Preparation of highly fluorinated polyurethanes

New polyurethanes, formed from a reaction of a prepolymer diol and a perfluorinated diisocyanate, are nonflammable and possess high corrosion resistance and good low temperature flexibility. Polymer hardness increases rapidly with increasing ratio of diisocaynate to diol, but its glass transition temperature is not adversely affected

Hydroxy terminated perfluoro ethers Patent

Chemical synthesis of hydroxy terminated perfluoro ethers as intermediates for highly fluorinated polyurethane resin

Preparation of highly fluorinated diols containing ether linkages.

Hydroxy-terminated perfluoroethers and polyurethane resins derived from ethers have outstanding chemical resistance and good thermal properties. They can be used as potting compounds, coatings, and seals. The hydroxy-terminated ethers serve as intermediates in the synthesis of highly fluorinated elastomers and adhesives

Highly fluorinated polyurethanes

The reaction perfluorinated hydroxyl terminated polyether with diisocyanate to form polyurethane is discussed. Data are given on the resin's oxidation stability, chemical resistance, and low temperature flexibility

Preparation of perfluoropolyether prepolymers

Fluorinated prepolymers are used to generate highly fluorinated polymers which possess most of the desirable properties of polytetrafluoroethylene, such as nonflammability and high corrosion resistance, while retaining good low temperature flexibility

Review: Insects in and out

Chapman, R.F. 1998: The Insects (Structure and Function). Cambridge University Press, Cambridge. Pp. 770

A note on some parasites of Merluccius capensis (Pisces) and their zoogeographical significance

During the Southeastern Atlantic Expedition of the German fishery research vessel "Walther Herwig" in 1967 the main emphasis lay on selective fishing of the South African hake Merluccius capensis (von BRANDT 1967). Some of the fish were found to be infested by ecto-and endoparasites both of which were collected whenever possible. Large plerocercoids of Dibothriorhynchus grossum whose adult stage lives in the South Atlantic Ocean in Lamna cornubica (L.SZIDAT, personal communication) were quite common as were cysticercoids of a Tetrarhynchus sp., which had also been reported in Cynoscion striatus off the Argentinian coast (MACDONAGH 1927, cited in Szidat, personal communication). Brownish nematodes were infesting the ovaries of several fish, but could not be identified. The most common ectoparasite to be observed was the parasitic isopod Livoneca raynaudii (fam. Cymothoidae) whose early larval stages were also found