Neutron Results on Stretched Polymers Question the Classical Model of Polymer Flow
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Neutron Results on Stretched Polymers Question the Classical Model of Polymer Flow

Scientific AchievementLeft frame: Illustration of SANS measurements on uniaxially elongated samples: the stretching is along the z axis, whereas the incident SANS beam is perpendicular to the xz plane. The right frame shows the spherical harmonic decomposition of the SANS spectrum of deformed polymer.

A new mathematical framework extracts details of molecular relaxation in deformed polymers from small-angle neutron scattering(SANS) results and shows disagreement with the classical model.

Significance and Impact

Understanding nonlinear flow behavior of entangled polymers plays a key role in the processing of commercial rubber and plastic products.

Research Details

– A novel method has been developed to extract “fingerprint features” of molecular relaxation of deformed polymer from SANS measurements.

– The results on stretched polystyrenes provide decisive evidence against the chain retraction mechanism of the classical tube model by Doi and Edwards, calling for a revision of the current theoretical picture for nonlinear rheology of entangled polymers

Z. Wang, C.N. Lam, W.-R. Chen, W. Wang, J. Liu, Y. Liu, L. Porcar, C.B. Stanley, Z. Zhao, K. Hong, and Y. Wang, “Fingerprinting Molecular Relaxation in Deformed Polymers,” Phys. Rev. X 7, 031003 (2017). DOI: 10.1103/PhysRevX.7.031003

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