| 摘要 |
Prepn. of a modified copolymer comprises heating a methacrylic acid copolymer (I) or acrylic acid, 0.001-1 wt.% of ring closure-accelerating agent (II) is added to the copolymer (I) and the mixt. is heated. The copolymer (I) pref. has a (meth)acrylic acid unit of 5-50 wt.%. The other copolymerisable monomer includes e.g. an olefin, vinyl chloride, acrylonitrile, aromatic vinyl or alkyl unsatd. carboxylate. The ring closure-accelerating agent (II) includes e.g. KOH, NaOH, Ca(OH)2, triethylamine, 2-phenylimidazole or Na salt of p-toluenesulphonium acid or sodium ethylate. The copolymer (I) is pref. heated to 150-350 deg.C pref. |
