Preparation And Characterization Of Colorful And Conductivity-Controlled Thermoplastic Polyurethane Film

This experiment was took to change the phenomenon that conductive composites prepared with carbon black were lack of color variety and decorative. We attempted to prepare colorful and conductive polymer composites by replacing carbon black with other conductive fillers and pigments. In addition, the thermoplastic polyurethane (TPU) have attracted more and more attention due to their excellent mechanical properties and processing performance as well as environmental protection. Therefore, our study is committed to the research and development of color and conductivity-controlled conductive thermoplastic polyurethane films.This paper is about the preparation of the black conductive TPU films, colorful and antistatic TPU films, chromatic and conductive TPU films with superconductive carbon black, conductive mica powder (DM-1), carbon fibers (CF) as conductive fillers, respectively, and iron red, organic red 144, iron yellow, organic yellow 151 as pigments with solvent blending method. The as-prepared films were investigated by the electrical properties, CIE color performance, dispersion and mechanical properties.The electrical measurements showed that the percolation threshold of superconductive carbon black in TPU matrix was 6%-7%, and the volume resistivity of the film is 3.03×103?·cm, which reached the level of conductivity. Moreover, the CIE color measurements showed that the superconductive carbon black had no effect on the color performance of films.The light grey antistatic TPU films were prepared by adding DM-1. And the red antistatic TPU films were prepared by adding DM-1 and iron red pigments, organic red 144 pigments, respectively. The yellow antistatic TPU films were prepared by adding DM-1 and iron yellow pigments, organic yellow 151 pigments, respectively. We found that the volume resistivity of the light grey antistatic TPU film was 6.82×109 ?·cm when DM-1 content was 23.1%, which reached the antistatic level. Under the same DM-1 content, its tensile strength was 26MPa. When the DM-1 content was 33.3%, its color performance became stable, while the dispersion of DM-1 in the TPU matrix became difficult. In addition, the light grey antistatic TPU films could be colored successfully with iron red pigments and organic red 144 pigments. And iron red pigments had a better color stability than organic red 144 pigments for light grey antistatic TPU films and was more consistent with single-constant Kubelka-Munk theory. Thereinto, the color performance of red antistatic TPU films became stable when the red iron pigments content was 2%. The light grey antistatic TPU films could also be colored successfully with iron yellow pigments. However, it was failed to color the light grey antistatic TPU films with organic yellow 151 pigments because of the color change from yellow to green. It is nice to see that the addition of above four pigments had little influence on the volume resistivity and tensile strength of chromatic antistatic TPU films.The conductive CF/TPU films and the conductive Ti-CF/TPU films were prepared with carbon fiber (CF) and modified carbon fiber by titanate coupling agent (Ti-CF) as conductive fillers, respectively. And the red conductive Ti-CF/TPU films were prepared through adding iron red pigments. We found that the conductive conductivity and mechanical properties of the conductive Ti-CF/TPU films were better than unmodified films, its percolation threshold was 5-6%. When Ti-CF content was 6%, its volume resistivity of the film was 961 ?·cm, which reached the level of conductivity. When Ti-CF content was 4%, the tensile strength was increased to 41.7MPa compared with pure TPU, but CF begun to twine from the optical microscope photographs of dispersion. The conductive Ti-CF/TPU films could be colored successfully with iron red pigments. When the iron red content was 2.5%, the color performance of red conductive Ti-CF/TPU films became stable. And the addition of iron red pigments had little influence on the volume resistivity and tensile strength of red conductive Ti-CF/TPU films.