scholarly journals A science friction story – Molecular interactions in semiflexible polymer networks

2021 ◽  
Author(s):  
Paul Mollenkopf ◽  
Dusan Prascevic ◽  
Martin Glaser ◽  
David M. Smith ◽  
Jörg Schnauß
Keyword(s):  
Molecular Interactions ◽  
Mechanical Response ◽  
Polymer Networks ◽  
Intermediate Frequency ◽  
Model Systems ◽  
Semiflexible Polymers ◽  
Friction Forces ◽  
Semiflexible Polymer ◽  
Frequency Regime ◽  
Nonlinear Deformations

AbstractEstablished model theories, developed to capture the mechanical behavior of soft complex materials composed of semiflexible polymers assume entropic interactions between filaments to determine the mechanical response. In recent studies, the general accepted tube model has been challenged in terms of its basic assumption about filament-filament interactions, but also because of its predictions regarding the frequency dependence of the elastic modulus in the intermediate frequency regime. A central question is how molecular interactions and friction between network constituents influence the rheological response of isotropic entangled networks of semiflexible polymers. It was shown that friction forces between aligned pairs of actin filaments are not negligible. Here, we systematically investigate the influence of friction forces and attractive interactions on network rheology by means of a targeted surface modification. We show that these forces have a qualitative and quantitative influence on the viscoelastic properties of semiflexible polymer networks and contribute to the response to nonlinear deformations. By comparing two polymer model systems with respect to their surface compositions we give a possible explanation about the origin of acting forces on a molecular level.

scholarly journals The role of stickiness in the rheology of semiflexible polymers

Soft Matter ◽  
2019 ◽  
Vol 15 (24) ◽  
pp. 4865-4872 ◽  
Author(s):  
Tom Golde ◽  
Martin Glaser ◽  
Cary Tutmarc ◽  
Iman Elbalasy ◽  
Constantin Huster ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Polymer Networks ◽  
Semiflexible Polymers ◽  
Semiflexible Polymer

The rheological properties of semiflexible polymer networks are strongly affected by a polymer specific stickiness.

scholarly journals Impact-sliding wear response of 2.25Cr1Mo steel tubes: Experimental and semi-analytical method

Friction ◽  
2021 ◽  
Author(s):  
Meigui Yin ◽  
Chaise Thibaut ◽  
Liwen Wang ◽  
Daniel Nélias ◽  
Minhao Zhu ◽  
...  
Keyword(s):  
Sliding Wear ◽  
Power Plants ◽  
Mechanical Response ◽  
Wear Behavior ◽  
Wear Test ◽  
Steel Tube ◽  
Wear Depth ◽  
Sliding Velocity ◽  
Friction Forces ◽  
The Impact

AbstractThe impact-sliding wear behavior of steam generator tubes in nuclear power plants is complex owing to the dynamic nature of the mechanical response and self-induced tribological changes. In this study, the effects of impact and sliding velocity on the impact-sliding wear behavior of a 2.25Cr1Mo steel tube are investigated experimentally and numerically. In the experimental study, a wear test rig that can measure changes in the impact and friction forces as well as the compressive displacement over different wear cycles, both in real time, is designed. A semi-analytical model based on the Archard wear law and Hertz contact theory is used to predict wear. The results indicate that the impact dynamic effect by the impact velocity is more significant than that of the sliding velocity, and that both velocities affect the friction force and wear degree. The experimental results for the wear depth evolution agree well with the corresponding simulation predictions.

scholarly journals Structure and mechanics of aegagropilae fiber network

2017 ◽  
Vol 114 (18) ◽  
pp. 4607-4612 ◽  
Author(s):  
Gautier Verhille ◽  
Sébastien Moulinet ◽  
Nicolas Vandenberghe ◽  
Mokhtar Adda-Bedia ◽  
Patrice Le Gal
Keyword(s):  
Mechanical Response ◽  
Posidonia Oceanica ◽  
Biological Tissues ◽  
Individual Response ◽  
Fiber Network ◽  
Friction Forces ◽  
Fiber Clustering ◽  
Wide Range ◽  
Natural Aggregates ◽  
The Individual

Fiber networks encompass a wide range of natural and manmade materials. The threads or filaments from which they are formed span a wide range of length scales: from nanometers, as in biological tissues and bundles of carbon nanotubes, to millimeters, as in paper and insulation materials. The mechanical and thermal behavior of these complex structures depends on both the individual response of the constituent fibers and the density and degree of entanglement of the network. A question of paramount importance is how to control the formation of a given fiber network to optimize a desired function. The study of fiber clustering of natural flocs could be useful for improving fabrication processes, such as in the paper and textile industries. Here, we use the example of aegagropilae that are the remains of a seagrass (Posidonia oceanica) found on Mediterranean beaches. First, we characterize different aspects of their structure and mechanical response, and second, we draw conclusions on their formation process. We show that these natural aggregates are formed in open sea by random aggregation and compaction of fibers held together by friction forces. Although formed in a natural environment, thus under relatively unconstrained conditions, the geometrical and mechanical properties of the resulting fiber aggregates are quite robust. This study opens perspectives for manufacturing complex fiber network materials.

scholarly journals Mechanics of Bundled Semiflexible Polymer Networks

2007 ◽  
Vol 99 (8) ◽  
Author(s):  
O. Lieleg ◽  
M. M. A. E. Claessens ◽  
C. Heussinger ◽  
E. Frey ◽  
A. R. Bausch
Keyword(s):  
Polymer Networks ◽  
Semiflexible Polymer

Properties of Highly Filled, Highly Plasticized, Semicrystalline Polymer Networks

1991 ◽  
Vol 64 (2) ◽  
pp. 181-201 ◽  
Author(s):  
Richard D. Vargo ◽  
Frank N. Kelley
Keyword(s):  
Tensile Strength ◽  
Mechanical Response ◽  
Polymer Networks ◽  
Three Dimensional ◽  
Important Variable ◽  
Failure Behavior ◽  
Energy Data ◽  
Viscoelastic Effects ◽  
Tearing Energy ◽  
Increasing Temperature

Abstract 1. Component reactivity of ingredients such as fillers and plasticizers is significant and is measurable by a technique developed during this work. 2. The undesirable syneresis problem common to these highly plasticized materials can be controlled through adjusting equivalence ratios. Syneresis can be controlled primarily by decreasing the crystallinity of the material. 3. Changing percent crystallinity with temperature is a very important variable controlling the physical properties, i.e., ultimate properties, tearing energy, and dynamic-mechanical response. 4. The tearing energy data did not display simple amorphous behavior, and, as such, could not be shifted using a reduced variables technique such as WLF shifting. All variables were needed to represent the data. Three dimensional plotting developed previously by von Merrwall et al. was utilized to represent the data. The resulting tear-energy data exhibit the normal viscoelastic effects of rate and temperature as well as the superposition of the effects of crystallinity on the tearing energy. A decrease in tearing energy with increasing temperature is primarily due to increasing crystallinity in the samples. Plasticizer decreased the tearing energy, while filler increased the tearing energy. Filler lessened the effects of temperature and plasticizer on tearing energy. 5. Ultimate property measurements using ring samples for these model propellants revealed that these materials did not behave in a simple thermo-rheological manner, since crystallinity effects are predominant in the tensile mode. Because of crystallinity and strain-induced crystallinity, the data could not be represented by a failure envelope as proposed by Smith. The presence of plasticizer has the effect of decreasing the tensile strength, while filler tends to increase the tensile strength for the plasticized systems. 6. A model is presented to explain the high strain-to-failure behavior of these systems. Further details of this work can be found in Reference 22.

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