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Branch point in a polymer. Polymer architecture in polymer science relates to the way branching leads to a deviation from a strictly linear polymer chain. [1] Branching may occur randomly or reactions may be designed so that specific architectures are targeted. [1] It is an important microstructural feature.
The steady-state concentration of the growing polymer chains is 10 −7 M by order of magnitude, and the average life time of an individual polymer radical before termination is about 5–10 s. A drawback of the conventional radical polymerization is the limited control of chain architecture, molecular weight distribution, and composition.
Living free radical polymerization is a type of living polymerization where the active polymer chain end is a free radical.Several methods exist. IUPAC recommends [1] to use the term "reversible-deactivation radical polymerization" instead of "living free radical polymerization", though the two terms are not synonymous.
An important microstructural feature of a polymer is its architecture and shape, which relates to the way branch points lead to a deviation from a simple linear chain. [25] A branched polymer molecule is composed of a main chain with one or more substituent side chains or branches.
Main RAFT equilibrium: This is the most important part in the RAFT process, [8] in which, by a process of rapid interchange, the present radicals (and hence opportunities for polymer chain growth) are "shared" among all species that have not yet undergone termination (P n • and S=C(Z)S-P n). Ideally the radicals are shared equally, causing ...
In polymer chemistry, branching is the regular or irregular attachment of side chains to a polymer's backbone chain. It occurs by the replacement of a substituent (e.g. a hydrogen atom ) on a monomer subunit by another covalently-bonded chain of that polymer; or, in the case of a graft copolymer , by a chain of another type.
In polymer chemistry, chain transfer is a polymerization reaction by which the activity of a growing polymer chain is transferred to another molecule: [1] [2] + + where • is the active center, P is the initial polymer chain, X is the end group, and R is the substituent to which the active center is transferred.
It provides increased control of molecular weight, molecular architecture and polymer composition while maintaining a low polydispersity (1.05-1.2). The halogen remaining at the end of the polymer chain after polymerization allows for facile post-polymerization chain-end modification into different reactive functional groups.