Rheological experiments at constant stress as efficient method to characterize polymeric materials

Helmut Münstedt

doi:10.1122/1.4866049

Time Dependances of the Resistance Coefficients of Polymeric Materials

INEOS OPEN ◽

10.32931/io2016a ◽

2020 ◽

Vol 3 ◽

Author(s):

A. V. Matseevich ◽

◽

A. A. Askadskii ◽

Keyword(s):

Time Dependence ◽

Physical Mechanism ◽

Polymeric Materials ◽

Resistance Coefficient ◽

Constant Stress ◽

Time To Rupture ◽

Structure Sensitive ◽

Material Durability ◽

Resistance Coefficients ◽

Extremal Character

One of the possible approaches to the analysis of a physical mechanism of time dependence for the resistance coefficients of materials is suggested. The material durability at the constant stress is described using the Zhurkov and Gul' equations and the durability at the alternating stress—using the Bailey criterion. The low strains lead to structuring of a material that is reflected in a reduction of the structure-sensitive coefficient in these equations. This affords 20% increase in the durability. The dependence of the resistance coefficient assumes an extremal character; the maximum is observed at the time to rupture lg tr ≈ 2 (s).

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Elasticity of Soft Polymers. Constant-Stress Elongation Tests

Rubber Chemistry and Technology ◽

10.5254/1.3543376 ◽

1952 ◽

Vol 25 (1) ◽

pp. 56-70

Author(s):

C. A. Dahlquist ◽

J. O. Hendricks ◽

N. W. Taylor

Keyword(s):

Time Dependence ◽

Viscous Flow ◽

Empirical Equation ◽

Relaxation Times ◽

Polymeric Materials ◽

Constant Stress ◽

Elastic Behavior ◽

Total Deformation ◽

Test Conditions ◽

Elastic Processes

Abstract The elastic properties of polymeric materials which are too soft to test on conventional stress-strain machines can be obtained by elongation at constant stress. A simple apparatus has been developed for maintaining constant stress during elongation. Data illustrate the time dependence of the elastic behavior of polymeric materials and demonstrate the usefulness of the constant-stress method in the evaluation of this time dependence. The constant-stress method is useful in the evaluation of plasticizers for gum rubbers. Because of the difficulty of separating highly delayed elastic elongation from viscous flow, the method has not been found practical as a tool for measurement of viscosity in the solid state. However, under most test conditions, viscous flow has been a negligible fraction of the total deformation. Several terms for delayed elasticity are required to fit an empirical equation to the elongation-time curves, and it seems probable that these terms are only an approximation of a very large number of delayed elastic processes having different relaxation times.

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Construction of Supramolecular Polymers with Different Topologies by Orthogonal Self-Assembly of Cryptand–Paraquat Recognition and Metal Coordination

Molecules ◽

10.3390/molecules26040952 ◽

2021 ◽

Vol 26 (4) ◽

pp. 952

Author(s):

Kai Wang ◽

Yuan-Guang Shao ◽

Feng-Zhi Yan ◽

Zibin Zhang ◽

Shijun Li

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Efficient Method ◽

Self Assembly ◽

Polymeric Materials ◽

Proton Nuclear Magnetic Resonance ◽

Supramolecular Polymers ◽

Pyridyl Group ◽

The Third ◽

And Diffusion

Recently, metal-coordinated orthogonal self-assembly has been used as a feasible and efficient method in the construction of polymeric materials, which can also provide supramolecular self-assembly complexes with different topologies. Herein, a cryptand with a rigid pyridyl group on the third arm derived from BMP32C10 was synthesized. Through coordination-driven self-assembly with a bidentate organoplatinum(II) acceptor or tetradentate Pd(BF4)2•4CH3CN, a di-cryptand complex and tetra-cryptand complex were prepared, respectively. Subsequently, through the addition of a di-paraquat guest, linear and cross-linked supramolecular polymers were constructed through orthogonal self-assembly, respectively. By comparing their proton nuclear magnetic resonance (1H NMR) and diffusion-ordered spectroscopy (DOSY) spectra, it was found that the degrees of polymerization were dependent not only on the concentrations of the monomers but also on the topologies of the supramolecular polymers.

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The Resolution and Contrast in Biological Sections Determined by Inelastic and Elastic Scattering

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071569 ◽

1973 ◽

Vol 31 ◽

pp. 224-225

Author(s):

D. L. Misell

Keyword(s):

Electron Microscopy ◽

Adverse Effect ◽

Elastic Scattering ◽

Inelastic Scattering ◽

Amorphous Carbon ◽

Polymeric Materials ◽

Chromatic Aberration ◽

Image Resolution ◽

Quantitative Estimates ◽

Elastic Ratio

In the electron microscopy of biological sections the adverse effect of chromatic aberration on image resolution is well known. In this paper calculations are presented for the inelastic and elastic image intensities using a wave-optical formulation. Quantitative estimates of the deterioration in image resolution as a result of chromatic aberration are presented as an alternative to geometric calculations. The predominance of inelastic scattering in the unstained biological and polymeric materials is shown by the inelastic to elastic ratio, I/E, within an objective aperture of 0.005 rad for amorphous carbon of a thickness, t=50nm, typical of biological sections; E=200keV, I/E=16.

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Application Of Electron Microscopy To Automotive Finish Defect Analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134892 ◽

1990 ◽

Vol 48 (2) ◽

pp. 258-259

Author(s):

Martin J. Mahon ◽

Patrick W. Keating ◽

John T. McLaughlin

Keyword(s):

Electron Microscopy ◽

Zero Tolerance ◽

Polymeric Materials ◽

Plant Management ◽

Defect Analysis ◽

X Ray ◽

Root Cause ◽

Cutting Out ◽

Foreign Materials ◽

Automotive Finish

Coatings are applied to appliances, instruments and automobiles for a variety of reasons including corrosion protection and enhancement of market value. Automobile finishes are a highly complex blend of polymeric materials which have a definite impact on the eventual ability of a car to sell. Consumers report that the gloss of the finish is one of the major items they look for in an automobile.With the finish being such an important part of the automobile, there is a zero tolerance for paint defects by auto assembly plant management. Owing to the increased complexity of the paint matrix and its inability to be “forgiving” when foreign materials are introduced into a newly applied finish, the analysis of paint defects has taken on unparalleled importance. Scanning electron microscopy with its attendant x-ray analysis capability is the premier method of examining defects and attempting to identify their root cause.Defects are normally examined by cutting out a coupon sized portion of the autobody and viewing in an SEM at various angles.

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Colloidal systems in soils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168050 ◽

1994 ◽

Vol 52 ◽

pp. 64-65

Author(s):

J. Thieme ◽

J. Niemeyer ◽

P. Guttman

Keyword(s):

Clay Minerals ◽

Polymeric Materials ◽

Spatial Arrangement ◽

High Specific Surface Area ◽

Turnover Rates ◽

Colloidal Systems ◽

Chemical Conditions ◽

Aggregation Phenomena ◽

Iron And Manganese ◽

Soil Colloids

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.

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Pyridyl disulfide-based thiol–disulfide exchange reaction: shaping the design of redox-responsive polymeric materials

Polymer Chemistry ◽

10.1039/d0py01215g ◽

2020 ◽

Vol 11 (48) ◽

pp. 7603-7624

Author(s):

Ismail Altinbasak ◽

Mehmet Arslan ◽

Rana Sanyal ◽

Amitav Sanyal

Keyword(s):

Exchange Reaction ◽

Functional Materials ◽

Polymeric Materials ◽

Disulfide Exchange ◽

Redox Responsive ◽

Synthetic Approaches

This review provides an overview of synthetic approaches utilized to incorporate the thiol-reactive pyridyl-disulfide motif into various polymeric materials, and briefly highlights its utilization to obtain functional materials.

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