Stress-Optical Properties of Rubber

1947 ◽  
Vol 20 (4) ◽  
pp. 907-909
Author(s):  
L. R. G. Treloar
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Quantitative Description ◽  
Refractive Indices ◽  
Chain Molecules ◽  
Strain Ellipsoid ◽  
Principal Axes ◽  
Special Case ◽  
Homogeneous Strain ◽  
Long Chain

Abstract Considerable progress in the quantitative description of the mechanical properties of rubber has taken place in recent years by the consideration of a rubber as a network of statistically kinked long-chain molecules. A treatment of the optical properties of strained rubber on this basis, with the assumption that the links of the molecular chain are themselves optically anisotropic, has been developed by Kuhn and Grün for the special case of simple elongation, and by me for general homogeneous strain. In the latter case, the rubber has three principal refractive indices, n1, n2, and n3, corresponding to the three principal axes of the strain ellipsoid.

scholarly journals Homogeneous deformation of the gneisses of Vesterland, South-West Greenland

1968 ◽  
Vol 78 ◽  
pp. 1-76
Author(s):  
J Watterson
Keyword(s):  
Three Dimensional ◽  
Homogeneous Deformation ◽  
Structural Development ◽  
Deformation Path ◽  
West Greenland ◽  
Strain Ellipsoid ◽  
South West ◽  
Principal Axes ◽  
The Relationship ◽  
Homogeneous Strain

Structural development of the migmatitic gneisses of the Vesterland area is described first by reference to successive fold episodes (FCF3) and then by reference to the estimated pattern of three-dimensional homogeneous strain. Mylonite zones, up to 2 km in width, are located along attenuated steep limbs of relatively open F3 folds. In acid gneisses F. folds are usually isoclinal, with axial planes and axes parallel to those of F1 folds. In basic gneisses F2 folds are of relatively open style and both axes and axial planes differ from those of F1 folds. The macroscopic penetrative fabric of the gneisses is of the L-S type in which three mutually perpendicular axes can be recognised on a variety of scales, the axes corresponding to the principal axes of the strain ellipsoid. The strain ellipsoid corresponding to deformation in the acid gneisses, as estimated from the disposition of discordant acid veins, is of prolate type, with deformation path (k) approximately 17, and axial ratios 1:3:100. The relationship between homogeneous deformation and varying styles and attitudes of F1 and F2 folds is discussed.

The Photoelastic Properties of Rubber. I. Theory of the Optical Properties of Strained Rubber

1948 ◽  
Vol 21 (2) ◽  
pp. 347-355
Author(s):  
L. R. G. Treloar
Keyword(s):  
Optical Constants ◽  
Light Propagation ◽  
Refractive Indices ◽  
Cube Root ◽  
Biaxial Crystal ◽  
Principal Stresses ◽  
Vulcanized Rubber ◽  
Principal Axes ◽  
The Difference ◽  
Homogeneous Strain

Abstract From the consideration of vulcanized rubber as a network of randomly kinked molecular chains, the optical constants corresponding to the most general type of homogeneous strain are derived. Under such a strain the rubber is shown to acquire the properties of an optically biaxial crystal, characterized by three principal refractive indices in the directions of the principal axes of strain. For directions of light propagation parallel to one of the principal axes, the birefringence is shown to be a simple function of the principal extensions and is, moreover, proportional to the difference between the two corresponding principal stresses. If the rubber is swollen with a liquid having the same refractive index as itself, the birefringence for a given state of strain varies inversely as the cube root of the swelling ratio, as do also the principal stresses.

scholarly journals DFT Study of Electronic Structure and Optical Properties of Kaolinite, Muscovite, and Montmorillonite

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 618
Author(s):  
Layla Shafei ◽  
Puja Adhikari ◽  
Wai-Yim Ching
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Electronic Structure ◽  
Hydrogen Bonds ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Bond Order ◽  
Deep Understanding ◽  
Pharmaceutical Applications ◽  
Structure Properties

Clay mineral materials have attracted attention due to their many properties and applications. The applications of clay minerals are closely linked to their structure and composition. In this paper, we studied the electronic structure properties of kaolinite, muscovite, and montmorillonite crystals, which are classified as clay minerals, by using DFT-based ab initio packages VASP and the OLCAO. The aim of this work is to have a deep understanding of clay mineral materials, including electronic structure, bond strength, mechanical properties, and optical properties. It is worth mentioning that understanding these properties may help continually result in new and innovative clay products in several applications, such as in pharmaceutical applications using kaolinite for their potential in cancer treatment, muscovite used as insulators in electrical appliances, and engineering applications that use montmorillonite as a sealant. In addition, our results show that the role played by hydrogen bonds in O-H bonds has an impact on the hydration in these crystals. Based on calculated total bond order density, it is concluded that kaolinite is slightly more cohesive than montmorillonite, which is consistent with the calculated mechanical properties.

scholarly journals Improving Rheological and Mechanical Properties of Various Virgin and Recycled Polypropylenes by Blending with Long-Chain Branched Polypropylene

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1137
Author(s):  
Sascha Stanic ◽  
Thomas Koch ◽  
Klaus Schmid ◽  
Simone Knaus ◽  
Vasiliki-Maria Archodoulaki
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Test ◽  
Reactive Extrusion ◽  
Original Material ◽  
Melt Flow Rate ◽  
Single Screw Extruder ◽  
Pp Blends ◽  
The Impact ◽  
Long Chain

Blends of two long-chain branched polypropylenes (LCB-PP) and five linear polypropylenes (L-PP) were prepared in a single screw extruder at 240 °C. The two LCB-PPs were self-created via reactive extrusion at 180 °C by using dimyristyl peroxydicarbonate (PODIC C126) and dilauroyl peroxide (LP) as peroxides. For blending two virgin and three recycled PPs like coffee caps, yoghurt cups and buckets with different melt flow rate (MFR) values were used. The influence of using blends was assessed by investigating the rheological (dynamic and extensional rheology) and mechanical properties (tensile test and impact tensile test). The dynamic rheology indicated that the molecular weight as well as the molecular weight distribution could be increased or broadened. Also the melt strength behavior could be improved by using the two peroxide modified LCB-PP blends on the basis of PODIC C126 or PEROXAN LP (dilauroyl peroxide). In addition, the mechanical properties were consistently enhanced or at least kept constant compared to the original material. In particular, the impact tensile strength but also the elongation at break could be increased considerably. This study showed that the blending of LCB-PP can increase the investigated properties and represents a promising option, especially when using recycled PP, which demonstrates a real “up-cycling” process.

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