Characterization of Kevlar Using Raman Spectroscopy

Washer, Glenn; Brooks, Thomas; Saulsberry, Regor

doi:10.1061/(asce)0899-1561(2009)21:5(226)

Cited by 28 publications

(14 citation statements)

References 17 publications

(47 reference statements)

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“…This poor signal to noise ration occurred at shorter wavelengths of incident light such as the 514 nm laser. Washer et al [54] made a similar comment. It was thought that using an incident light of longer wavelength might enhance the resolution.…”

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confidence: 76%

“…Washer et al [54] stated that Raman spectrum characteristics such as position, bandwidth, and relative intensity of peaks can vary depending on environmental agents such as thermal and ultra violet exposures. Since each Raman peak is related to a specific vibrational mode in the polymer, any defects can change the vibrational modes and consequently the Raman spectrum characteristics.…”

mentioning

confidence: 99%

“…Washer et al [54] examined a series of new and thermally aged strand specimens of para-aramid using an incident laser of various wavelengths and power levels. They found that a laser with a 647 nm wavelength and 7 mW power level provided the most suitable Raman spectrum for analysis among those available wavelengths (488, 647, 752, and 1064 nm) and power levels of laser.…”

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confidence: 99%

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Assessment of Factors Affecting the Continuing Performance of Firefighters’ Protective Clothing: A Literature Review

Rezazadeh

Torvi

2010

Fire Technol

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There has been some research into the level of damage and changes to important properties of firefighters' protective clothing after exposure to conditions such as elevated temperature and ultra violet radiation. However, at this time, the results are not comprehensive enough to develop a standard procedure to estimate the remaining useful life of firefighters' protective clothing. There is also a need to develop non-destructive techniques to evaluate clothing, for most tests used to evaluate properties of clothing are destructive, and visual cues cannot completely assess the level of deterioration of the properties of thermal protective fabrics. In this paper, major factors that affect the continuing performance of firefighters' protective clothing and their effects on the service life of the clothing are reviewed. Some nondestructive methods which have been employed in different studies to evaluate the degradation of physical properties of firefighters' protective clothing are also described, along with statistical and probabilistic methods for estimating the useful life of materials. Suggestions for future research, which will assist fire departments in determining the level of damage to clothing, and estimating its remaining useful life are also discussed.

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confidence: 76%

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confidence: 99%

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confidence: 99%

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Assessment of Factors Affecting the Continuing Performance of Firefighters’ Protective Clothing: A Literature Review

Rezazadeh

Torvi

2010

Fire Technol

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“…Cen et al [2] focused on Kevlar Ò 29, while the work by Washer et al [15] is based on Kevlar Ò 49. The K49 fiber structure has larger crystallite size resulting in lower total crystal surface area, and has a higher orientation angle of the crystalline structure resulting in a 50% higher modulus than K29.…”

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confidence: 98%

Evaluating the effect of nano-particle additives in Kevlar® 29 impact resistant composites

Manero

Gibson

Freihofer

et al. 2015

Composites Science and Technology

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“…[13] The fundamental changes in the molecular structure have been observed through in situ x-ray diffraction and other spectroscopic methods. [14][15][16] However, very little quantitative information is available on how the evolution of the structure of polymer chains affects the mechanical properties of the material. Herein, we describe a novel nanomechanical tensile testing methodology, called continuous dynamic analysis (CDA) that not only provides accurate measures of quasi-static properties, but also determines the dynamic storage and loss moduli as a continuous function of strain.…”

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confidence: 99%

Continuous dynamic analysis: evolution of elastic properties with strain

Basu

Hay

Swindeman³

et al. 2014

MRS Communications

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Mechanical strain triggers changes in inherent molecular structure, especially in polymeric and biological materials. Unlike conventional techniques, we demonstrate a novel dynamic mechanical characterization method to study the effect of this structural evolution with strain on elastic properties. During tensile characterization of small diameter fibers, we quantitatively measured the viscoelastic properties as a continuous function of strain. While this approach is useful to characterize the elastic properties of metal microwires independent of applied strain, it is extremely important for fundamental understanding of molecular changes and their effect on the viscoelastic properties in materials such as polymer fiber and spider silk.The mechanical behavior at nano/microscale has been a subject of considerable interest in both the physical and biological sciences. The interest has been sparked by continued progress in the miniaturization of components for microelectronic applications, [1,2] synthesis of nanostructured materials for biomedical scaffolds, [3,4] as well as the recognition that many biological tissues and fibers exhibit superlative mechanical performance. [5][6][7] A good example is the sustained effort in characterizing, synthesizing, and understanding the behavior of spider silks, many of which are stronger than steel and exhibits higher toughness than Kevlar. [8,9] Fabrication of nano-and microfibers with similar properties has also showed promise in biomedical and composite applications.Mechanical characterization of materials at nano/microscale presents significant challenges due to the small forces and extensions that must be applied and measured. Some of the challenges have been addressed with recent advances in depthsensing nanoindentation technique, and in situ deformation studies inside an electron microscope. Quasi-static tensile mechanical properties of fibers with less than a few 10's of μm in diameter have also been reported in literature. [10][11][12] However, the challenge is slightly different for soft and ductile materials in the form of small diameter fibers-below 100 µm-which require extremely small forces but can sustain large amounts of strain. In addition, polymeric and biological fibers often exhibit strain-dependent or time-dependent properties, leading to difficulties in interpreting their mechanical properties by conventional techniques. Unlike metals and ceramics, mechanical deformation in polymeric materials involves evolution of the molecular network. [13] The fundamental changes in the molecular structure have been observed through in situ x-ray diffraction and other spectroscopic methods. [14][15][16] However, very little quantitative information is available on how the evolution of the structure of polymer chains affects the mechanical properties of the material. Herein, we describe a novel nanomechanical tensile testing methodology, called continuous dynamic analysis (CDA) that not only provides accurate measures of quasi-static properties, but also determines the d...

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Characterization of Kevlar Using Raman Spectroscopy

Cited by 28 publications

References 17 publications

Assessment of Factors Affecting the Continuing Performance of Firefighters’ Protective Clothing: A Literature Review

Assessment of Factors Affecting the Continuing Performance of Firefighters’ Protective Clothing: A Literature Review

Evaluating the effect of nano-particle additives in Kevlar® 29 impact resistant composites

Continuous dynamic analysis: evolution of elastic properties with strain

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