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miscible polymer blends (homogeneous polymer blends): Polymer blend that is a single-phase structure. In this case, one glass transition temperature will be observed. The use of the term polymer alloy for a polymer blend is discouraged, as the former term includes multiphase copolymers but excludes incompatible polymer blends. [3]
Novel polymeric alloy (NPA) is a polymeric alloy composed of polyolefin and thermoplastic engineering polymer with enhanced engineering properties. NPA was developed for use in geosynthetics . One of the first commercial NPA applications was in the manufacturer of polymeric strips used to form Neoloy® cellular confinement systems (geocells) .
These blends are automatically dosed with fixed setpoints usually through feeders/hoppers. It is mostly a blend of copolymers such as ABS , SAN , SMA etc. with additives such as anti-oxidants , UV-stabilizers and other value adding agents and sometimes a strengthening component is added such as glass fibre .
, where ΔS is the change in entropy of mixing, R is the gas constant, Φ is the volume fraction of each polymer, and x is the number of segments of each polymer. [3] x 1 and x 2 increase with higher degrees of polymerization and thus molecular weight. Since most useful polymers are high in molecular weight, the change in entropy experienced ...
Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator. The reaction results in a polymer which is also soluble in the chosen solvent. Heat released by the reaction is absorbed by the solvent, reducing the reaction rate.
Paul Flory was awarded the Nobel Prize in Chemistry in 1974 for his work on polymer random coil configurations in solution in the 1950s. Stephanie Kwolek developed an aramid, or aromatic nylon named Kevlar, patented in 1966. Karl Ziegler and Giulio Natta received a Nobel Prize for their discovery of catalysts for the polymerization of alkenes.
These may be liquid solutions (e.g. in aqueous solution), or solid solutions (e.g. a substance which has been plasticized). [2] The introduction into the polymer of small amounts of a solvent (plasticizer) reduces the temperature of glass transition, the yield temperature, and the viscosity of a melt.
Some polymer solutions also have a lower critical solution temperature (LCST) or lower bound to a temperature range of partial miscibility. As shown in the diagram, for polymer solutions the LCST is higher than the UCST, so that there is a temperature interval of complete miscibility, with partial miscibility at both higher and lower temperatures.