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The Y fragment ls a new active center which adds more monomer M to form a new growing chain YM n °. [9] This can happen in free radical polymerization for chains RM n °, in ionic polymerization for chains RM n + or RM n –, or in coordination polymerization. In most cases chain transfer will generate a by-product and decrease the molar mass ...
The kinetics and rates of step-growth polymerization can be described using a polyesterification mechanism. The simple esterification is an acid-catalyzed process in which protonation of the acid is followed by interaction with the alcohol to produce an ester and water. However, there are a few assumptions needed with this kinetic model.
The second form of the equation is valid at steady-state polymerization, as the chains are being initiated at the same rate they are being terminated (R i = R t). [5] An exception is the class of living polymerizations, in which propagation is much slower than initiation, and chain termination does not occur until a quenching agent is added. In ...
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.
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. [1] [2] [3] There are many forms of polymerization [4] and different systems exist to categorize them. IUPAC definition for ...
The methods used to determine the degree of crystallinity can be incorporated over time to measure the kinetics of crystallization. The most basic model for polymer crystallization kinetics comes from Hoffman nucleation theory. The crystallization process of polymers does not always obey simple chemical rate equations. Polymers can crystallize ...
Atom transfer radical polymerization (ATRP) is an example of a reversible-deactivation radical polymerization. Like its counterpart, ATRA, or atom transfer radical addition, ATRP is a means of forming a carbon-carbon bond with a transition metal catalyst. Polymerization from this method is called atom transfer radical addition polymerization ...
Interfacial polymerization has proven difficult to model accurately due to its nature as a nonequilibrium process. [7] [9] [11] These models provide either analytical or numerical solutions. [9] [11] The wide range of variables involved in interfacial polymerization has led to several different approaches and several different models.