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The retro appeal of old Bakelite products has made them collectible. [4] The creation of a synthetic plastic was revolutionary for the chemical industry, which at the time made most of its income from cloth dyes and explosives. Bakelite's commercial success inspired the industry to develop other synthetic plastics.
Phenol-formaldehyde resins, as a group, are formed by a step-growth polymerization reaction that can be either acid- or base-catalysed.Since formaldehyde exists predominantly in solution as a dynamic equilibrium of methylene glycol oligomers, the concentration of the reactive form of formaldehyde depends on temperature and pH.
The most commonly produced plastic consumer products include packaging made from LDPE (e.g. bags, containers, food packaging film), containers made from HDPE (e.g. milk bottles, shampoo bottles, ice cream tubs), and PET (e.g. bottles for water and other drinks). Together these products account for around 36% of plastics use in the world.
Nylon 11 is seen to have increased dimensional stability in the presence of moisture due to its low concentration of amides. Nylon 11 experiences 0.2-0.5% length variation and 1.9% weight variation after 25 weeks of submersion in water in comparison to 2.2-2.7% elongation variation and 9.5% weight variation for Nylon 6. [2]
Since 2008, Japan has increased plastic recycling, but still has a large amount of plastic wrapping which goes to waste. Plastic recycling in Japan is a potential US$90 billion market. [26] It is possible to rapidly convert polyethylene to hydrogen and graphene by heating. The energy needed is much less than for producing hydrogen by electrolysis.
Polyurethane synthesis, wherein the urethane groups −NH−(C=O)−O− link the molecular units A kitchen sponge made of polyurethane foam . Polyurethane (/ ˌ p ɒ l i ˈ jʊər ə ˌ θ eɪ n,-j ʊəˈr ɛ θ eɪ n /; [1] often abbreviated PUR and PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) links.
HDPE is known for its high strength-to-density ratio. [4] The density of HDPE ranges from 930 to 970 kg/m 3. [5] Although the density of HDPE is only marginally higher than that of low-density polyethylene, HDPE has little branching, giving it stronger intermolecular forces and tensile strength (38 MPa versus 21 MPa) than LDPE. [6]
Paper chemicals designate a group of chemicals that are used for paper manufacturing, or modify the properties of paper. These chemicals can be used to alter the paper in many ways, including changing its color and brightness, or by increasing its strength and resistance to water. [1] The chemicals can be defined on basis of their usage in the ...