• Korea-Australia Rheology Journal
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• v.17 no.4
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• pp.165-170
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• 2005

In this study, high intensity ultrasound was employed to induce mechano-chemical degradation during melt mixing of polycarbonate (PC) and a series of styrene-acrylonitrile (SAN) copolymers. It was confirmed that generation of macroradicals of constituent polymers can lead to in-situ copolymer formation by their mutual combination, which should be an efficient path to compatibilize immiscible polymer blends and stabilize their phase morphology in the absence of other chemical agents. Based on the effectiveness of the compatibilization by ultrasound assisted mixing process, we investigated the effects of viscosity ratio of PC and SAN and AN content in SAN on the compatibilization of PC/SAN blends. It was found that effectiveness of compatibilization is optimal when the AN content is in the range of favorable interaction with PC and the viscosity of the matrix is higher than that of the dispersed phase. In addition, changes in the interfacial tension between PC and SAN were assessed by examining relaxation spectra which were obtained from measuring rheological properties of ultrasonically treated blends.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.150-155
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• 2004

The base material of optical disc is the amorphous polymer, polycarbonate. So crack growth on the rotating optical disc could happen by the static centrifugal force. This phenomenon is called static fatigue. Today's CD-R disc drive is being operated over 10,000 RPM. This is increasing the possibility of the disc fracture when operating. In this reason, new method to measure the static fatigue threshold quality and the way to calculate the threshold J-integral value and the safe crack length of the optical disc are studied. Finally the environmental effect to optical disc is also studied in this paper.

• Electrical & Electronic Materials
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• v.7 no.5
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• pp.409-416
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• 1994

A double layered photoreceptor using phthalocyanine dye was made by dip-coating method. The under cutting layer(UCL) was coated with A1$\_$2/O$\_$3/ or polyamide, and the charge generation layer(CGL) was formed by .tau.-type metal-free phthalocyanine. The oxadiazole was used as a charge transport layer(CTL) and polycarbonate and poly(vinyl butyral) was employed as a host polymer. The .tau.-H$\_$2/Pc had an absorption peak around 780nm, which coincided with the emitting wavelengths of GaAlAs diode lasers. Maximum charge acceptance of CTL that gives thickness of 12.mu.m was -900V by corona charge of -6.0kV. In photo-induced discharge measurements, residual potential was less than -20V and sufficient for ordinary use, and sample films using of poly(vinyl butyral) was showed good charge retention. In printing test, drum that was employed polycarbonate as a host polymer showed the good print quality.

• Polymer(Korea)
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• v.34 no.3
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• pp.237-241
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• 2010

Mechanical characteristics and chemical resistance have been investigated for PC/PBT blends. The changes in mechanical performance of PC/PBT blends was monitored during the treatment with both the PC thinner and general-purpose thinner to figure out the chemical resistance. The PC thinner greatly affected the mechanical properties of PC/PBT blends compared with general-purpose thinner. In the case of PC thinner treatment, the mechanical performance was improved with increased PC content at lower PC content ranges, say below 50%. However the mechanical performance was dropped rapidly at higher PC content ranges due to poor chemical resistance of PC. Transparent pure PC specimen became opaque after chemical treatment with PC thinner, and this can be interpreted by solvent-induced crystallization.

• Tribology and Lubricants
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• v.30 no.5
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• pp.278-283
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• 2014

Carbon nanotubes (CNTs) are used in various composite materials to enhance electrical, thermal and mechanical properties of composite materials. In this study, we investigate the wear characteristics of polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blends containing multi-walled carbon nanotubes (MWCNTs). PC/ABS blends are commonly used in many industrial applications such as cellular phones and display cases and MWCNTs have been added to the PC/ABS blends to improve their electromagnetic interference shielding (EMS). We performed wear tests on PC/ABS blends containing MWCNTs under reciprocating linear sliding conditions with chrome steel balls as a counterpart material. The normal loads were 10, 30, 50, 70, 100 N, the sliding speed was 10 mm/s, the stroke length was 15 mm, and the tests lasted 900 s. The MWCNTs included in the PC/ABS blends lower the wear volume and friction coefficient of the composites. We analyzed the wear debris collected from the composites during the tests in terms of the MWCNT concentration using inductively coupled plasma optical emission spectroscopy. The results show that the quantity of MWCNTs in the debris is proportional to the concentration of MWCNTs in the composite, indicating that the exposure of the MWCNTs to environments by wear could be increased with their concentration in the composite.

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.54-62
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• 1994

Bisphenol A polycarbonate(PC) and polyethylene terephthalate(PET) was blended with methylmethacrylate-butadiene-styrene(MBS) copolymer for the improvement of impact resistance strength PC/PET alloy blending with PC more than 15 parts to 100 parts of PET usually have poor compatability, but increased the compatability characteristics of PC/PET alloy prepared by addition of MBS compatabilizer. The compatability of PC and PET using compatabilizer, MBS was determined by measuring the thermal characteristics of Tg difference between PC and PET, and crystallization temperature, Tcc. As the Tg difference becoming narrow to $60^{\circ}C$, and Tcc decreasing to $150^{\circ}C$, the comparability of PC and PET was increased. And also tough rate impact strength to PC/PET alloy using MBS was increased, in case more than 15 parts of PC being blended to PET.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.159-165
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• 2004

The shrinkages of injection molded parts are different in molding operational conditions and mold design. It also differs from resins. The shrinkages of injection molded parts for PBT (polybutylene terephthalate), PC (polycarbonate),and glass reinforced PBT and PC have been studied for various operational conditions of injection molding. The part shrinkage of crystalline polymer, PBT was higher than that of amorphous polymer, PC by about two times. The part shrinkages of both polymers decreased as glass fiber content increases. Higher Injection temperature and lower injection pressure resulted in a higher shrinkage in both PBT and PC resins. As mold temperature increases the part shrinkage of PC decreased. However, the part shrinkage of PBT increased as mold temperature increases. The part shrinkage of both PBT and PC resins decreased as gate size increases since the pressure delivery is mush easier for a larger gate size. The part shrinkage of flow direction was less than that of the perpendicular direction to the flow for both pure and glass fiber reinforced resins. The part shrinkage at the position close to the gate was less than that of the position far from the gate.

• Transactions of Materials Processing
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• v.13 no.6 s.70
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• pp.515-521
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• 2004

The shrinkages of injection molded parts are different in molding operational conditions and mold design. It also differs from resins. The shrinkages of injection molded parts fur PBT (polybutylene terephthalate), PC (polycarbonate), and glass reinforced PBT and PC have been studied for various operational conditions of injection molding. The part shrinkage of crystalline polymer, PBT was higher than that of amorphous polymer, PC by about two times. The part shrinkages of both polymers decreased as glass fiber content increases. Higher injection temperature and lower injection pressure resulted in a higher shrinkage in both PBT and PC resins. As mold temperature increases the part shrinkage of PC decreased. However, the part shrinkage of PBT increased as mold temperature increases. The part shrinkages of PBT and PC resins decreased as gate size increases since the pressure delivery is mush easier for a larger gate size. The part shrinkage of flow direction was less than that of the perpendicular direction to the flow for both pure and glass fiber reinforced resins. The part shrinkage at the position close to the gate was less than that of the position far from the gate.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.611-616
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• 2020

Polycarbonate (PC) materials having electrical insulation properties, are thermoplastic material and are easily processed, have excellent strength and heat resistance characteristics, and also have transparent and hard characteristics. In this study, we tried to derive the ε-N curve of strain-life, which shows the relationship between the strain characteristics and the life of the material when repeated impact loads are applied to the PC plastic material. As the impact load increased to 3.0kg, 4.0kg, 5.0kg, and 6.0kg, the strain also increased linearly to 0.033, 0.041, 0.046, and 0.055. At 3.0kg of mass impact, the test piece broke with 12000 impact cycles, 8400 times at 3.5kg, 7400 times at 4.0kg, 6600 times at 4.5kg, 4700 times at 5.0kg, 3000 times at 5.5kg, and 1000 times at 6.0kg. The number of fractures exponentially decreased as the load gradually increased. Using these results, an ε-N curve for PC plastic was derived.

• Polymer(Korea)
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• v.36 no.6
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• pp.761-767
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• 2012

The polycarbonate (PC)-based optical diffusers for direct-lit LED backlight unit were prepared by using extrusion compounding followed by compression molding process. The application of inorganic porous silica particles as a diffusing agent in addition to conventional poly(methyl methacrylate) (PMMA) beads was attempted, and the optical, thermal, and mechanical properties of the prepared diffusers were investigated. The morphological observations revealed that the diffusing agents could be uniformly dispersed in the PC matrix without agglomeration by high shear stress generated during extrusion process. The incorporation of the porous silica particles mixed with PMMA beads remarkably enhanced the luminance uniformity with respect to both location and view angle for the diffuser, while minimizing the reduction in the absolute luminance, as compared with the diffuser containing only PMMA beads. In addition, thermal and mechanical properties of the diffusers were shown to be improved upon addition of the porous silica particles.