The Prime Importance of Second-Order Effects in Rigid-Rod Polymers

1988 ◽  
Vol 134 ◽  
Author(s):  
Steven J. Deteresa ◽  
Richard J. Farris
Keyword(s):  
Compressive Stress ◽  
High Performance ◽  
Second Order ◽  
Shear Instability ◽  
Polymer Fibers ◽  
Order Effects ◽  
Axial Tensile ◽  
High Performance Polymer ◽  
Rigid Rod ◽  
Axial Compressive Stress

ABSTRACTThe torsion modulus of high performance rigid-rod polymer fibers is shown to be dependent on axial tensile stress. This behavior is one of at least second-order elasticity. Fiber ultimate tensile strengths are of the same magnitude as torsion moduli, and increases in torsion moduli in excess of 200% were observed for fibers under tension. Consideration of the effect of an axial compressive stress on fiber torsion modulus leads to a prediction of an elastic shear instability that initiates at a compressive stress approximately equal in magnitude to the zero-stress torsion modulus. Hence, it is concluded that the compressive strengths of high performance polymer fibers are limited by the onset of an elastic microstructural instability.

X-ray Diffraction Studies of the Axial Tensile Modulus of Rigid-Rod Polymer Fibers

1988 ◽  
Vol 134 ◽  
Author(s):  
P. Galen Lenhert ◽  
W. Wade Adams
Keyword(s):  
Tensile Modulus ◽  
Polymer Fibers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Axial Tensile ◽  
Heat Treated ◽  
Before And After ◽  
Control Computer ◽  
Rigid Rod ◽  
Fiber Sample

ABSTRACTWe report the design and use of a device to measure the axial tensile modulus of high modulus fibers by following the change in the meridional X-ray spacings as a function of applied tension. The device, which mounts on a Picker 4-circle automated diffractometer, applies tension to the fiber sample by a cantilever arrangement. Tension is measured by a strain gauge bridge on the cantilever arm. The tension is adjusted and read by the control computer, a VAX 11/730. Measurements made on PBZT and PBO fibers before and after heat treatment are reported. For PBZT fibers (as spun, and heat treated at 525° C and 650° C) with tensile moduli of 186, 283 and 290 GPa, the X-ray determined moduli are 348, 385 and 395 GPa. For PBO fibers (as spun and heat treated at 600° C and 665° C) with tensile moduli of 166, 318 and 290 GPa, the X-ray determined moduli are 387, 477 and 433 GPa. These modulus values are to be compared with theoretical values presented by Wierschke in the previous paper and sonic modulus values discussed by Jiang et al in the following paper.

scholarly journals Surface Activation of High Performance Polymer Fibers: A Review

2022 ◽  
pp. 1-32
Author(s):  
Carolin Gleissner ◽  
Justus Landsiedel ◽  
Thomas Bechtold ◽  
Tung Pham
Keyword(s):  
High Performance ◽  
Polymer Fibers ◽  
Surface Activation ◽  
High Performance Polymer

scholarly journals Experimental and Theoretical Research on the Compression Performance of CFRP Sheet Confined GFRP Short Pipe

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Feng Li ◽  
Qilin Zhao ◽  
Li Chen ◽  
Guojian Shao
Keyword(s):  
Compressive Stress ◽  
Theoretical Research ◽  
Geometrical Parameters ◽  
Hollow Section ◽  
Compression Performance ◽  
Iterative Calculation ◽  
Axial Tensile ◽  
Cfrp Sheet ◽  
Combined Structure ◽  
Axial Compressive Stress

The axial compressive strength of unidirectional FRP made by pultrusion is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. A theoretical iterative calculation approach was suggested to predict the ultimate axial compressive stress of the combined structure and analyze the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure. In this paper, the experimental and theoretical research on the CFRP sheet confined GFRP short pole was extended to the CFRP sheet confined GFRP short pipe, namely, a hollow section pole. Experiment shows that the bearing capacity of the GFRP short pipe can also be heightened obviously by confining CFRP sheet. The theoretical iterative calculation approach in the previous paper is amended to predict the ultimate axial compressive stress of the CFRP sheet confined GFRP short pipe, of which the results agree with the experiment. Lastly the influences of geometrical parameters on the new combined structure are analyzed.

Effect of Ti+, Ar+, N+ and He+ Ion Implantation on Aramid Fiber Adhesive Properties

1989 ◽  
Vol 170 ◽  
Author(s):  
J. Kalantar ◽  
D. S. Grummon ◽  
L. T. Drzal ◽  
I. H. Loh ◽  
R. A. Moody
Keyword(s):  
High Performance ◽  
Weak Interactions ◽  
Polymer Fibers ◽  
Environmental Stability ◽  
Adhesive Properties ◽  
Matrix Adhesion ◽  
High Performance Polymer ◽  
Reinforcement Fiber ◽  
Fiber Matrix ◽  
High Degree

AbstractComposites made with high performance polymer fibers can achieve axial properties comparable to those which use inorganic reinforcements, but with somewhat inferior interfacial properties. A high degree of chain alignment in polyaramids, such as Kevlar, produces weak interactions between adjacent polymers, resulting in poor transverse strength in the fiber, and low interfacial shear strength in composite systems. The latter controls many composite properties, such as transverse, shear and flexural strengths. Also, by reducing the tendency to form weak interfacial boundary layers, good fiber-matrix adhesion can enhance environmental stability. For these reasons, modifications to reinforcement fiber surfaces that promote fiber-matrix adhesion are frequently used to improve the performance of composites.

Polymeric Based Conducting Nanocomposites: Controlling The Distribution of the Conducting Phase

1998 ◽  
Vol 519 ◽  
Author(s):  
Richard. A. Vaia ◽  
Jar-Wha Lee ◽  
William Click ◽  
Gary Price ◽  
Chyi-Shan Wang
Keyword(s):  
High Performance ◽  
Phase Distribution ◽  
Reduction Reaction ◽  
Polymer Fibers ◽  
Conducting Phase ◽  
Metal Precursor ◽  
Flexible Polymer ◽  
Subsequent Conversion ◽  
Rigid Rod

AbstractThe optimization of bulk properties of polymeric based nano– and mesoscale composites require the ability to spatially control phase distribution. In this study, electrical conductivity is introduced by incorporation of a metal precursor via infiltration into the polymer host and subsequent conversion in–situ by a reducing agent, templating the morphology of the polymer matrix. Distribution of nano– and mesoscale metal particles in isotropic and anisotropic swollen polymer hosts is discussed relative to metal precursor and reducing reagent diffusion and their in–situ bimolecular reduction reaction. The swelling and infiltration procedure employed to form the composites is generally applicable to rigid–rod, semi–flexible and flexible polymer matrices and not restricted to special synthesis of metal containing or complexing polymers. As an example, high–performance rigid–rod polymer fibers containing an interpenetrating network of polymer microfibrils and silver are produced with d.c. conductivities in excess of 104 S/cm and tensile

scholarly journals Functional Coatings on High‐Performance Polymer Fibers for Smart Sensing

2020 ◽  
Vol 30 (14) ◽  
pp. 1910555 ◽  
Author(s):  
Henning Galinski ◽  
Daniel Leutenegger ◽  
Martin Amberg ◽  
Fabio Krogh ◽  
Volker Schnabel ◽  
...  
Keyword(s):  
High Performance ◽  
Polymer Fibers ◽  
Functional Coatings ◽  
High Performance Polymer ◽  
Smart Sensing
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