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Rubber Pollution
Rubber pollution, similar to plastic pollution, occurs in various environments, and originates from a variety of sources, ranging from the food industry processing chain to tire wear. Synthetic and natural rubber dust and fragments now occur in food, airborne as particulates in air pollution, hidden in the earth as soil pollution, and in waterways, lakes and the sea. Causes Tyre and road wear particles (TRWP) Vehicle tire wear is a major source of rubber pollution, other sources can be from artificial turf(usually made from shredded old tires) and rubber O-rings and seals. Tyre and road wear particles (TRWP) or tire wear particles (TWP) are a direct result of the road surface abrasion during vehicle transit and are thought to be released into the environment at a rate of 6 million tons year, with the United States and the European Union emitting roughly 1120,000 and 1327,000 tons annually. Both brand and season application affect the tire composition but rubber is usually t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Pollution
Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are categorized by size into micro-, meso-, or macro debris. Plastics are inexpensive and durable, making them very adaptable for different uses; as a result, manufacturers choose to use plastic over other materials. However, the chemical structure of most plastics renders them resistant to many natural processes of environmental degradation, degradation and as a result they are slow to degrade. Together, these two factors allow large volumes of plastic to enter the environment as mismanaged waste which persists in the ecosystem and travels throughout food webs. Plastic pollution can afflict land, waterways and oceans. It is estimated that 1.1 to 8.8'' ''million tonnes of plastic waste enters the ocean from coastal communities each year. It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five Territories of the United States, major island territories and United States Minor Outlying Islands, various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's List of countries and dependencies by area, third-largest land area and List of countries and dependencies by population, third-largest population, exceeding 340 million. Its three Metropolitan statistical areas by population, largest metropolitan areas are New York metropolitan area, New York, Greater Los Angeles, Los Angel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrofuramide
Hydrofuramide is a condensation product of three molar equivalents of furfural with two molar equivalents of ammonia. Hydrofuramide is a crystalline solid with a melting point of 118-119 °C. The molecule may be described as a diimine with three pendant furanyl rings. Hydrofuramide is a versatile specialty chemical with applications in diverse areas, including rubber additives, pharmaceutical intermediates, preservatives, and rodenticides. Synthesis Hydrofuramide was prepared in 1960 by Kapur via the reaction of furfural with aqueous ammonia in chilled ethanol solution. Reactions The reactive imine double bonds of hydrofuramide are easily reduced. Reduction with aqueous sodium borohydride yields ''N'',''N''-bisfurfuryl-2-furylmethanediamine, useful as an antihypertensive drug compound. Catalytic hydrogenation of hydrofuramide with Raney nickel in the presence of ammonia in ethanol yields mixtures of furfurylamine and difurfurylamine. By contrast, hydrogenation in aceti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonyl Sulfide
Carbonyl sulfide is the chemical compound with the linear formula . It is a colorless flammable gas with an unpleasant odor. It is a linear molecule consisting of a carbonyl double bonded to a sulfur atom. Carbonyl sulfide can be considered to be intermediate between carbon dioxide and carbon disulfide, both of which are valence isoelectronic with it. Occurrence Carbonyl sulfide is the most abundant sulfur compound naturally present in the atmosphere, at , because it is emitted from oceans, volcanoes and deep sea vents. As such, it is a significant compound in the global sulfur cycle. Measurements on the Antarctica ice cores and from air trapped in snow above glaciers ( firn air) have provided a detailed picture of OCS concentrations from 1640 to the present day and allow an understanding of the relative importance of anthropogenic and non-anthropogenic sources of this gas to the atmosphere. Some carbonyl sulfide that is transported into the stratospheric sulfate lay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiozonant
An antiozonant, also known as anti-ozonant, is an organic compound that prevents or retards damage caused by ozone. The most important antiozonants are those which prevent degradation of elastomers like rubber. A number of research projects study the application of another type of antiozonants to protect plants as well as salmonids that are affected by the chemicals. Effect of ozone Many elastomers are rich in unsaturated double bonds, which can react with ozone present in the air in process known as ozonolysis. This reaction breaks the polymer chains, degrading the mechanical properties of the material. The most obvious effect of this is cracking of the elastomer (ozone cracking), which is exacerbated by mechanical stress. The rate of degradation is effected both by the chemical structure of the elastomer and the amount of ozone in the environment. Elastomers which are rich in double bonds, such as natural rubber, polybutadiene, styrene-butadiene rubber and nitrile rubber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6PPD-quinone
6PPD is an organic chemical widely used as stabilising additive (or antidegradant) in rubbers, such as NR, SBR and BR; all of which are common in vehicle tires. Although it is an effective antioxidant it is primarily used because of its excellent antiozonant performance. It is one of several antiozonants based around ''p''-phenylenediamine. It has been used in rubber since the late 1970s, but has been the subject of increasing scrutiny since 2021, when it was determined that its oxidation product (6PPD-Q) causes pre-spawn mortality in coho salmon. Manufacturing 6PPD is prepared by reductive amination of methyl isobutyl ketone (which has six carbon atoms, hence the '6' in the name) with phenyl phenylenediamine (PPD). This produces a racemic mixture. Application 6PPD is a common rubber antiozonant found in vehicle tires. It is mobile within the rubber and slowly migrates to the surface via blooming. On the surface it forms a "scavenger-protective film" that reacts with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monomer
A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemistry classifies monomers by type, and two broad classes based on the type of polymer they form. By type: * natural vs synthetic, e.g. glycine vs caprolactam, respectively * polar vs nonpolar, e.g. vinyl acetate vs ethylene, respectively * cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively By type of polymer they form: * those that participate in condensation polymerization * those that participate in addition polymerization Differing stoichiometry causes each class to create its respective form of polymer. : The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compound (chemistry), compounds, produces unique physical property, physical properties including toughness, high rubber elasticity, elasticity, viscoelasticity, and a tendency to form Amorphous solid, amorphous and crystallization of polymers, semicrystalline structures rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microplastics
Microplastics are "synthetic solid particles or polymeric matrices, with regular or irregular shape and with size ranging from 1 μm to 5 mm, of either primary or secondary manufacturing origin, which are insoluble in water." Microplastics are dangerous to human health and the environment because they contain harmful chemicals which leak into the air, water, and food. Microplastics cause pollution by entering natural ecosystems from a variety of sources, including cosmetics, clothing, construction, renovation, food packaging, and industrial processes. The term ''microplastics'' is used to differentiate from larger, non-microscopic plastic waste. Two classifications of microplastics are currently recognized. Primary microplastics include any plastic fragments or particles that are already 5.0 mm in size or less before entering the environment. These include microfibers from clothing, microbeads, plastic glitter and plastic pellets (also known as nurdles). Seconda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Commission Joint Research Centre
The Joint Research Centre (JRC) is the European Commission's science and knowledge service which employs scientists to carry out research in order to provide independent scientific advice and support to European Union (EU) policy. Leadership The JRC is a directorate-general of the European Commission under the responsibility of Iliana Ivanova, the European Commissioner for Innovation, Research, Culture, Education and Youth. The current acting Director-General of the JRC is Bernard Magenhann. Its Board of Governors assists and advises the Director-General on matters relating to the role and the scientific, technical and financial management of the JRC. Structure Composed of strategy and coordination, knowledge production, knowledge management and support directorates, the JRC is spread across six sites in five EU countries: in Belgium (Brussels and Geel), Germany (Karlsruhe, Institute for Transuranium Elements), Italy (Ispra), the Netherlands (Petten), and Spain (Seville). T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road Debris
Road debris, a form of road hazard, is debris that accumulates on or off a road. Road debris includes substances, materials, and objects that are foreign to the normal roadway environment. Debris may be produced by vehicular or non-vehicular sources, although in all cases it is considered litter, a form of solid waste., AAA Foundation for Traffic Safety press release o"The Safety Impact of Vehicle-Related Road Debris" Gerry Forbes and John Robinson, June 2004 Debris may tend to collect in areas where vehicles do not drive, such as on the edges (shoulder), around traffic islands, and junctions. Road spray or tire kickup is road debris (usually liquid water) that has been kicked up, pushed out, or sprayed out from, a tire. In 2004, a AAA Foundation for Traffic Safety study revealed that vehicle-related road debris caused 25,000 accidents and nearly 100 deaths a year. Causes Road debris can be caused by various factors, including objects falling off vehicles or natural disaster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exhaust Gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack, or propelling nozzle. It often disperses downwind in a pattern called an ''exhaust plume''. It is a major component of motor vehicle emissions (and from stationary internal combustion engines), which can also include crankcase blow-by and evaporation of unused gasoline. Air pollution from burning fossil fuels is estimated to kill over 5 million people each year. Motor vehicle emissions are a common source of air pollution and are a major ingredient in the creation of smog in some large cities. Composition The largest part of most combustion gas is nitrogen (N2), water vapor (H2O) (except with pure-carbon fuels), and carbon dioxide (CO2) (except for fuels without carbon); these are not toxic or noxiou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
