Editing Polymer (section)

===Chemical properties===
The attractive forces between polymer chains play a large part in determining the polymer's properties. Because polymer chains are so long, they have many such interchain interactions per molecule, amplifying the effect of these interactions on the polymer properties in comparison to attractions between conventional molecules. Different side groups on the polymer can lend the polymer to [[ionic bonding]] or [[hydrogen bonding]] between its own chains. These stronger forces typically result in higher tensile strength and higher crystalline melting points.

The intermolecular forces in polymers can be affected by [[dipole]]s in the monomer units. Polymers containing [[amide]] or [[carbonyl]] groups can form [[hydrogen bond]]s between adjacent chains; the partially positively charged hydrogen atoms in N-H groups of one chain are strongly attracted to the partially negatively charged oxygen atoms in C=O groups on another. These strong hydrogen bonds, for example, result in the high tensile strength and melting point of polymers containing [[carbamate|urethane]] or [[urea]] linkages. [[Polyester]]s have [[intermolecular force#Dipole-dipole interactions|dipole-dipole bonding]] between the oxygen atoms in C=O groups and the hydrogen atoms in H-C groups. Dipole bonding is not as strong as hydrogen bonding, so a polyester's melting point and strength are lower than [[Kevlar]]'s ([[Twaron]]), but polyesters have greater flexibility. Polymers with non-polar units such as polyethylene interact only through weak [[Van der Waals force]]s. As a result, they typically have lower melting temperatures than other polymers.

When a polymer is dispersed or dissolved in a liquid, such as in commercial products like paints and glues, the chemical properties and molecular interactions influence how the solution flows and can even lead to [[self-assembly]] of the polymer into complex structures. When a polymer is applied as a coating, the chemical properties will influence the adhesion of the coating and how it interacts with external materials, such as [[superhydrophobic]] polymer coatings leading to water resistance. Overall the chemical properties of a polymer are important elements for designing new polymeric material products.