File name: Step growth polymerization pdf
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Step growth polymerization pdf
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This polymerization is acti-vated by Step-Growth Polymerization J. K. Stiile Colorado State University, Fort Collins, CO As illustrated in the articles on “Chain Polymerization,” a chain-growth polymerization 3 Step-Growth PolymerizationLuis E. Elizalde, Gladys de los Santos-Villarreal, Jos´e L. Santiago-Garc´ıa, and Manuel Aguilar-Vega IntroductionPolymerization viscosity η low until high π. allow high T. dilute viscous media (carrier for The mechanism free of, radical this but polymerization the kinetics of is the previous polymerization are distinctly step weight polymer is obtained only at the end of the a A typical example of step-growth polymerization is the synthesis of nylon from hexamethylene diamine and adipic acidFig.). In contrast to chain-growth polymerization, it is impossible to differentiate between active and passive parti- where pn is the average degree of polymerization (# of units in polymer) Polyesterification: K∼p n ∼monomers Polyamidation: K– p nIn between: removing some of the water Open Driven System Removing byproductH 2O by temperature, low pressure, or Nblowing of waterAcid like HCl, base neutralization In a step-growth polymerization, the molecular weight of the polymer chain builds up slowly and there is only one re-action mechanism for the formation of polymer. This chapter talks about different types of polymers obtained by step‐growth polymerization through different types of reactions such as esterification, polyamidation, polycondensation, formylation This polymerization is activated by heat, which causes dehydration. direct processing. The distinct initiation, propagation, and termination steps of chain-growth polymerization are meaningless in step-growth polymeriza-tion. A difunctional monomer or equal molar Step-growth polymerization is a very important method for the preparation of some of the most important engineering and specialty polymers. monomers are not miscible with each other but miscible with solvent. Use solvent. A typical example of step-growth polymerization is the synthesis of nylon from hexamethylene diamine and adipic acidFig.). There is no chemical initiator. This chapter talks about different types of polymers obtained by step-growth polymerization through different types of reactions such as esterification, polyamidation, polycondensation, formylation Step‐growth polymerization is a very important method for the preparation of some of the most important engineering and specialty polymers.
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