Advances in Sustainable Polyurethanes

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Applications".

Deadline for manuscript submissions: closed (25 June 2022) | Viewed by 23709

Special Issue Editors

Department of Chemical Engineering, Chonbuk National University, Jeonju 54896, Korea
Interests: self-healing network polymers; recycling of crosslinked polymers; rheology; vitrimer; nanocomposites
Special Issues, Collections and Topics in MDPI journals
Technical Research Institute of Jungwoo Fine Chemical, Junbuk 570350, Korea
Interests: bio-mass-based polymers; self-healing polymers; chemical recycling of polymers

Special Issue Information

Dear Colleagues,

Polyurethanes are versatile polymers for foams, fibers, adhesives, coatings, sealants, and elastomers today. The future success of the polyurethane industry will rely on the development of sustainable polyurethanes derived from renewable feedstocks that are safe in both production and use and that can be recycled or disposed of in ways that are environmentally innocuous. Meeting these criteria in an economical manner cannot be achieved without transformative basic research on the sustainability of polyurethanes.

This Special Issue focuses on the synthesis of bio-based monomers and polyurethanes from renewable resources to support technological advancements in bio-based monomers synthesis through biorefining, chemical recycling, synthesis of self-healing polymers, and property evaluations for current and emerging future applications of sustainable polyurethanes.

Prof. Dr. Dai-Soo Lee
Dr. Se-Ra Shin
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • polyurethane
  • sustainability
  • renewable resources
  • chemical recycling
  • self-healing
  • synthesis
  • property

Published Papers (7 papers)

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Research

20 pages, 4758 KiB  
Article
Tailor-Made Bio-Based Non-Isocyanate Polyurethanes (NIPUs)
by Juan Catalá, Irene Guerra, Jesús Manuel García-Vargas, María Jesús Ramos, María Teresa García and Juan Francisco Rodríguez
Polymers 2023, 15(6), 1589; https://doi.org/10.3390/polym15061589 - 22 Mar 2023
Cited by 7 | Viewed by 3367
Abstract
Non-isocyanate polyurethanes (NIPUs) based on biobased polyamines and polycarbonates are a sustainable alternative to conventional polyurethanes (PU). This article discloses a novel method to control the crosslinking density of fully biobased isocyanate-free polyurethanes, synthesized from triglycerides carbonated previously in scCO2 and different [...] Read more.
Non-isocyanate polyurethanes (NIPUs) based on biobased polyamines and polycarbonates are a sustainable alternative to conventional polyurethanes (PU). This article discloses a novel method to control the crosslinking density of fully biobased isocyanate-free polyurethanes, synthesized from triglycerides carbonated previously in scCO2 and different diamines, such as ethylenediamine (EDA), hexamethylenediamine (HMDA) and PriamineTM-1075 (derived from a dimerized fatty acid). As capping substances, water or bioalcohols are used in such a way that the crosslinking density can be adjusted to suit the requirements of the intended application. An optimization of the NIPU synthesis procedure is firstly carried out, establishing the polymerization kinetics and proposing optimal conditions set for the synthesis of the NIPUs. Then, the influence of the partial blocking of the active polymerization sites of the carbonated soybean oil (CSBO), using monofunctional amines, on the physical properties of the NIPUS is explored. Finally, the synthesis of fully biobased NIPUs with a targeted crosslinking density is achieved using hybrid NIPUs, employing partially carbonated oil and H2O or ethanol as blockers to achieve the desired physical properties in a very precise manner. Full article
(This article belongs to the Special Issue Advances in Sustainable Polyurethanes)
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12 pages, 3928 KiB  
Article
Electromagnetic-Wave Absorption Properties of 3D-Printed Thermoplastic Polyurethane/Carbonyl Iron Powder Composites
by Yinsong Zheng and Yan Wang
Polymers 2022, 14(22), 4960; https://doi.org/10.3390/polym14224960 - 16 Nov 2022
Cited by 3 | Viewed by 1801
Abstract
To develop a composite filament with an electromagnetic-wave-absorbing function suitable for 3D printing, we combined thermoplastic polyurethane (TPU) as the matrix material and carbonyl iron powder (CIP) as the absorbing agent to prepare TPU/CIP composites by melt blending. The composites passed through a [...] Read more.
To develop a composite filament with an electromagnetic-wave-absorbing function suitable for 3D printing, we combined thermoplastic polyurethane (TPU) as the matrix material and carbonyl iron powder (CIP) as the absorbing agent to prepare TPU/CIP composites by melt blending. The composites passed through a single-screw extruder to obtain a filament with 2.85 mm in diameter. Different absorber structures were printed using fused deposition modeling, and their absorption properties were tested using the bow method. The results showed that by increasing CIP content, the electromagnetic-wave absorption performance gradually improved, while the mechanical properties substantially decreased. When the mass fraction of the CIP was 60%, the TPU/CIP composite showed good absorption properties and could be prepared into a filament that met the requirements for fused deposition modeling. Simulation results of plate-wave-absorption performance showed that, when the plate thickness was 3 mm, the minimum reflection loss was −21.98 dB, and the effective absorption bandwidth (for reflection loss below −10 dB) was 3.1 GHz (4.55–7.65 GHz). After the TPU/CIP composite was printed into honeycomb, pyramid, and other absorber structures, the absorption performance was further improved. For a structure printed with a gradient-wall honeycomb structure at 3 mm thickness, the effective absorption bandwidth was 4.64 GHz (8.48–13.12 GHz), and the minimum reflection loss was −36.69 dB. The effective absorption bandwidth of the pyramid structure reached 15.88 GHz (2.12–18 GHz), and the minimum reflection loss was −49.75 dB. Full article
(This article belongs to the Special Issue Advances in Sustainable Polyurethanes)
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11 pages, 2742 KiB  
Article
Polyurethane/Vermiculite Foam Composite as Sustainable Material for Vertical Flame Retardant
by Lívia R. P. Silva Tenório Alves, Márcio Davi Tenório C. Alves, Luzia M. Castro Honorio, Alan I. Moraes, Edson C. Silva-Filho, Ramón Peña-Garcia, Marcelo B. Furtini, Durcilene A. da Silva and Josy A. Osajima
Polymers 2022, 14(18), 3777; https://doi.org/10.3390/polym14183777 - 09 Sep 2022
Cited by 3 | Viewed by 1595
Abstract
Rigid polyurethane foams were prepared by the one-step expandable foam method using casting molding followed by forming clay-based composites. Polyurethane/vermiculite foam composites (PU/VMT) were controlled based on adding the percentage of clay in the formulation. The effects of composite modifications were evaluated by [...] Read more.
Rigid polyurethane foams were prepared by the one-step expandable foam method using casting molding followed by forming clay-based composites. Polyurethane/vermiculite foam composites (PU/VMT) were controlled based on adding the percentage of clay in the formulation. The effects of composite modifications were evaluated by X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), and scanning electron microscopy (SEM/EDS) applied to the flame retardancy explored by the vertical burn test. The results indicated that adding clay controlled the particle size concerning polyurethane (PU) foams. However, they exhibited spherical structures with closed cells with relatively uniform distribution. XRD analysis showed the peaks defined at 2θ = 18° and 2θ = 73° relative to the crystallinity in formation and interaction of rigid segments were identified, as well as the influence of crystallinity reduction in composites. In the flame test, the flame retardant surface was successful in all composites, given the success of the dispersibility and planar orientation of the clay layers and the existence of an ideal content of vermiculite (VMT) incorporated in the foam matrix. Full article
(This article belongs to the Special Issue Advances in Sustainable Polyurethanes)
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15 pages, 2648 KiB  
Article
Synthesis of Jatropha-Oil-Based Polyester Polyol as Sustainable Biobased Material for Waterborne Polyurethane Dispersion
by Murni Sundang, Nur Sjanrah Nurdin, Sariah Saalah, Yamunah Jaibalah Singam, Syeed SaifulAzry Osman Al Edrus, Noor Maizura Ismail, Coswald Stephen Sipaut and Luqman Chuah Abdullah
Polymers 2022, 14(18), 3715; https://doi.org/10.3390/polym14183715 - 06 Sep 2022
Cited by 7 | Viewed by 1718
Abstract
The utilization of vegetable oil in the production of polymeric material has gained interest due to its proven ability to replace nonrenewable petroleum sources, as it is readily modified via chemical reaction to produce polyol and subsequently for polyurethane production. Jatropha oil (JO), [...] Read more.
The utilization of vegetable oil in the production of polymeric material has gained interest due to its proven ability to replace nonrenewable petroleum sources, as it is readily modified via chemical reaction to produce polyol and subsequently for polyurethane production. Jatropha oil (JO), a second-generation feedstock, is one of the suitable candidates for polyester polyol synthesis because it contains a high percentage of unsaturated fatty acids. In this study, jatropha-based polyester polyols (JOLs) with different hydroxyl values were successfully synthesized via a two-step method: epoxidation followed by oxirane ring-opening reaction. Ring-opening reagents; methanol, ethanol, and isopropanol were used to produce polyol with hydroxyl number of 166, 180, and 189 mg/KOH, respectively. All the synthesized JOLs exhibited a Newtonian to shear thinning behavior in the measured shear rate ranges from 10 to 1000 s−1 at 25 °C. The viscosity of a JOL ring-opened with methanol, isopropanol, and ethanol was 202, 213, and 666 mPa·s, respectively, at 20 °C and 100 s−1, which is within the range of commercially available polyols. Successively, the JOLs were reacted with isophorone diisocyanate (IPDI) to produce polyurethane prepolymer by utilizing 2,2-dimethylol propionic acid (DMPA) as an emulsifier. The prepolymer was then dispersed in water to produce a waterborne polyurethane dispersion. Colloidal stability of the jatropha-based polyurethane dispersions (JPUDs) were investigated by particle size analysis. A JPUD with a small particle size in the range of 6.39 to 43.83 nm was obtained, and the trend was associated with the soft segment of the polyol in the formulation. The zeta potentials of the JPUs ranged from −47.01 to −88.9 mV, indicating that all synthesized JPUs had high dispersity and stability. The efficient synthesis procedure, low cost, and excellent properties of the resulting product are thought to offer an opportunity to use jatropha oil as a sustainable resource for polyester polyol preparation. Full article
(This article belongs to the Special Issue Advances in Sustainable Polyurethanes)
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17 pages, 4102 KiB  
Article
Microstructure and Mechanical Properties of PU/PLDL Sponges Intended for Grafting Injured Spinal Cord
by Anna Lis-Bartos, Dariusz Szarek, Małgorzata Krok-Borkowicz, Krzysztof Marycz, Włodzimierz Jarmundowicz and Jadwiga Laska
Polymers 2020, 12(11), 2693; https://doi.org/10.3390/polym12112693 - 16 Nov 2020
Cited by 1 | Viewed by 2136
Abstract
Highly porous, elastic, and degradable polyurethane and polyurethane/polylactide (PU/PLDL) sponges, in various shapes and sizes, with open interconnected pores, and porosity up to 90% have been manufactured. They have been intended for gap filling in the injured spinal cord. The porosity of the [...] Read more.
Highly porous, elastic, and degradable polyurethane and polyurethane/polylactide (PU/PLDL) sponges, in various shapes and sizes, with open interconnected pores, and porosity up to 90% have been manufactured. They have been intended for gap filling in the injured spinal cord. The porosity of the sponges depended on the content of polylactide, i.e., it decreased with the increase of polylactide content. The rise of polylactide content caused an increase of Young modulus and rigidity as well as a more complex morphology of the polyurethane/polylactide blends. The mechanical properties, in vitro toxicity, and degradation in artificial cerebrospinal fluid were tested. Sponges underwent continuous degradation with varying degradation rates depending on the polymer composition. In vitro cell studies with fibroblast cultures proved the biocompatibility of the polymers. Based on the obtained results, the designed PU/PLDL sponges appeared to be promising candidates for bridging gaps within injured spinal cord in further in vitro and in vivo studies. Full article
(This article belongs to the Special Issue Advances in Sustainable Polyurethanes)
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26 pages, 3664 KiB  
Article
Production of Biodegradable Palm Oil-Based Polyurethane as Potential Biomaterial for Biomedical Applications
by Fang Hoong Yeoh, Choy Sin Lee, Yew Beng Kang, Shew Fung Wong, Sit Foon Cheng and Wei Seng Ng
Polymers 2020, 12(8), 1842; https://doi.org/10.3390/polym12081842 - 17 Aug 2020
Cited by 25 | Viewed by 5849
Abstract
Being biodegradable and biocompatible are crucial characteristics for biomaterial used for medical and biomedical applications. Vegetable oil-based polyols are known to contribute both the biodegradability and biocompatibility of polyurethanes; however, petrochemical-based polyols were often incorporated to improve the thermal and mechanical properties of [...] Read more.
Being biodegradable and biocompatible are crucial characteristics for biomaterial used for medical and biomedical applications. Vegetable oil-based polyols are known to contribute both the biodegradability and biocompatibility of polyurethanes; however, petrochemical-based polyols were often incorporated to improve the thermal and mechanical properties of polyurethane. In this work, palm oil-based polyester polyol (PPP) derived from epoxidized palm olein and glutaric acid was reacted with isophorone diisocyanate to produce an aliphatic polyurethane, without the incorporation of any commercial petrochemical-based polyol. The effects of water content and isocyanate index were investigated. The polyurethanes produced consisted of > 90% porosity with interconnected micropores and macropores (37–1700 µm) and PU 1.0 possessed tensile strength and compression stress of 111 kPa and 64 kPa. The polyurethanes with comparable thermal stability, yet susceptible to enzymatic degradation with 7–59% of mass loss after 4 weeks of treatment. The polyurethanes demonstrated superior water uptake (up to 450%) and did not induce significant changes in pH of the medium. The chemical changes of the polyurethanes after enzymatic degradation were evaluated by FTIR and TGA analyses. The polyurethanes showed cell viability of 53.43% and 80.37% after 1 and 10 day(s) of cytotoxicity test; and cell adhesion and proliferation in cell adhesion test. The polyurethanes produced demonstrated its potential as biomaterial for soft tissue engineering applications. Full article
(This article belongs to the Special Issue Advances in Sustainable Polyurethanes)
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14 pages, 398 KiB  
Article
Recovery of Flexible Polyurethane Foam Waste for Efficient Reuse in Industrial Formulations
by Gabriel Kiss, Gerlinde Rusu, Francisc Peter, Ionuț Tănase and Geza Bandur
Polymers 2020, 12(7), 1533; https://doi.org/10.3390/polym12071533 - 10 Jul 2020
Cited by 33 | Viewed by 6434
Abstract
Ester polyurethane (PU) foam waste was reacted at atmospheric pressure in an autoclave and using microwaves with diethylene glycol (DEG) at different PU/DEG ratios in the presence of diethanolamine as a catalyst to find the glycolysis conditions that allow for the improved recovery [...] Read more.
Ester polyurethane (PU) foam waste was reacted at atmospheric pressure in an autoclave and using microwaves with diethylene glycol (DEG) at different PU/DEG ratios in the presence of diethanolamine as a catalyst to find the glycolysis conditions that allow for the improved recovery of the PU foam waste and enable the recycling of the whole glycolysis product in foam formulations suitable for industrial application. The recycled polyol was characterized by dynamic viscosity, hydroxyl number, water content, and density, while thermal stability was assessed using thermogravimetric analysis. In the PU foam formulation, 1% and 5% of the glycolyzed material was reused. The relationship between the reuse level of the recycled polyol and the physical properties of the foam was thoroughly investigated. It was observed that both hardness and air flow decreased with increasing recycled polyol content, particularly for the polyester type foam, while tensile strength and compression strength increased. Depending on the amount of recycled polyol and catalyst used, polyether-based foams could be obtained with a low air permeability, needed in special applications as sealed foams, or with higher air permeability desirable for comfort PU foams. The results open the way for further optimization studies of industrial polyurethane foam formulations using a glycolysis process without any separation stage. Full article
(This article belongs to the Special Issue Advances in Sustainable Polyurethanes)
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