Préparation et étude de la stabilité thermique des polyuréthanes

Abstract

This work is focused on the synthesis of different polyurethanes and poly (ether-urethanes) by polycondensation. One of these diols (PEG1000, hydroquinone and Resorcinol) is reacted with2.4-toluene diisocyanate or Hexamethylene diisocyanate and traces of Na2CO3 (catalyst) in the presence of chlorobenzène as solvent under reflux for three hours. Tri-ethylamine was used to improve the molecular weight of polymers. The FT-IR spectra of the synthesized polyurethanes and poly (ether-urethanes) showed the disappearance of (–OH,-N=C=O) functions and the appearance of urethane (–CO-NH-) which confirm the formationof polyurethanes. The TG/DTG data indicates that polymers containing aromatic segments are thermally more stable than polymers containing soft segments (aliphatic chain). On the other hand, poly ( ether-urethanes ) and fully aromatic polyurethanes exhibit one stage of decomposition reaching maximum rate of evolutionat 400°Cand550°C, respectively. However, aliphatic/aromatic polyurethanes exhibit tow stages of degradations with maximumrates of evolutions around 350°Cand440°C. It has been found that; tri-ethylamine, N(C2H3)3, is more effective than sodium carbonate during the polymerization reaction.