Search results
Results from the WOW.Com Content Network
Monomer to RAFT reagent: gives the expected degree of polymerization (that is, the number of monomer units in each polymer chain) and can be used to estimate the molecular weight of the polymer by Equation (1) (see below). [12] [14] RAFT reagent to initiator: determines the end groups on the polymer chains.
4,4′-Azobis(4-cyanopentanoic acid) (ACPA) is a free radical initiator used in polymer synthesis. [1] ACPA is a water-soluble initiator used in both heterogeneous and homogeneous free-radical polymerizations. It is used as an initiator in reversible addition−fragmentation chain transfer polymerization (RAFT).
RAFT is a degenerative chain transfer process and is free radical in nature. RAFT agents contain di- or tri-thiocarbonyl groups, and it is the reaction with an initiator, usually AIBN, that creates a propagating chain or polymer radical. This polymer chain then adds to the C=S and leads to the formation of a stabilized radical intermediate.
a.) Shows the general form of CpA initiators with one Cp ring and a coordinated Nitrogen b.) Shows the CpA initiator used in the living polymerization of 1-hexene (5) CpA initiators have one cyclopentadienyl substituent and one or more nitrogen substituents coordinated to the metal center (generally a Zr or Ti) (Odian). The dimethyl ...
To initiator: a polymer chain reacts with an initiator, which terminates that polymer chain, but creates a new radical initiator (Figure 21). This initiator can then begin new polymer chains. Therefore, contrary to the other forms of chain transfer, chain transfer to the initiator does allow for further propagation.
Azobisisobutyronitrile (abbreviated AIBN [1]) is an organic compound with the formula [(CH 3) 2 C(CN)] 2 N 2.This white powder is soluble in alcohols and common organic solvents but is insoluble in water.
Controlled radical polymerization, namely reversible addition−fragmentation chain-transfer polymerization (RAFT), is a common method for the polymerization of acrylates, methacrylates and acrylamides. Usually, a thiocarbonate is used in combination with an effective initiator for RAFT. The thiocarbonate moiety can be functionalized at the R ...
High energy initiation refers to the generation of chain carriers by radiation. Chemical initiation is due to a chemical initiator. For the case of radical polymerization as an example, chain initiation involves the dissociation of a radical initiator molecule (I) which is easily dissociated by heat or light into two free radicals (2 R°).