Co‐injection molding of immiscible polymers: Skin‐core structure and adhesion studies

Gomes, M. J. M.; Martino, Daniela Di; Pontes, A. J.; Viana, J. C.

doi:10.1002/pen.22012

Cited by 18 publications

(18 citation statements)

References 19 publications

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“…The acceptable calculation is obtained through the eigenvalue-based optimal fitting approximation of the orthotropic closure family. To handle this complicated tensor system, Tseng et al [25,26] A RPR (α) (10) where .…”

Section: Model For Fiber Orientation Distributionmentioning

confidence: 99%

“…Seldén [8] monitored different process conditions and found out the skin-to-core material ratio is the main factor causing break-through problems. Moreover, the correlation between internal material distributions, process condition, and material property are discussed in many previous studies [9][10][11]. The cavity-filling ratio of skin material determines the break-through location.…”

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confidence: 99%

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Investigation on the Fiber Orientation Distributions and Their Influence on the Mechanical Property of the Co-Injection Molding Products

Huang

Chen

2019

Polymers

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In recent years, due to the rapid development of industrial lightweight technology, composite materials based on fiber reinforced plastics (FRP) have been widely used in the industry. However, the environmental impact of the FRPs is higher each year. To overcome this impact, co-injection molding could be one of the good solutions. But how to make the suitable control on the skin/core ratio and how to manage the glass fiber orientation features are still significant challenges. In this study, we have applied both computer-aided engineering (CAE) simulation and experimental methods to investigate the fiber feature in a co-injection system. Specifically, the fiber orientation distributions and their influence on the tensile properties for the single-shot and co-injection molding have been discovered. Results show that based on the 60:40 of skin/core ratio and same materials, the tensile properties of the co-injection system, including tensile stress and modulus, are a little weaker than that of the single-shot system. This is due to the overall fiber orientation tensor at flow direction (A 11 ) of the co-injection system being lower than that of the single-shot system. Moreover, to discover and verify the influence of the fiber orientation features, the fiber orientation distributions (FOD) of both the co-injection and single-shot systems have been observed using micro-computerized tomography (µ-CT) technology to scan the internal structures. The scanned images were further utilizing Avizo software to perform image analyses to rebuild the fiber structure. Specifically, the fiber orientation tensor at flow direction (A 11 ) of the co-injection system is about 89% of that of the single-shot system in the testing conditions. This is because the co-injection part has lower tensile properties. Furthermore, the difference of the fiber orientation tensor at flow direction (A 11 ) between the co-injection and the single-shot systems is further verified based on the fiber morphology of the µ-CT scanned image. The observed result is consistent with that of the FOD estimation using µ-CT scan plus image analysis. the fiber makes the microstructures inside FRP more complicated than that of general thermoplastics, it causes the recycling of FRP to be very difficult. As higher amounts of FRP are consumed, higher environmental impacts are needed to be addressed now and in future [7]. To overcome this impact, co-injection molding, based on the mechanical recycling process, could be a good solution.Co-injection molding is commonly used as a daily accessory, and in many other contexts. Basically, the co-injection technology can provide several advantages with integrating materials to reduce cost. This technology also allows for the reuse of materials, offers an upgrade in production efficiency, and can make raw skin/recycled core structures. However, there are some challenges for co-injection processes. For example, how to visualize and control suitable skin/core material distribution is very difficult during the processing. To deal w...

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Section: Model For Fiber Orientation Distributionmentioning

confidence: 99%

mentioning

confidence: 99%

Investigation on the Fiber Orientation Distributions and Their Influence on the Mechanical Property of the Co-Injection Molding Products

Huang

Chen

2019

Polymers

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“…Core material selection has historically been chosen to reduce costs through sourcing of recycled or cheaper polymers . Furthermore the core can include reinforcements such as fibers or particles which have been known to improve upon the skin/core interface …”

Section: Introductionmentioning

confidence: 99%

“…Materials must share similar thermal expansion and shrinkage to prevent delamination at the polymer‐polymer interface. The presence of interfacial bonding, through either chemical adhesion or mechanical interlocking of the two interfaces, also contributes to a successful CIM product . Appropriate material selection enables the proper distribution of the core within the skin material.…”

Section: Introductionmentioning

confidence: 99%

Study of the effect of processing conditions on the co‐injection of PBS/PBAT and PTT/PBT blends for parts with increased bio‐content

Zaverl

Valerio

Misra

et al. 2014

J of Applied Polymer Sci

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This work studies the effect of processing parameters on mechanical properties and material distribution of co-injected polymer blends within a complex mold shape. A partially bio-sourced blend of poly(butylene terephthalate) and poly(trimethylene terephthalate) PTT/PBT was used for the core, with a tough biodegradable blend of poly (butylene succinate) and poly (butylene adipate-co-terephthalate) PBS/PBAT for the skin. A 1 =2 factorial design of experiments is used to identify significant processing parameters from skin and core melt temperatures, injection speed and pressure, and mold temperature. Interactions between the processing effects are considered, and the resulting statistical data produced accurate linear models indicating that the co-injection of the two blends can be controlled. Impact strength of the normally brittle PTT/PBT blend is shown to increase significantly with co-injection and variations in core to skin volume ratios to have a determining role in the overall impact strength. Scanning electron microscope images were taken of co-injected tensile samples with the PBS/PBAT skin dissolved displaying variations of mechanical interlocking occurring between the two blends.

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“…Re-use the product as a filler is only scarcely applied in plastics and rubber industry but it forms an economically attractive way of re-using old materials. Co-injection molding techniques allow to form an object which inside consists of reused polymers while the outside consists of virgin material [7]. Another example of re-use as filler can be found in the tire industry where the objective is to substitute a few percent of the virgin rubber in car tires by partly devulcanized rubber from old tires.…”

Section: Illustrationsmentioning

confidence: 99%

Product engineering and sustainability

Janssen

2016

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Chemical engineering has made a substantial contribution to the improvement of the environment during the last decades. Many processes have become more sustainable and harmful waste streams are minimised. However, considerable improvement of sustainability can still be obtained in product engineering and design. Especially the aspects that are important at the end of the life cycle of the product can be improved considerably. A priority list for the design of more sustainable products is presented and illustrated with examples of daily chemical engineering practice.

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Co‐injection molding of immiscible polymers: Skin‐core structure and adhesion studies

Cited by 18 publications

References 19 publications

Investigation on the Fiber Orientation Distributions and Their Influence on the Mechanical Property of the Co-Injection Molding Products

Investigation on the Fiber Orientation Distributions and Their Influence on the Mechanical Property of the Co-Injection Molding Products

Study of the effect of processing conditions on the co‐injection of PBS/PBAT and PTT/PBT blends for parts with increased bio‐content

Product engineering and sustainability

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