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Kraton polymers are styrenic block copolymer (SBC) consisting of polystyrene blocks and rubber blocks. The rubber blocks consist of polybutadiene, polyisoprene, or their hydrogenated equivalents. The tri-block with polystyrene blocks at both extremities linked together by a rubber block is the most important polymer structure observed in SBC.
In polymer chemistry, free-radical polymerization (FRP) is a method of polymerization by which a polymer forms by the successive addition of free-radical building blocks (repeat units). Free radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules .
Living polymerization is a popular method for synthesizing block copolymers since the polymer can be synthesized in stages, each stage containing a different monomer. Additional advantages are predetermined molar mass and control over end-groups .
block copolymer: A copolymer that is a block polymer. In the constituent macromolecules of a block copolymer , adjacent blocks are constitutionally different, i.e. adjacent blocks comprise constitutional unit derived from different species of monomer or from the same species of monomer but with a different composition or sequence distribution ...
In one copolymer, the monomers can be almost perfectly alternating. [1] but (random) copolymerisation with less than 50% maleic anhydride content is also possible. [2] The polymer is formed by a radical polymerization, using an organic peroxide as the initiator. The main characteristics of SMA copolymer are its transparent appearance, high heat ...
Preparation of block copolymers by iodine-transfer polymerization was also described by Tatemoto and coworkers in the 1970s. [11] Although use of living free radical processes in emulsion polymerization has been characterized as difficult, [12] all examples of iodine-transfer polymerization have involved emulsion polymerization. Extremely high ...
Today's NYT Connections puzzle for Friday, December 13, 2024The New York Times
Graft copolymers are a branched copolymer where the components of the side chain are structurally different than that of the main chain. Graft copolymers containing a larger quantity of side chains are capable of wormlike conformation, compact molecular dimension, and notable chain end effects due to their confined and tight fit structures. [1]