| 摘要 |
<p>The invention relates to the production of high molecular weight vinyl lactam-quaternized amino acrylamide copolymers having less than 0.1 % residual unreacted monomer, which comprises: subjectinmg the monomers to solution polymerization in the presence of a buffering agent having chelating properties for complexing with traces of heavy metals; controlling the pH of the polymerization to a level above 5.5 while continuously ebulating nitrogen gas through the system during reaction and incrementally adding a free radical initiator in 2 to 4 stages during the conversion to copolymer. The invention also relates to the substantially pure vinyl lactam-acrylamide copolymer having a Brookfield viscosity of at least 75,000 cps. and a residual monomer content below 0.5 wt. %, for example less than 1,000 ppm.</p> |
