Explanation

Also known as cationic polymerization. Ionic chain polymerization in which the chain activating center is cation. The initiators are electrophilic reagents such as Lewis acid, protonic acid, carbocation, oxygen pick ion, sulfur pick ion, phosphorous wrong ion, quaternary ammonium ion and some molecular carriers that can perform polymerization after full polarization, such as some esters. The activation or conditioning energy of chain initiation and chain growth reactions of ethers is low. The monomer is inserted into the ion pair according to the head tail structure, and has certain control over the chain configuration. The chain growth process is accompanied by intramolecular rearrangement reaction. The growing active center has the same charge, and can not be terminated by double groups. It mainly terminates by chain transfer to monomer or solvent, or single groups terminate by reducing chain transfer reaction at low temperature. Cationic reactive species are very active, characterized by rapid development, rapid growth, easy transfer and difficult termination. The olefin monomer with electron donor group (such as isobutene, vinyl ether, styrene, etc.) reacts due to the increase of the density of the electron cloud on the double bond and the dispersion and stability of the generated cation electrons. Cyclic monomer containing oxygen, nitrogen and other heteroatoms (such as cyclic ether, cyclolactone, cycloacetal, cyclosiloxane, etc.) can also be ring opening polymerization through positive ions. The discovery of activity has created conditions for macromolecule design.

Classification