For you materials engineers:
Ting Ge1, Flint Pierce2,3, Dvora Perahia3, Gary S. Grest2, and Mark O. Robbins1
1Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
2Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
3Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
Received 20 November 2012; published 28 February 2013; corrected 6 March 2013
Large-scale simulations of thermal welding of polymers are performed to investigate the rise of mechanical strength at the polymer-polymer interface with the welding time tw. The welding process is at the core of integrating polymeric elements into devices as well as in the thermal induced healing of polymers, processes that require the development of interfacial strength equal to that of the bulk. Our simulations show that the interfacial strength saturates at the bulk shear strength long before polymers diffuse by their radius of gyration. Along with the strength increase, the dominant failure mode changes from chain pullout at the interface to chain scission as in the bulk. The formation of sufficient entanglements across the interface, which we track using a primitive path analysis, is required to arrest catastrophic chain pullout at the interface. The bulk response is not fully recovered until the density of entanglements at the interface reaches the bulk value. Moreover, the increase of interfacial strength before saturation is proportional to the number of interfacial entanglements between chains from opposite sides.
© 2013 American Physical Society
URL:
[
link.aps.org]
DOI:
10.1103/PhysRevLett.110.098301
PACS:
82.35.Gh, 68.35.Fx, 81.20.Vj, 83.10.Mj
