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UHMWPE is polyethylene with a molecular weight numbering in the millions, usually between 3.5 and 7.5 million amu. [25] The high molecular weight makes it a very tough material, but results in less efficient packing of the chains into the crystal structure as evidenced by densities of less than high-density polyethylene (for example, 0.930–0. ...
Consider the example of polyethylene terephthalate (PET or "polyester"). The monomers which could be used to create this polymer are ethylene glycol and terephthalic acid: HO-CH 2-CH 2-OH and HOOC-C 6 H 4-COOH In the polymer, there are two structural units, which are -O-CH 2-CH 2-O- and -CO-C 6 H 4-CO- The repeat unit is -CH 2-CH 2-O-CO-C 6 H 4 ...
Epoxide monomers may be cross linked with themselves, or with the addition of a co-reactant, to form epoxy; BPA is the monomer precursor for polycarbonate; Terephthalic acid is a comonomer that, with ethylene glycol, forms polyethylene terephthalate. Dimethylsilicon dichloride is a monomer that, upon hydrolysis, gives polydimethylsiloxane.
Polyethylene terephthalate, even though produced from two different monomers (ethylene glycol and terephthalic acid), is usually regarded as a homopolymer because only one type of repeat unit is formed. Ethylene-vinyl acetate contains more than one variety of repeat unit and is a
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]
In place of the monomer name used in source-based nomenclature, structure-based nomenclature uses that of the "preferred constitutional repeating unit" (CRU). [9] It can be determined as follows: A large enough part of the polymer chain is drawn to show the structural repetition.
Other monomer units, such as formaldehyde hydrates or simple aldehydes, are able to polymerize themselves at quite low temperatures (ca. −80 °C) to form trimers; [3] molecules consisting of 3 monomer units, which can cyclize to form ring cyclic structures, or undergo further reactions to form tetramers, [3] or 4 monomer-unit compounds.
1-octene. Octene is an alkene with the formula C 8 H 16.Several isomers of octene are known, depending on the position and the geometry of the double bond in the carbon chain.. The simplest isomer is 1-octene, an alpha-olefin used primarily as a co-monomer in production of polyethylene via the solution polymerization process.