Biaxial extensional flow behavior of monodisperse polystyrene melts

抄録

<jats:title>Abstract</jats:title><jats:p>Biaxial extensional flow behavior of monodisperse polystyrene melts has been investigated by using a lubricated squeezing flow method at constant strain rates. Master curves for the biaxial stress growth coefficient η<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/tex2gif-stack-1.gif" xlink:title="urn:x-wiley:03237648:media:ACTP010460309:tex2gif-stack-1" /> are obtained by applying the time‐temperature superposition principle. The coefficient η<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/tex2gif-stack-2.gif" xlink:title="urn:x-wiley:03237648:media:ACTP010460309:tex2gif-stack-2" /> deviates from a linear viscoelastic curve at very small strain such as 0.1, and then approaches a quasi steady state. The quasi‐steady‐state viscosity η<jats:sub>B,qs</jats:sub> decreases with the strain rate η<jats:sub>B</jats:sub>. At very small strain rates, the coefficient η<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/tex2gif-stack-3.gif" xlink:title="urn:x-wiley:03237648:media:ACTP010460309:tex2gif-stack-3" /> increases again after the quasi steady state and becomes much larger than the linear viscoelastic curve. The strain rate dependence curves of η<jats:sub>B,qs</jats:sub> obtained for different molecular weight samples can be superposed to give a super master curve using the weight‐average relaxation time η<jats:sub>0</jats:sub> as a reducing parameter. It is found that the biaxial viscosity η<jats:sub>B,qs</jats:sub> begins to decrease at much smaller reduced strain rate (ϵ<jats:sub>B</jats:sub>τ<jats:sub>0</jats:sub>=0.01) compared with the shear viscosity, which begins to decrease at reduced strain rate of about 1.0.</jats:p>

収録刊行物

被引用文献 (7)*注記

もっと見る

詳細情報

問題の指摘

ページトップへ