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Vulcanization is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to include the hardening of other (synthetic) rubbers via various means. Examples include silicone rubber via room temperature vulcanizing and chloroprene rubber (neoprene) using metal oxides.
Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition. Polymers and particularly plastics are subject to degradation at all stages of their product life cycle, including during their initial processing, use, disposal into the environment and recycling. The rate of this degradation varies significantly; biodegradation can take decades, whereas some industrial processes can completely decompose a polymer in hours.
EPDM rubber is a type of synthetic rubber that is used in many applications. Dienes used in the manufacture of EPDM rubbers are ethylidene norbornene (ENB), dicyclopentadiene (DCPD), and vinyl norbornene (VNB). 4-8% of these monomers are typically used.
Autoxidation refers to oxidations brought about by reactions with oxygen at normal temperatures, without the intervention of flame or electric spark. The term is usually used to describe the gradual degradation of organic compounds in air at ambient temperatures. Many common phenomena can be attributed to autoxidation, such as food going rancid, the 'drying' of varnishes and paints, and the perishing of rubber. It is also an important concept in both industrial chemistry and biology. Autoxidation is therefore a fairly broad term and can encompass examples of photooxygenation and catalytic oxidation.
FKM is a family of fluorocarbon-based fluoroelastomer materials defined by ASTM International standard D1418, and ISO standard 1629. It is commonly called fluorine rubber or fluoro-rubber. FKM is an abbreviation of Fluorine Kautschuk Material. All FKMs contain vinylidene fluoride as a monomer. Originally developed by DuPont, FKMs are today also produced by many companies, including: Daikin (Dai-El), 3M (Dyneon), Solvay S.A. (Tecnoflon), HaloPolymer (Elaftor), Gujarat Fluorochemicals (Fluonox), and several Chinese manufacturers. Fluoroelastomers are more expensive than neoprene or nitrile rubber elastomers. They provide additional heat and chemical resistance. FKMs can be divided into different classes on the basis of either their chemical composition, their fluorine content, or their cross-linking mechanism.
A geomembrane is very low permeability synthetic membrane liner or barrier used with any geotechnical engineering related material so as to control fluid migration in a human-made project, structure, or system. Geomembranes are made from relatively thin continuous polymeric sheets, but they can also be made from the impregnation of geotextiles with asphalt, elastomer or polymer sprays, or as multilayered bitumen geocomposites. Continuous polymer sheet geomembranes are, by far, the most common.
In polymers, such as plastics, thermal degradation refers to a type of polymer degradation where damaging chemical changes take place at elevated temperatures, without the simultaneous involvement of other compounds such as oxygen. Simply put, even in the absence of air, polymers will begin to degrade if heated high enough. It is distinct from thermal-oxidation, which can usually take place at less elevated temperatures.
Polymer stabilizers are chemical additives which may be added to polymeric materials, such as plastics and rubbers, to inhibit or retard their degradation. Common polymer degradation processes include oxidation, UV-damage, thermal degradation, ozonolysis, combinations thereof such as photo-oxidation, as well as reactions with catalyst residues, dyes, or impurities. All of these degrade the polymer at a chemical level, via chain scission, uncontrolled recombination and cross-linking, which adversely affects many key properties such as strength, malleability, appearance and colour.
In polymer chemistry photo-oxidation is the degradation of a polymer surface due to the combined action of light and oxygen. It is the most significant factor in the weathering of plastics. Photo-oxidation causes the polymer chains to break, resulting in the material becoming increasingly brittle. This leads to mechanical failure and, at an advanced stage, the formation of microplastics. In textiles the process is called phototendering.
Oxo-biodegradation is a process of plastic degradation utilizing oxidation to reduce the molecular weight of plastic, rendering the material accessible to bacterial and fungal decomposition. To change the Molecular structure in order to break down under sunlight, the plastic can be broken down and eaten by microorganisms. Oxo-biodegradable plastics- composed of polymers such as polyethylene (PE) or polypropylene (PP) -contain a prodegradant catalyst, typically a salt of manganese or iron.
Biodegradable additives are additives that enhance the biodegradation of polymers by allowing microorganisms to utilize the carbon within the polymer chain as a source of energy. Biodegradable additives attract microorganisms to the polymer through quorum sensing after biofilm creation on the plastic product. Additives are generally in masterbatch formation that use carrier resins such as polyethylene (PE), polypropylene (PP), polystyrene (PS) or polyethylene terephthalate (PET).
The Charles Goodyear Medal is the highest honor conferred by the American Chemical Society, Rubber Division. Established in 1941, the award is named after Charles Goodyear, the discoverer of vulcanization, and consists of a gold medal, a framed certificate and prize money. The medal honors individuals for "outstanding invention, innovation, or development which has resulted in a significant change or contribution to the nature of the rubber industry". Awardees give a lecture at an ACS Rubber Division meeting, and publish a review of their work in the society's scientific journal Rubber Chemistry and Technology.
The Melvin Mooney Distinguished Technology Award is a professional award conferred by the American Chemical Society, Rubber Division. Established in 1983, the award is named after Melvin Mooney, developer of the Mooney viscometer and of the Mooney-Rivlin hyperelastic law. The award consists of an engraved plaque and prize money. The medal honors individuals "who have exhibited exceptional technical competency by making significant and repeated contributions to rubber science and technology".
Dr. J. Reid Shelton was a professor of chemistry at Case Western University in Cleveland, Ohio. He is known for his work on oxidation and antioxidants in rubber, and for his application of laser-Raman spectroscopy to the study of sulfur vulcanization. His research on synthetic rubber was particularly important during World War II, when access to natural rubber in Southeast Asia was cut off by the Japanese, and the new SR made from styrene and butadiene displayed stability problems.
Conservation and restoration of objects made from plastics is work dedicated to the conservation of objects of historical and personal value made from plastics. When applied to cultural heritage, this activity is generally undertaken by a conservator-restorer.
Russell A. Livigni is a rubber industry scientist and executive noted for his discovery and development of high trans styrene-butadiene rubber, a crystallizing rubber that provides superior oxidation resistance relative to natural rubber.
Charles Michael Roland was Head of the Polymer Physics Section at the Naval Research Lab in Washington DC from 1989 to 2015. His research was concerned primarily with the dynamics of condensed matter, including polymers and liquid crystals, with applications to military armor and infrastructure protection. He is noted for his development of elastomeric coatings for blast protection, and for diverse accomplishments in the field of elastomer science. From 1991-1999, he served as the 8th editor of the scientific journal Rubber Chemistry and Technology, and a Fellow of the American Physical Society and the Institute of Materials, Minerals, and Mining (UK).
Aubert Y. Coran (1932-2020) was an American scientist noted for his contributions to thermoplastic elastomers and vulcanization chemistry of rubber. In 1983, he won the Melvin Mooney Distinguished Technology Award, bestowed by the American Chemical Society to individuals "who have exhibited exceptional technical competency by making significant and repeated contributions to rubber science and technology". In 1995, the rubber division of the American Chemical Society bestowed on Coran the Charles Goodyear Medal in honor of his international contributions to polymer science and development.
N-Isopropyl-N′-phenyl-1,4-phenylenediamine (often abbreviated IPPD) is an organic compound commonly used as an antiozonant in rubbers. Like other p-phenylenediamine-based antiozonants it works by virtue of its low ionization energy, which allows it to react with ozone faster than ozone will react with rubber. This reaction converts it to the corresponding aminoxyl radical (R2N–O•), with the ozone being converted to a hydroperoxyl radical (HOO•), these species can then be scavenged by other antioxidant polymer stabilizers.
Shingo Futamura is a rubber industry materials scientist noted for his concept of the deformation index.
References
- ↑ LACY, WHITNEY. "Ken Gillen earns lifetime achievement award". Sandia.gov. United States Government. Retrieved 3 August 2022.
- ↑ "Kenneth T. Gillen wins 2020 Melvin Mooney Distinguished Technology Award". badgerchemistnews.chem.wisc.edu/. U Wisconsin Madison. Retrieved 25 January 2023.
- ↑ Celina, M.; Gillen, K. T.; Assink, R. A. (December 2005). "Accelerated aging and lifetime prediction: Review of non-Arrhenius behaviour due to two competing processes". Polymer Degradation and Stability. 90 (3): 395–404. doi:10.1016/j.polymdegradstab.2005.05.004 . Retrieved 25 January 2023.
- ↑ Gillen, KT; Celina, M; Clough, RL; Wise, J (1997). "Extrapolation of Accelerated Aging Data - Arrhenius or Erroneous?". Trends in Polymer Science. 5 (8): 250–257. Retrieved 25 January 2023.
- ↑ Gillen, KT; Terrill, ER; Winter, RM (2001). "Modulus Mapping of Rubbers Using Micro- and Nano-Indentation Techniques". Rubber Chemistry and Technology. 74 (3): 428–450. doi:10.5254/1.3547646 . Retrieved 25 January 2023.
- ↑ Rappe, Mollie. "Burning Rubber". sandia.gov. Sandia National Laboratories. Retrieved 25 January 2023.
- ↑ Duhlev, Rumen (2007). "Publisher's Note". Polymer Degradation and Stability. 92 (1): 1. doi: 10.1016/j.polymdegradstab.2006.10.001 . Retrieved 25 January 2023.
- ↑ "Rubber Division names top award winners for 2020". Rubber and Plastics News. Crain. 8 October 2019. Retrieved 25 January 2023.