摘要 |
<p>Substantially benzene-free copolymers of maleic anhydride and alkyl vinyl ethers having benzene present in an amount of less than 1 ppm and toluene present in an amount of about 2.0 wt. % or less are provided by treating the copolymer powder with toluene at a temperature of about 115 °C to about 125 °C.</p> |