Emerging Trends in Nonisocyanate Polyurethane Foams: A Review DOI Creative Commons

Chen Chuan Lim,

Michelle Jui Hsien Ong,

Mingyue Wu

et al.

ACS Engineering Au, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 31, 2024

Polyurethane foams (PUF) are essential materials known for their exceptional chemical and mechanical properties, making them ubiquitous in a wide range of applications. Conventionally, PUF produced through polyaddition reactions between polyols polyisocyanates at room temperature, where water plays critical role this process by hydrolyzing the isocyanates, leading to release carbon dioxide (CO2) as blowing agent. In recent years, isocyanates have raised significant concerns industries consumers due high toxicity. Therefore, driving need explore alternative synthesis routes that do not involve use isocyanates. Nonisocyanate polyurethane (NIPUF) derived from aminolysis cyclic carbonates emerged most promising solution replace conventional method producing PUF. Despite this, challenging aspect lies identifying suitable foaming strategy NIPUF can satisfy both sustainability performance requirements. view first part review focuses on background, chemistry, challenges second part, chemistry various strategies used prepare discussed analyzed. Finally, outlook future research focus areas outlined.

Language: Английский

The multifaceted role of water as an accelerator of the crosslinking reaction of isocyanate-free polyurethane net-works DOI Creative Commons
Florent Monie, Thomas Vidil, Étienne Grau

et al.

Published: June 21, 2024

Polyhydroxyurethane (PHU) thermosets are the most promising isocyanate-free substitutes to polyurethane ones when targeting main applications of PU business (coatings, adhesives, foams). However, curing their solvent-free formulations at near room temperatures is often very slow and requires utilization organocatalysts, limiting large-scale deployment technology. Herein, we study impact water, introduced as an additive (2 10 wt.%), on crosslinking rate common thermosetting PHU composed a polycyclic carbonate diamine. Rheology measurements, using multi-frequency approach, indicate that even small amounts water (< 5 wt.%) impressively shorten gel times, by up folds 40 °C. The methodology highlights for first time strong interactions with growing network during reaction. It suggests breaks down multiple intra-/inter-molecular H-bond within clusters, consequently enhancing molecular mobility delaying vitrification (hydroplasticization), both phenomena contributing accelerate rate. On top that, through combination model reactions computational calculations, demonstrate actual catalyst cyclic aminolysis. Eventually, thanks its multifaceted role, can efficiently substitute organocatalysts (e.g. TBD, DBU) usually required cure ambient temperature. This work demonstrates use in cost-effective, non-toxic, robust solution production materials, free any organocatalyst. offers prospects PHU-based materials requiring mild processing conditions.

Language: Английский

Citations

1
Reprocessable, Self-Healing, and Creep-Resistant Covalent Adaptable Network Made from Chain-Growth Monomers with Dynamic Covalent Thionourethane and Disulfide Cross-Links DOI
Tong Wang, Yixuan Chen, Boran Chen

et al.

ACS Macro Letters, Journal Year: 2024, Volume and Issue: 13(9), P. 1147 - 1155

Published: Aug. 16, 2024

We synthesized covalent adaptable networks (CANs) made from chain-growth comonomers using nonisocyanate thiourethane chemistry. derivatized glycidyl methacrylate with cyclic dithiocarbonate (GMA-DTC), did a free-radical polymerization of n-hexyl GMA-DTC to obtain statistical copolymer 8 mol % GMA-DTC, and cross-linked it difunctional amine. The dynamic thionourethane disulfide bonds lead CAN reprocessability full recovery the cross-link density; temperature dependence rubbery plateau modulus indicates that associative character dominates response. exhibits complete self-healing at 110 °C tensile property excellent creep resistance 90–100 °C. Stress relaxation 140–170 reveals an activation energy 105 ± 6 kJ/mol, equal (Ea) poly(n-hexyl methacrylate) backbone α-relaxation. hypothesize CANs exclusively or predominantly dynamics have their stress-relaxation Ea defined by α-relaxation Ea. This hypothesis is supported stress studies on similar poly(n-lauryl methacrylate)-based CAN.

Language: Английский

Citations

1
Increasing the Cross-Link Density in a Dual Dissociative and Associative Polythiourethane Covalent Adaptable Network Improves Both Creep Resistance and Extrudability DOI
Sergio Serna, Nathan S. Purwanto, Logan M. Fenimore

et al.

Published: Jan. 1, 2024

Download This Paper Open PDF in Browser Add to My Library Share: Permalink Using these links will ensure access this page indefinitely Copy URL DOI

Language: Английский

Citations

0
Biobased, Catalyst-Free Non-Isocyanate Polythiourethane Foams:Highly Dynamic Nature Affords Fast Reprocessability, Extrudability and Refoamability DOI
John M. Torkelson, Yixuan Chen, Nathan S. Purwanto

et al.

Published: Jan. 1, 2024

We have developed a series of reprocessable, re-foamable, biobased, catalyst-free non-isocyanate polythiourethane (NIPTU) network foams crosslinked via the auto-oxidation pendant thiol groups into disulfides. Capitalizing on interplay fast ring-opening cyclic thiocabonate to create linear backbones and slightly slower disulfide crosslinks, gelling reaction synchronized well with vaporization physical blowing agent. Different agents were used achieve facile tunability morphological properties. In addition, incorporating small amount trifunctional crosslinker significantly enhanced compressive mechanical properties foam. Moreover, we leveraged rapid dynamic exchange reprocessability extrudability NIPTU foams. demonstrated that are intrinsically self-healable reprocessable by compression molding. observed stress relaxation at temperatures above 160 °C, prompting us explore continuous processing techniques like extrusion pseudo-injection Spent can be extruded bulk films 180 °C excellent property retention. Additionally, our system demonstrated, for first time, foam-to-foam recycling polyurethanes. By adding sodium bicarbonate agent spent prior extrusion, CO2 gas was generated during leading cellular structure. Ultimately, this study highlights superior sustainability advantages foams: catalyst-free, synthesis tunability, self-healing capability, amenability towards family reprocessing including molding, films, extrusion.

Language: Английский

Citations

0
Emerging Trends in Nonisocyanate Polyurethane Foams: A Review DOI Creative Commons

Chen Chuan Lim,

Michelle Jui Hsien Ong,

Mingyue Wu

et al.

ACS Engineering Au, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 31, 2024

Polyurethane foams (PUF) are essential materials known for their exceptional chemical and mechanical properties, making them ubiquitous in a wide range of applications. Conventionally, PUF produced through polyaddition reactions between polyols polyisocyanates at room temperature, where water plays critical role this process by hydrolyzing the isocyanates, leading to release carbon dioxide (CO2) as blowing agent. In recent years, isocyanates have raised significant concerns industries consumers due high toxicity. Therefore, driving need explore alternative synthesis routes that do not involve use isocyanates. Nonisocyanate polyurethane (NIPUF) derived from aminolysis cyclic carbonates emerged most promising solution replace conventional method producing PUF. Despite this, challenging aspect lies identifying suitable foaming strategy NIPUF can satisfy both sustainability performance requirements. view first part review focuses on background, chemistry, challenges second part, chemistry various strategies used prepare discussed analyzed. Finally, outlook future research focus areas outlined.

Language: Английский

Citations

0