Polyamide melt, additives Moisture

Thermal studies (DSC) indicate a very high moisture absorption rate for pure PAI-1. The amide linkage m PAI, as in case of polyamides, is known to be very moisture sensitive and undergoes hydrolysis and chain scission when in the melt state in the presence of moisture. PAI-2 does not indicate the same moisture absorption properties observed in PAI-1. Addition of only 10% LCP decreases the moisture absorption of the blend dramatically. The T of the pure components and the blends increases on heat treatment. The presence of LCP is seen to inhibit the imidization of PAI. The major fiictors affecting imidization are temperature, time and diffusion of the water of imidization through the molded part. The presence of LCP which has good barrier properties, inhibits the diffusion of the NMP solvent and water of imidization which in turn inhibits the reaction. The T transition for PAI in DSC... 

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