Aliphatic polycarbonate-based polyurethane nanostructured materials. The influence of the composition on thermal stability and degradation

Thermal properties of new materials usually determine their applicability to special purpose. In order to follow the influence of the composition on the thermal decomposition pattern of segmented polycarbonate-polyurethanes (PC-PUs), a series of unfilled and filled elastomers based on different polycarbonate diols and their mixtures, hexamethylene diisocyanate and 1,4-butane diol as chain extender were synthesized. Hard segment (HS) content in final materials was in the range from 8 to 35 wt.%. Nanocomposites were obtained by dispersion of organically modified bentonite additive (1 wt.%). Thermogravimetric analysis coupled with differential scanning calorimetry (TG-DSC) was used to study the influence of macrodiol chain constitution, HS content and bentonite addition on the decomposition of PC-PUs under dynamic temperature conditions. It was found that the highest thermal stability belongs to the elastomers prepared without chain extender. The decomposition temperatures (To) of PC-PUs increase with decreasing HS content. The significant enhancement of thermal stability is achieved in polyurethanes with higher HS content and well dispersed nano-scale layered bentonite particles. The regularity in thermal decomposition pattern and the hard segment content is used to determine the composition of polyurethane materials.