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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.
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 ...
As with other living radical polymerization techniques, RAFT allows chain extension of a polymer of one monomer with a second type of polymer to yield a block copolymer. In such a polymerisation, there is the additional challenge that the RAFT agent for the first monomer must also be suitable for the second monomer, making block ...
Polystyrene foam blows in the wind and floats on water due to its low specific gravity. It can have serious effects on the health of birds and marine animals that swallow significant quantities. [71] Juvenile rainbow trout exposed to polystyrene fragments show toxic effects in the form of substantial histomorphometrical changes. [72]
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.
Block copolymers can be made this way. RDRP allows for control of molecular weight and dispersity. However, this is very difficult to achieve and instead a pseudo-living polymerization occurs with only partial control of molecular weight and dispersity. [15] ATRP and RAFT are the main types of complete radical polymerization.
In addition, some carbon nanotube polymer is used for electronical devices. Controlled living chain-growth conjugated polymerization will also enable the synthesis of well-defined advanced structures, including block copolymers. Their industrial applications extend to water purification, biomedical devices and sensors. [11]
The composition and structural type of the copolymer depend on these reactivity ratios r 1 and r 2 according to the Mayo–Lewis equation, also called the copolymerization equation or copolymer equation, [7] [6] for the relative instantaneous rates of incorporation of the two monomers.