Linear poly(urethane urea) containing a biodegradable soft segment and a hard segment built solely from methyl-2,6-diisocyanatehexanoate (LDI) is presented, using a procedure where no chain extender is required. By having LDI in excess, together with a soft segment, and adding water in the vapor phase continuously creates amines in situ resulting in hard segments containing multiple LDI units linked via urea linkages. As soft segments, polymers of trimethylene carbonate (TMC) and copolymers of TMC, epsilon-caprolactone, and D,L-lactic acid (DLLA) were used. High inherent viscosity, 0.95-1.65 dL/g, was afforded even when DLLA-containing soft segments were used, which usually undergo aminolysis. With a hard segment content between 12% and 18%, all of the materials showed very high elongation at breakage, ranging from 1600% to 4700%, and an elastic modulus from 2.1 to 140 MPa. This one-pot synthesis is simple and has now been shown to be applicable to a large number of systems.

Poly(urethane urea)s with hard segments derived only from diisocyanate linked via urea linkages were synthesized using a new and simple one-pot method. The creation of urea linkages were done via creating the amine in situ by adding water in vapor phase slowly and continuously. This synthesis method eliminates the tedious control to approach stoichiometry, is less sensitive to impurities, involves no intermediate isolation steps, and does not involve any chain extender. A study using a two-armed poly(ε-caprolactone) as soft segment and methyl 2,6-diisocyantohexanoate (LDI) as the hard segment was performed. The length of the hard segment was varied from 4.8 to 11.6 LDI units. Stress−strain measurements showed an increase in elastic modulus, 146 to 235 MPa, when increasing the hard segment length, while the elongation at break decreased, 980 to 548%. IR spectroscopy showed an increase in hydrogen bonding when increasing the hard segment length. The synthesis was also shown to be applicable to common diisocyanates such as HDI, TDI, and MDI.

Summary. 1. The total content of contractive substance in human sperm was determined from 155 specimens of sperm by titration on rabbit intestine in vitro, with prostaglandin as the standard. The content varied greatly in different specimens, but contractive substance was met with in all of them. 2. In certain specimens the factor which is active on rabbit intestine consists – apart from prostaglandin and choline – of at least one other substance, which leads to a very rapid increase in tonus and is indifferent to atropine. 3. There is no correlation between the total content of contractive substance and the motility and life of the spermatozoa.

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