Chapter 26, Problem 26.57P

Interpretation Introduction

Interpretation:

Considering the following series of $\text{poly }\left(\text{phenyleneoxide}\right)$ polymers A–D and their glass transition temperatures, it is to be explained how the differences in structure can account for the differences in ${\text{T}}_{\text{g}}$.

Concept introduction:

Polymers that have stronger types of intermolecular interactions generally have a higher ${\text{T}}_{\text{g}}$ and ${\text{T}}_{\text{m}}$. If the polymer has pendant groups that occur regularly, then the Tm will increase because these groups increase the barrier to rotation about single bonds. With less rotation about the main chain, the polymer can more easily arrange itself into a crystal lattice and achieve more extensive intermolecular interactions. The regular occurrence of pendant groups along a polymer chain increases ${\text{T}}_{\text{g}}$ and ${\text{T}}_{\text{m}}$.