Process analysis of spray atomization of dissolved polymers for manufacturing of blood-compatible textile implants

2017 ◽  
Vol 48 (5) ◽  
pp. 926-940 ◽  
Author(s):  
Ingo Nadzeyka ◽  
Eleonore Bolle ◽  
Martin Moos ◽  
Paula Kunitz ◽  
Ulrich Steinseifer ◽  
...  
Keyword(s):  
Manufacturing Process ◽  
Process Analysis ◽  
High Volume ◽  
Porous Polymer ◽  
Polymer Materials ◽  
Vascular Prostheses ◽  
Positioning Systems ◽  
Basic Parameters ◽  
Woven Structures ◽  
Pressure Nozzle

The use of porous polymer materials for vascular prostheses demonstrates promising results. Fleece-like non-woven structures can be generated by atomization of dissolved polycarbonate urethanes. This article focuses on the manufacturing process for the fleece structures. The solution is atomized through a high-volume low-pressure nozzle. The solvent evaporates during time of flight to target, so that small fibres are formed from each drop of solution. By using different rotating molds and positioning systems, tubular shapes or open surfaces can be generated. The manufacturing process is described in detail. The usability of different grades of polycarbonate urethane is tested and the time necessary for evaporation of the solvent from the mesh is assessed. The influence of several basic parameters on the mechanical properties of the generated non-woven material is analysed and discussed.

Cryostructuration as a tool for preparing highly porous polymer materials

2011 ◽  
Vol 2 (5) ◽  
pp. 1059 ◽  
Author(s):  
Harald Kirsebom ◽  
Bo Mattiasson
Keyword(s):  
Porous Polymer ◽  
Polymer Materials ◽  
Highly Porous

The Hybrid Compression Moulding of Structural Composite Materials for Automotive Applications

2020 ◽  
Vol 843 ◽  
pp. 3-8 ◽  
Author(s):  
Helena C. Simmonds ◽  
Neil C. Reynolds ◽  
Kenneth N. Kendall
Keyword(s):  
Composite Materials ◽  
Manufacturing Process ◽  
Fibre Composite ◽  
Material Design ◽  
High Volume ◽  
Ford Motor Company ◽  
Compression Moulding ◽  
Cycle Times ◽  
Class Project ◽  
Automotive Suspension

The Innovate-UK-funded Composite Lightweight Automotive Suspension System (CLASS) project, led by Ford Motor Company and partnered by Gestamp UK, GRM Consulting and WMG, investigated the use of carbon fibre reinforced composite materials to decrease the weight of a complex automotive rear suspension component in support of reduction in vehicle emissions. A multi-material design comprising discontinuous fibre composite (C-SMC), aligned fibre composite laminate (prepreg) and steel was developed. A high volume hybrid compression moulding manufacturing process was developed at WMG, achieving total press cycle times of around 5 minutes. Prototype parts were manufactured and evaluated using materials characterisation techniques to validate the manufacturing methods. The optimum C-SMC charge pattern was investigated to achieve complete fill with minimal pre-processing. Destructive and nondestructive analysis of the hybrid parts was performed to understand resultant hybrid material macrostructure. This innovative design and manufacturing process resulted in a component 35% lighter than the original multi-piece steel design.

Large Deformation Behavior of Porous Polymer Materials With 3D Random Pore Structure: Experimental Investigation and FEM Modeling

2019 ◽  
Author(s):  
Kanako Emori ◽  
Tatsuma Miura ◽  
Akio Yonezu
Keyword(s):  
Plastic Deformation ◽  
Pore Structure ◽  
Creep Deformation ◽  
Deformation Behavior ◽  
Superposition Principle ◽  
Critical Role ◽  
Test Sample ◽  
Porous Polymer ◽  
Polymer Materials ◽  
Polymeric Membrane

Abstract This study investigates the deformation behavior of porous polymer materials with 3D random pore structure. The test sample has sub-micron-sized pores with an open cellular structure, which plays a critical role for water purification. The base polymer is PVDF (polyvinylidene difluoride). First, the surface and cross section of the sample are observed using FESEM to investigate the microstructure (cell size and geometry of the cell ligament, etc). Next, uni-axial tensile loading is carried out for polymeric membrane and it is found that the membranes underwent elasto-plastic deformation. In order to establish a numerical model, finite element metod (FEM) is employed. Using a software of Surface Evolver, 3D random pore structure is created in the representative volume element (RVE). The established computational model can predict both elastic deformation and plastic deformation. Furthermore, viscoplastic deformation behavior (i.e. time-dependent deformation and creep deformation) is investigated, experimentally and numerically. In particular, creep compliance is measured, and we investigate the effect of applied loading on creep deformation behavior. Using the time–temperature–stress superposition principle (TTSSP), we obtain a new master curve, which covers higher stress level, and successfully establish an FEM model of creep deformation of the test sample. The present model enables the prediction of the macroscopic and microscopic deformation behavior of the porous materials, by taking into account of 3D random pore structure.

scholarly journals Preparation of Porous Biodegradable Polymer and Its Nanocomposites by Supercritical CO2Foaming for Tissue Engineering

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Xia Liao ◽  
Haichen Zhang ◽  
Ting He
Keyword(s):  
Carbon Dioxide ◽  
Tissue Engineering ◽  
Polymer Nanocomposites ◽  
Biodegradable Polymer ◽  
Processing Parameters ◽  
Porous Polymer ◽  
Polymer Materials ◽  
Biodegradable Materials ◽  
High Level ◽  
Foaming Technology

Using supercritical carbon dioxide (scCO2) as an alternative to conventional methods in the preparation of porous biodegradable polymer and polymer/nanocomposites for tissue engineering has attracted increasing interest in recent years due to the absence of using organic solvents and the ability to incorporate thermosensitive biologicals without loss of bioactivity. Additionally, scCO2can exert a high level of control over porosity and morphology of scaffolds by tuning the processing parameters. This paper describes the newly achievements on the preparation of porous polymer materials using scCO2foaming technology with focus on the porous biodegradable materials and its nanocomposites relevant to tissue engineering.

scholarly journals Long-Term Biostability of Pet Vascular Prostheses

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Florence Dieval ◽  
Foued Khoffi ◽  
Riaz Mir ◽  
Walid Chaouch ◽  
Didier Le Nouen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Manufacturing Process ◽  
Vascular Prosthesis ◽  
Chemical Degradation ◽  
Medical Complications ◽  
Human Metabolism ◽  
Vascular Prostheses ◽  
In Vivo Degradation

PET Vascular prostheses are susceptible to physical modification and chemical degradation leading sometimes to global deterioration and rupture of the product. To understand the mechanisms of degradation, we studied 6 vascular prostheses that were explanted due to medical complications. We characterized their level of degradation by comparing them with a virgin prosthesis and carried out physicochemical and mechanical analyses. Results showed an important reduction of the fabric’s mechanical properties in specific areas. Moreover, PET taken from these areas exhibited structural anomalies and was highly degraded even in virgin prostheses. These results suggest that vascular prostheses have weak areas prior to implantation and that these areas are much more prone to in vivo degradation by human metabolism. Manufacturing process could be responsible for these weaknesses as well as designing of the compound. Therefore, we suggest that a more controlled manufacturing process could lead to a vascular prosthesis with enhanced lifespan.

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