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Preparation and properties of imide-containing elastic polymers from elastic polyureas and pyromellitic dianhydride

✍ Scribed by Kiyotsugu Asai; Shin-Ichi Inoue; Hiroshi Okamoto


Publisher
John Wiley and Sons
Year
2000
Tongue
English
Weight
211 KB
Volume
38
Category
Article
ISSN
0887-624X

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✦ Synopsis


A new approach to obtain imide-containing elastic polymers (IEPs) via elastic and high-molecular-weight polyureas, which were prepared from ␣-(4-aminobenzoyl)--[(4-aminobenzoyl)oxy]-poly(oxytetramethylene) and the conventional diisocyanates such as tolylene-2,4-diisocyanate(2,4-TDI), tolylene-2,6-diisocyanate(2,6-TDI), and 4,4Ј-diphenylmethanediisocyanate (MDI), was investigated. IEP solutions were prepared in high yield by the reaction of the polyureas with pyromellitic dianhydride in N-methyl-2-pyrrolidone (NMP) at 165°C for 3.7-5.2 h. IEPs were obtained by the thermal treatment at 200°C for 4 h in vacuo after NMP was evaporated from the resulting IEP solutions. We assumed a mechanism of the reaction via N-acylurea from the identification of imide linkage and amid acid group in IEP solutions. NMR and FTIR analyses confirmed that IEPs were segmented polymers composed of imide hard segment and poly(tetramethylene oxide) (PTMO) soft segment. The dynamic mechanical and thermal analyses indicated that the IEPs prepared from 2,6-TDI and MDI showed a glass-transition temperature (T g ) at about Ϫ60°C, corresponding to T g of PTMO segment, and suggested that microphase-separation between the imide segment and the PTMO segment occured in them. TGA studies indicated the 10% weight-loss temperatures (T 10 ) under air for IEPs were in the temperature range of 343-374°C. IEPs prepared from 2,6-TDI and MDI showed excellent tensile properties and good solvent resistance.


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