Diisocyanate Dimethylacetamide

To obtain the polyurethanes, typically a prepolymer was first prepared by reacting the diisocyanate with various diols in dimethylformamide or dimethylacetamide in a two to one molar ratio at 100-110°C for two hours under nitrogen atmosphere. A solution of chain extenders, such as BEP, was then added to the prepolymer reaction mixture and further reacted another three hours. The polymer was isolated by quenching the reaction mixture in cold water. Fine white powder was obtained with a typical yield of around 90%. 

We have prepared and characterized three linear isosorbide containing polyurethanes with toluene diisocyanate (TDI), 4,4 -diphenylmethane diisocyanate (MDI), and 1,6-hexamethylene diisocyanate (HMDI) P(I-TDI), P(I-MDI), and P(I-HMDI). These polyurethanes have been synthesized as described in the experimental section by solution polymerization of isosorbide with the corresponding diisocyanate in dimethylacetamide using dibutyl-tin dilaurate as the catalyst at 75 C for 24 hours. All polymers have been isolated in quantitative yield by precipitation in methanol or water (5). 

The pendant hydroxyl groups of cellobiose have been confirmed to be useful for crosslinking of its polymers in the presence of additional amount of diisocyanate. Cross-linked insoluble films have been obtained by casting a polymer solution in dimethylacetamide containing 7% of additional amount of MDI. 

The step 1 product (70.88 mmol) was dissolved in dimethylacetamide (157 g) at 70°C and then treated with 2,4-tolylene diisocyanate (71.08 mmol) and reheated for 3 hours. The mixture was then treated with additional 2,4-tolylene diisocyanate (2.24 mmol) and heated to 80°C for 4 hours where the solution viscosity increased to 20.7 Pa s at 50°C. The solution was then heated to 60°C and cast on a releasable glass substrate followed by heat treatment for 2 hours at 60°C and for 3 hours at 110°C to obtain a film having a thickness of 200 p,m. 

Polyurethane. [This polymer was supplied by R. A. Auerbach, Lord Corporation.] The polyurethane was composed of a soft segment of poly(tetramethylene glycol) with a molecular weight of 1000 and a hard segment of p-diphenylmethane 4,4 -diisocyanate (MDI), and was chain extended with ethylenediamine (7). A solution of 7 wt % polyurethane in N,N-dimethylacetamide was used to cast the films. The phase-separated samples (ANN) were prepared by annealing the film at 135°C for 90 min in a helium atmosphere, and the mixed, nonphase-separated samples (NEQ)... 

Abstract The miscibility behavior in blends of polyethersulfone (Victrex PES) with the polyimide PI 2080, (the condensation product of 3,3, 4,4 -benzophenone tetracarboxylic dianhydride [BDTA] and a 4 1 mixture of 2,4-toluene diisocyanate and 4,4 -diphenylmethane diisocyanate) or with the polyimide XU 218 (the condensation product of BDTA and 5(6)-amino-l-(4 -aminophenyl)-l,3,3 -trimethylindane) was investigated using differential scanning calorimetry, dynamic mechanical analysis and thcmiogravimetric analysis. The effects of solvents (dimethylacetamide, tetramethylene sulfone, dimethyl sulfoxide and l-methyl-2-pyrrolidone) on miscibility were studied and one solvent, tetramethylene sulfone was found to have a plasticizing effect. In the absence of solvent, the equilibrium phase boundary for these blends was in the experimentally inaccessable region below the Tg-composition line. The phase boundary at zero solvent concentration was obtained by extrapolation using data collected in the presence of the plasticizer. 

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