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POLYMERS, Knowledge Points - Coggle Diagram

- - - - Inter-molecular forces: viscosity, vapor pressure
      - Mechanical Properties
      - Solubility, dissolution process: swelling process
  - - - Most linear polymers having branched structures with flexible chains are thermoplastic
    - - Thermosetting polymers
    - - same composition, different atomic configurations
      - Isomeric states of the above structures
        
        Geometrical isomers
        
        Cis
        
        Trans
        
        Stereo-isomers
        
        Syndiotactic
        
        Atactic
        
        Isotactic
    - - Chain flexibility
      - Skeletal elements
        
        Thermal stability Si, P
        
        Photolytic stability
        
        Flammability: aliphatic C,P
        
        Electric conductivity: conjugated C=C bonds, P=N bonds
      - Side groups
        
        aliphatic, fluorine, tri-methyl-silyl, phenyl ring : hydrophobic
        
        Hydroxyl, sodium carboxylate or amino units: hydrophilic
- - - - Chain Propagation
      - Chain termination
      - Chain transfer
      - Initiation
        
        Four steps of initiation
        
        Cat-ionic
        
        Chain termination
        
        Chain transfer
        
        Chain propagation
        
        Characteristics
        
        Chain not as "living" as anionic polymerization
        
        Used to produce a variety of synthetic rubber materials
        
        Exposure to water must be controlled carefully
        
        Initiation
        
        Anionic
        
        Organometallic initiator: n-butyllithium or sodium naphthalenide
        
        Characteristics
        
        More control over the chain length
        
        More control over repeat unit
        
        More control over the polymerization mechanism
        
        More control over MW distribution
        
        Coordination(ZN catalyst)
        
        A transition metal ( Group IV metals like Ti, Zr, Hf) can form & an organoaluminium compound(co-catalyst)
        
        Characteristics
        
        Disadvantages: low molecular weight & broad molecular weight distribution
        
        Improved Z-N catalyst: metallocene
        
        Can produce pure isotactic or syndiotactic polypoylen, better controller over the chain length & molecular weight distribution
        
        Control stereo-isomerism
        
        Free radical
        
        Initiator usually decompose into free radicals under polymerizing temperature
        
        Peroxide or AZO derivative
        
        Radiation (photo initiator)
        
        Peroxide and AZO can also form radials under light irradiation forming photo initiators
        
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        Characteristics
        
        Free radicals undergo side reactions
        
        Usually have very broad molecular weight distributions
        
        Accelerated by increase in T
        
        Chain tranfer
        
        Chain termination
        
        Chain propagation