Thangamani Rajkumar† , Venugopalan Rajasudha*, Arunjunai Raj Mahendran**, and Chinnaswamy Thangavel Vijayakumar***
Department of Chemistry, Rajah Serfoji Government College (Affiliated to Bharathidasan University), Thanjavur - 613005, Tamilnadu, India
*Department of Chemistry, Bon Secours College for Women, Thanjavur - 613006, Tamilnadu, India
**Wood K Plus-Competence Center for Wood Composites and Wood Chemistry, Altenberger Strasse 69, A-4040 Linz, Austria
***Department of Polymer Technology, Kamaraj College of Engg. & Tech., S.P.G.C. Nagar,
K. Vellakulam Post - 625701, Tamilnadu, India
Reproduction, stored in a retrieval system, or transmitted in any form of any part of this publication is permitted only by written permission from the Polymer Society of Korea.
Polyurethanes (PUs) were prepared from solvent and catalyst free reaction mixture containing polyethylene glycol (PEG), 4,4’-methylene diphenyl diisocyanate (MDI) and 1,3-bis(2-hydroxyethoxy) benzene (HER) and/or castor oil (CAO). PUs were characterized using the Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopic methods. Thermal studies on PUs using differential scanning calorimetric (DSC) and thermogravimetric analysis coupled with FTIR (TG/FTIR) proved that CAO-extended PUs were thermally more stable than HER extended PUs. The partial and complete replacement of HER content in PUs using CAO enhanced the thermal stability by shifting degradation temperature to higher temperature (5-15 °C) and enhancing the char residue. The parameters derived from DSC traces, thermogram and differential thermogram confirmed that PUs synthesized using PEG 1500 are thermally more stable than the PUs prepared using PEG 4000. The probable degradation mechanism to study the role of β-hydrogen on the thermal stability was proposed and discussed based on the results of TG/FTIR.
Keywords: β-hydrogen, mechanism, polyurethane, synthesis, thermal degradation.
2021; 45(4): 511-519
Published online Jul 25, 2021
Department of Chemistry, Rajah Serfoji Government College (Affiliated to Bharathidasan University), Thanjavur - 613005, Tamilnadu, India