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Problem # 1 Using the data below you are to select concentrations of initiator and CTA that will give poly(vinyl acetate) with an initial molecular weight (assuming disproportion termination only) of 15,000. The polymerization (at 60°C) should be 50% complete in 8 min. Reactant Monomer: vinyl acetate FW Initial Concentration (g/l) 86.09 500.0 Initiator: 2,2'-azo-bis-2-isobutyl-4-methylvaleronitrile 332 Transfer agent: benzyl mercaptan 124.21 Solvent: methanol to make 1 L, $k_i$=3.78x10$^{-4}$ s$^{-1}$, $k_p$=15x10$^3$ L/mol-s, $k_t$=600x10$^6$ L/mol-s, $C_s$=0.885 Problem # 2 The molecular weight of polymer when vinyl butyrate is polymerized in an inert solvent is 500,000. With all other conditions the same, addition of 5 g/l of 1-dodecanethiol decreases the molecular weight to just 150,000. What concentration of 1-dodecanethiol will give a molecular weight of 275,000 (keeping in mind that all other conditions remain the same)?

          Problem # 1 Using the data below you are to select
concentrations of initiator and CTA that will give poly(vinyl
acetate) with an initial molecular weight (assuming
disproportion termination only) of 15,000. The polymerization
(at 60°C) should be 50% complete in 8 min.
Reactant
Monomer: vinyl acetate
FW Initial Concentration (g/l)
86.09
500.0
Initiator: 2,2'-azo-bis-2-isobutyl-4-methylvaleronitrile 332
Transfer agent: benzyl mercaptan
124.21
Solvent: methanol to make 1 L, $k_i$=3.78x10$^{-4}$ s$^{-1}$, $k_p$=15x10$^3$
L/mol-s, $k_t$=600x10$^6$ L/mol-s, $C_s$=0.885
Problem # 2 The molecular weight of polymer when vinyl
butyrate is polymerized in an inert solvent is 500,000. With all
other conditions the same, addition of 5 g/l of 1-dodecanethiol
decreases the molecular weight to just 150,000. What
concentration of 1-dodecanethiol will give a molecular weight of
275,000 (keeping in mind that all other conditions remain the
same)?

Problem # 1 Using the data below you are to select
concentrations of initiator and CTA that will give poly(vinyl
acetate) with an initial molecular weight (assuming
disproportion termination only) of 15,000. The polymerization
(at 60°C) should be 50% complete in 8 min.
Reactant
Monomer: vinyl acetate
FW Initial Concentration (g/l)
86.09
500.0
Initiator: 2,2'-azo-bis-2-isobutyl-4-methylvaleronitrile 332
Transfer agent: benzyl mercaptan
124.21
Solvent: methanol to make 1 L, ki=3.78x10^-4 s^-1, kp=15x10^3
L/mol-s, kt=600x10^6 L/mol-s, Cs=0.885
Problem # 2 The molecular weight of polymer when vinyl
butyrate is polymerized in an inert solvent is 500,000. With all
other conditions the same, addition of 5 g/l of 1-dodecanethiol
decreases the molecular weight to just 150,000. What
concentration of 1-dodecanethiol will give a molecular weight of
275,000 (keeping in mind that all other conditions remain the
same)?

Added by Gary B.

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