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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 ...
[42] [43] For example, the chain-growth copolymer of vinyl chloride and vinyl acetate is random. [39] Block copolymers have long sequences of different monomer units. [39] [40] Polymers with two or three blocks of two distinct chemical species (e.g., A and B) are called diblock copolymers and triblock copolymers, respectively. Polymers with ...
If enough of the block copolymer molecules that make up a polymersome are cross-linked, the polymersome can be made into a transportable powder. [2] Polymersomes can be used to make an artificial cell if hemoglobin and other components are added. [13] [14] The first artificial cell was made by Thomas Chang. [15]
In addition, block copolymers can exist as many types, including triblock (A-B-A), alternating block (A-B-A-B-A-B), etc. Of these three types, block and gradient copolymers are commonly synthesized through living polymerizations, due to the ease of control living polymerization provides.
The stiff homopolymer PVAc, but mostly the softer copolymer, a combination of vinyl acetate and ethylene, vinyl acetate ethylene (VAE), is also used in paper coatings, paint and other industrial coatings, as a binder in nonwovens in glass fibers, sanitary napkins, filter paper and in textile finishing.
If the blend is made of two polymers, two glass transition temperatures will be observed. compatible polymer blends: Immiscible polymer blends that exhibit macroscopically uniform physical properties. The macroscopically uniform properties are usually caused by sufficiently strong interactions between the component polymers. [2]
Advanced polymerization techniques have been established for the preparation of covalent copolymers, however supramolecular copolymers are still in its infancy and is slowly progressing. In recent years, all plausible category of supramolecular copolymers such as random, alternating, block, blocky, or periodic has been demonstrated in a broad ...
Polyether block amide or PEBA is a thermoplastic elastomer (TPE). It is known under the tradename of PEBAX® ( Arkema ) and VESTAMID® E ( Evonik Industries ). It is a block copolymer obtained by polycondensation of a carboxylic acid polyamide ( PA6 , PA11 , PA12 ) with an alcohol termination polyether ( Polytetramethylene glycol PTMG), PEG ).