| 摘要 |
1,181,001. Depolymerization. DEUTSCHE GOLD-UND SILBER-SCHEIDEAN STALT. 26 Jan., 1967 [5 Feb., 1966], No. 3920/67. Heading C2C. Monomers are prepared from finely-ground polymers (particle size not more than 6 mm. derived from monomers with a conjugatable bond system, by subjecting them to airseparation and pyrolysis at a temperature at least 100‹ C., and preferably between 300‹ and 500‹ C. above the depolymerization temperature polybutadiene, polystyrenes, polyformaldehyde and polymethyl methacrylate are mentioned and an example describes the treatment of polymethyl methacrylate in an apparatus comprising a cleavage tube, stabilizer, cooling and purification systems. |
