ALTERNATING POLYESTERAMIDES BASED ON 1,4-BUTYLENE TEREPHTHALAMIDE .3.ALTERNATING POLYESTERAMIDES BASED ON MIXTURES OF LINEAR DIOLS (4NTM,P)

Strictly alternating polyesteramides consisting of 1,4-butylene tereph thalamide diester and mixtures of aliphatic diols have been synthesise d in the melt in the presence of a titanium catalyst. To increase the molecular weight a solid state post condensation was applied. The comp osition was determined with H-1 NMR. The thermal properties were analy sed with differential scanning calorimetry (DSC) and dynamic mechanica l thermal analysis (DMTA). With the mixture of diols the structural re gularity of the diester part in polymers was disturbed. Although this disturbance caused the polymers to be fast crystallising (Delta T < 32 degrees), highly crystalline polymers. It was found that the melting temperature decreased linearly with increasing length of the diols in the mixture. The melting temperatures with the mixtures of diols were lower than with a single diol. The reason for this is probably thinner lamella. Mechanical tests on the melt processed polyesteramides showe d high glass transition temperatures and a high modulus above the glas s transition temperature. These polyesteramides have a T-g/T-m ratio o f 0.70-0.72. This high ratio is probably due to the relatively low mel ting temperatures. The water absorption, is close to the values for po lyesters (1.3-1.7 wt%). Disturbing the alternating structure of the po lyesteramide by esteramide interchange reactions resulted in a loss of the thermal and mechanical properties. (C) 1997 Elsevier Science Ltd.