Chap._200015 - (b) What are the rates of initiation,...

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1. In a batch polymerization reaction of styrene (with the concentration of 2 M) in 2 liter cyclohexane solvent. The polymerization is initiated by the thermal decomposition of BPO initiator (with the concentration of2 x 10 -3 M) at 75 °C. (a) Show by chemical equations of the polymerization. (b) How long will it take to achieve 50 % monomer conversion? (k p =1 x 10 3 liter/mole-sec, k t = 7.0 X 10 7 liter/mole-sec, f = 0.7 and the half-life time of the initiator at 75 °C is 4 hours and 85 °C is 1.5 hours). (c) How much polymer (g) is obtained after achieving 50 % monomer conversion? 2. If the above polymerization reaction (at 75 °C) is carried out in a continuous reaction process with constant monomer and initiator concentration, 2 and 2 x 10 -3 M, respectively. (a) What is the concentration of propagating site [M*] at the steady state condition.
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Unformatted text preview: (b) What are the rates of initiation, propagation, and termination (R i , R p and R t )? (c) How long will it take to prepare 1.04 Kg of polystyrene? (d) What is the average polymer molecular weight? (e) If the polymerization temperature is changed to 85 C, what is the time saving in producing 1.04 Kg polymer and average molecular weight of polymer? 3. Describe an anionic polymerization reaction in details (initiator, monomer, termination agent, their quantities, and reaction conditions) to prepare 104 g polystyrene with molecular weight of 104,000 g/mole. 4. Describe the components of an emulsion polymerization system. Compare the pros and cons of emulsion polymerization as a process condition in comparison to bulk and solution polymerization....
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