Vinyl chloride, \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CHCl}\), undergoes copolymerization with 1,1 -dichloroethylene, \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CCl}_{2},\) to form a polymer commercially known as Saran. Draw the structure of the polymer, showing the repeating monomer units.

Understanding the structure of polymers is essential in materials science and chemistry. Polymers are large, long-chain molecules made up of repeating structural units called monomers. These monomers can be identical or different, leading to various types of polymers with unique properties.

Consider a beaded necklace as an analogy for polymers; each bead represents a monomer, and the stringing together of these beads forms the polymer chain. Just as different beads can create necklaces with diverse characteristics, different monomers can create a range of polymer materials.

In the copolymerization process, two different monomers are combined. A polymer like Saran, for instance, is formed from vinyl chloride and dichloroethylene, resulting in a chain that alternates between the two types of monomers. This interspersing changes the physical and chemical characteristics of the polymer, often improving properties like chemical resistance, flexibility, or strength.

Understanding the intricacies of this structure is imperative for grasping why certain materials behave the way they do, which is crucial for innovations in material design and application.

Vinyl chloride, represented by the chemical formula \(\mathrm{H}_2\mathrm{C}=\mathrm{CHCl}\), is a significant monomer in the production of several types of polymeric materials. Its structure features an ethylene backbone, with one of the hydrogens replaced by a chlorine atom.

The presence of the chlorine atom provides vinyl chloride with unique properties that are valuable in polymer chemistry. For instance, the chlorine molecule is much more massive than a hydrogen atom, which affects the physical properties of the resulting polymer. Moreover, the chlorine atom makes the vinyl chloride monomer more reactive in polymerization reactions, given its electronegativity and size.

Vinyl chloride is highly versatile and, when polymerized into polyvinyl chloride (PVC), it creates a stiff and durable material used in a myriad of products, from pipes to vinyl records. The role of vinyl chloride in copolymerization with other monomers is equally important, as it lends its properties to the resulting copolymer, enhancing its functionality for specific uses.

Dichloroethylene, specifically 1,1-dichloroethylene with the formula \(\mathrm{H}_2\mathrm{C}=\mathrm{CCl}_2\), stands out in copolymerization reactions due to its symmetrically substituted chlorine atoms. These chlorines are located on the same carbon, which yields different reactivity and properties than a monomer with chlorines on separate carbons.

The dichloroethylene molecule plays a crucial role when copolymerized with vinyl chloride. The two chlorine atoms add density and rigidity to the polymer, which in turn affects its thermal stability and chemical resistance.

Materials like Saran wrap, derived from the copolymerization of dichloroethylene and vinyl chloride, showcase how the incorporation of chlorinated monomers yields polymers with exceptional barrier properties against gases and moisture. This makes Saran and similar materials ideal for applications requiring preservation from environmental factors.