Effects of moisture on the thermal expansion of poly(methylmethacrylate)

Drotning, W. D.; Roth, E.P.

doi:10.1007/bf01139031

Cited by 40 publications

(37 citation statements)

References 2 publications

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“…1ï-12 r°in In estimating the temperature sensitivity of a pre-strained POFBG, the values of TEC and TOC in the selected temperature range and humidity can be obtained from [6,9]. However, the magnitude of the calculated temperature sensitivity of a pre-strained POFBG is much larger than achieved in the experiment, even though the varying values of TEC and TOC have been considered.…”

Section: Thermo-optic Effect Of Pmma Based Optical Fibermentioning

confidence: 97%

“…The effects of moisture on the thermal expansion of compression-moulded PMMA were investigated by dilatometry in [8]. Moisture conditioning at high relative humidity, immersion in water, or vacuum drying were used to prepare PMMA specimens at different moisture contents [9]. Least-squares fitting was used to determine the constant and linear CTE terms as a function of percent weight gain to provide an expression for the CTE of PMMA against weight gain and temperature, as follows , = 59.3 + 4.26 + 0.222 + 0.139 × 10 (5) where w is in % weight gain.…”

Section: Tec and Toc Of Pmmamentioning

confidence: 99%

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Factors influencing the temperature sensitivity of PMMA based optical fiber Bragg gratings

Zhang

Webb

2014

SPIE Proceedings

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The Bragg wavelength of a PMMA based fiber grating is determined by the effective core index and the grating pitch, which, in temperature sensing, depend on the thermo-optic and thermal expansion coefficients of PMMA. These two coefficients are a function of surrounding temperature and humidity. Amorphous polymers including PMMA exhibit a certain degree of anisotropic thermal expansion. The anisotropic nature of expansion mainly depends on the polymer processing history. The expansion coefficient is believed to be lower in the direction of the molecular orientation than in the direction perpendicular to the draw direction. Such anisotropic behavior of polymers can be expected in drawn PMMA based optical fiber, and will lead to a reduced thermal expansion coefficient and larger temperature sensitivity than would be the case were the fiber to be isotropic. Extensive work has been carried out to identify these factors. The temperature responses of gratings have been measured at different relative humidity. Gratings fabricated on annealed and non-annealed PMMA optical fibers are used to compare the sensitivity performance as annealing is considered to be able to mitigate the anisotropic effect in PMMA optical fiber. Furthermore an experiment has been designed to eliminate the thermal expansion contribution to the grating wavelength change, leading to increased temperature sensitivity and improved response linearity.

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Section: Thermo-optic Effect Of Pmma Based Optical Fibermentioning

confidence: 97%

Section: Tec and Toc Of Pmmamentioning

confidence: 99%

Factors influencing the temperature sensitivity of PMMA based optical fiber Bragg gratings

Zhang

Webb

2014

SPIE Proceedings

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“…[10][11][12][13][14][15] Values previously reported in literatures are adopted, however, the kinematic viscosity of solids over MHz frequency has not been characterized experimentally to our knowledge. To find the kinematic viscosity of the solids used in CPOT, the value is assumed to be homogeneous over the CPOT structure and is fitted to match the calculated frequency spectrum of the pressure wave with the measured one as shown in Fig.…”

Section: Physical Properties Used For Calculationmentioning

confidence: 99%

Generation of planar blast waves using carbon nanotubes-poly-dimethylsiloxane optoacoustic transducer

Moon

Fan

et al. 2017

AIP Advances

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We have generated planar blast waves over the large area using carbon nanotubes(CNT)-poly-dimethylsiloxane(PDMS) optoacoustic transducer. Pulse laser is absorbed by CNT and converted to heat, and the heat is transferred to PDMS inducing its thermal expansion and blast wave generation. To theoretically describe the planar blast wave generation, we build one-dimensional simulation model and find analytical solutions for temperature and pressure distributions. The analytical solution validated by the experimental data sheds light on how to improve the performance of the new transducer. Resonance of acoustic waves inside the transducer is also discussed. The new optoacoustic transducer optimized based on the fundamental understandings will be useful in generating high quality blast waves for research and industrial applications.

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“…A linear response can be expected if the thermo-optic coefficient and thermal expansion coefficient are constant. However, both coefficients are affected by water content [2,7]. In fact the temperature response of the POF can be explained by the direct thermal effects and the change in relative humidity due to the temperature change.…”

Section: Discussionmentioning

confidence: 99%

Nonlinear response in polymer optical fibre Bragg grating based sensors

2012

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PMMA based polymer optical fibre Bragg gratings have been used for humidity, temperature and concentration sensing. Due to the water affinity of PMMA, the characteristic wavelength of the grating is largely modulated by the water content in the fibre. The rate of water transportation between fibre and surrounding depends on the permeability coefficient for PMMA, which is a function of surrounding temperature and humidity. This leads to increased water content with increasing humidity and temperature. Consequently the wavelength of the grating shows a nonlinear change over varying humidity and temperature. This nonlinearity needs to be calibrated prior to sensor application.

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Effects of moisture on the thermal expansion of poly(methylmethacrylate)

Cited by 40 publications

References 2 publications

Factors influencing the temperature sensitivity of PMMA based optical fiber Bragg gratings

Factors influencing the temperature sensitivity of PMMA based optical fiber Bragg gratings

Generation of planar blast waves using carbon nanotubes-poly-dimethylsiloxane optoacoustic transducer

Nonlinear response in polymer optical fibre Bragg grating based sensors

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