MatSE 443

Introduction to the Materials Science of Polymers

Penn State University

Introduction to the Materials Science of Polymers

Penn State University

PC Painter and MM Coleman Essentials of Polymer Science(DEStech Publications) |

## Chapter 4

**Concepts that you must know:**

- What is "Flory's Assumption"?
- Definitions: reaction rate, rate constant, and concentrations of reactants. How do they relate with each-other ?
- Step-Growth kinetics: extend of reaction (p), concentration of molecules vs. concentration of functional groups, time-dependence of reaction (eq. 4.16, notice the typo!). Go through Exercise 1 below.
- Free Radical kinetics: definitions of four stages/mechanisms (initiation, propagation, termination, and chain transfer), conversion, steady-state assumption. Go through Exercise 2 below.
- Free Radical kinetics: what is kinetic chain length, calculate the kinetic chain length (eq. 4.35, 4.36), understand how it relates to the instantaneous and the average molecular weight of the produced polymer
- Effect of Chain Transfer phenomena on the molecular weight (eq. 4.42(typo), 4.43)

**Important Exercises:**

- * Go through the calculation of step-growth kinetics (pg. 93-96), make sure that you understand eq.4-20 [incl. c=c
_{o}(1-p)] - * Go through the calculation of free radical kinetics (pg. 96-106), make sure that you understand steady state assumption and kinetic chain length