Decamethylene Diamine Route

The diamine (AA) monomer used for the AABB polyamide PAlOlO, PA1012, and PAIOT is decamethylene diamine (DMDA or 1,10-diaminodecane). As DMDA is derive from sebacic acid it belongs to the abovementioned sebacic acid route. 

There are several processing steps involved to form DMDA from sebacic acid [10]. Firstly, sebacic acid is exposed and reacts with a nitrogen source such as gaseous ammonia to form diammonium sebacate. Upon continuous dehydration at elevated temperatures (200-220 °C) the dinitrile octamethylene dicyanide (C10H16N2) is formed which, after purification, is hydrogenated (80-100 °C, 2.5 MPa) in the presence of KOH and a nickel catalyst. Pure DMDA is subsequently obtained through vacuum distillation. 

The formation of PA 1010 from sebacic acid and decamethylene diamine, like other AABB polyamides, is conducted using the nylon salt polycondensation technique. PA1012 is formed by the petro-based dodecanoic diacid (DDDA) and DMDA. PAIOT is formed by DMDA and terephthalic acid, a diacid with a benzene ring as a backbone. 

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