Dynamic viscoelasticity measurements were carried out for N, N-dimethylacetamide solutions of polyacrylonitrile (PAN) frozen at −40 °C to characterize the effect of concentration in the frozen state in relation to the freezing and thawing method of the PAN gel. The storage (G′) and loss moduli (G″) were measured for samples obtained by separating the frozen and unfrozen regions during the thawing step. The G′ were also acquired for solutions without the separation (referred to as post-thawing solution), written as ${G^{\prime }}_{\text{fro}}^{}$ ${G^{\prime }}_{\text{unfro}}^{}$ and ${G^{\prime }}_{{}_{\text{post}-\text{thaw}}}^{}$ for frozen region, unfrozen region, and post-thawing solution, respectively. The relationship, ${G^{\prime }}_{\text{unfro}}^{}$ < ${G^{\prime }}_{{}_{\text{post}-\text{thaw}}}^{}$ < ${G^{\prime }}_{\text{fro}}^{}$ was observed, showing that regions of higher and lower concentrations were developed in the thawing step. (${G^{\prime }}_{\text{fro}}^{}$/${G^{\prime }}_{{}_{\text{post}-\text{thaw}}}^{}$) was considered a relative index of the concentration increase, to be compared for those of the initial and later stages within the thawing step. (${G^{\prime }}_{\text{fro}}^{}$/${G^{\prime }}_{{}_{\text{post}-\text{thaw}}}^{}$) was much greater than 1 in the initial stage, and then decreased and approached 1 in the later stage. The behavior of (${G^{\prime }}_{\text{fro}}^{}$/${G^{\prime }}_{{}_{\text{post}-\text{thaw}}}^{}$) was discussed with reference to the effects of freezing time and concentration on the gelation time. The microscopic separation between the dilute and concentrated phases induced at the freezing step was proposed as the physical process to interpret the viscoelastic data.

对在-40℃下冷冻的聚丙烯腈（PAN）的N，N-二甲基乙酰胺溶液进行了动态粘弹性测量，以表征在冷冻状态下浓度相对于PAN凝胶的冷冻和解冻方法的影响。存储（G' ）和损耗模量（G“ ），用于通过在解冻工序中分离出冷冻和解冻的区域获得的样品进行测定。的G'分别还获得了解决方案，而分离（称为后解冻的溶液），写为${G^{\prime }}_{\text{来回}}^{}$ ${G^{\prime }}_{\text{来回}}^{}$ 和 ${G^{\prime }}_{{}_{\text{邮政}-\text{解冻}}}^{}$分别用于冷冻区，未冷冻区和解冻后溶液。关系，${G^{\prime }}_{\text{来回}}^{}$ < ${G^{\prime }}_{{}_{\text{邮政}-\text{解冻}}}^{}$ < ${G^{\prime }}_{\text{来回}}^{}$观察到，表明在解冻步骤中形成了较高和较低浓度的区域。（${G^{\prime }}_{\text{来回}}^{}$/${G^{\prime }}_{{}_{\text{邮政}-\text{解冻}}}^{}$）被认为是浓度增加的相对指数，将其与解冻步骤中初始阶段和后期阶段的相对指数进行比较。（${G^{\prime }}_{\text{来回}}^{}$/${G^{\prime }}_{{}_{\text{邮政}-\text{解冻}}}^{}$）在初始阶段远大于1，然后下降并在后期接近1。（的行为${G^{\prime }}_{\text{来回}}^{}$/${G^{\prime }}_{{}_{\text{邮政}-\text{解冻}}}^{}$讨论了冷冻时间和浓度对胶凝时间的影响。在冷冻步骤中诱导的稀相和浓相之间的微观分离被提议为解释粘弹性数据的物理过程。