Reduced stress‐optical coefficient of polycarbonate by antiplasticization

Nobukawa, Shogo; Hasunuma, Seiki; Sako, Takumi; Miyagawa, Azusa; Yamaguchi, Masayuki

doi:10.1002/polb.24433

Cited by 13 publications

(7 citation statements)

References 18 publications

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“…Although in general photoelastic birefringence is determined by chemical structure, there have been various recent attempts to reduce it. One successful method is to add an antiplasticizer, suggesting that low‐molecular‐weight additives are able to change the stress‐optical coefficient . Therefore, in the present study we also evaluated the photoelastic birefringence in the glassy state.…”

Section: Resultsmentioning

confidence: 99%

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Structure and optical properties of transparent polyamide 6 containing lithium bromide

Sato

Ito

Maeda

et al. 2018

J Polym Sci B Polym Phys

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We investigated the effects of lithium bromide (LiBr) on the structure and properties of polyamide 6 (PA6). The strong iondipole interactions between lithium cations and the amide groups in PA6 greatly increased the glass transition temperature (T g ) and retarded the crystallization rate of PA6. As a result, compressionmolded PA6 blends were highly transparent and had high T g values. The rheological terminal region was obvious in the blends because the ion-dipole interactions weakened at high temperatures. This indicates that the melt processability was barely affected by LiBr. We also evaluated the optical anisotropy of the polymer to determine its suitability as a functional optical film. We found that hot-stretched blend films had large positive orientation birefringence with significantly weak wavelength dispersion, which can be attributed to the enhanced anisotropic polarizability of PA6. We also found that the stress-optical coefficient in the glassy region decreased with increasing LiBr content.

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Section: Resultsmentioning

confidence: 99%

“…As shown in Figure , LiBr decreased the stress‐optical coefficient, demonstrating that unfavorable birefringence can be reduced. The increased modulus in the glassy region and/or the reduced localized motion due to ion–dipole interactions may be the origins of this phenomenon …”

Section: Resultsmentioning

confidence: 99%

Structure and optical properties of transparent polyamide 6 containing lithium bromide

Sato

Ito

Maeda

et al. 2018

J Polym Sci B Polym Phys

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“…The lm containing 10 wt% TEC had the highest E′ value, which was more than 10% higher than that of the pure ISB-PC lm. This phenomenon has been called antiplasticization, and originates from a decrease in the free volume fraction [43][44][45][46][47][48]. Owing to the reduction in free volume, an antiplasticized system has good gas barrier properties [48] and reduced thermal expansion [46].…”

Section: Resultsmentioning

confidence: 99%

Antiplasticizing effect of triethyl citrate on an isosorbide-based polycarbonate

HAN,

kida,

Yamaguchi

2024

Preprint

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The effects of triethyl citrate (TEC) on the viscoelastic properties of a copolycarbonate comprising isosorbide and 1,4-cyclohexanedimethanol (ISB-PC) were studied in both the molten and solid states. TEC acted as an antiplasticizer for ISB-PC and increased its modulus in the glassy state, as demonstrated in a blend comprising 10 wt% TEC. Because antiplasticization reduces the free volume fraction, the water content of the copolycarbonate films, which is known to affect various properties, decreased following the addition of TEC. Furthermore, TEC greatly decreased the zero-shear viscosity. The experimental values were much lower than those predicted by the Berry–Fox formula. This suggested that the monomeric frictional coefficient was reduced. In other words, a small amount of TEC greatly enhances the flowability of ISB-PC.

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“…Following this procedure and aiming to verify the repeatability of the residual stress pattern, the photoelasticity calculation procedure is performed on three injected parts for each condition listed in Table 1 . In addition, the residual stress distribution of polycarbonate is calculated using an average value of the optical stress coefficient, which depends on the glass transition temperature and the polycarbonate modulus [ 11 , 21 ].…”

Section: Methodsmentioning

confidence: 99%

Analysis of the Stress Field in Photoelasticity Used to Evaluate the Residual Stresses of a Plastic Injection-Molded Part

2023

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The degree of quality of thermoplastic injection-molded parts can be established based on their weight, appearance, and defects. However, the conditions of the injection process may induce effects on the mechanical performance of the injected parts, and the residual stresses can cause cracks or early failures when an external load or force is applied. To evaluate these mechanical behaviors, different experimental techniques have been reported in the literature, where digital photoelasticity has stood out both for being a non-contact technique and for achieving quantitative results through sophisticated computational algorithms. Against this background, our proposal consists of analyzing the overall residual stress distribution of parts injected under different molding conditions by using digital photoelasticity. In this case, the specimens are subjected to bending strength tests to identify possible effects of the injection process conditions. The findings show that, at mold temperatures of 80 °C, flow-induced residual stresses increase with packing pressure. However, these internal stress levels do not affect the external load applied by the mechanical bending test, while the mass injected at higher levels of packing pressure helps to increase the bending strength of the injected part. At lower mold temperatures (50 °C), the mechanical strength of the injected part is slightly reduced, possibly due to a lower effect of the packing pressure.

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Reduced stress‐optical coefficient of polycarbonate by antiplasticization

Cited by 13 publications

References 18 publications

Structure and optical properties of transparent polyamide 6 containing lithium bromide

Structure and optical properties of transparent polyamide 6 containing lithium bromide

Antiplasticizing effect of triethyl citrate on an isosorbide-based polycarbonate

Analysis of the Stress Field in Photoelasticity Used to Evaluate the Residual Stresses of a Plastic Injection-Molded Part

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