Swelling and Stress Relaxation of Stretched Gels near the Volume Phase Transition Point

拉伸凝胶在体积相变点附近的膨胀和应力松弛

• 批准号: 08651076
• 负责人: TAKIGAWA Toshikazu
• 金额: $ 1.28万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08651076/
• 关键词: Polymer Gel; Volume Phase Transition; Uniaxial Elongation; Swelling; Stress Relaxation; Diffusion; ゲル

Swelling and mechanical properties were investigated for poly (acrylamide)(PAAm) and poly (N-isopropylacrylamide)(PNIPA) gels. The degree of swelling and equilibrium stress values under uniaxial deformation were measured for PAAm gels and were compared with those from the theoretical prediction. The values obtained from the experiment agreed fairly well with the theoretical prediction. Deswelling kinetics of PNIPA gels measured by a temperature (T) jump across the volume phase transition temperature showed that the relaxation time for the volume change is of the same order of magnitude of the vanishing time of the heterogeneous region inside the gels at long times. The relaxation time decreased with increasing final temperature of the T-jump. Initial Young's modulus (E_0) of PNIPA gels were measured both in swollen and collapsed states, and the concentration dependence of E_0 was investigated. The value of E_0 in the collapsed state was much higher than that estimated using the values in the swollen state, suggesting that the number of crosslinks increased at the volume phase transition from swollen to collapsed states. The crosslinks were considered to be a sequence of hydrogen bonds between the polymer chains.

研究了聚丙烯酰胺（PAAm）和聚N-异丙基丙烯酰胺（PNIPA）凝胶的溶胀和力学性能。单轴变形下的溶胀度和平衡应力值的PAAm凝胶进行了测量，并与理论预测的那些进行了比较。从实验中得到的值与理论预测相当吻合。通过温度（T）跨越体积相变温度的跳跃测量PNIPA凝胶的去溶胀动力学表明，体积变化的弛豫时间与凝胶内部的非均相区域在长时间内的消失时间具有相同的数量级。弛豫时间随T跃终温的升高而减小。测量了PNIPA凝胶在溶胀和塌陷状态下的初始杨氏模量（E_0），并研究了E_0的浓度依赖性。塌陷状态下的E_0值远高于溶胀状态下的E_0值，表明在从溶胀状态到塌陷状态的体积相变过程中交联数目增加。交联被认为是聚合物链之间的氢键序列。

项目成果

瀧川 敏算: "Osmotic Poisson′s Ratio and Equilibriom Stress of Poly (acrylamide)Gels" Polym.J.28. 1012-1013 (1996)

Toshikazu Takikawa：“聚（丙烯酰胺）凝胶的渗透泊松比和平衡应力”Polym.J.28（1996）。

Toshikazu Takigawa: "Osmotic Poisson's Ratio and Equilibrium Stress of Poly(acrylamide)Gels" Polymer Journal. 28・11. 1012-1013 (1996)

泷川俊和：“聚丙烯酰胺凝胶的渗透泊松比和平衡应力”聚合物杂志 28・11（1996）。

Toshikazu Takigawa: "Stress Relaxation of Poly(N-isopropylacrylamide)Gels in the Collapsed State" J.Soc.Rheol.Jpn.25(4). 207-209 (1997)

Toshikazu Takikawa：“聚（N-异丙基丙烯酰胺）凝胶在塌陷状态下的应力松弛”J.Soc.Rheol.Jpn.25(4)。

瀧川敏算: "Change in Young′s Modulus of Poly (N-isopropylacrylamide) Gels by Volume Phase Transition" Polymer Gels & Networks. (1998)

Tosisa Takikawa：“通过体积相变改变聚（N-异丙基丙烯酰胺）凝胶的杨氏模量”聚合物凝胶和网络（1998）。

Toshikazu Takigawa: "Osmotic Poisson's Ratio and Equilibrium Stress of Poly(acrylamide)Gels" Polym.J.28(11). 1012-1013 (1996)

Toshikazu Takikawa：“聚（丙烯酰胺）凝胶的渗透泊松比和平衡应力”Polym.J.28(11)。