycle to Outdoor Exposure for the Determination of the Environmental Instability of Polyethylene Films Using HT-GPC Analysis

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 591
Author(s):  
Gavin Hill ◽  
Celine Moreira ◽  
Florence Huynh ◽  
Ana Trufasila ◽  
Faith Ly ◽  
...  
Keyword(s):  
Physical Property ◽  
Gel Permeation Chromatography ◽  
Outdoor Exposure ◽  
Accelerated Weathering ◽  
Micro Particles ◽  
Exposure Site ◽  
Plastic Materials ◽  
Physico Chemical ◽  
Environmental Instability ◽  
Insight Into

Accelerated UV-weathering cycles are predominately used for evaluating the durability of plastic materials, particularly polyethylene (PE) films. The point of failure for this testing is usually the loss of a physical property, such as the loss of tensile strength over time. For plastics designed to be instable under environmental conditions, the accelerated weathering cycles are yet to be defined and their correlation to outdoor exposure has yet to be made. This study demonstrates the utility of a newly defined temperate accelerated UV-weathering cycle, recently codified in the British Standard PAS 9017:2020. In addition, the effectiveness of the laboratory weathering cycle has been correlated to real-world outdoor exposure through simultaneous testing of the same samples at a specialist outdoor exposure site in Florida. The utility of the testing methodology and the performance of the polyethylene samples was demonstrated through the use of High Temperature Gel Permeation Chromatography (HT-GPC) analysis. The data led to a detailed insight into the physico-chemical changes occurring in the PE films upon exposure to environmental stimuli. By comparison, and surprisingly, the techniques employed appear to provide an insight into the processes in which secondary micro-particles of PE are formed from macro-polyethylene samples. The temperate accelerated UV-weathering cycle over 14 days demonstrated an approximate correlation to 90 days of outdoor exposure in Florida for the PE film studied.

scholarly journals Temperate UV-Accelerated Weathering Cycle Combined with HT-GPC Analysis and Drop Point Testing for Determining the Environmental Instability of Polyethylene Films

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2373
Author(s):  
Celine Moreira ◽  
Richard Lloyd ◽  
Gavin Hill ◽  
Florence Huynh ◽  
Ana Trufasila ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Outdoor Exposure ◽  
Accelerated Weathering ◽  
Polyethylene Films ◽  
Parallel Testing ◽  
Mapping Analysis ◽  
Environmental Instability ◽  
Weight Analysis ◽  
Physical Changes ◽  
Ir Spectroscopic

Polyethylene films are one of the most frequently used packaging materials in our society, due to their combination of strength and flexibility. An unintended consequence of this high use has been the ever-increasing accumulation of polyethylene films in the natural environment. Previous attempts to understand their deterioration have either focused on their durability using polymer analysis; or they have focused on changes occurring during outdoor exposure. Herein, this study combines those strategies into one, by studying the chemical and physical changes in the polyethylene structure in a laboratory using molecular weight and IR spectroscopic mapping analysis, combined with temperate UV-accelerated weathering cycles. This approach has been correlated to real-world outdoor exposure timeframes by parallel testing of the sample polyethylene films in Florida and France. The formation of polyethylene microparticles or polyethylene waxes is elucidated through comparison of drop point testing and molecular weight analysis.

Exposure of Polymeric Glazing Materials Using NREL’s Ultra-Accelerated Weathering System (UAWs)

2010 ◽  
Author(s):  
Carl Bingham ◽  
Gary Jorgensen ◽  
Amy Wylie
Keyword(s):  
Light Intensity ◽  
Thermal Effects ◽  
Outdoor Exposure ◽  
Exposure Chamber ◽  
Accelerated Weathering ◽  
Intensity Level ◽  
Design And Implementation ◽  
Different Temperatures ◽  
Exposure Testing ◽  
Ultraviolet Irradiance

NREL’s Ultra-Accelerated Weathering System (UAWS) selectively reflects and concentrates natural sunlight ultraviolet irradiance below 475 nm onto exposed samples to provide accelerated weathering of materials while keeping samples within realistic temperature limits. This paper will explain the design and implementation of the UAWS which allow it to simulate the effect of years of weathering in weeks of exposure. Exposure chamber design and instrumentation will be discussed for both a prototype UAWS used to test glazing samples as well as a commercial version of UAWS. Candidate polymeric glazing materials have been subjected to accelerated exposure testing at a light intensity level of up to 50 UV suns for an equivalent outdoor exposure in Miami, FL exceeding 15 years. Samples include an impact modified acrylic, fiberglass, and polycarbonate having several thin UV-screening coatings. Concurrent exposure is carried out for identical sample sets at two different temperatures to allow thermal effects to be quantified along with resistance to UV.

Comparison of QUV accelerated weathering to outdoor exposure for PVC compounds

1991 ◽  
Vol 13 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Elvira B. Rabinovitch ◽  
Robert S. Butler
Keyword(s):  
Outdoor Exposure ◽  
Accelerated Weathering

scholarly journals Evaluation of the Impacts of Four Weathering Methods on Two Acrylic Paints: Showcasing Distinctions and Particularities

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 121 ◽  
Author(s):  
Antoine Cogulet ◽  
Pierre Blanchet ◽  
Véronic Landry
Keyword(s):  
Uv Radiation ◽  
Outdoor Exposure ◽  
Accelerated Weathering ◽  
Accurate Assessment ◽  
End Use ◽  
Weathering Resistance ◽  
Weathering Process ◽  
Acrylic Paints

Two commercial waterborne wood acrylic paints were applied to wood samples and the weathering resistance of samples was tested using four different weathering methods: outdoor exposure in Arizona (USA), Florida (USA), and the province of Quebec (Canada), and accelerated weathering in a QUV (fluorescent) weatherometer. Degradation was characterised by colorimetric and FTIR analyses. FTIR confirmed the importance of paint composition in the resistance of samples to weathering. Polymer sensitivity to UV radiation was clearly evident. An interpretation of discoloration in terms of either the energy received by the samples or the length of exposure is presented. Strong differences existed between the four weathering methods. Particularities of each method are discussed and recommendations regarding their application for effective testing are proposed. Overall, in addition to accelerated weathering tests, we conclude that it is necessary to test paints in an end-use environment for accurate assessment of their likely performance. This study confirms the multifactorial aspect of the weathering process.

Determination of substituent distribution of viscoses by GPC

Holzforschung ◽  
2006 ◽  
Vol 60 (5) ◽  
pp. 467-473 ◽  
Author(s):  
Axel Rußler ◽  
Antje Potthast ◽  
Thomas Rosenau ◽  
Thomas Lange ◽  
Bodo Saake ◽  
...  
Keyword(s):  
Enzymatic Degradation ◽  
Laser Light ◽  
Gel Permeation Chromatography ◽  
Narrow Molecular Weight Distribution ◽  
Substitution Pattern ◽  
Degradation Pattern ◽  
Long Time ◽  
Ultrasonic Degradation ◽  
Insight Into

Abstract Based on previous investigations on the substitution pattern of stabilized and fresh viscose, different viscoses were analyzed by gel permeation chromatography (GPC) with multiple-angle laser light scattering, refractive index (RI), and UV detection. Viscoses derivatized with N-methyl-N-phenyl-iodoacetanilide are stable over a long time and largely improve handling for analytical purposes. In addition, the derivatized xanthogenate groups exhibit UV absorbance that can be used to detect their distribution along the polymer molecule, once the polymer is dissolved. UV assay indicated that in technical viscoses the distribution of substituents is uniform. Enzymatic degradation with endoglucanases was followed by analysis of the degradation pattern by GPC. Even though the degree of substitution (DS) of xanthogenate groups ranged from γ=0.4 to 0.6, endoglucanases were able to slightly degrade the viscose. Ultrasonic degradation resulted in a narrow molecular weight distribution (MWD), notably without cleavage of substituents, and was also used to improve the solubility of the stabilized viscoses for further analysis. The techniques applied provide more insight into the xanthogenate distribution along the MWD. Remarkable differences in the degradation behavior of both viscose samples were observed.

Histolocalization and physico-chemical characterization of dihydrochalcones: Insight into the role of apple major flavonoids

2013 ◽  
Vol 90 ◽  
pp. 78-89 ◽  
Author(s):  
Matthieu Gaucher ◽  
Thomas Dugé de Bernonville ◽  
David Lohou ◽  
Sylvain Guyot ◽  
Thomas Guillemette ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Physico Chemical ◽  
Insight Into

Crystal structure of a major seed storage protein, 11S proglobulin, from Amaranthus hypochondriacus: Insight into its physico-chemical properties

2012 ◽  
Vol 135 (2) ◽  
pp. 819-826 ◽  
Author(s):  
Mary Rose Tandang-Silvas ◽  
Cerrone S. Cabanos ◽  
Laura Denisse Carrazco Peña ◽  
Ana Paulina Barba De La Rosa ◽  
Juan Alberto Osuna-Castro ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Storage Protein ◽  
Seed Storage Protein ◽  
Chemical Properties ◽  
Seed Storage ◽  
Amaranthus Hypochondriacus ◽  
Physico Chemical ◽  
Insight Into

Strategies for the reduction of Legionella in biological treatment systems

2016 ◽  
Vol 74 (4) ◽  
pp. 816-823 ◽  
Author(s):  
R. Nogueira ◽  
K.-U. Utecht ◽  
M. Exner ◽  
W. Verstraete ◽  
K.-H. Rosenwinkel
Keyword(s):  
Legionella Pneumophila ◽  
Biological Treatment ◽  
Municipal Wastewater ◽  
Cooling System ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Micro Particles ◽  
Treated Effluent ◽  
Wastewater Stream ◽  
Insight Into

A community-wide outbreak of Legionnaire's disease occurred in Warstein, Germany, in August 2013. The epidemic strain, Legionella pneumophila Serogruppe 1, was isolated from an industrial wastewater stream entering the municipal wastewater treatment plant (WWTP) in Wartein, the WWTP itself, the river Wäster and air/water samples from an industrial cooling system 3 km downstream of the WWTP. The present study investigated the effect of physical–chemical disinfection methods on the reduction of the concentration of Legionella in the biological treatment and in the treated effluent entering the river Wäster. Additionally, to gain insight into the factors that promote the growth of Legionella in biological systems, growth experiments were made with different substrates and temperatures. The dosage rates of silver micro-particles, hydrogen peroxide, chlorine dioxide and ozone and pH stress to the activated sludge were not able to decrease the number of culturable Legionella spp. in the effluent. Nevertheless, the UV treatment of secondary treated effluent reduced Legionella spp. on average by 1.6–3.4 log units. Laboratory-scale experiments and full-scale measurements suggested that the aerobic treatment of warm wastewater (30–35 °C) rich in organic nitrogen (protein) is a possible source of Legionella infection.

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