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Design and Synthesis of Functional Polyurethane

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Macromolecular Chemistry".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 7693

Special Issue Editors


E-Mail Website
Guest Editor
School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Interests: functional polyurethane; high-strength hydrogels; 3D printing materials; smart materials; biomedical materials

E-Mail Website
Guest Editor
School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Interests: functional polyurethane; waterborne polyurethane

Special Issue Information

Dear Colleagues,

Polyurethane, prepared from various isocyanates, diol or diamine chain extenders and polyols, is a fundamental polymer material widely used in a wide range of application fields. Through the selection of suitable raw materials, structural modification, modification of soft and hard segments, changing of the NCO:OH ratio, nanofiller dispersion, and chemical functionalization, polyurethanes with highly tunable physical–chemical properties can be fabricated. Functional polyurethanes in particular not only present unique properties but also have great application prospects in advanced fields, such as biomedical application, 3D printing area, sensors, and so on.

This Special Issue focuses on the design and synthesis of functional polyurethane, welcoming original research and reviews on (1) functional polyurethanes originated from bio-based raw materials, (2) biomedical polyurethane materials, (3) polyurethane-based hydrogels, (4) polyurethane-based smart materials including self-healing, shape-memory materials, sensors, and so on, (5) high-performance polyurethanes, (6) advanced polyurethane for 3D printing, and (7) biodegradable polyurethanes.

Prof. Dr. Xinling Wang
Dr. Dandan Zhu
Guest Editors

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Keywords

  • high-performance
  • biomedical
  • self-healing
  • biodegradable
  • bio-based
  • 3D printing
  • shape-memory
  • hydrogels

Published Papers (4 papers)

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Research

11 pages, 2480 KiB  
Article
Design, Preparation and Properties of Polyurethane Dispersions via Prepolymer Method
by Lijuan Sun and Hongmei Jiang
Molecules 2023, 28(2), 625; https://doi.org/10.3390/molecules28020625 - 07 Jan 2023
Cited by 4 | Viewed by 1743
Abstract
A waterborne polyurethane dispersion for foamed synthetic leather base was designed and prepared using prepolymer method. There are many variables in the emulsification and chain-extension process of waterborne polyurethane (WPUR) dispersions prepared by prepolymer method. This work thoroughly evaluated the impacts of the [...] Read more.
A waterborne polyurethane dispersion for foamed synthetic leather base was designed and prepared using prepolymer method. There are many variables in the emulsification and chain-extension process of waterborne polyurethane (WPUR) dispersions prepared by prepolymer method. This work thoroughly evaluated the impacts of the steps of adding emulsified water, the temperature of the prepolymer and emulsified water, and concentration of ammonia water on WPUR dispersions by investigating the particle sizes/distributions and the mechanical stability. Changes in the temperature of the prepolymer and emulsified water, the concentration of ammonia water, and the step of adding emulsified water showed great impacts on the appearance and particle size of dispersions. Decreasing the temperature of the prepolymer and emulsified water and increasing the dilution ration of H2O to ethylenediamine (EDA) led to safe emulsification and dispersions with good appearance and narrow particle size distributions can be prepared. Surprising results were obtained by adding emulsified water in two steps, WPUR dispersions with a small particle size, narrow particle distribution and excellent tensile properties can be obtained. The optimized WPUR1 was applied to prepare water-based synthetic leather base after mechanical foaming, and the base presented the desired high performance, such as high folding resistance and peel strength. Full article
(This article belongs to the Special Issue Design and Synthesis of Functional Polyurethane)
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19 pages, 8943 KiB  
Article
Preparation of Low Volatile Organic Compounds Silver Paste Containing Ternary Conductive Fillers and Optimization of Their Performances
by Youliang Cheng, Jin Zhang, Changqing Fang, Wenke Qiu, Hao Chen, Haonan Liu and Ying Wei
Molecules 2022, 27(22), 8030; https://doi.org/10.3390/molecules27228030 - 19 Nov 2022
Cited by 2 | Viewed by 1857
Abstract
Conductive silver paste is a key material in the fields of printed circuits and printed electronic devices. However, the preparation of conductive silver paste with low-cost and volatile organic compounds (VOCs) is still a challenge. In this work, conductive silver pastes with excellent [...] Read more.
Conductive silver paste is a key material in the fields of printed circuits and printed electronic devices. However, the preparation of conductive silver paste with low-cost and volatile organic compounds (VOCs) is still a challenge. In this work, conductive silver pastes with excellent comprehensive performances were developed by using water-borne polyurethane (WPU) as the bonding phase and using the ternary mixture of Ag microflakes (Ag MFs), Ag nanowires (Ag NWs), and Ag nanoparticles (Ag NPs) as the conductive phase. WPU endowed conductive silver pastes with the adhesion along with releasing a few VOCs during the curing. Results showed that a small amount of Ag NPs or Ag NWs dramatically enhanced the electrical conductivity of silver paste paint film filled only with Ag MFs. The electrical resistivity for optimal ternary mixture conductive silver paste was 0.2 × 10−3 Ω∙cm, and the conductive phase was composed of 20.0 wt% Ag MFs, 7.5 wt% Ag NWs, and 2.5 wt% Ag NPs. Meanwhile, the adhesive strength and hardness of silver paste paint film were effectively improved by increasing the curing temperature. The optimal overall performance of the conductive silver pastes was achieved at the curing temperature of 160 °C. Therefore, this work can provide a new route for preparing conductive silver pastes with high performances. Full article
(This article belongs to the Special Issue Design and Synthesis of Functional Polyurethane)
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20 pages, 3316 KiB  
Article
The Multi-Step Chain Extension for Waterborne Polyurethane Binder of Para-Aramid Fabrics
by Ge Ma, Qianshu Wang, Jun Ye, Lifan He, Longhai Guo, Xiaoyu Li, Teng Qiu and Xinlin Tuo
Molecules 2022, 27(21), 7588; https://doi.org/10.3390/molecules27217588 - 05 Nov 2022
Cited by 1 | Viewed by 1332
Abstract
The comprehensive balance of the mechanical, interfacial, and environmental requirements of waterborne polyurethane (WPU) has proved challenging, but crucial in the specific application as the binder for high-performance polymer fiber composites. In this work, a multi-step chain extension (MCE) method was demonstrated using [...] Read more.
The comprehensive balance of the mechanical, interfacial, and environmental requirements of waterborne polyurethane (WPU) has proved challenging, but crucial in the specific application as the binder for high-performance polymer fiber composites. In this work, a multi-step chain extension (MCE) method was demonstrated using three kinds of small extenders and one kind of macro-chain extender (CE) for different chain extension steps. One dihydroxyl blocked small molecular urea (1,3-dimethylolurea, DMU) was applied as one of the CEs and, through the hybrid macrodiol/diamine systems of polyether, polyester, and polysiloxane, the WPU was developed by the step-by-step optimization on each chain extending reaction via the characterization on the H-bonding association, microphase separation, and mechanical properties. The best performance was achieved when the ratio of polyether/polyester was controlled at 6:4, while 2% of DMU and 1% of polysiloxane diamine was incorporated in the third and fourth chain extension steps, respectively. Under the condition, the WPU exhibited not only excellent tensile strength of 30 MPa, elongation of break of about 1300%, and hydrophobicity indicated by the water contact angle of 98°, but also effective interfacial adhesion to para-aramid fabrics. The peeling strength of the joint based on the polysiloxane incorporated WPU after four steps of chain extension was 430% higher than that prepared through only two steps of chain extension. Moreover, about 44% of the peeling strength was sustained after the joint had been boiling for 40 min in water, suggesting the potential application for high-performance fabric composites. Full article
(This article belongs to the Special Issue Design and Synthesis of Functional Polyurethane)
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16 pages, 2856 KiB  
Article
Studying the Suitability of Nineteen Lignins as Partial Polyol Replacement in Rigid Polyurethane/Polyisocyanurate Foam
by Christián Henry, Akash Gondaliya, Mark Thies and Mojgan Nejad
Molecules 2022, 27(8), 2535; https://doi.org/10.3390/molecules27082535 - 14 Apr 2022
Cited by 8 | Viewed by 2305
Abstract
In this study, nineteen unmodified lignins from various sources (hardwood, softwood, wheat straw, and corn stover) and isolation processes (kraft, soda, organosolv, sulfite, and enzymatic hydrolysis) were used to replace 30 wt.% of petroleum-based polyol in rigid polyurethane/polyisocyanurate (PUR/PIR) foam formulations. Lignin samples [...] Read more.
In this study, nineteen unmodified lignins from various sources (hardwood, softwood, wheat straw, and corn stover) and isolation processes (kraft, soda, organosolv, sulfite, and enzymatic hydrolysis) were used to replace 30 wt.% of petroleum-based polyol in rigid polyurethane/polyisocyanurate (PUR/PIR) foam formulations. Lignin samples were characterized by measuring their ash content, hydroxyl content (Phosphorus Nuclear Magnetic Resonance Spectroscopy), impurities (Inductively Coupled Plasma), and pH. After foam formulation, properties of lignin-based foams were evaluated and compared with a control foam (with no lignin) via cell morphology, closed-cell content, compression strength, apparent density, thermal conductivity, and color analysis. Lignin-based foams passed all measured standard specifications required by ASTM International C1029-15 for type 1 rigid insulation foams, except for three foams. These three foams had poor compressive strengths, significantly larger cell sizes, darker color, lower closed-cell contents, and slower foaming times. The foam made with corn stover enzymatic hydrolysis lignin showed no significant difference from the control foam in terms of compressive strength and outperformed all other lignin-based foams due to its higher aliphatic and p-hydroxyphenyl hydroxyl contents. Lignin-based foams that passed all required performance testing were made with lignins having higher pH, potassium, sodium, calcium, magnesium, and aliphatic/p-hydroxyphenyl hydroxyl group contents than those that failed. Full article
(This article belongs to the Special Issue Design and Synthesis of Functional Polyurethane)
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