| 摘要 |
<p>This invention relates to a process for modifying a poly(alkylene carbonate) polyahl to increase its molecular weight. The process comprises contacting the poly(alkylene carbonate) polyahl with at least one modifier having a plurality of moieties that are reactive with the carbonate and/or active hydrogen moieties of the poly(alkylene carbonate) polyahl at elevated temperature and at a pressure at which at least one compound other than a monoalkylene glycol, which compound is at least as volatile as a tetraethylene glycol, is removed in the gaseous state from the poly(alkylene carbonate) polyahl under conditions such that the molecular weight of the poly(alkylene carbonate) polyahl is increased an the poly(alkylene carbonate) polyahl backbone or side chain is modified by reaction with the modifier. The modifiers which are suitable for use in the practice of this invention include polyfunctional materials which are reactive with the carbonate and/or active hydrogen moieties of poly(alkylene carbonate) polyahls. Examples of these materials are polyols, polyamines, polyamides, polymercaptans and polyacids. These modifiers are employed in an amount of from 5 to 80 percent by weight based on the weight of the poly(alkylene carbonate) polyahl and the modifier. The process of this invention is useful for producting materials for applications in flexible urethane foams, rigid urethane foams, urethane/urea elastomers and plastics, adhesives, functional fluids and surfactants.</p> |
