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Radical copolymerization

Radical copolymerization. Regular copolymer. Random copolymer. Block copolymer. Graft copolymer. Actual copolymer (case). . Free Radical Copolymerization. Chap 12. Free Radical Copolymerization. Copolymer Equation. Only Binary Case Two Monomers; M1 + M2. Steady State Assumption.

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Radical copolymerization

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  1. Radical copolymerization Regular copolymer Random copolymer Block copolymer Graft copolymer Actual copolymer (case) . Free Radical Copolymerization

  2. Chap 12. Free Radical Copolymerization Copolymer Equation Only Binary Case Two Monomers; M1 + M2 Steady State Assumption and chain transfer & termination compared w/ propagation ……①

  3. Copolymer Equation ……② Instantaneous ratio of monomers in copolymer From ① and ② where monomer reactivity ratio , COPOLYMER EQ.

  4. Meaning of r & Definition of f1, F1 Meaning of r characterizes the reactivity of the 1 radical with respect to the two monomers 1 and 2 then homopolymerization growth is preferred then only reaction with 2 will occur Define f1, F1 f1, f2 : mole fractions of monomers in feed F1, F2 : mole fractions of monomers in polymer From ③, ④ …… ③ ……⑤ how come? Homework! ……④

  5. Ideal Copolymerization Ideal Copolymerization Most ionic copolymerizations are characterizes bythe ideal type of behavior When , the two monomers show equal reactivities toward both propagating species

  6. Ideal Copolymerization or One of the monomer us nire reactive than The other toward both propagating speces. The copolymer will contain a larger proportion of the more reactive monomer in random placement 1 F1 0 f1 Surfing to the internet For further details about Ideal Copolymerization Click next homepage. http://www.chem.rochester.edu/~chem421/copoly.htm

  7. Alternating Copolymerization Alternating Copolymerization or As r1, r2 approach to zero, alternating tendency can be observed → If perfect alternation! If plots cross the line representing , If , then become homopolymer

  8. Alternating Copolymerization Mean of Cross-over Point At these crossover points the copolymer and feed compositions are the same and copolymerization occurs whthout a change in the feed composition Such copolymerizaions are termed Azeotropic copolymeriztions. Condition of Azeotropic copolymeriztion and ∵

  9. Alternating Copolymerization ∴

  10. Alternating Copolymerization ( and ) Both types of propagating species preferentially add monomer M1. there is a tendency toward consecutive Homopolymerization of the two monomers. And then monomer M2 will subsequently homopolymerize. In the result r1r2=1 ideal or random fix r2=0.5 Addition monimer A and A* Can not prepare copolymer It’s alternating upto 0.5, and above 0.5 there’s no formation of copolymer

  11. Alternating Copolymerization r2=0.5 azeotropic comp alternating r2=0.5 r1=1 no azeotrope r1, r2 > 1 Case tend to be a block copolymerization

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