Q9(a)(ii). Polyurethane: characteristic use and repeating unit
What is the characteristic application of polyurethane polymers? Provide repeating unit formed by reaction between the following monomers. [4,4′-methylenediphenyl diisocyanate and ethane-1,2-diol; structures given in the paper]
Answer in brief
Characteristic use: polyurethane foams (cushioning and thermal insulation). Repeating unit: [–CO–NH–C₆H₄–CH₂–C₆H₄–NH–CO–O–CH₂CH₂–O–]ₙ
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Coverspolyurethaneurethane linkageMDIstep-growth polymerisationpolyurethane foam
All parts of Question 9
- 9(a)(i) Dieckmann condensation, then NaBH₄ reduction5 marks
- 9(a)(ii) Polyurethane: characteristic use and repeating unit5 marks
- 9(b)(i) HBr and buta-1,3-diene: kinetic and thermodynamic control5 marks
- 9(b)(ii) Sharpless asymmetric epoxidation of an allylic alcohol5 marks
- 9(c) Structure from IR, NMR and mass spectra: C₁₀H₁₃NO₂10 marks