tailieunhanh - Conductive Polymers and Plastics in Industrial Applications Part 9

Tham khảo tài liệu 'conductive polymers and plastics in industrial applications part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Conductive Elastomer Foams 165 Table 1. Comparison of mechanical properties of PU and PPy PU foams Properties PU PPy PU Tensile strength 105 N m2 Elongation at break 143 160 Tear strength 103 N m Compression set Conductivity S cm 10-10 10-5 SEM or in the micrograph which indicates that the polymerization technique effectively isolated the conductive polymer within the dense polymer phase. That was also confirmed by the absence of marking when the conductive foams were rubbed upon a piece of white paper neat PPy is black and readily marks paper . The PPy had a granular texture with a grain size of about m. EDAX spectra showed three distinct emission peaks Si K keV Cl K keV and Fe K keV . The Si was due to the surfactant used in preparation of the foam. The strong Cl K peak was mostly due to Cl- dopant ions for the PPy and the weak Fe K peak was either from dopant ions in the form of FeCl4 or residual FeCl2 byproduct that was not removed during washing of the product. THERMAL STABILITY AND MECHANICAL PROPERTIES TGA thermograms of neat PU foam and the PPy PU composites were similar between 0-400oC which indicates that the in situ polymerization process did not affect the thermal stability of the PU foam. The mechanical properties of a PPy PU composite and the parent PU foam are compared in Table 1. Although the mechanical data are limited they do demonstrate that incorporation of low concentrations of PPy into the foam was not deleterious to the foam mechanical properties. In addition the resilience of the composite foam was qualitatively similar to that of the neat PU foam. CONCLUSIONS A process was developed for producing conductive elastomeric foams by polymerizing conductive polypyrrole or copolymers of pyrrole and N-methyl pyrrole in the cell walls and struts of a preformed polyurethane foam. The process consisted of first diffusing an oxidant into the dense polymer phase of a solvent-swollen foam and then diffusing