Desenvolvimento e caracterização de compósitos de elastômero termoplástico de poliuretano (TPU) com argila

Abstract

In this study thermoplastic polyurethane (TPU) composites were obtained with different nanoclay contents (0, 1, 3 for all cases and 10 wt% in some cases). The nanoclay Cloisite 30B (C30B) was dispersed in the TPU matrix by melt processing (twin-screw extruder; TPU-E composites) and during bulk polymerization (TPU-S composites). The synthesis method involved the two-step bulk polymerization of polyesterpolyol (Mw = 2.000 g mol-1) and diphenylmethanediisocyanate (MDI) with 1,4-butanediol as the chain extender. The dispersion state of the nanoclay particles and its effect on the mechanical properties of the composites was investigated. The characterization of TPU/nanoclay composites was carried out by means of scanning electron microscopy, energy dispersion microanalysis and X-ray diffraction. The mechanical characterization was performed through determination of the tensile and tear strengths. The TPU-E 3 wt% composite showed the best improvement with increases in stress, strain, and energy at break (28%, 35%, and 88%, respectively), compared to the TPU-E (sample without nanoclay). The differential scanning calorimetry and thermogravimetry analyses for the TPU-S and TPU-E composites indicated that the nanoclay did not affect the glass transition, melt, and degradation temperatures of the polymeric matrix.