To explain why the C-O-C bonds between the phenyl rings have a bond angle closer to 120° than 109.5°. Concept introduction: Polymers that can withstand high temperatures without degrading are highly desirable, so chemists often try to introduce thermal stability into polymers. An example is poly(ether ether ketone ) , or PEEK , which is stable to temperatures above 500 °C. PEEK is so thermally stable because its main chain is very rigid, and that rigidity is an outcome of the extended conjugation throughout the entire repeating unit.

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Chapter 26, Problem 26.18YT

Interpretation Introduction

Interpretation:

To explain why the C-O-C bonds between the phenyl rings have a bond angle closer to 120° than 109.5°.

Concept introduction:

Polymers that can withstand high temperatures without degrading are highly desirable,

so chemists often try to introduce thermal stability into polymers. An example is poly(ether ether ketone), or PEEK, which is stable to temperatures above 500 °C. PEEK is so thermally stable because its main chain is very rigid, and that rigidity is an outcome of the extended conjugation throughout the entire repeating unit.

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