A constitutive analysis of extensional flows of polyisobutylene
作者:
M. H. Wagner,
A. Demarmels,
期刊:
Journal of Rheology
(AIP Available online 1990)
卷期:
Volume 34,
issue 6
页码: 943-958
ISSN:0148-6055
年代: 1990
DOI:10.1122/1.550107
出版商: The Society of Rheology
关键词: Integral viscoelastic constitutive equation;Polyisobutylene melt;Extensional flow;First normal stress difference;Second normal stress difference;ORGANIC POLYMERS;2−METHYLPROPENE;MELTS;STRAINS;RHEOLOGY;VISCOELASTICITY
数据来源: AIP
摘要:
By analyzing uniaxial, planar, ellipsoidal, and equibiaxial extension data, a viscoelastic constitutive equation of the single integral form is derived for a polyisobutylene (PIB) melt. Within experimental limits, time and strain effects are separable. The strain dependence corresponds to a Mooney‐type combination of Finger and Cauchy tensors, modified by a damping functionh(I1,I2), which depends on the strain invariantsI1andI2of the Finger tensor. It is shown that the ratio of the second to the first normal stress difference in shear flow β can be extracted from planar extension experiments. For the PIB melt considered, β turns out to be negative and equal to β=−0.27, and to be independent of strain. The influence of β on the tensions in general extensional flow is discussed.
点击下载:
PDF
(616KB)
返 回