Question

Another way of producing highly crosslinked polyesters (see Exercise 84) is to use glycerol. Alkyd resins are a polymer of this type. The polymer forms very tough coatings when baked onto a surface and is used in paints for automobiles and large appliances. Draw the structure of the polymer formed from the condensation of

Explain how individual polymer chains could be crosslinked.

Short answer

There are two possible linkage types. The first one is when the first and the third -OH groups react with acid groups. The second one is when the first and the second-OH groups react with acid groups. Linkage between two parallel chains is possible via the remaining - OH group from glycerol.

Step-by-step solution

To explain the individual polymer chains could be crosslinked

Two possible condensation polymers are shown below in the picture. The first picture presents a polymer reaction. The second picture shows the first and the second - OH groups from glycerol react with acid groups.

Cross linkage is also possible between different parallel chains when the remaining -O H group marked with red color from glycerol reacts with - COOH acid group.

Hence There are two possible linkage types. The first one is when the first and the third -OH groups react with acid groups. The second one is when the first and the second-OH groups react with acid groups. Linkage between two parallel chains is possible via the remaining - OH group from glycerol.