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A Study on a Prepolymerization Process of Aromatic‐Contained Polyamide Copolymers PA(66‐co‐6T) via One‐Step Polycondensation
Author(s) -
Zhang CaiLiang,
Wan Li,
Gu XuePing,
Feng LianFang
Publication year - 2015
Publication title -
macromolecular reaction engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 32
eISSN - 1862-8338
pISSN - 1862-832X
DOI - 10.1002/mren.201500006
Subject(s) - hexamethylenediamine , condensation polymer , prepolymer , polymer chemistry , polyamide , terephthalic acid , polymerization , nylon 66 , copolymer , adipic acid , chemistry , materials science , polymer , organic chemistry , polyester , polyurethane
A facile one‐step polycondensation approach to prepare a prepolymer of aromatic‐contained polyamide using terephthalic acid (PTA), adipic acid (ADA), hexamethylenediamine (HMDA) as raw materials was explored systematically. The prepolymerization process was divided into four stages: formation of nylon salt, temperature rising, polycondensation, and venting. In the first stage, PTA and ADA react completely with HMDA to form salts in 40 min at 50 °C. The system is then heated up. The salts do not react until the temperature reaches 200 °C, irrespective of the heating rate. After the temperature is above 200 °C, the polymerization degree of the prepolymer increases with increasing temperature and/or increasing time. In the venting stage, the polycondensation reaction continues to proceed. After 40% of the total amount of water is removed, the molecular weight of the prepolyamide increases dramatically and even far exceeds that of the polycondensation stage. Moreover, a longer venting time or a lower pressure drop rate is beneficial for the polycondensation of nylon salts. GPC, FTIR, and NMR analyses show that the molecular weight of the as‐synthesized prepolyamide decreases with increasing feed ratio between PTA and ADA. However, this feed ratio does not affect much its composition.