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Living polymerization: A chain polymerization from which chain transfer and chain termination are absent. Note : In many cases, the rate of chain initiation is fast compared with the rate of chain propagation, so that the number of kinetic-chain carriers is essentially constant throughout the polymerization.
Living cationic polymerization is a living polymerization technique involving cationic propagating species. [1] [2] It enables the synthesis of very well defined polymers (low molar mass distribution) and of polymers with unusual architecture such as star polymers and block copolymers and living cationic polymerization is therefore as such of commercial and academic interest.
Using a compound with multiple dithio moieties (often termed a multifunctional RAFT agent) can result in the formation of star, brush and comb polymers. Taking star polymers as an example, RAFT differs from other forms of living radical polymerization techniques in that either the R- or Z-group may form the core of the star (See Figure 10).
Living polymerization is often used for making pH sensitive polymers because molecular weight distribution of the final polymers can be controlled. Examples include group transfer polymerization (GTP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (RAFT). [1]
Living free radical polymerization is a type of living polymerization where the active polymer chain end is a free radical. Several methods exist. 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.
Polysaccharides are linear or branched chains of sugar carbohydrates; examples include starch, cellulose, and alginate. Other examples of biopolymers include natural rubbers (polymers of isoprene), suberin and lignin (complex polyphenolic polymers), cutin and cutan (complex polymers of long-chain fatty acids), melanin, and polyhydroxyalkanoates ...
Animals found living underground near deep-sea hydrothermal vents. Will Dunham. October 17, 2024 at 10:29 AM. ... in an example of connectivity between the seafloor and underground ecosystems.
A special case of chain-growth polymerization leads to living polymerization. Ziegler–Natta polymerization allows considerable control of polymer branching. Polymerization of ethylene. Diverse methods are employed to manipulate the initiation, propagation, and termination rates during chain polymerization.