Chap._900001 - of polymer chain, so that the end group...

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Chapter 9 Polymer Synthesis (II): Polycondensation (Step-Growth) Polymerization 9.1 Polymerization Through Functional Groups Polymerization usually proceeds by the reaction between two different functional groups. urethane amide ester - H 2 O - H 2 O H H O O O O-C-N N-C O-C OH + HOOC NH 2 + HOOC OH + O=C=N * Polycondensation Reaction and Condensation Polymers (Polyester, Polyamide, Polyurethane. .) It requires bifunctional monomer which contains two functional groups Monomer prosesses Monomer processes two but same functional groups two different functional groups k p k p x x HOOC COOH NH 2 H 2 N H O C-N R R R R' R O H C-N O C-N H R' R n n nH 2 N COOH R HOOC R' COOH + H 2 N NH 2 R - H 2 O - H 2 O H H O O C-N N-C During or at the end of polymerization reaction, the number of [COOH] or [NH 2 ] represents the number
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Unformatted text preview: of polymer chain, so that the end group analysis can be used to determine the extend of polymerization and polymer molecular weight. * Stepwise Reaction Step polymerization proceede by the molecules reacting with each other. (i) the monomer dsiappear in the very eraly stage of the reaction (ii) a relatively slow increase in molecular weigth of the polymer (iii) Rate constant (kp) is independent of the reaction time and polymer molecular weight In general, it is true until the polymer having very high molecular weight (iv) The successful synthesis of high polymers (M n > 10,000 g/mole) requires equal moles of two functional groups and high conversion (> 99%)...
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