What does the monomer unit of polyester look like? and what’s its chemical formula?

             The monomers of polyesters are,

                                  (i) A Dicarboxylic Acid

                                  (ii) A Dialcohol

Explanation:

                     As depicted from name polyester is a macromolecule which contains numerous ester functional groups. Ester is formed by the condensation of Carboxylic acid and alcohol as shown,

                            R-COOH  +  R'OH  →  RCOOR'  +  H₂O

Therefore, in order to utilize this reaction for the formation of long chain of polyesters then one can use a dicarboxylic compounds and dialcohol compounds. This will allow to propagate the chain length depending upon the requirement. Hence, the general reaction for the formation of polyester is shown below. The circle and rectangle specifies different moieties which imparts different characters to the polyester.

h let me think

pie chart because it is in percents ( % )