リサイクルPTFE焼成体の組織構造と機械強度に与える乳化重合PTFE粉末添加の影響

抄録

PTFE compacts fabricated using recycled PTFE powder show much lower mechanical strength than those fabricated using virgin PTFE powder. We reported in the previous paper that its main reason was the fibrous morphology which the virgin PTFE had but the recycled PTFE did not have. Then, in order to heighten the mechanical strength of the recycled PTFE compacts, we focused on the emulsion of PTFE which is called “dispersion” because the dry powder is easy to become a fiber form by suffering external stress. So in this study, PTFE compacts were fabricated using recycle PTFE and dispersion powder mixtures and the microstructure and mechanical properties of the obtained PTFE compacts were investigated. The porosity of the PTFE compacts decreased with an increase in dispersion powder content, was under 1% at more than 50wt% dispersion powder content and was 0% at 100wt% dispersion powder content. These results indicate that the PTFE compacts fabricated using recycle PTFE containing more than 50wt% dispersion powder can densify almost completely. Tensile strength of the PTFE compacts increased with an increase in dispersion powder content, that of the PTFE compact fabricated using recycle PTFE containing 50wt% dispersion powder reached 90% of that of the PTFE compact fabricated using only dispersion powder and was four times larger than that of the PTFE compact fabricated using only recycle PTFE powder, which resulted from not only poreless microstructure but also entangled structure of fibrous dispersion powder surrounding recycle PTFE particles. In addition, such PTFE compacts had lower tensile strength and larger tensile elongation, compared with those fabricated from normal virgin PTFE powders, which shows that they are particular PTFE compacts.