scholarly journals Are Medical Grade Bioabsorbable Polymers a Viable Material for Fused Filament Fabrication?

2019 ◽  
Vol 13 (3) ◽  
Author(s):  
Jaclyn Schachtner ◽  
Michael Frohbergh ◽  
Noreen Hickok ◽  
Steven Kurtz
Keyword(s):  
Lumbar Fusion ◽  
Dimensional Accuracy ◽  
Gel Permeation Chromatography ◽  
Raw Material ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
Polyether Ether Ketone ◽  
The Cost ◽  
Degradation Properties ◽  
Medical Grade

Lumbar fusion surgery has grown in popularity as a solution to lower back pain. Surgical site infection (SSI) is a serious complication of spinal surgery, affecting as high as 8.5% of the patient population. If the SSI cannot be eradicated with intravenous antibiotics, the next step is second surgery, which increases the cost imposed on the patient and extends recovery time. An implantable ultrasound-triggered polyether ether ketone device for the dispersal of antibiotics has been developed as a potential solution. In this study, the device was constructed of bioabsorbable medical grade polymer, enabling gradual degradation, and manufactured via fused filament fabrication (FFF). A novel bioabsorbable filament was manufactured and validated with gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The filament was consistent in molecular weight and thermal properties (p = 0.348 and p = 0.487, respectively). The filament was utilized for FFF of the device. Dimensional accuracy of the device was assessed with μCT analysis. Dimensional differences between the printed device and intended design were minimal. Degradation of raw material, filament, and the device was performed in accordance to ASTM F1635-16 for a month to determine how melting the material impacted the degradation properties. The degradation rate was found to be similar among the samples weeks one through three however, the raw material degraded at a slower rate by the final week (p = 0.039). This study demonstrated the feasibility of utilizing medical grade bioabsorbable polymers in FFF.

scholarly journals Effects of Two Melt Extrusion Based Additive Manufacturing Technologies and Common Sterilization Methods on the Properties of a Medical Grade PLGA Copolymer

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 572
Author(s):  
Marion Gradwohl ◽  
Feng Chai ◽  
Julien Payen ◽  
Pierre Guerreschi ◽  
Philippe Marchetti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Additive Manufacturing ◽  
Ethylene Oxide ◽  
Medical Devices ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
Manufacturing Technologies ◽  
Medical Grade

Although bioabsorbable polymers have garnered increasing attention because of their potential in tissue engineering applications, to our knowledge there are only a few bioabsorbable 3D printed medical devices on the market thus far. In this study, we assessed the processability of medical grade Poly(lactic-co-glycolic) Acid (PLGA)85:15 via two additive manufacturing technologies: Fused Filament Fabrication (FFF) and Direct Pellet Printing (DPP) to highlight the least destructive technology towards PLGA. To quantify PLGA degradation, its molecular weight (gel permeation chromatography (GPC)) as well as its thermal properties (differential scanning calorimetry (DSC)) were evaluated at each processing step, including sterilization with conventional methods (ethylene oxide, gamma, and beta irradiation). Results show that 3D printing of PLGA on a DPP printer significantly decreased the number-average molecular weight (Mn) to the greatest extent (26% Mn loss, p < 0.0001) as it applies a longer residence time and higher shear stress compared to classic FFF (19% Mn loss, p < 0.0001). Among all sterilization methods tested, ethylene oxide seems to be the most appropriate, as it leads to no significant changes in PLGA properties. After sterilization, all samples were considered to be non-toxic, as cell viability was above 70% compared to the control, indicating that this manufacturing route could be used for the development of bioabsorbable medical devices. Based on our observations, we recommend using FFF printing and ethylene oxide sterilization to produce PLGA medical devices.

scholarly journals Fluoropolymer/Glycidyl Azide Polymer (GAP) Block Copolyurethane as New Energetic Binders: Synthesis, Mechanical Properties, and Thermal Performance

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2706
Author(s):  
Minghui Xu ◽  
Xianming Lu ◽  
Ning Liu ◽  
Qian Zhang ◽  
Hongchang Mo ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Mechanical Performance ◽  
Gel Permeation Chromatography ◽  
Raw Material ◽  
Toluene Diisocyanate ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Glycidyl Azide Polymer ◽  
The Impact ◽  
Glycidyl Azide

In order to enhance the application performance of glycidyl azide polymer (GAP) in solid propellant, an energetic copolyurethane binder, (poly[3,3-bis(2,2,2-trifluoro-ethoxymethyl)oxetane] glycol-block-glycidylazide polymer (PBFMO-b-GAP) was synthesized using poly[3,3-bis(2,2,2-trifluoro-ethoxymethyl)oxetane] glycol (PBFMO), which was prepared from cationic polymerization with GAP as the raw material and toluene diisocyanate (TDI) as the coupling agent via a prepolymer process. The molecular structure of copolyurethanes was confirmed by attenuated total reflectance-Fourier transform-infrared spectroscopy (ATR–FTIR), nuclear magnetic resonance spectrometry (NMR), and gel permeation chromatography (GPC). The impact sensitivity, mechanical performance, and thermal behavior of PBFMO-b-GAP were studied by drop weight test, X-ray photoelectron spectroscopic (XPS), tensile test, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA), respectively. The results demonstrated that the introduction of fluoropolymers could evidently reduce the sensitivity of GAP-based polyurethane and enhance its mechanical behavior (the tensile strength up to 5.75 MPa with a breaking elongation of 1660%). Besides, PBFMO-b-GAP exhibited excellent resistance to thermal decomposition up to 200 °C and good compatibility with Al and cyclotetramethylene tetranitramine (HMX). The thermal performance of the PBFMO-b-GAP/Al complex was investigated by a cook-off test, and the results indicated that the complex has specific reaction energy. Therefore, PBFMO-b-GAP may serve as a promising energetic binder for future propellant formulations.

Functionalization of MWNTs and its Influence on Thermal Performance of Modified Diphenyl Ether Polyimide Films

2020 ◽  
Vol 993 ◽  
pp. 654-661
Author(s):  
Xue Fang ◽  
Gui Ming Su ◽  
Hai Jian Jiang ◽  
Yu Liang Ma ◽  
Mei Hui Song ◽  
...  
Keyword(s):  
Diphenyl Ether ◽  
Gel Permeation Chromatography ◽  
Decomposition Temperature ◽  
Raw Material ◽  
Doping Amount ◽  
Polyimide Films ◽  
Scanning Calorimetry ◽  
Mixed Acid ◽  
Temperature Ranges ◽  
The Impact

In this paper, we treated MWNTs by Fendon oxidation method and mixed acid method, finding the factors of functionalized effect affecting MWNTs. And added MWNTs treated to PI matrix for the study of the impact of MWNTs treated on thermal properties of the films. We using 3,3/,4,4/-diphenyl ether tetraacid dianhydride (ODPA) and 4,4'-diamino diphenyl ether (ODA) as raw material, mixing functional MWNTs and monomer by situ polymerization, then MWNTs / PAA hybrid glue was prepared. The molecular weight and distribution of the polyamic acid were measured by gel permeation chromatography (GPC), and the effects of different addition amounts on the product were examined. The PI/MWNTs films were prepared using an automatic film applicator, and finally the PI films were obtained by thermal imidization. The thermal behavior of the imidization process of the product was determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The results showed that the PAA film has thermodynamic behavior at 150 ° C and 280 ° C approximately, which could be regarded as the kinetic interruption temperature of the imidization reaction. The dehydration cyclization reaction mainly occured in these two temperature ranges, moreover, the addition of MWNTs had no significant effect on the thermal decomposition temperature of the material which doping amount that does not affect the mechanical strength.

scholarly journals Recycling and Reprocessing of Thermoplastic Polyurethane Materials towards Nonwoven Processing

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1917 ◽  
Author(s):  
Bastian Wölfel ◽  
Andreas Seefried ◽  
Vincent Allen ◽  
Joachim Kaschta ◽  
Christopher Holmes ◽  
...  
Keyword(s):  
Molar Mass ◽  
Mechanical Performance ◽  
Thermoplastic Polyurethane ◽  
Gel Permeation Chromatography ◽  
Raw Material ◽  
Molecular Characteristics ◽  
Processing Load ◽  
Scanning Calorimetry ◽  
Nonwoven Fabrics ◽  
Property Changes

Thermoplastic Polyurethane (TPU) is a unique tailorable material due to the interactions of hard and soft segments within the block-copolymer chain. Therefore, various products can be created out of this material. A general trend towards a circular economy with regards to sustainability in combination with TPU being comparably expensive is of high interest to recycle production as well as post-consumer wastes. A systematic study investigating the property changes of TPU is provided, focusing on two major aspects. The first aspect focuses on characterizing the change of basic raw material properties through recycling. Gel permeation chromatography (GPC) and processing load during extrusion indicate a decrease in molar mass and consequently viscosity with an increasing number of recycling cycles. This leads to a change in morphology at lower molar mass, characterized by differential scanning calorimetry (DSC) and visualized by atomic force microscope (AFM). The change in molar mass and morphology with increasing number of recycling cycles has an impact on the material performance under tensile stress. The second aspect describes processing of the recycled TPU to nonwoven fabrics utilizing melt blowing, which are evaluated with respect to relevant mechanical properties and related to molecular characteristics. The molar mass turns out to be the governing factor regarding mechanical performance and processing conditions for melt blown products.

Resource efficiency in deinked pulp production: a review

TAPPI Journal ◽  
2014 ◽  
Vol 13 (11) ◽  
pp. 37-43 ◽  
Author(s):  
LIISA KOTANEN ◽  
MIKA KÖRKKÖ ◽  
ARI ÄMMÄLÄ ◽  
JOUKO NIINIMÄKI
Keyword(s):  
Waste Disposal ◽  
Resource Efficiency ◽  
Raw Material ◽  
Ecological Strategy ◽  
Recycled Paper ◽  
Paper Production ◽  
Recycled Pulp ◽  
Current State ◽  
The Cost ◽  
Pulp Production

The use of recovered paper as a raw material for paper production is by far the most economical and ecological strategy for the disposal of waste paper. However, paper production from recovered paper furnish generates a great amount of residues, and the higher the demand requirements for the end product, the higher the amount of rejected material. The reason for this is that the selectivity of the deinking process is limited; therefore, some valuable components are also lost in reject streams. The rejection of usable components affects the economics of recycled paper production. As the cost of waste disposal continues to increase, this issue is becoming more and more severe. This paper summarizes the current state of the resource efficiency in recycled pulp production and provides information on the volumes of rejected streams and the usable material within them. Various means to use these reject streams are also discussed, including the main findings of a recent thesis by the main author. This review summarizes current internal and external use of reject streams generated in the deinking operations.

SELISIH BIAYA PRODUKSI SEBAGAI ALAT PENGENDALIAN MANAJEMEN PT INDO PUSAKA BERAU

2019 ◽  
Vol 3 (02) ◽  
pp. 397
Author(s):  
SAFITRI NURHIDAYATI ◽  
RIZKI AMELYA SYAM
Keyword(s):  
Raw Materials ◽  
Field Research ◽  
Analytical Tool ◽  
Production Costs ◽  
Raw Material ◽  
Labor Costs ◽  
Material Costs ◽  
Library Research ◽  
The Difference ◽  
The Cost

This study aims to analyze whether the difference that occurs in the cost of raw materials, direct labor, and factory overhead costs between the standard costs and the actual costs in PLTU LATI is a difference that is favorable or unfavorable. Data collection techniques with field research and library research. The analytical tool used is the analysis of the difference in raw material costs, the difference in direct labor costs and the difference in factory overhead costs. The hypothesis in this study is that the difference allegedly occurs in the cost of raw materials, direct labor costs, and factory overhead costs at PT Indo Pusaka Berau Tanjung Redeb is a favorable difference. The results showed that the difference in the cost of producing MWh electricity at PT Indo Pusaka Berau Tanjung Redeb in 2018, namely the difference in the price of raw material costs Rp. 548,029.80, - is favorable, the difference in quantity of raw materials is Rp. 957,216,602, - is (favorable) , the difference in direct labor costs Rp 2,602,642,084, - is (unfavorable), and the difference in factory overhead costs Rp 8,807,051,422, - is (favorable) This shows that the difference in the overall production cost budget is favorable or profitable. This beneficial difference shows that the company is really able to reduce production costs optimally in 2018.  

scholarly journals Biocompatibility studies of polyurethane electrospun membranes based on arginine as chain extender

2021 ◽  
Vol 32 (9) ◽  
Author(s):  
Georgina Alejandra Venegas-Cervera ◽  
Andrés Iván Oliva ◽  
Alejandro Avila-Ortega ◽  
José Manuel Cervantes-Uc ◽  
Leydi Maribel Carrillo-Cocom ◽  
...  
Keyword(s):  
Fourier Transforms ◽  
Cell Attachment ◽  
Human Fibroblasts ◽  
Gel Permeation Chromatography ◽  
Electrospinning Process ◽  
Chain Extender ◽  
Cellular Interaction ◽  
Scanning Calorimetry ◽  
Polyurethane Membranes ◽  
Electrospun Membranes

AbstractElectrospun polymers are an example of multi-functional biomaterials that improve the material-cellular interaction and aimed at enhancing wound healing. The main objective of this work is to fabricate electrospun polyurethane membranes using arginine as chain extender (PUUR) in order to test the fibroblasts affinity and adhesion on the material and the polymer toxicity. Polyurethane membranes were prepared in two steps: (i) the polyurethane synthesis, and ii) the electrospinning process. The membranes were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. The evaluation of PUUR as a scaffolding biomaterial for growing and developing of cells on the material was realized by LIVE/DEAD staining. The results show that the fluorescent surface area of human fibroblasts (hFB), was greater in control dense membranes made from Tecoflex than in electrospun and dense PUUR. From SEM analysis, the electrospun membranes show relatively uniform attachment of cells with a well-spread shape, while Tecoflex dense membranes show a non-proliferating round shape, which is attributed to the fiber’s structure in electrospun membranes. The cell morphology and the cell attachment assay results reveal the well spreading of hFB cells on the surface of electrospun PUUR membranes which indicates a good response related to cell adhesion.

scholarly journals Recycling Potential for Non-Valorized Plastic Fractions from Electrical and Electronic Waste

Recycling ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 33
Author(s):  
Laura Strobl ◽  
Thomas Diefenhardt ◽  
Martin Schlummer ◽  
Tanja Leege ◽  
Swetlana Wagner
Keyword(s):  
Flame Retardants ◽  
Electronic Waste ◽  
Gel Permeation Chromatography ◽  
Scanning Calorimetry ◽  
Separation Processes ◽  
Melt Flow Rate ◽  
Density Fractions ◽  
Material Recycling ◽  
Other Substances ◽  
Electrical And Electronic Waste

This paper describes a study for waste of electrical and electronic equipment (WEEE) to characterise the plastic composition of different mixed plastic fractions. Most of the samples studied are currently excluded from material recycling and arise as side streams in state-of-the-art plastics recycling plants. These samples contain brominated flame retardants (BFR) or other substances of concern listed as persistent organic pollutants or in the RoHS directive. Seventeen samples, including cathode ray tube (CRT) monitors, CRT televisions, flat screens such as liquid crystal displays, small domestic appliances, and information and communication technology, were investigated using density- and dissolution-based separation processes. The total bromine and chlorine contents of the samples were determined by X-ray fluorescence spectroscopy, indicating a substantial concentration of both elements in density fractions above 1.1 g/cm3, most significantly in specific solubility classes referring to ABS and PS. This was further supported by specific flame retardant analysis. It was shown that BFR levels of both polymers can be reduced to levels below 1000 ppm by dissolution and precipitation processes enabling material recycling in compliance with current legislation. As additional target polymers PC and PC-ABS were also recycled by dissolution but did not require an elimination of BFR. Finally, physicochemical investigations of recycled materials as gel permeation chromatography, melt flow rate, and differential scanning calorimetry suggest a high purity and indicate no degradation of the technical properties of the recycled polymers.

scholarly journals Metallization of Thermoplastic Polymers and Composites 3D Printed by Fused Filament Fabrication

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Alessia Romani ◽  
Andrea Mantelli ◽  
Paolo Tralli ◽  
Stefano Turri ◽  
Marinella Levi ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Test Sample ◽  
Tensile Tests ◽  
Layer By Layer ◽  
Post Processing ◽  
Thermoplastic Polymers ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Manufacturing Technologies

Fused filament fabrication allows the direct manufacturing of customized and complex products although the layer-by-layer appearance of this process strongly affects the surface quality of the final parts. In recent years, an increasing number of post-processing treatments has been developed for the most used materials. Contrarily to other additive manufacturing technologies, metallization is not a common surface treatment for this process despite the increasing range of high-performing 3D printable materials. The objective of this work is to explore the use of physical vapor deposition sputtering for the chromium metallization of thermoplastic polymers and composites obtained by fused filament fabrication. The thermal and mechanical properties of five materials were firstly evaluated by means of differential scanning calorimetry and tensile tests. Meanwhile, a specific finishing torture test sample was designed and 3D printed to perform the metallization process and evaluate the finishing on different geometrical features. Furthermore, the roughness of the samples was measured before and after the metallization, and a cost analysis was performed to assess the cost-efficiency. To sum up, the metallization of five samples made with different materials was successfully achieved. Although some 3D printing defects worsened after the post-processing treatment, good homogeneity on the finest details was reached. These promising results may encourage further experimentations as well as the development of new applications, i.e., for the automotive and furniture fields.

scholarly journals Modulation of Crystallinity through Radiofrequency Electromagnetic Fields in PLLA/Magnetic Nanoparticles Composites: A Proof of Concept

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4300
Author(s):  
Marta Multigner ◽  
Irene Morales ◽  
Marta Muñoz ◽  
Victoria Bonache ◽  
Fernando Giacomone ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnetic Nanoparticles ◽  
Electromagnetic Fields ◽  
Biomedical Applications ◽  
Infrared Camera ◽  
Proof Of Concept ◽  
Scanning Calorimetry ◽  
Radiofrequency Electromagnetic Fields ◽  
Degradation Properties ◽  
Heat Released

To modulate the properties of degradable implants from outside of the human body represents a major challenge in the field of biomaterials. Polylactic acid is one of the most used polymers in biomedical applications, but it tends to lose its mechanical properties too quickly during degradation. In the present study, a way to reinforce poly-L lactic acid (PLLA) with magnetic nanoparticles (MNPs) that have the capacity to heat under radiofrequency electromagnetic fields (EMF) is proposed. As mechanical and degradation properties are related to the crystallinity of PLLA, the aim of the work was to explore the possibility of modifying the structure of the polymer through the heating of the reinforcing MNPs by EMF within the biological limit range f·H < 5·× 109 Am−1·s−1. Composites were prepared by dispersing MNPs under sonication in a solution of PLLA. The heat released by the MNPs was monitored by an infrared camera and changes in the polymer were analyzed with differential scanning calorimetry and nanoindentation techniques. The crystallinity, hardness, and elastic modulus of nanocomposites increase with EMF treatment.

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