METHOD FOR PREPARING POLYAMIDE BY ANIONIC RING-OPENING COPOLYMERIZATION AND POLYAMIDE PREPARED THEREBY

The present invention relates to a method for preparing a polyamide by anionic ring-opening copolymerization in consideration of the reactivity between a monomer and an alkali metal-based initiator. The present invention relates to a method for preparing a polyamide by anionic ring-opening copolymerization and a polyamide prepared thereby, in which, by adding a metal hydride, which is an alkali metal-based initiator, to a lactam having higher reactivity therewith, a production rate of an anion-initiated monomer is increased, thus enabling polymerization with a high conversion rate within a short polymerization reaction time to obtain a polymer having a uniform molecular weight. In the method for preparing the polyamide by anionic ring-opening copolymerization (AROP), a metal hydride is added as an alkali metal-based initiator in an amount of 0.01-20 parts by weight based on 100 parts by weight of two or more lactams, and the alkali metal-based initiator is mixed with a lactam having higher reactivity among two lactams. Therefore, the metal hydride, which is the alkali metal-based initiator, is added to the monomer having high reactivity therewith to increase a production rate of an anion-initiated monomer and improve a conversion rate into a random copolymer.