Stress-optical analysis of fluids

Philippoff, W.

doi:10.1007/bf01989069

Cited by 24 publications

(17 citation statements)

References 7 publications

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“…Qualitatively consistent with very limited experimental data is the prediction 13,14 that ∆n should be proportional to the recoverable strain, Only at long times, when steady state is attained and D R (t) becomes constant, does the stress optical rule strictly adhere. A more striking deviation from eq 1 was seen during recovery experiments on 1,4-polybutadiene melts and networks.…”

Section: Introductionsupporting

confidence: 72%

Optical Birefringence of Polyisobutylene during Creep and Recovery

2001

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Creep and recovery rheooptical measurements were conducted on linear polyisobutylenes, with viscosity-average molecular weights in the range from 4.2 × 10 5 to 4.7 × 10 6 g/mol. To isolate the contribution of chain ends to the birefringence, the temperature of each experiment was adjusted to yield equivalent creep strains for each sample. Higher molecular weight PIB exhibited less change in the birefringence during creep, but the birefringence during recovery was independent of molecular weight. The sign of the birefringence during the stress-free recovery was opposite (i.e., corresponding to tension) to that during creep, even though the macroscopic deformation was compression.

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Section: Introductionsupporting

confidence: 72%

Optical Birefringence of Polyisobutylene during Creep and Recovery

2001

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“…The master curves for fin are even transformed into straight lines if plotted vs fiO" 12/sin 2X. as shown in Figure 4 for polyisobutylene in white oil over a range of three decades of birefringence (Philippoff 1960). Such observations are the best proof of the rheo-optical law, i.e.…”

Section: Birefringence In Laminar Flow With Transverse Gradientmentioning

confidence: 97%

“…10000 Figure 4 Proportionality of birefringence An= nl-nil and main stress difference u 1 -u 11 = Au 12/sin 2X of polyisobutylene in white oil (Philippoff 1960).…”

Section: Birefringence In Laminar Flow With Transverse Gradientmentioning

confidence: 99%

Optical Effects in Flow

Peterlin¹

1976

Annu. Rev. Fluid Mech.

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“…We observed the flow birefringence phenomena [13][14][15] using the photoelastic method to measure the growth and relaxation processes of birefringence in the weld-line region and investigated the molecular orientation in that region. Figure 1 illustrates the placement of a polarizer, an analyzer, and quarter wave planes in the experimental setup for the birefringence measurements.…”

Section: Measurement Principlementioning

confidence: 99%

Welding Flow of Low Density Polyethylene Melt

Mitsuhashi

Nishimura

Yamamoto

et al. 2003

Journal of Textile Engineering

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Weld-lines degrade the mechanical and optical properties of products. This is because the polymer molecules near the weld-line highly orient owing to the elongational flow and the molecular orientation is fixed by solidification of the polymer melts before it returns to a random condition. Birefringence experiments were, therefore, carried out for welding flows of a low density polyethylene (LDPE) past a spider supporting a mandrel. The die used in the present study has a glass window to observe the birefringence pattern. The birefringence in the polymer melts was measured by the photoelastic method. The purpose of the present study is to elucidate the effect of the die temperature, spider shapes and a viscoelastic property of polymer melts on the anisotropy of the molecular orientation in the stress relaxation process downstream of the spider. The birefringence pattern in the welding flow of LDPE was measured at the die temperature T190, 205 °C and the polymer melts temperature 719O °C for flow rates of 0.7, 1.0, 2.2, 2.9, 4.6 cm3ls. The results showed that complete relaxation of birefringence depended on the flow rate. For high die temperature (205 °C), the distance necessary for the relaxation of molecular orientation was short. Moreover, the birefringence pattern in the welding flow was numerically calculated using the single-mode Giesekus model as a constitutive equation, and the results were compared with the experimental data. The numerical predictions agreed with the experimental results.

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Stress-optical analysis of fluids

Cited by 24 publications

References 7 publications

Optical Birefringence of Polyisobutylene during Creep and Recovery

Optical Birefringence of Polyisobutylene during Creep and Recovery

Optical Effects in Flow

Welding Flow of Low Density Polyethylene Melt

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