Alternating polyesteramides based on 1,4-butylene terephthalamide: 4. alternating polyesteramides based on glycols (4NT glycol)

Polyetheresteramides (PEEAs) have been synthesised in the melt from 1,4-butylene terephthalamide and ethylene or propylene glycols. The ethylene glycols were ethylenediol, diethylene glycol, triethylene glycol and tetraethylene glycol. The propylene glycols were 1,3-propanediol and the mixtures of 1,2- and 1,3-propylenediols, 1,2/1,3-propanediol, dipropylene glycol and tripropylene glycol. The melting temperatures of the PEEAs decreased with increasing length of the glycols. The ethylene glycols have higher melting temperatures than the 1,2/1,3-propylene glycols. The undercooling for these polymers determined at 20°C min−1 was low (20–35°C), suggesting a very high rate of crystallisation of the copolymers. Injection moulded samples were analysed with dynamic mechanical thermal analysis. The glass transition temperature for the ethylenediol polymer was 122°C and the Tg decreased with increasing glycol length to 42°C for the tetraethylene glycol. The Tg/Tm ratio for these polymers was high (0.69–0.70). The dimensional stability of these copolymers above the Tg was high. The diethylene glycol PEEA had a melting temperature of 262°C, a glass transition temperature of 103°C, a shear modulus at 150°C of 180 MF'a, an undercooling of 28°C, a stress at break of 65 MPa and a modulus of 2.9 GPa.