缩聚反应与逐步加聚反应（Polycondensation and stepwise addition polymerization）.doc

缩聚反应与逐步加聚反应（Polycondensation and stepwise addition polymerization） The third chapter is condensation polymerization and stepwise polymerization Section 1 Characteristics and classification of polycondensation reaction 1. polycondensation reaction: Condensation reactions between monomers or oligomers of two or more functional groups containing two or more functional groups. 2. general formula: [M]m[M]n [M]m+n 3. main products: nylon, polyester, phenolic resin, urea formaldehyde resin, amino resin, alkyd resin, unsaturated polyester, epoxy resin, silicone rubber, polysulfide rubber, furan resin, polycarbonate and so on. 4. uses: engineering plastics, fibers, rubber, adhesives and coatings. I. characteristics of polycondensation 1. characteristics of polycondensation (1) stepwise: a series of condensation reactions are completed gradually (2) reversibility: reversible equilibrium reaction (3) complexity: besides chain growth reaction, there are chain cleavage, exchange and other side reactions. Comparison of 2. polycondensation reactions with addition polymerization See table 3-1 Two. Classification of polycondensation reactions 1. classification according to the macromolecular geometry of the product (1) linear polycondensation Concept: the monomer participating in the reaction has two functional groups The macromolecules formed in the reaction develop in two directions The product is linear structure For example: diacids and diols generate polyester (PET) Two yuan of dicarboxylic acid and amine to produce polyamide (nylon) General formula of reaction: N bBb a AAan [AB]nb (2n1) ab N aAb a [A]nb (n-1) ab Characteristics: the viscosity of the reaction system thickens gradually, and the product is soluble, fusible and thermoplastic. (2) bulk polycondensation Concepts: (1) at least one monomer in the monomer participating in the reaction has more than two functional groups In reaction, macromolecules develop in three directions The product is the shape structure Examples: