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In chain-growth polymerization the propagation step is the addition of a monomer to the growing chain. The word kinetic is added to chain length in order to distinguish the number of reaction steps in the kinetic chain from the number of monomers in the final macromolecule, a quantity named the degree of polymerization. In fact the kinetic ...
RAFT agent Z groups in decreasing order of reactivity. Recommended monomers: 1-4: MMA, HPMAM; 5: MMA, HPMAM (partial control); 7-11: VAc, NVP; 1-6: St, MA, AM, AN; 7-10: St, MA, AM, AN (partial control) Guidelines have been provided for selection of R and Z groups based on the monomer to be polymerised and these are summarised in Figures 6 and 7.
In polymer chemistry, suspension polymerization is a heterogeneous radical polymerization process that uses mechanical agitation to mix a monomer or mixture of monomers in a liquid phase, such as water, while the monomers polymerize, forming spheres of polymer. [2] The monomer droplets (size of the order 10-1000 μm) are suspended in the liquid ...
The light may be absorbed either directly by the reactant monomer (direct photopolymerization), or else by a photosensitizer which absorbs the light and then transfers energy to the monomer. In general, only the initiation step differs from that of the ordinary thermal polymerization of the same monomer; subsequent propagation, termination, and ...
Usage of monomer in the reaction: Rapid loss of monomer early in the reaction: Some monomer remains even at long reaction times Reaction steps: Similar steps repeated throughout reaction process: Different steps operate at different stages of mechanism (i.e. initiation, propagation, termination, and chain transfer) Average molecular weight
The degree of polymerization, or DP, is the number of monomeric units in a macromolecule or polymer or oligomer molecule. [1] [2] [3]For a homopolymer, there is only one type of monomeric unit and the number-average degree of polymerization is given by ¯ ¯ = ¯, where ¯ is the number-average molecular weight and is the molecular weight of the monomer unit.
At the same time, these electron-donating groups attached to the monomer must be able to stabilize the resulting cationic charge for further polymerization. Some reactive olefin monomers are shown below in order of decreasing reactivity, with heteroatom groups being more reactive than alkyl or aryl groups. Note, however, that the reactivity of ...
However in step-growth polymerization the monomer is consumed very quickly to dimer, trimer and oligomer. The degree of polymerization increases steadily during the whole polymerization process. The type of polymerization of a given monomer usually depends on the functional groups present, and sometimes also on whether the monomer is linear or ...