Cast polyurethanes Analysis

In order to understand the effect of high MW diols on the formation of amorphous hard segments and their interaction with the crystalline hard segments, FT-IR analysis of the cast polyurethanes was performed. Samples were cast as films on a NaCl plate from a hot dimethyl sulphoxide (DMSO) solution. 

Solutions of Biomer were obtained from Ethicon Inc. Biomer is poly (ether polyurethane) which contains urea linkage in the hard segment according to our IR analysis (19). Films of Biomer were cast on clean glass plates by diluting the polymer solution in dimethyl acetyl-amide. The films were dried in a vacuum oven at 50°C for 24 hr. The final film thickness was around 125/a. GPC analysis showed that the content of oligomers in Biomer was also negligible. Kel-F82, which is a copolymer composed of chlorotrifluoroethylene (97%) and vinylidene fluoride (3% ), was obtained from the 3M Company. 

The influence of the high MW diols present in the HER chain extenders on the transition behavior of cast elastomers was studied by DSC analysis. Figure 8.3 compares the DSC curves of HQEE, HER-HP and different HER-TG extended polyurethanes. The transitions, which are observed to occnr above room temperature, are associated with the melting of... 

Hydrocyclones can be manufactured from dough-molded compound fiberglass, cast iron, or sheet metal lined with polyurethane. Metal and fiberglass cyclones are lined with rubber or with hard metal (Ni-hard or 28% chrome white iron). Burgess and Abulnaga (1991) presented a finite element analysis of fiberglass cyclones. 

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