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Plastics degrade by a variety of processes, the most significant of which is usually photo-oxidation. Their chemical structure determines their fate. Polymers' marine degradation takes much longer as a result of the saline environment and cooling effect of the sea, contributing to the persistence of plastic debris in certain environments. [57]
The properties of polyethylene depend strongly on type. The molecular weight, crosslinking, and presence of comonomers all strongly affect its properties. It is for this structure-property relation that intense effort has been invested into diverse kinds of PE. [7] [19] LDPE is softer and more transparent than HDPE. For medium- and high-density ...
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.
Alpha-olefins such as 1-hexene may be used as co-monomers to give an alkyl branched polymer (see chemical structure below), although 1-decene is most commonly used for lubricant base stocks. [8] 1-hexene, an example of an alpha-olefin. Many poly-alpha-olefins have flexible alkyl branching groups on every other carbon of their polymer backbone ...
LDPE has SPI resin ID code 4 Schematic of LDPE branching structure. Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene.It was the first grade of polyethylene, produced in 1933 by John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. [1]
Polyoxymethylene was discovered by Hermann Staudinger, a German chemist who received the 1953 Nobel Prize in Chemistry. [7] He had studied the polymerization and structure of POM in the 1920s while researching macromolecules, which he characterized as polymers.
Polymer chemistry is a sub-discipline of chemistry that focuses on the structures, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry , analytical ...
Polyetherimide (PEI; branded as Ultem [1]) is an amorphous, amber-to-transparent thermoplastic with characteristics similar to the related plastic PEEK.When comparing PEI to PEEK, the former is cheaper but has lower impact strength and a tighter temperature range.