| abstract |
In a process for the production of linear segmented polyurethane by simultaneous reaction of macrodiols, low-molecular diols as chain-lengthener and aromatic diisocyanate, in a solvent in the presence of catalyst, and in the presence of catalytic amounts of a magnesium or calcium salt, an aromatic carboxylic acid macrodiol, monomeric, lower-molecular diol and aromatic diisocyanate are reacted, the macrodiol being used in such amounts as to adjust in the prepared polyurethane a weight ratio of soft segment to hard segment of about 4:1 to 1:4. Preferred embodiments include reaction at temperature from about 70 DEG to 120 DEG C.; use of an inert solvent; and having the concentration of starting material amount to about 10-40% by weight relative to the mixture of starting material and solvent. Also provided are polyurethanes obtained according to this process, having a molecular non-uniformity from 2 to 7. Preferred embodiments include that the polyurethane have an average molecular weight from 60,000 to 250,000. The polyurethanes are useful for the production of membranes, specifically those to be used for sterile filtration or blood oxygenation. |