Thermo-mechanical properties of Polyamide 6 chemically modified by chain extension with Polyamide/Polycarbonate blend.

A Polycarbonate/Polyamide (PCPA) blend was used as chain extender in a melt compounding process with a Polyamide 6 (PA6), by using a twin screw extruder. The chain extension capability of the PCPA blend was evaluated through rheological, thermal and mechanical tests. Rheological tests on the compounded pellets and relative viscosity measurements on solubilized samples evidenced an increase of the viscosity values with the chain-extender amount and with the high temperature residence time. Terminal group analysis confirmed the increase of the molecular weight with the PCPA content and highlighted a preferential reactivity of the chain extender with amminic end groups. DSC tests showed a slight crystallinity decrease with the PCPA content, while both melting and crystallization temperatures were unaffected. Elastic and yield properties of chain-extended PA6 were similar to that of neat PA6 at differentmolecular weights,while crystallinity drop due to chain extension produced an increase of the strain at break values.