Polymer–polymer mutual diffusion via rheology of coextruded multilayers

Zhao, Rui; Macosko, Christopher W.

doi:10.1002/aic.11136

Cited by 26 publications

(17 citation statements)

References 34 publications

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“…Asymmetry arises due to the different degree of deformation at weld sites t p−1 and b p . The Kramer model [29] describes the mutual diffusion of two different molecular weight polymers [32]. However, since the FFF problem discussed here involves a single molecular weight inter-diffusing between different-mobility environments, a polymer chain will inherit the relaxation characteristics of the environment into which it is diffusing.…”

Section: Mutual Diffusion Approximationmentioning

confidence: 99%

Disentanglement effects on welding behaviour of polymer melts during the fused-filament-fabrication method for additive manufacturing

McIlroy

Olmsted

2017

Polymer

235

227

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Although 3D printing has the potential to transform manufacturing processes, the strength of printed parts often does not rival that of traditionally-manufactured parts. The fused-filament fabrication method involves melting a thermoplastic, followed by layer-by-layer extrusion of the molten viscoelastic material to fabricate a three-dimensional object. The strength of the welds between layers is controlled by interdiffusion and entanglement of the melt across the interface. However, diffusion slows down as the printed layer cools towards the glass transition temperature. Diffusion is also affected by high shear rates in the nozzle, which significantly deform and disentangle the polymer microstructure prior to welding. In this paper, we model non-isothermal polymer relaxation, entanglement recovery, and diffusion processes that occur post-extrusion to investigate the effects that typical printing conditions and amorphous (non-crystalline) polymer rheology have on the ultimate weld structure. Although we find the weld thickness to be of the order of the polymer size, the structure of the weld is anisotropic and relatively disentangled; reduced mechanical strength at the weld is attributed to this lower degree of entanglement.

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Section: Mutual Diffusion Approximationmentioning

confidence: 99%

Disentanglement effects on welding behaviour of polymer melts during the fused-filament-fabrication method for additive manufacturing

McIlroy

Olmsted

2017

Polymer

235

227

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“…Evidently, the calculation of the diffusion coefficient of polymers, whether the self-diffusion coefficient or the mutual diffusion coefficient, is a gigantic task, especially considering that a large number of parameters are needed. It should also be mentioned that Zhao and Macosko (89) proposed a different model from a phenomenological aspect for the mutual diffusion coefficient in their HDPE/LLDPE (linear low density polyethylene) multilayer system by fitting the complex viscosity variation that theoretically calculated from Fick's law to the experimental data.…”

Section: Experimental Aspectsmentioning

confidence: 99%

Coextrusion of Multilayer Structures, Interfacial Phenomena

Lamnawar

Zhang

Maazouz

2013

Encyclopedia of Polymer Science and Technology

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International audienceThe focus of this overview is to give a state-of-the-art knowledge on coextrusion and rheology at the interface of multilayer polymers. In this article, we summarize important experimental and fundamental aspects given in the literature in regard to structure-processing-properties relationships. In addition, the modeling of the interfacial phenomena and the role of the interphase on the flow stability in coextrusion are also discussed

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“…The high surface-to-volume ratio, which gives a large amount of specific interfacial area, greatly magnifies a small change in the interface and produces macroscopically measurable quantities. Thus, it is an ideal model system for studying interfacial phenomena such as interdiffusion [26,27,36,37], reaction [38][39][40][41][42], and slip [43,44] at polymer-polymer interface.…”

Section: Introductionmentioning

confidence: 99%

Adhesion and delamination failure mechanisms in alternating layered polyamide and polyethylene with compatibilizer

Jiang

et al. 2009

Polymer Engineering & Sci

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The effects of compatibilizer and the number of layers on the interfacial adhesion and delamination model of coextruded microlayer samples consisting of alternating layers of high-density polyethylene (HDPE) and polyamide 6 (PA6) were studied with T-peel test. When more maleic anhydride-grafted HDPE was incorporated into HDPE layer, the interfacial delamination model changed from adhesive to cohesive failure in the case of bilayer samples. For high-layer samples, the results of X-ray photoelectron spectroscopy showed that the areal density of copolymers at the interfaces increased with increasing number of layers due to strong and durable shearing forces during microlayer coextrusion. Scanning electron microscopy observation revealed that the interfacial delamination model changed from single-to multiple-interface delamination when the number of layers increased from 16 to 32. The crack propagation included a large number of layer-layer jumps. The peel strength of microlayer samples was found to be greatly influenced by the interfacial delamination mechanisms.

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Polymer–polymer mutual diffusion via rheology of coextruded multilayers

Cited by 26 publications

References 34 publications

Disentanglement effects on welding behaviour of polymer melts during the fused-filament-fabrication method for additive manufacturing

Disentanglement effects on welding behaviour of polymer melts during the fused-filament-fabrication method for additive manufacturing

Coextrusion of Multilayer Structures, Interfacial Phenomena

Adhesion and delamination failure mechanisms in alternating layered polyamide and polyethylene with compatibilizer

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