Temperature-Dependent Dynamic Mechanical Analysis−Fourier Transform Infrared Study of a Poly(ester urethane) Copolymer

2002 ◽  
Vol 35 (23) ◽  
pp. 8794-8801 ◽  
Author(s):  
Haochuan Wang ◽  
Steven R. Aubuchon ◽  
Darla Graff Thompson ◽  
Jill C. Osborn ◽  
Anderson L. Marsh ◽  
...  
Author(s):  
A Arul Jeya Kumar ◽  
M Prakash

In today's scenario, most of the research works are carried out on the replacement of synthetic fibers using eco-friendly materials called natural fibers. Although there are many research findings in connection with natural fibers, in this work, a new combination of natural fiber having high biomedical potential is reinforced in the polymer composite. Three different weight fractions of polylactic acid, basalt, and Cissus quadrangularis fibers were melt mixed using twin-screw extruder named as PBCQ 1, PBCQ 2, and PBCQ 3. The mechanical, physical, and thermomechanical properties were studied by testing tensile, flexural, impact, hardness, water absorption, Fourier-transform infrared spectroscopy, and dynamic mechanical analysis of the injection-molded biomedical composite specimens prepared as per ASTM standards. It was noticed that the PBCQ 2 composite has the maximum elongation strength, bending strength, shear strength, and shore D hardness compared to other composites taken in this study. Water absorption of PBCQ 1 and PBCQ 2 composites are relatively less than PBCQ 3. The scanning electron microscopy micrograph of PBCQ composites shows tight bonding between the matrix and fibers. The adhesion of matrix and fibers was confirmed by Fourier-transform infrared spectroscopy graph, which indicates the stretching of molecular structure for the occurrence of O–H, C=O, and C–H links. The dynamic mechanical analysis curve of the PBCQ 2 composite indicates high storage modulus and less loss modulus compared to PBCQ 1 and PBCQ 3 due to the low weight percentage of basalt fiber in these composites.


Author(s):  
Jing Qiao ◽  
Alireza V. Amirkhizi ◽  
Kristin Schaaf ◽  
Sia Nemat-Nasser

In this work, the material properties of a series of fly ash/polyurea composites were studied. Dynamic mechanical analysis was conducted to study the effect of the fly ash volume fraction on the composite’s mechanical properties, i.e., on the material’s frequency- and temperature-dependent storage and loss moduli. It was found that the storage and loss moduli of the composite both increase as the fly ash volume fraction is increased. The storage and loss moduli of the composites relative to those of pure polyurea initially increase significantly with temperature and then slightly decrease or stay flat, attaining peak values around the glass transition region. The glass transition temperature (measured as the temperature at the maximum value of the loss modulus) shifted toward higher temperatures as the fly ash volume fraction increased. Additionally, we present the storage and loss moduli master curves for these materials obtained through application of the time-temperature superposition on measurements taken at a series of temperatures.


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