Skip to main content
Ch.12 - Solids and Modern Materials
Chapter 12, Problem 87

An addition polymerization forms the polymer originally used as Saran™ wrap. It has the following structure −[CCl2−CH2]−n. Draw the structure of the monomer.

Verified step by step guidance
1
Identify the repeating unit in the polymer structure, which is −[CCl2−CH2]−.
Recognize that in addition polymerization, the polymer is formed by the repeated addition of monomers that contain a double bond.
Determine the structure of the monomer by considering the repeating unit. The monomer should have a double bond between the carbon atoms.
The repeating unit −[CCl2−CH2]− suggests that the monomer is likely to be CCl2=CH2, where the double bond is between the two carbon atoms.
Draw the structure of the monomer CCl2=CH2, showing the double bond between the carbon atoms and the two chlorine atoms attached to one of the carbons.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Addition Polymerization

Addition polymerization is a process where unsaturated monomers, typically containing double bonds, react to form a polymer. This reaction involves the breaking of the double bond in the monomer, allowing the monomers to link together in a chain-like structure. The process is initiated by heat, light, or chemical initiators, and is commonly used to create various plastics, including polyvinyl chloride (PVC) and polyethylene.
Recommended video:
Guided course
02:55
Addition Reactions

Monomer Structure

A monomer is a small, simple molecule that can join together with other monomers to form a polymer. In the case of Saran™ wrap, the monomer is dichloroethylene, which has the structure CCl2=CH2. Understanding the monomer's structure is crucial for visualizing how it polymerizes and forms the repeating units in the polymer chain.
Recommended video:
Guided course
01:42
Resonance Structures

Polymer Representation

Polymers are often represented using a repeating unit notation, denoted as [CCl2−CH2]−n, where 'n' indicates the number of repeating units. This notation highlights the structure of the polymer while simplifying the representation of potentially very large molecules. Recognizing how to derive the monomer from the polymer structure is essential for understanding the relationship between monomers and their corresponding polymers.
Recommended video:
Guided course
04:13
Crystalline vs Amorphous Solids