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Rathner R, Leimhofer C, Roland W, Hammer A, Löw-Baselli B, Steinbichler G, Hild S. Improving Layer Adhesion of Co-Extruded Polymer Sheets by Inducing Interfacial Flow Instabilities. Polymers (Basel) 2022; 14:polym14030587. [PMID: 35160575 PMCID: PMC8838223 DOI: 10.3390/polym14030587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/17/2022] [Accepted: 01/27/2022] [Indexed: 02/05/2023] Open
Abstract
Co-extrusion is commonly used to produce polymer multilayer products with different materials tailoring the property profiles. Adhesion between the individual layers is crucial to the overall performance of the final structure. Layer adhesion is determined by the compatibility of the polymers at the interface and their interaction forces, causing for example the formation of adhesive or chemical bonds or an interdiffusion layer. Additionally, the processing conditions, such as temperature, residence time, cooling rate, and interfacial shear stress, have a major influence on the interactions and hence resulting layer adhesion. Influences of temperature and residence time are already quite well studied, but influence of shear load on the formation of an adhesion layer is less explored and controversially discussed in existing literature. In this work, we investigated the influence of different processing conditions causing various shear loads on layer adhesion for a two-layer co-extruded polymer sheet using a polypropylene and polypropylene talc compound system. Therefore, we varied the flow rates and the flow geometry of the die. Under specific conditions interfacial flow instabilities are triggered that form micro layers in the transition regime between the two layers causing a major increase in layer adhesion. This structure was analyzed using confocal Raman microscopy. Making use of these interfacial flow instabilities in a controlled way enables completely new opportunities and potentials for multi-layer products.
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Affiliation(s)
- Raffael Rathner
- Institute of Polymer Processing and Digital Transformation, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria; (R.R.); (A.H.); (B.L.-B.); (G.S.)
- Pro2Future GmbH, Altenberger Str. 69, 4040 Linz, Austria
| | - Claudia Leimhofer
- Institute of Polymer Science, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria; (C.L.); (S.H.)
| | - Wolfgang Roland
- Institute of Polymer Processing and Digital Transformation, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria; (R.R.); (A.H.); (B.L.-B.); (G.S.)
- Pro2Future GmbH, Altenberger Str. 69, 4040 Linz, Austria
- Correspondence:
| | - Alexander Hammer
- Institute of Polymer Processing and Digital Transformation, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria; (R.R.); (A.H.); (B.L.-B.); (G.S.)
| | - Bernhard Löw-Baselli
- Institute of Polymer Processing and Digital Transformation, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria; (R.R.); (A.H.); (B.L.-B.); (G.S.)
| | - Georg Steinbichler
- Institute of Polymer Processing and Digital Transformation, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria; (R.R.); (A.H.); (B.L.-B.); (G.S.)
| | - Sabine Hild
- Institute of Polymer Science, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria; (C.L.); (S.H.)
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Hammer A, Roland W, Zacher M, Praher B, Hannesschläger G, Löw-Baselli B, Steinbichler G. In Situ Detection of Interfacial Flow Instabilities in Polymer Co-Extrusion Using Optical Coherence Tomography and Ultrasonic Techniques. Polymers (Basel) 2021; 13:polym13172880. [PMID: 34502920 PMCID: PMC8434255 DOI: 10.3390/polym13172880] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 11/16/2022] Open
Abstract
Co-extrusion is a widely used processing technique for combining various polymers with different properties into a tailored multilayer product. Individual melt streams are combined in a die to form the desired shape. Under certain conditions, interfacial flow instabilities are observed; however, fundamental knowledge about their onset and about critical conditions in science and industry is scarce. Since reliable identification of interfacial co-extrusion flow instabilities is essential for successful operation, this work presents in situ measurement approaches using a novel co-extrusion demonstrator die, which is fed by two separate melt streams that form a well-controlled two-layer co-extrusion polymer melt flow. An interchangeable cover allows installation of an optical coherence tomography (OCT) sensor and of an ultrasonic (US) measurement system, where the former requires an optical window and the latter good direct coupling with the cover for assessment of the flow situation. The feasibility of both approaches was proven for a material combination that is typically found in multilayer packaging applications. Based on the measurement signals, various parameters are proposed for distinguishing reliably between stable and unstable flow conditions in both measurement systems. The approaches presented are well suited to monitoring for and systematically investigating co-extrusion flow instabilities and, thus, contribute to improving the fundamental knowledge about instability onset and critical conditions.
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Affiliation(s)
- Alexander Hammer
- Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria; (W.R.); (M.Z.); (B.L.-B.); (G.S.)
- Correspondence:
| | - Wolfgang Roland
- Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria; (W.R.); (M.Z.); (B.L.-B.); (G.S.)
- Pro2Future GmbH, Altenberger Strasse 69, 4040 Linz, Austria
| | - Maximilian Zacher
- Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria; (W.R.); (M.Z.); (B.L.-B.); (G.S.)
- Pro2Future GmbH, Altenberger Strasse 69, 4040 Linz, Austria
| | | | | | - Bernhard Löw-Baselli
- Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria; (W.R.); (M.Z.); (B.L.-B.); (G.S.)
| | - Georg Steinbichler
- Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria; (W.R.); (M.Z.); (B.L.-B.); (G.S.)
- Institute of Polymer Injection Molding and Process Automation, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria
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Johnson AR, Forster SP, White D, Terife G, Lowinger M, Teller RS, Barrett SE. Drug eluting implants in pharmaceutical development and clinical practice. Expert Opin Drug Deliv 2021; 18:577-593. [PMID: 33275066 DOI: 10.1080/17425247.2021.1856072] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Introduction: Drug eluting implants offer patient convenience and improved compliance through less frequent dosing, eliminating repeated, painful injections and providing localized, site specific delivery with applications in contraception, ophthalmology, and oncology.Areas covered: This review provides an overview of available implant products, design approaches, biodegradable and non-biodegradable polymeric materials, and fabrication techniques with a focus on commercial applications and industrial drug product development. Developing trends in the field, including expanded availability of suitable excipients, development of novel materials, scaled down manufacturing process, and a wider understanding of the implant development process are discussed and point to opportunities for differentiated drug eluting implant products.Expert opinion: In the future, long-acting implants will be important clinical tools for prophylaxis and treatment of global health challenges, especially for infectious diseases, to reduce the cost and difficulty of treating chronic indications, and to prolong local delivery in difficult to administer parts of the body. These products will help improve patient safety, adherence, and comfort.
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Affiliation(s)
- Ashley R Johnson
- Pharmaceutical Sciences, Merck & Co., Inc., Merck & Co., Inc., Rahway, NJ, USA
| | - Seth P Forster
- Pharmaceutical Sciences, Merck & Co., Inc., Merck & Co., Inc., Rahway, NJ, USA
| | | | - Graciela Terife
- Pharmaceutical Sciences, Merck & Co., Inc., Merck & Co., Inc., Rahway, NJ, USA
| | - Michael Lowinger
- Pharmaceutical Sciences, Merck & Co., Inc., Merck & Co., Inc., Rahway, NJ, USA
| | | | - Stephanie E Barrett
- Pharmaceutical Sciences, Merck & Co., Inc., Merck & Co., Inc., Rahway, NJ, USA
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Yu H, Li J, Guo S. Three‐dimensional isothermal simulation of PP melt flow in laminating‐multiplying elements based on the finite element method. POLYM ENG SCI 2019. [DOI: 10.1002/pen.25050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Huaning Yu
- The State Key Laboratory of Polymer Materials EngineeringPolymer Research Institute of Sichuan University Chengdu Sichuan 610065 China
| | - Jiang Li
- The State Key Laboratory of Polymer Materials EngineeringPolymer Research Institute of Sichuan University Chengdu Sichuan 610065 China
| | - Shaoyun Guo
- The State Key Laboratory of Polymer Materials EngineeringPolymer Research Institute of Sichuan University Chengdu Sichuan 610065 China
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Bondon A, Lamnawar K, Maazouz A. Experimental investigation of a new type of interfacial instability in a reactive coextrusion process. POLYM ENG SCI 2015. [DOI: 10.1002/pen.24146] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Arnaud Bondon
- Université de Lyon; Lyon France
- CNRS, UMR 5223, Ingénierie des Matériaux Polymères, INSA Lyon; Villeurbanne France
| | - Khalid Lamnawar
- Université de Lyon; Lyon France
- CNRS, UMR 5259, INSA-Lyon, LaMCoS, Laboratoire de Mécanique des Contacts et des Structures; Villeurbanne France
| | - Abderrahim Maazouz
- Université de Lyon; Lyon France
- CNRS, UMR 5223, Ingénierie des Matériaux Polymères, INSA Lyon; Villeurbanne France
- Hassan II Academy of Science and Technology; Rabat Morocco
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Martyn MT, Coates PD. Pressure Variation during Interfacial Instability in the Coextrusion of Low Density Polyethylene Melts. INT POLYM PROC 2013. [DOI: 10.3139/217.2786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Pressure variation during the coextrusion of two low density polyethylene melts was investigated. Melt streams were delivered to a die from two separate extruders to converge in a 30°° geometry to form a two layer extrudate. Melt flow in the confluent region and die land to the die exit was observed through side windows of a visualisation cell. Stream velocity ratio was varied by control of extruder screw speeds. Layer thickness ratios producing wave type interfacial instability were quantified for each melt coextruded on itself and for the combined melts. Stream pressures and screw speeds were monitored and analysed. Wave type interfacial instability was present during the processing of the melts at specific, repeatable, stream layer ratios. Increased melt elasticity appeared to promote this type of instability. Analysis of process data indicates little correlation between perturbations in extruder screw speeds and stream pressures. The analysis did however show covariance between the individual stream pressure perturbations. Interestingly there was significant correlation even when interfacial instability was not present. We conclude that naturally occurring variation in extruder screw speeds do not perturb stream pressures and, more importantly, natural perturbations in stream pressures do not promote interfacial instability.
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Affiliation(s)
- M. T. Martyn
- IRC in Polymer Science and Technology, School of Engineering, Design and Technology, University of Bradford, Bradford, UK
| | - P. D. Coates
- IRC in Polymer Science and Technology, School of Engineering, Design and Technology, University of Bradford, Bradford, UK
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Liu H, Deng X, Huang Y, Huang X, Li M. Three-dimensional viscoelastic simulation of the effect of wall slip on encapsulation in the coextrusion process. JOURNAL OF POLYMER ENGINEERING 2013. [DOI: 10.1515/polyeng-2013-0108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
A three-dimensional viscoelastic numerical simulation was developed for a two-layer coextrusion through a rectangular channel by using the finite element method. The Phan-Thien and Tanner model was considered as viscoelastic constitutive equations. The generalized Navier’s law was adopted to found the slip boundary condition. The numerical results of the effects of the wall slip coefficient and the flow rate on the interface profile and the degree of encapsulation were compared with the experimental results of previous researchers. It was found that the interfacial offset and the degree of encapsulation increased with the increase of the wall slip coefficient and the flow rate, and the growing rate was large when the wall slip coefficient was between 106 and 108. We were able to control the interface shape and the degree of encapsulation at the die exit by varying the wall slip coefficient and the magnitude of the melt flow rate.
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Sedlacek T, Lengalova A, Zatloukal M, Cermak R, Saha P. Pressure and Temperature Dependence of LDPE Viscosity and Free Volume: The Effect of Molecular Structure. INT POLYM PROC 2013. [DOI: 10.3139/217.1909] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Temperature and pressure dependencies of shear and elongational viscosities were examined using rotational and capillary rheometers. Two different batches of the same polymer grade have shown that the molecular structure diversion significantly influences the magnitudes of pressure coefficients, which vary more than the temperature coefficients. The pressure effect on viscosity notably depends on the amount of long-chain branching in polymer. Further, the paper shows that pVT data analysis via the Simha-Somcynsky equation of state can be employed to reveal differences in temperature and pressure viscosity dependencies through the free volume fraction.
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Affiliation(s)
- T. Sedlacek
- Polymer Centre, Tomas Bata University in Zlín, Zlín, Czech Republic
| | - A. Lengalova
- Polymer Centre, Tomas Bata University in Zlín, Zlín, Czech Republic
| | - M. Zatloukal
- Polymer Centre, Tomas Bata University in Zlín, Zlín, Czech Republic
| | - R. Cermak
- Department of Polymers Engineering, Tomas Bata University in Zlín, Zlín, Czech Republic
| | - P. Saha
- Polymer Centre, Tomas Bata University in Zlín, Zlín, Czech Republic
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Uematsu H, Tanoue S, Iemoto Y, Sugimoto M, Taniguchi T, Koyama K. Development of Polymer Extrusion Extruder for Evaluating with a Small Amount of Polymeric Material. INT POLYM PROC 2013. [DOI: 10.3139/217.2559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
We developed the extrusion system to evaluate the extrusion behavior such as the shear viscosity, which is one of basic properties, and the processability of mono/multilayer film with a small amount of polymeric material. In order to measure the shear viscosity, the gear pump, the return path and the pressure sensors were introduced into the extruder with intermeshing co-rotating twin screws. The viscosity could be evaluated on-line from the volumetric flow rate of molten polymer and the pressure drop in the return path before film processing. The capacity of gear pump, the shape and size of return path were optimized to evaluate the viscosity of polymeric material, which generally undergoes shear rate of 10 ∼ 1000 s−1 in the film processing. The apparatus for mono and multilayer film processing consisted of two extruders including the multichannel feedblock and T-die with the manifold and land section. The compact feedblock was designed to receive two feedstreams, so that the product can have two layers. We investigated the on-line viscosity measurement methodology and the processability, which is the neck-in phenomenon for monolayer film and the interface stability for multilayer film, using typical polymer material of 30 grams at once. The viscosity evaluated with our system corresponded with the result of commercial rheometer. It was also confirmed that the processability of mono and multilayer film could be evaluated quantitatively with our system.
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Affiliation(s)
- H. Uematsu
- Department of Polymer Science and Engineering, Yamagata University, Yamagata, Japan
- Department of Fiber Amenity Engineering, University of Fukui, Fukui, Japan
| | - S. Tanoue
- Department of Fiber Amenity Engineering, University of Fukui, Fukui, Japan
| | - Y. Iemoto
- Department of Fiber Amenity Engineering, University of Fukui, Fukui, Japan
| | - M. Sugimoto
- Department of Polymer Science and Engineering, Yamagata University, Yamagata, Japan
| | - T. Taniguchi
- Department of Polymer Science and Engineering, Yamagata University, Yamagata, Japan
- Department of Chemical Engineering, Kyoto University, Katsura-Campus, Kyoto, Japan
| | - K. Koyama
- Department of Polymer Science and Engineering, Yamagata University, Yamagata, Japan
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