Glass Fiber-reinforced Polycarbonate Research Articles

Design, performance, and cost savings of using GF-PC additively manufactured tooling for stamping of HSS 590 sheet metal

Conventional sheet metal forming tooling in the automotive industry is made up of hardened steel and used for mass-production. Prototype tooling made of metal is durable, but it is only used for a small number of parts despite its high cost, contributing heavily to the vehicle development cost. Additive Manufacturing (AM) offers a low-cost alternative for fabricating tooling suitable for low-volume production. This study investigates the feasibility of using AM polymer composite tooling for the stamping of 1.5 mm thickness HSS 590 steel sheets through a two-pronged approach – experimental and numerical analysis. Sheet metal stamping experiments were conducted with glass fiber reinforced polycarbonate (GF-PC) AM polymer tooling and their performance was evaluated based on various metrics such as tool deformation and part accuracy. Finite element simulations of the stamping process were performed, which accurately captured the tool deformations seen in experiments with the use of anisotropic material models. The effective use of simulations in optimizing process parameters to achieve the desired final part geometry is also demonstrated. The GF-PC AM polymer composite tooling was found to be well suited for low volume production applications with potential cost savings.

Mechanical characterization of aesthetic orthodontic brackets by the dynamic indentation method.

The objective of this study is to investigate the mechanical properties, such as the dynamic hardness and indentation elastic modulus, of commercially available aesthetic orthodontic brackets, such as ceramic and plastic brackets, by the dynamic micro-indentation method. Five ceramic brackets, which were made of alumina (both monocrystalline and polycrystalline forms) or zirconia, and two plastic brackets, which were made of glass fiber-reinforced polycarbonate or polyamide, were tested. There were significant differences in the mechanical properties of the monocrystalline and polycrystalline alumina brackets. The mechanical properties of the glass fiber-reinforced plastic bracket were significantly superior to these of the non-glass-fiber-reinforced plastic bracket. The differences in the crystal structures of the ceramic brackets surface affected the dynamic hardness and indentation elastic modulus. Furthermore, the short glass fibers contained in the plastic bracket might contribute to the improvement of the mechanical properties.

Color Changes and Mechanical Properties of Glass Fiber Reinforced Polycarbonate Composites after Thermal Aging.

Thermal aging of polymer matrix composites exert significant influence on their properties and applications. This paper studied the color changes and mechanical properties of glass fiber reinforced polycarbonate (GF-PC) composites after aging at different temperatures, and the correlation between the trend of color changes and mechanical properties after aging was discussed. The GF-PC composites were aged at 85 °C, 100 °C, 115 °C, 130 °C and 145 °C, respectively. Thereafter, CIELAB colors were used to characterize the color changes of the composites after aging. Tensile and three-point bending tests were carried out to determine the mechanical properties of the composites. According to the values of CIELAB color, the color changes and the color difference (ΔE) of the GF-PC composites after aging were calculated, which showed that color of the GF-PC composite aged at 100 °C changed the most. The color changes of the composites after aging mainly comes from the change of brightness (L value), which was 25.067 for the Raw GF-PC composite. When the aging temperature increased from 85 °C to 100 °C, the brightness of the composites also increased, but decreased when the aging temperature is above 100 °C and continues to rise. Coincidentally, the trend of the mechanical properties of GF-PC composites is closely associated with color changes in the aging temperature range of 85 °C to 145 °C. The tensile and flexural strength of the composites reached the maximum value 72 MPa and 131 MPa, respectively, after aged at 100 °C. It can be speculated that the brightness of the GF-PC composites correlates with trends observed in its tensile strength and bending strength.

Steady finite-amplitude Rayleigh–Bénard convection of ethylene glycol–copper nanoliquid in a high-porosity medium made of 30% glass fiber-reinforced polycarbonate

In the paper, we make linear and nonlinear stability analyses of Rayleigh–Benard convection in a Newtonian nanoliquid-saturated high-porosity medium. Single-phase model is used for nanoliquids, and values of thermophysical quantities concerning ethylene glycol–copper nanoliquid-saturated porous medium are calculated using mixture theory or phenomenological relations. The study is carried out for free-free, rigid-rigid and rigid-free isothermal boundaries. Boundary effects on onset of convection are shown to conform to classical predictions. The addition of copper nanoparticles to ethylene glycol is shown to lead to advanced onset of convection in the porous medium and thereby to a substantial increase in heat transport. Theoretical explanation is provided for the enhanced heat transfer situation in the medium. With suitable scaling in quantities, the result concerning heat transfer in ethylene glycol–copper nanoliquid-saturated porous medium is shown to be obtainable from those of ethylene glycol-saturated porous medium without copper nanoparticles. Nanoparticles serve the purpose of cooling and porous matrix retains the heat, thereby meaning that residence time of heat in the system can be regulated by using nanoparticles and porous matrix.

Effect of chemical blowing agent, melt temperature, and mold temperature on the fluidity of glass fiber-reinforced polycarbonate in injection molding

ABSTRACTGlass fiber (GF) reinforced polycarbonate (PC) is a composite material that is used in the production of mobile phones, automobiles, LCD monitors, and laptops. With an increase in the GF content, the fluidity of the composite material decreases owing to the flow resistance of GF. A decrease in the fluidity leads to a decrease in processability and moldability; thus, applications of GF reinforced polymers are limited. Here, we investigated whether the fluidity of GF reinforced PC can be increased by using a chemical blowing agent (CBA) and by controlling the melt temperature and mold temperature. In this study, PC was reinforced with GF (45 wt%) using a CBA. Samples of GF reinforced PC were injection molded with respect to varying variables such as CBA content, melt temperature, and mold temperature. We used a spiral mold to compare the fluidity and measured the spiral flow length of the samples. The results indicated that increase in the CBA content increased the fluidity of GF reinforced PC. Furthermore, the results confirmed that the addition of CBA exhibits a considerably higher effect on fluidity than an increase in the melt temperature or mold temperature. Our findings are expected to significantly impact the expanding applications of GF reinforced plastics in the future.

Flame retardancy and toughening modification of glass fiber-reinforced polycarbonate composites

Different kinds of flame retardant and toughened glass fiber (GF)-reinforced polycarbonate composites were fabricated through melt extrusion blending and injection molding. Methacrylate-butadiene-styrene (MBS), styrene-maleic anhydride (SMA), ethylene methylacrylate (EMA), and silicon acrylate rubber (SiR) were used as toughness modifiers. Two kinds of aryl phosphorus, namely, triphenyl phosphate (TPP) and resorcinol bis(diphenyl phosphate) (RDP), and oligomeric siloxane-containing potassium dodecyl diphenylsulfone sulfonate (SiKSS) were adopted as flame retardants (FRs). The V-notched Izod impact test revealed that SiR could significantly improve the toughness of GF-reinforced polycarbonate composites. The flame retardancy of FR PC/GF/SiR composites was investigated by the UL-94 vertical burning test. The FR PC/GF/SiR composites showed good flame retardancy with a V0 rating when 9 wt% TPP, 6 wt% TPP/RDP, or 0.2 wt% SiKSS was added. The effect of the FRs on the mechanical properties, rheological properties and heat deflection temperature of PC/GF/SiR composites was also investigated. The toughness and flame retardancy of glass fiber (GF)-reinforced polycarbonate (PC) composites were tested by adding four impact modifiers and three kinds of flame reardants. Silicon acrylate rubber (SiR) could significantly toughen the composites by 2.52 times. Then only by addition of 0.2 wt% oligomeric siloxane-containing potassium dodecyl diphenylsulfone sulfonate (SiKSS), PC/GF/SiR composites can achieve good flame retardancy with a V0 rating in UL-94 burning vertical test. This formulation also maintained the system a relative high heat deflection temperature around 120 °C.

Development of a rapid thermal cycling molding with electric heating and water impingement cooling for injection molding applications

A rapid thermal cycling molding (RTCM) technology with electric heating and water impingement cooling is developed. To illustrate the feasibility of this technology in injection molding, a RTCM mold for cover plate is constructed. Experimental measurements and numerical simulations are conducted to evaluate the mold thermal response. The results show that the desired characteristics of high mold heating and cooling efficiencies are achieved. A new cavity insert-fixing mode is proposed to alleviate the thermal stress in cavity insert. It is found that the maximum thermal stress can be reduced by 75% for the constructed RTCM mold with the new mode, which is expected to result in greatly improved mold fatigue life. The surface quality of both polycarbonate (PC) and 20% glass fiber-reinforced PC (GF-PC) cover plates molded using the developed RTCM technology is dramatically improved and the surface defects that usually occur in conventional injection molding (CIM) process are eliminated. Meanwhile, the molding cycle time is not significantly increased for the RTCM process in comparison to the CIM process. So the feasibility of the RTCM technology developed for injection molding applications is successfully demonstrated.

Preparation, mechanical, and in vitro properties of glass fiber-reinforced polycarbonate composites for orthodontic application.

Generally, orthodontic treatment uses metallic wires made from stainless steel, cobalt-chromium-nickel alloy, β-titanium alloy, and nickel-titanium (Ni-Ti) alloy. However, these wires are not esthetically pleasing and may induce allergic or toxic reactions. To correct these issues, in the present study we developed glass-fiber-reinforced plastic (GFRP) orthodontic wires made from polycarbonate and E-glass fiber by using pultrusion. After fabricating these GFRP round wires with a diameter of 0.45 mm (0.018 inch), we examined their mechanical and in vitro properties. To investigate how the glass-fiber diameter affected their physical properties, we prepared GFRP wires of varying diameters (7 and 13 µm). Both the GFRP with 13-µm fibers (GFRP-13) and GFRP with 7 µm fibers (GFRP-7) were more transparent than the metallic orthodontic wires. Flexural strengths of GFRP-13 and GFRP-7 were 690.3 ± 99.2 and 938.1 ± 95.0 MPa, respectively; flexural moduli of GFRP-13 and GFRP-7 were 25.4 ± 4.9 and 34.7 ± 7.7 GPa, respectively. These flexural properties of the GFRP wires were nearly equivalent to those of available Ni-Ti wires. GFRP-7 had better flexural properties than GFRP-13, indicating that the flexural properties of GFRP increase with decreasing fiber diameter. Using thermocycling, we found no significant change in the flexural properties of the GFRPs after 600 or 1,200 cycles. Using a cytotoxicity detection kit, we found that the glass fiber and polycarbonate components comprising the GFRP were not cytotoxic within the limitations of this study. We expect this metal-free GFRP wire composed of polycarbonate and glass fiber to be useful as an esthetically pleasing alternative to current metallic orthodontic wire.

Surface roughness of three types of modern plastic bracket slot floors and frictional resistance

To quantitatively analyze the surface roughness of the slot floors of three types of modern plastic brackets and to measure static frictional force during sliding mechanics in vitro. Control groups comprised stainless steel brackets and monocrystalline ceramic brackets. Test groups comprised three types of 0.022-in slot, Roth prescription, plastic, maxillary right central incisor brackets. Test groups included glass fiber-reinforced polycarbonate, filler-reinforced polycarbonate, and hybrid polymer with inserted metal slot brackets. The static frictional resistance caused by sliding movements with an archwire (stainless steel) in vitro was quantitatively analyzed. Both scanning electron microscope and three-dimensional optical surface profiling were used. Scanning electron microscope and three-dimensional optical surface profiler revealed that all as-received brackets had irregular slot floor surfaces, and both irregularity and roughness increased after the archwire sliding test. The ceramic brackets in the control group showed significantly lower surface roughness values and higher frictional values during the archwire sliding test compared with the other brackets. The glass or filler-reinforced plastic brackets exhibited significantly higher static frictional values than the metallic slot type brackets (P < .001). The hybrid polymer with inserted metal slot brackets showed relatively lower surface roughness and frictional values compared with the stainless steel control bracket. Glass or filler-reinforced plastic brackets showed higher frictional resistance than metallic slot-type brackets. A plastic bracket with inserted metal slot may be the best choice among plastic brackets for low frictional resistance and to avoid damage from sliding movements of the archwire.

Analysis of creep behavior in thermoplastics based on visco-elastic theory

Plastics and fiber-reinforced plastics (FRP) are used in the aerospace industry because of their mechanical properties. However, despite their excellent high-temperature mechanical properties, plastics and FRP eventually deform visco-elastically at high temperatures. Most of the research has focused on the creep behavior of FRPs, but few studies have investigated the linear visco-elastic behavior. Linear visco-elastic behavior and non-linear visco-elastic behavior occur with physical aging in these plastics. In this study, the non-linear visco-elastic behavior of plastics and FRP was investigated based on the bending creep deformation of polycarbonate (PC) and polyoxymethylene (POM). Moreover, the effects of the fiber volume fraction on the creep characteristics were investigated using glass fiber-reinforced polycarbonate (GFRPC). The creep deformation was calculated using the linear visco-elastic theory based on these effects, and comparison between experimental and estimated data showed that the creep analysis sufficiently predicted the creep behavior.

Polycarbonate/Short Glass Fiber Reinforced Composites — Physico-mechanical, Morphological and FEM Analysis

A series of polycarbonate (PC), reinforced with short glass fiber (SGF) in different weight ratios viz., 10, 20 and 30%, has been fabricated by melt mixing with the aid of a twin screw extruder, in order to study the influence of glass fiber reinforcement on PC. The test specimens were fabricated as per ASTM standards and evaluated for their physico-mechanical properties. Incorporation of short glass fiber to PC enhances the tensile behavior of the composites significantly. The morphological behavior of PC composites has been performed using a scanning electron microscope (SEM). The experimentally measured tensile results were used to estimate the stress distribution in the bearing component, made of glass fiber reinforced polycarbonate (GFR-PC) composite, using three-dimensional finite element analysis (FEA).

Effect of Physical Aging on Creep Behavior of Glass Fiber Reinforced Polycarbonate

An important thing of FRPs to use in structural member is to understand the visco-elastic behavior of them. In this study, creep behavior of glass fiber reinforced Polycarbonate (GFRPC) was researched. Before the creep test, GFRPCs were heated for various times at test temperature for aging treatment to research the effect of physical aging. The result shows that creep behavior of GFRPCs with various aging treatment could be able to make master curves of creep compliance on each aging conditions. And time-temperature shift factors with various aging conditions represented good agreement to time-temperature superposition principle of Arrhenius type plotting. To research the effect of physical aging quantitatively, it was compared with the master curves of various aging conditions. Therefore, the effect that the physical aging exerted on the visco-elasticity behavior was able to be understood including the existence of the fiber content.

OS15-3-1 Estimation Corresponding to Temperature Change of Creep Behavior on Glass Fiber Reinforced-Polycarbonate

Thermoplastic resin was practically used without post cure treatment and physical aging treatment which is called "molded material". For such materials, it is known that creep behavior and physical aging occur simultaneously. And the effect of physical aging has the time and temperature dependency. The effect was occurred on the materials after molded, and the effect saved on the materials as the thermal history. This history has big influence on mechanical properties, especially creep properties. Therefore, it is necessary to understand the progress of the physical aging. In this report, the creep deformation of polycarbonate (PC) was researched to grasp the effect of physical aging on creep behavior. Two types of materials were prepared. One was "molded material", and another was pre-physical aged material. It was confirmed that the effect had the time and temperature dependency, and it had been able to apply the time-pre-aging time superposition principle and time-pre-aging temperature superposition principle of physical aging on creep behavior. The estimation corresponding to temperature change of creep deformation became possible using this superposition principle. The estimation result of the creep deformation of glass fiber reinforced polycarbonate (GFRPC) with temperature change during a creep test had the tendency similar to the experimental data. Therefore, it should be able to estimate the creep behavior with arbitrary thermal history since the materials reached to the saturated state of physical aging.

Estimating creep deformation of glass-fiber-reinforced polycarbonate

Thermoplastic resin and fiber-reinforced thermo-plastics (FRTPs) were used without post-cure treatment as “molded material.” For such materials, creep behavior and physical aging occur simultaneously. This study examined the creep behavior of polycarbonate (PC) and glass-fiber-reinforced polycarbonate (GFRPC) injection moldings, including the effect of physical aging and fiber content, and determined that the time–temperature superposition principle could be applied to the creep behavior for different fiber contents. The effects of physical aging on creep behavior were evaluated quantitatively on pure resin and with various fiber contents without heat treatment. We found that the effect of physical aging could be evaluated with the proposed factor, “aging shift rate.” To discuss the linearity of viscoelasticity in FRTPs, this study used two shift factors: time and modulus shift factors. The fiber content affected creep behavior by both retarding and restraining it through changing the elastic modulus. This was shown by generating a grand master curve of creep compliance, which included the effects of time, temperature, and fiber content. Using the grand master curve of creep compliance and shift factors, it was possible to estimate the creep deformation of molded materials under varying conditions and fiber contents. The estimated creep deformation gave a very good fit to the experimental creep deformation.

Comparison of strength and damage for notched FRP plates made by injection molding with that from machining

The strength and damage for two kinds of notched specimen have been investigated. We used an injection molded specimen (IM specimen) made by injection molding using a metal mold of a notched specimen, and a machined specimen (M specimen) made from plate by machining. The orientation of the fiber near the notch roots in the IM specimen and the M specimen is slightly different. The investigation was accomplished by obtaining experimental data of the static tension and fatigue tests on the notched plate of a short glass fiber-reinforced polycarbonate. To evaluate the damage near the notch root, we measured the luminance distributions by means of a luminance-measuring system with a CCD camera. The stress concentration and the similarity of stress distribution near the notch root of the IM specimen were compared with those of the M specimen. For the two kinds of specimen, for both of which the maximum elastic stress, σ max, and notch-root radius ρ were equal to each other, the strength and the process of damage initiation were similar under static tension. On the other hand, the number of loading cycles to fatigue damage initiation of the M specimen was fewer than that of the IM specimen.

K-0931 引張りを受ける短繊維強化PC切欠平板における微小破壊(J05-5 強度・破壊機構解析(2))(J05 複合材料の加工と評価)

An experimental program is presented which examines the microfracture in the damaged zone near the notch root of FRP plates. This is accomplished by observation of the damaged zone in notched plates of a glass fiber-reinforced polycarbonate under tension. The process of initiation and growth of damage was measured by means of the luminance measurement technique with a CCD camera during loading and unloading in tension tests. Closer observation on the cracks on the notch root surface revealed that numerous microcracks initiated on the notch root at the early stage. Several microcracks joined together and grew into a crack. The process of initiation and growth of the microcracks produced the decline of luminance near the notch root.

223 ガラス繊維強化ポリカーボネート切欠平板の引張りのもとでの損傷域の観察(OS 高分子および高分子複合材料)

223 ガラス繊維強化ポリカーボネート切欠平板の引張りのもとでの損傷域の観察(OS 高分子および高分子複合材料)

鈍くて浅い切欠きをもつＦＲＰ板の静荷重による破壊

The fracture criterion of notched FRP plates based on the concept of stress concentration and the similarity of stress distribution near the notch root is investigated experimentally. An experimental method is presented for examining the fracture strength of notched FRP plates under static loads. The investigation is accomplished by obtaining experimental data on the tension and bending tests of a glass fiber-reinforced polycarbonate plates containing blunt and shallow notches. For sharp-notched specimens, the stress distributions near the notch root are the same in all specimens, for which both the maximum elastic stress and notch-root radius are equal to each other. Therefore, the maximum elastic stress at fracture is determined by the notch-root radius only. On the other hand, for blunt-notched specimens the situation is much more complex. The experimental results were discussed in terms of a combination of the maximum elastic stress, notch-root radius and the width of notch section. Applying the fracture criterion derived here, the experimental results for blunt-notched specimens can be clearly explained.

Microfracture in the fatigue-damage zone of notched FRP plates

Considering the stress concentration and the similarity of stress distribution near the notch root, we have obtained a fatigue failure criterion for notched FRP plates in terms of a combination of the maximum elastic stress, the notch-root radius and the number of loading cycles to fatigue-damage initiation. To evaluate the fatigue damage near the notch root during fatigue test, we measured successively the luminance distributions by means of the luminance measurement technique with a CCD camera. The aims of the present research are to provide experimental evidence of the validity of the fatigue failure criterion as mentioned above and to show that the decrease of luminance is associated with irreversible damage and microfracture. The investigation is accomplished by obtaining experimental data of fatigue tests on the notched plates of a glass fiber-reinforced polycarbonate. To reveal the initiation and growth of microfracture along with the luminance decline, we observed the transverse section of the fatigue-damage zone near the notch root. The experiment shows that numerous microcracks initiated the end corner of a glass fiber and it is likely that several microcracks joined together and grew into a main crack.

Damage Evaluation for Notched Plates of Glass Fiber-Reinforced Polycarbonate

Damage Evaluation for Notched Plates of Glass Fiber-Reinforced Polycarbonate