A polyamide was prepared by bulk polymerization of hexamethylene diamine (9.22 g) with adipic acid (11.68 g) at 280 °C. Analysis of the whole reaction product showed that it contained 2.6 × 10−3 mol of carboxylic acid groups. Evaluate the number-average molar mass M – n of the polyamide, and also estimate its weight-average molar mass M – w by assuming that it has the most probable distribution of molar mass.
Answers
Answer:
polyamide was prepared by bulk polymerization of hexamethylene diamine (9.22 g) with adipic acid (11.68 g) at 280 degree C. Analysis of the whole reaction product showed that it contained 2.6 times 10^-3 mol of carboxylic acid groups. Evaluate the number-average molar mass M_a of the polyamide, and also estimate its weight-average molar mass by assuming that it has the most probable distribution of molar mass. One kilogram of a polyester with a number-average molar mass M_a = 10,000 g mol^-1 is mixed with one kilogram of another polyester with a M_a = 30,000 g mol^-1. The mixture then is heated to a temperature at which ester interchange occurs and the heating continued until full equilibration is achieved. Assuming that the two original polyester samples and the new polyester, produced by the ester interchange reaction, have the most probable distribution of molar mass, calculate M_a and weight-average molar mass M_w for the mixture before and after the ester interchange reaction. Consider 1:1 stoichiometric polymerization of 1, 4-diaminobutane with sebacoyl chloride. Write down a balanced chemical equation for the polymerization. Name the polymer formed by this polymerization. Using the Carothers equation, calculate the extent of reaction required to produce this polymer with a number-average molar mass M_a = 25.0 kg mol^-1. You should neglect the effects of end groups on molar mass. Explain briefly the consequences of including 1, 1, 4, 4-tetraminobutane in the polymerization with an exact stoichiometric ratio of 2:1:4 of 1, 4-diaminobutane to 1, 1, 4, 4-tetraminobutane to sebacoyl chloride.