Study on Nylon 6 Synthesis via Anionic Polymerization Using Azetidine-2,4-diones as the Activators

• Main Authors: Hsin-Yi, Wei, 魏欣怡
• Other Authors: 戴憲弘
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/77557112602501694593

碩士 === 國立中興大學 === 化學工程學系 === 93 === This research focused on the study of anionic ring-opening polymerization of caprolactum to synthesize Nylon 6 using structurally varied azetidine-2, 4-diones as the activators. The polymerizations were carried out by a one-step melt-process to find out the effects of activator’s concentration, types (aromatic or aliphatic), functionalities ( n=1 and 2), substituents (on azetidine-2,4-dione ring) as well as those of reaction temperature on polymerization rates. The aim is to find the best activator and optimal condition for possible application in reaction injection polymerization of Nylon 6 (Nylon RIM). In the aromatic series, different aliphatic substituent groups at 3,3’-prosition of azetidine-2,4-dione rings showed great effects on conversion rate and time of Nylon 6’s crystallization. It was found that aromatic bisazetidine-2,4-diones based on MDI with 3,3’-diethyl- or 3-ethyl-3’-butyl-groups exhibited the best overall performances which were twice as fast than that of N,N’-isophthaloyl-bis-caprolactam in getting high molecular weight Nylon 6 (molecular wt. of ~70,000) in about 70 seconds at 140℃. Unexpectedly, substitution of less-hindered di-methyl groups at 3, 3’-positions of the ring resulted in a slower polymerization and crystallization of Nylon 6. Complications of cross-linking and branching in the polymerization seemed responsible for this abnormality. Further study on Nylon-6 polymerizations were also conducted with bis-azetidine-2, 4-diones possessing long-chained polyether groups derived from Jeffamine D4000 Polymerization of Nylon-6 on the azetidine-2,4-dione prepolymers resulted in the formation of triblock-type systems. As might be expected in these cases, the polymerization rate of caprolactum was inversely proportional to the content of polyether groups in the prepolyemrs due to dilution. The triblock polymer prepared exhibited a well-organized phase-segregation in its morphology.