Ultrasonic Investigation of the Gelation Process of Poly(Acrylamide) Gels
Ultrasonic Investigation of the Gelation Process of Poly(Acrylamide) Gels
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DOI：
10.1002/masy.200651029
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发表时间：
2006-10
影响因子：
--
通讯作者：
T. Norisuye;A. Strybulevych;M. Scanlon;J. Page
中科院分区：
文献类型：
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作者：
T. Norisuye;A. Strybulevych;M. Scanlon;J. Page
研究了聚丙烯酰胺（PAAm）水凝胶成胶过程中超声声速和衰减随时间的变化规律。纵向超声脉冲通过凝胶样品传输并连续记录，以获得作为时间和频率的函数的波的幅度和相位，从而能够确定PAAm凝胶的衰减系数α和相速度v p。该反应的特征在于：（1）α和vp的初始快速增加，和（2）在这两个量通过与PAAm凝胶化的放热反应相关的峰之后，随后降低。vp的平方与样品的纵向模量成正比，与密度成反比，老化凝胶的vp值小于凝胶化前的值。进一步研究了交联剂浓度依赖性，以研究伴随相分离的凝胶化过程。
The time evolution of ultrasonic velocity and attenuation has been investigated in-situ during the gelation process of polyacrylamide (PAAm) hydrogels. Longitudinal ultrasonic pulses were transmitted through the gel samples and continuously recorded to obtain the magnitude and phase of the waves as a function of time and frequency, enabling the attenuation coefficient, α, and phase velocity, v p , of PAAm gels to be determined. The reaction was characterized by (1) an initial rapid increase in α and v p , and (2) a subsequent reduction after both quantities passed through a peak associated with the exothermic reaction for the PAAm gelation. The square of v p is proportional to the longitudinal modulus of the sample and inversely proportional to the density, and the values of v p for the aged gels were smaller than those before the gelation. The cross-linker concentration dependence was further examined in order to investigate the gelation process accompanied by phase separation.