Question $1.(20$ pts$)$ Polyethylene terephthalate $($PET$),(C_{10}{H}_8{O}_4{)}_n,$ is a plastic resin and the

most common type of polyester used commercially. Its density $($amorphous$)$ is $1\mathrm{.}35\frac{g}{c}{m}^3.$

The molecular structure is given below:

$($a$)(3$ pts$)$ Briefly outline the facts $($importance$,$ uses, processing, etc$)$ about PET $($hint:

recall the in$-$class presentation$).$

$($b$)$ pts$)$ Experimental chain dimensions for PET melt at $275C$ are given by

$\frac{(\text{:}{h}^2\text{:}{)}_o}{M}$~~$0\mathrm{.}90{}^{2}mo\frac{l}{g}.$ Estimate $C_{},$ the statistical segment length, and the

persistence length for this commercially important polymer. Based on these numbers,

is PET a flexible polymer or not? What would you expect based on the molecular

structure?

$($c$)(5$ pts$)$ What are the lengths of a fully extended $($assuming no crystallization occurs

upon extension$)$ and a collapsed globule of PET chain with molar mass $M=100,000$

$\frac{g}{m}ol.$ How do these numbers differ from the chain dimension in melt and why?

$($d$)(3$ pts$)$ There are three major types of polymerization reactions. Typical molecular

weight versus conversion plots are shown below. Put the number next to each

nolvmerization tvne.

Step$-$growth

Chain$-$growth

$,$ Living $($controlled$)$ polymerization

$($e$)(2$ pts$)$ The synthesis scheme of PET is given below. What type of polymerization is

this? Polyethylene terephthalate $($PET$),($C$10$H$8$O$4)$n $,$ is a plastic resin and the

most common type of polyester used commercially. Its density $($amorphous$)$ is $1\mathrm{.}35$ g$/$cm$3$

$.$

The molecular structure is given below:

$($a$)(3$ pts$)$ Briefly outline the facts $($importance$,$ uses, processing, etc$)$ about PET $($hint:

recall the in$-$class presentation$).$

$($b$)(7$ pts$)$ Experimental chain dimensions for PET melt at $275$ oC are given by

$2$

$0\mathrm{.}90$

o

h M $$

$$

$2$ mol$/$g$.$ Estimate

C$$

$,$ the statistical segment length, and the

persistence length for this commercially important polymer. Based on these numbers,

is PET a flexible polymer or not? What would you expect based on the molecular

structure?

$($c$)(5$ pts$)$ What are the lengths of a fully extended $($assuming no crystallization occurs

upon extension$)$ and a collapsed globule of PET chain with molar mass M$=100,000$

g$/$mol$.$ How do these numbers differ from the chain dimension in melt and why?

$($d$)(3$ pts$)$ There are three major types of polymerization reactions. Typical molecular

weight versus conversion plots are shown below. Put the number next to each

polymerization type.

$$ Step$-$growth

$$ Chain$-$growth

$$ Living $($controlled$)$ polymerization

$($e$)(2$ pts$)$ The synthesis scheme of PET is given below. What type of polymerization is this?