Review
Polymer Science
Norman S. Allen, Michele Edge, Sajid Hussain
Summary: Discolouration or yellowing phenomenon is a significant concern in the formulation, processing, and post-use of polymer materials. It can limit the acceptance of polymer applications in various products, such as clear films, bottles, white goods, and recycling processes. The yellowing can be attributed to additives, particularly phenolic/amine antioxidants, or inherent properties of polymers, such as polyesters, polycarbonates, epoxy-amines, and polystyrene. Overcoming this issue in industrial applications can be challenging. The article discusses the chemistry behind yellowing and presents effective modes of stabilization and inhibition, including unconventional examples and structural developments for optimizing additive performance. Chemical treatment processes using polyglycols and chemical reducing agents are also presented as potential solutions. The aim is to provide a clearer understanding of the chemistries involved in yellowing and offer insights for resolving potential issues in polymer manufacture and processing.
POLYMER DEGRADATION AND STABILITY
(2022)
Article
Food Science & Technology
Kanyasiri Rakariyatham, Dayong Zhou, Ting Lu, Fawen Yin, Zhuoliang Yu, Deyang Li, Yan Shen, Beiwei Zhu
Summary: A combination of longan peel extract, vitamin E, and ascorbyl palmitate showed synergistic effects against lipid oxidation in refined tuna oil, significantly increasing induction period and decreasing peroxide value, conjugated dienes, and thiobarbituric acid reactive substances. This combination also maintained levels of polyunsaturated fatty acids comparable to a synthetic antioxidant and resulted in a synergistic decrease of free radicals in the oil, enhancing the protective effects against lipid oxidation.
LWT-FOOD SCIENCE AND TECHNOLOGY
(2021)
Article
Polymer Science
Barbara Abaroa-Perez, Sara Ortiz-Montosa, Jose Joaquin Hernandez-Brito, Daura Vega-Moreno
Summary: This study evaluated and quantified the degradation state of marine microplastic polyethylene pellets with different aging stages using YI determination and FTIR spectrum analysis. A color palette related to microplastic color and YI was developed for visual percentage representation, and the relationship with the adsorption rate of persistent organic pollutants on the microplastic surface was determined.
Review
Materials Science, Multidisciplinary
Valentina Marturano, Angela Marotta, Sarai Agustin Salazar, Veronica Ambrogi, Pierfrancesco Cerruti
Summary: In recent years, there has been increasing global concern about the depletion of fossil fuels and the environmental impact of oil-based compounds, which has led to the development of more sustainable approaches in the development of polymer-based materials. The replacement of synthetic additives with natural compounds in polymer commodities is gradually taking place, and the production of bio-plastics is predicted to grow exponentially. However, these materials may have limitations in terms of processability and end-use, prompting academic and industrial communities to focus on fully bio-based formulations with improved performance and tailored for specific applications.
PROGRESS IN MATERIALS SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Abdessamie Kellil, Spyros Grigorakis, Sofia Loupassaki, Dimitris P. Makris
Summary: This study focused on investigating the thermal decomposition of Quercetin (Qt) and the impacts of antioxidants on its degradation. An empirical sigmoidal model was proposed to trace degradation kinetics, and degradation pathways were analyzed through liquid chromatography-tandem mass spectrometry. Antioxidants were found to retard Qt degradation in a manner dependent on Qt/antioxidant molar ratio, with consistent degradation products identified. The study demonstrated the detrimental effects of heating on Qt and proposed a model that could be useful for interpreting the degradation behavior of other polyphenols.
APPLIED SCIENCES-BASEL
(2021)
Article
Polymer Science
Adchara Padermshoke, Tomoko Kajiwara, Yingjun An, Mamiko Takigawa, Toan Van Nguyen, Hiroyasu Masunaga, Yutaka Kobayashi, Hiroshi Ito, Sono Sasaki, Atsushi Takahara
Summary: This study investigates the effects of oxo-biodegradable additives on the photo-oxidation of four types of polyolefin polymers. The results suggest that the additives promote the photo-oxidative degradation of the polymers, particularly PE polymers. Among the additive-containing polymers, itPP exhibits the highest degradation rate, while HDPE has the slowest.
Article
Materials Science, Characterization & Testing
Clement Freymond, Alain Guinault, Carole Charbuillet, Bruno Fayolle
Summary: The thermal degradation of post-consumed ABS/HIPS and PP/PE blends from waste electrical and electronic equipment was investigated by multiple extrusions for recycling purposes. The molar mass, melt flow index, and ultimate elongation of the recycled blends were evaluated as a function of extrusion cycles. The results revealed a similar degradation mechanism for both ABS/HIPS and PP/PE blends, with ABS/HIPS exhibiting higher thermomechanical resistance. An innovative embrittlement criterion based on MFI measurements was proposed for the analysis of post-consumed polymer blends.
Article
Engineering, Chemical
Jiajie Xu, Changyu Yan, Zhaojiang Wu, Miaoling Xu, Tuo Wei, Tingchao He, Wenhua Zhou, Yi Zhang, Junmin Zhang, Bo Yang
Summary: In this study, a synergistic reduction-oxidation process using natural organic matters (NOMs) as an organic photocatalyst was proposed for complete degradation of nitrobenzene. The results showed that 4,7-dihydroxycoumarin (4,7-DHC) could generate both reductive organic free radicals and oxidative OH radicals sustainably under UV light irradiation, leading to high NB degradation efficiency. Moreover, 4,7-DHC showed high photocatalytic activity at a wide range of pH values and exhibited extensive degradability to coexisted pollutants in NB-contaminated wastewater.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Article
Engineering, Chemical
Xin Liu, Yi Li, Mengyuan Li, Na Xie, Junfeng Zhang, Yanzhou Qin, Yan Yin, Michael D. Guiver
Summary: The introduction of ferrocyanide-ferricyanide (Fc (II)-Fc (III)) redox cycle has been found to significantly enhance the chemical stability of proton exchange membranes (PEMs), leading to improved durability and longevity in proton exchange membrane fuel cells (PEMFCs). Additionally, the incorporation of Fc (II)/Fc (III) species not only enhances the performance of composite membranes, but also increases proton sites, thereby improving conductivity and power output.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Polymer Science
Muriel Ferry, Floriane Carpentier, Manon Cornaton
Summary: Understanding the aging mechanism of cable insulating materials is crucial for predicting their end-of-life and timely replacement in the context of nuclear power plant lifetime extension. Different formulated crosslinked polyethylenes have been irradiated under oxidative conditions to quantify gases emitted and consumed, revealing the primary processes and interactions involved between molecules in the materials.
Article
Green & Sustainable Science & Technology
Chi Hou Lau, Suyin Gan, Harrison Lik Nang Lau, Lai Yee Lee, Suchithra Thangalazhy-Gopakumar, Hoon Kiat Ng
Summary: This review discusses the use of natural and synthetic additives in biodiesel. Due to the complexity and lack of research, the application of natural antioxidants in biodiesel remains uncertain. Purification and profiling of natural antioxidants, as well as further studies on their oxidation mechanisms and environmental impacts, will provide better guidance for manufacturers and end-users.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Agriculture, Multidisciplinary
Josafat A. Hernandez-Becerra, Angelica A. Ochoa-Flores, Maria T. Rodriguez-Estrada, Hugo S. Garcia
Summary: The addition of antioxidants, BHT and TBHQ, to cooked shrimp significantly inhibited the formation of cholesterol oxidation products (COPs) and astaxanthin degradation during solar drying. The antioxidants reduced COPs formation and protected astaxanthin, leading to a product with higher astaxanthin content and lower presence of hazardous COPs.
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
(2023)
Article
Chemistry, Multidisciplinary
Igor D. D. Borges, Eduardo C. M. Faria, Jean F. M. Custodio, Vitor S. S. Duarte, Fernanda S. S. Fernandes, Christian G. G. Alonso, Flavio O. Sanches-Neto, Valter H. H. Carvalho-Silva, Guilherme R. R. Oliveira, Hamilton B. B. Napolitano
Summary: Biodiesel production is a promising strategy to reduce diesel consumption and contribute to climate change, but its stability remains a challenging issue. Organic additives are being investigated to improve stability and reduce harmful emissions, with this study focusing on the stability of B15 and the potential of antioxidants as additives for diesel-biodiesel blends. Using a machine learning computational platform, a systematic description of oxidation stability was conducted.
Article
Chemistry, Applied
Norman S. Allen, Michele Edge
Summary: This article discusses the importance of antioxidants, light stabilizers, processing aids, and fillers/pigments in polymer systems and their interactions. It emphasizes the synergism and antagonism in performances and color problems, with a special focus on PVC. The use of filled polymers leads to complex additive interactions, resulting in extreme outcomes.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2021)
Article
Environmental Sciences
Ting Wang, Taobo Huang, Huan Jiang, Ruoqi Ma
Summary: This study explored the reaction pathway of atrazine degradation by BDD electrode through compound-specific isotope fractionation analysis, revealing a significant correlation between H-2 and C-13 isotope fractionation. Radical quenching identified that ·OH radicals played a dominant role in the overall degradation reaction.
Article
Chemistry, Applied
Norman S. Allen, Michele Edge
Summary: This article discusses the importance of antioxidants, light stabilizers, processing aids, and fillers/pigments in polymer systems and their interactions. It emphasizes the synergism and antagonism in performances and color problems, with a special focus on PVC. The use of filled polymers leads to complex additive interactions, resulting in extreme outcomes.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2021)
Article
Chemistry, Applied
Norman S. Allen, Andrew P. Jones, Christopher M. Liauw, Michele Edge, Klaus Keck-Antoine, Joeng-Ho Yeo
Summary: The study found that a 20:80 phenol:thioester ratio provided the best long-term thermal stability (LTTS), with the reverse effect seen for processing stabilization (80:20), highlighting the antioxidant nature of the two stabilizers. Preblending the stabilizers to form a no-dust blend improved LTTS, indicating better additive dispersion and removal of volatile impurities. In high-temperature applications like under the bonnet of automobiles, minimizing stabilizer losses and maximizing synergy are important considerations for the long-term stabilization of polypropylene.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2021)
Article
Chemistry, Applied
Norman S. Allen, Andrew P. Jones, Christopher M. Liauw, Michele Edge, Klaus Keck-Antoine, Joeng-Ho Yeo
Summary: The study found that a 20:80 phenol:thioester ratio provided the best long-term thermal stability for polypropylene, and further investigated the incorporation of high surface area inorganic substrates to limit stabilizer mobility and enhance stability. The results showed potential improvements in long-term stabilization of polypropylene and highlighted the importance of minimizing stabilizer losses and maximizing synergy in high-temperature applications.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2021)
Article
Chemistry, Applied
Norman S. Allen, Christopher M. Liauw, Michele Edge, Eric Hoang, Eusebio Fontan
Summary: This study examined the degradation and stabilization of a variety of polyethylenes during multiple extrusions, revealing crosslinking reactions in HDPE and LLDPE initiated at unsaturated groups. Stabilizer packages effectively inhibited carbonyl growth, but did not prevent MFI changes due to crosslinking reactions, except for one LLDPE variant.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2022)
Article
Chemistry, Applied
Norman S. Allen, Michele Edge, Sajid Hussain
Summary: The study evaluated the optimal synergistic melt blending of 18 antioxidants and light stabilizers using differential scanning calorimetry (DSC) analysis. Only three systems showed true eutectic mixtures, but effective lower temperature melt blends were still possible up to 230 degrees C. The presence of strong eutectic behavior was often associated with specific interactions between additives, affecting the overall efficacy of the melt blends.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2022)
Article
Chemistry, Applied
Norman S. Allen, Michele Edge, Claire Hill, Julie Maltby Kerrod
Summary: The UV-Vis absorption properties of a range of nano-particle titanium dioxides can be optimized through different calcination and wet milling methodologies, with TiO2 particles with a crystallite size of 25 nm demonstrating the best properties. UV/visible absorption spectroscopy is sensitive to particle size and is a useful tool for assessing nano-TiO2 dispersions.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2022)
Article
Chemistry, Organic
Sajid Hussain, Norman S. Allen
Summary: This study describes the synthesis of functionalized C60 and novel fullerene polymers using pyrrolidine substitution. The addition of azomethine ylide was found to be a versatile method for the derivatization of [60]fullerene. Low molecular weight hydroxy fulleropyrrolidines were prepared through the cycloaddition of azomethine ylide to [60]fullerene using N-methyl glycine and benzaldehyde derivatives. The resulting fulleropyrrolidine monomer could be polymerized using benzoyl peroxide as an initiator.
Article
Chemistry, Organic
Sajid Hussain, Norman S. Allen
Summary: This paper describes the synthesis of crosslinked and branched chain C60 polymers to increase the amount of C60 content and molecular weight in the polymer. The method involved the preparation of fulleropyrrolidines through a [3+2] cycloaddition reaction and the synthesis of various types of fullerene polymers using fulleropyrrolidine acrylic monomers. The study found that the cycloaddition process was a powerful tool for fullerene functionalization, resulting in stable cycloadducts. The addition of azomethine ylide provided a versatile method for the derivatization of [60] fullerene.
Article
Chemistry, Applied
Norman S. Allen, Karmele del Teso Sanchez, Michele Edge, Christopher M. Liauw, Sajid Hussain, Keith Hall
Summary: Different polymerization catalyst systems have a significant impact on the production of extractable thermo-oxidative degradation products during melt processing cycles. These products include volatile organoleptic components such as hydrocarbons, alcohols, aldehydes, ketones, and carboxylic acids. The identification of these components is important for quality modification and determining toxicity and leachability with food products.
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
(2023)