Abstract:In this study, blends of cyclo-olefin copolymers (COC) that had different monomer compositions and poly(Acrylonitrile-Butadiene-Styrene) (ABS) were prepared and variations in their morphological, rheological, and dynamic mechanical properties were investigated. In the morphological analyses, it was seen that all blends with 50/50% composition had a co-continuous morphology, while droplet-matrix morphology was observed for the other compositions. Melt-state shear modulus and viscosity increased with the additio… Show more
“…[13][14][15] Although semicrystalline polymers are usually more chemical resistant and less brittle than their amorphous counterparts, amorphous COC TOPAS grades have been more widely used in microfluidic applications, such as microvalves or droplet generators, than the COC TOPAS E-140. Although COC TOPAS E-140 has been used in some research works in polymer science, [16][17][18] to date, little literature on the characterization and processing of this material for microfluidics application has been reported. [19,20] These materials can be processed by thermoforming, hot embossing, and injection molding (IM), allowing with them the mass production of microfluidic devices.…”
Point‐of‐care (PoC) and organ‐on‐chip (OoC) devices represent promising microfluidic applications for in vitro analysis and miniaturized analytical studies, reducing the need for traditional animal‐based tests for drug discovery and toxicity studies. Using thermoplastics in microfluidic device manufacturing provides interesting functionalities for expansion of these devices into market. However, market growth requires manufacturing large quantities for low cost, which can be achieved using injection molding techniques. This work involves the design of a microfluidic device with different aspect ratio channels to compare injection molding (IM) and injection‐compression molding (ICM) processes, as well as the design and manufacturing of a metallic insert containing machined inverted microstructures. Injected parts are validated visually, dimensionally, and functionally. The differences between both techniques and two grades of cyclic olefin copolymer materials are analyzed to evaluate microfluidic device mass production feasibility concluding that although the machining process for inverted high aspect ratio microstructures is not mature yet, both IM and ICM processes allow the mass manufacturing of microfluidic devices in thermoplastic. Parts processed by ICM show better replicability of microfluidic structures and less internal stresses generate during the injection process than IM parts, highlighting the potential of this process to achieve thermoplastic microfluidic devices to market.
“…[13][14][15] Although semicrystalline polymers are usually more chemical resistant and less brittle than their amorphous counterparts, amorphous COC TOPAS grades have been more widely used in microfluidic applications, such as microvalves or droplet generators, than the COC TOPAS E-140. Although COC TOPAS E-140 has been used in some research works in polymer science, [16][17][18] to date, little literature on the characterization and processing of this material for microfluidics application has been reported. [19,20] These materials can be processed by thermoforming, hot embossing, and injection molding (IM), allowing with them the mass production of microfluidic devices.…”
Point‐of‐care (PoC) and organ‐on‐chip (OoC) devices represent promising microfluidic applications for in vitro analysis and miniaturized analytical studies, reducing the need for traditional animal‐based tests for drug discovery and toxicity studies. Using thermoplastics in microfluidic device manufacturing provides interesting functionalities for expansion of these devices into market. However, market growth requires manufacturing large quantities for low cost, which can be achieved using injection molding techniques. This work involves the design of a microfluidic device with different aspect ratio channels to compare injection molding (IM) and injection‐compression molding (ICM) processes, as well as the design and manufacturing of a metallic insert containing machined inverted microstructures. Injected parts are validated visually, dimensionally, and functionally. The differences between both techniques and two grades of cyclic olefin copolymer materials are analyzed to evaluate microfluidic device mass production feasibility concluding that although the machining process for inverted high aspect ratio microstructures is not mature yet, both IM and ICM processes allow the mass manufacturing of microfluidic devices in thermoplastic. Parts processed by ICM show better replicability of microfluidic structures and less internal stresses generate during the injection process than IM parts, highlighting the potential of this process to achieve thermoplastic microfluidic devices to market.
“…In another study, morphological, rheological, and dynamic mechanical properties of blends of cyclo‐olefin copolymers (COC) with different monomer compositions and poly(Acrylonitrile‐Butadiene‐Styrene) (ABS) were investigated by Kurt et al [ 28 ] All blends with 50/50% composition had a co‐continuous morphology, while droplet‐matrix morphology was observed for the other compositions. It was seen that the modulus values were reduced with the addition of ABS in the blends prepared with COC with 82% norbornene content.…”
This paper deals with the fatigue life analysis of a blend of natural rubber (NR) and styrene‐butadiene rubber (SBR) with and without nanoclay particles. Various damage parameters based on strain are investigated. A nonlinear finite element analysis is carried out by using ABAQUS. To formulate the life prediction models, the measured fatigue life is used together with various damage parameters. It is shown that all the damage parameters can estimate the fatigue lives effectively with correlation coefficients greater than 0.9. There is a good agreement between the obtained fatigue live predictions and the measured fatigue results. The effect of various parameters such as true strain and nanoparticles' loading is also investigated. The results of sensitivity analysis show that the strain has a greater effect on the variation of the rubber compounds' fatigue life. The test samples' fracture surface is assessed via scanning electron microscopy (SEM). SEM results show that as the strain increases, the test samples softly fail while the fracture surface of the nanocomposite is roughened by the addition of nanoclay.
The blends of poly(butylene-adipate-co-terephthalate)/poly(ethylene-vinyl alcohol) (PBAT/EVOH) with varying amounts of graphene oxide (GO) were prepared by melt mixing. The localization of GO in PBAT and at the interface was confirmed by morphological evaluation. The dual effect of GO in degradation of PBAT phase and interface improvement of PBAT/EVOH was examined by rheological measurements and models. The results showed that the improved interfacial interaction induced by GO dominates its degradation effect in PBAT. Rheological analysis revealed that the interfacial elasticity originating from GO dominates the total elasticity of the system, resulting in an increase in the final elasticity. Generalized Fractional Zener (GFZ) model was used to analyze elasticity of the polymer blend and its nanocomposites with a well fit to the experimental results. Also, the Lee–Park model was used to distinguish the effects of particle interactions as well as interface strengthening from deterioration of matrix modulus due to PBAT degradation by GO. The increased elasticity of the interface showed that the strengthening effect of GO at the interface overcomes its degradation effect. Also, the application of Coran model to analyze phase homogeneity revealed a linear increase in interfacial interaction with GO concentration.
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