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The styrene monomer (from which polystyrene is made) is a cancer suspect agent. [109] Styrene is "generally found in such low levels in consumer products that risks aren't substantial". [110] Polystyrene which is used for food contact may not contain more than 1% (0.5% for fatty foods) of styrene by weight. [111]
Styrene is an organic compound with the chemical formula C 6 H 5 CH=CH 2.Its structure consists of a vinyl group as substituent on benzene.Styrene is a colorless, oily liquid, although aged samples can appear yellowish.
The mass-average molecular mass, M w, is also related to the fractional monomer conversion, p, in step-growth polymerization (for the simplest case of linear polymers formed from two monomers in equimolar quantities) as per Carothers' equation: ¯ = + ¯ = (+), where M o is the molecular mass of the repeating unit.
Another method of achieving the desired molecular weight is by addition of a small amount of monofunctional monomer, a monomer with only one functional group. The monofunctional monomer, often referred to as a chain stopper, controls and limits the polymerization of bifunctional monomers because the growing polymer yields chain ends devoid of ...
The degree of polymerization, or DP, is the number of monomeric units in a macromolecule or polymer or oligomer molecule. [1] [2] [3]For a homopolymer, there is only one type of monomeric unit and the number-average degree of polymerization is given by ¯ ¯ = ¯, where ¯ is the number-average molecular weight and is the molecular weight of the monomer unit.
Polystyrene sulfonic acid, the acid whose salts are the polystyrene sulfonates, has the idealized formula (CH 2 CHC 6 H 4 SO 3 H) n. The material is prepared by sulfonation of polystyrene: (CH 2 CHC 6 H 5) n + n SO 3 → (CH 2 CHC 6 H 4 SO 3 H) n. Several methods exist for this conversion, which can lead to varying degree of sulfonation.
SMA polymers with a high molecular weight are widely used in engineering plastic applications, normally in the impact modified and optional glass fibre filled variants. Alternatively, SMA is applied using its transparency in combination with other transparent materials like PMMA or the heat resistance to heat-boost other polymers materials like ...
The kinetic chain length v is a measure of the average number of monomer units reacting with an active center during its lifetime and is related to the molecular weight through the mechanism of the termination. Without chain transfer, the kinetic chain length is only a function of propagation rate and initiation rate.