| 摘要 |
PURPOSE:To prevent a keloidal appearance from occurring in a post expansion process and to prepare a polystyrene foam having a good fit to the mold and excellent strengths by introducing a long alkyl chain into a styrenic polymer. CONSTITUTION:A polystyrene foam is prepd. from a polystyrene resin having a wt.-average mol.wt. of 150000-600000 and comprising structural units of formula I (wherein (l), (m), and (n) are each 1-20; and R1 to R4 are each H, 1-5C alkyl, cyclohexyl, or phenyl, and at least one of them is 2-5C alkyl) and formula II (wherein R1 is H or CH3; and R2 is H or 1-5C alkyl). The molar ratio of the structural units of formula I to those of formula II is pref. 0.006-0.000006. The polystyrene resin is prepd. by polymerizing a styrenic monomer in the presence of an initiator comprising a low-temp. decomposable org. peroxide having at least three repeating units of formula III (wherein (l), (m), (n) and R1 to R4 are each as defined above). |
