Effective role of eco-friendly acetyl tributyl citrate in large-scale catalyst-free synthesis of waterborne polyurethanes without volatile organic compounds

Li, Xin‐Gui; Xie, Yun-Bin; Huang, Mei‐Rong; Umeyama, Tomokazu; Ohara, Tomoya; Imahori, Hiroshi

doi:10.1016/j.jclepro.2019.07.018

Cited by 32 publications

(22 citation statements)

References 61 publications

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“…Compared with solvent‐based polyurethanes, WPUs have advantages such as excellent mechanical performance, flexibility, elasticity, transportation safety, non‐toxic and harmless property, which is widely used in coating, adhesive, printing ink, and leather finishing areas 1–3 . To date, most of the researches on WPUs, however, are limited to the synthetic processes and mechanical properties 4–6 …”

Section: Introductionmentioning

confidence: 99%

Conventionally facile fabrication of mechanically robust waterborne polyurethane with self‐healing and photoluminescence

Yuan

et al. 2021

J of Applied Polymer Sci

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It is of much importance to synthesize waterborne polyurethane (WPUs) that simultaneously broaden the fields of applications and functions in a green strategy. In this paper, a novel class of WPUs were facilely prepared through the copolymerization between polytetrahydrofuran ether diol (PTMG), isophorone diisocyanate, and 2,2‐bis(hydroxymethyl)propionic acid, which can achieve multiple functions of self‐healing and photoluminescence after incorporating carbon quantum dots (CQs) into the WPUs. The prepared WPUs emulsion showed uniform size distribution from 61.97 nm to171.3 nm with different PTMG molecular weights. Especially, the maximum tensile strength and elongation at break of the WPUs can reach up to 69.78 MPa and 1879.99%, showing superior mechanical performance. After fractured surfaces held contact for 12 h at elevated temperature, the self‐healing efficiency of the pristine WPUs can reach 21.39% for tensile strength and 24.79% for elongation at break. After adding CQs, the synthesized WPUs can also remain nearly the same tensile strength and elongation at break. Significantly, the self‐healing WPUs with CQs can emit a bright orange fluorescence under ultraviolet light, showing outstanding photoluminescence. This kind of designed material takes advantages of simple preparation, no release of organic solvents during use, nontoxicity and harmlessness.

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Section: Introductionmentioning

confidence: 99%

Conventionally facile fabrication of mechanically robust waterborne polyurethane with self‐healing and photoluminescence

Yuan

et al. 2021

J of Applied Polymer Sci

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“…This is an active area of research, with some groups focusing on new chemistry or novel formulations 3 to achieve useful properties and other groups developing sustainable approaches to WB 2K-PU coatings. 4 We are particularly interested in developing a deeper mechanistic understanding of film formation in more traditional coatings formulations, with the idea that this mechanistic study, applied to a broad range of polyols, will enable a more rational approach to optimization of these coatings.…”

Section: ■ Introductionmentioning

confidence: 99%

Characterization of an Aqueous Dispersion of a Hydrophilic Polyisocyanate for Waterborne Two-Pack Polyurethane Coatings

Zhou

Liu

Zhang

et al. 2020

ACS Appl. Polym. Mater.

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Waterborne two-component polyurethanes (WB 2K-PUs) represent an environmentally friendly alternative to solvent-borne coatings, with reduced use of volatile organic compounds (VOCs). These coatings still cannot achieve the outstanding performance of solvent-borne 2K-PU formulations. In many WB 2K-PU formulations, a key step involves coalescence between polyol latex particles and nanoparticles formed from a water-dispersible polyisocyanate (PIC). Interactions between the PIC and the polyol take place both in the aqueous medium and after application of the coating to a substrate. A deeper understanding of this mechanism should guide improvements in formulations to improve WB 2K-PU coating performance. Our long-term goal is to investigate the film formation mechanism of a series of different polyol nanoparticles with aqueous dispersions of PICs based on a hexamethylene diisocyanate (HDI) trimer; as a first step in this direction, we examined the nature of the nanoparticles formed by dispersing an oligo-ethylene glycol (OEG)-modified HDI trimer in water. Typical techniques for nanoparticle size characterization (dynamic light scattering (DLS) and capillary hydrodynamic fractionation chromatography, (CHDF)) led to misleading information. These techniques indicated the presence of uniform nanoparticles with a diameter of ca. 100 nm that persisted for days. In contrast, DOSY 1 H NMR gave a diameter of 20 nm. Nanoparticle tracking analysis (NTA) confirmed the presence of the larger particles, but showed that they represented only 18 wt % of the dispersion. Over time, the isocyanate groups in the particles reacted with water, and the nanoparticles evolved from liquid droplets to mechanically robust polyurea particles. At this stage, imaging by electron microscopy showed a predominance of 20 nm particles. The kinetics of this chemical transformation was monitored by Fourier transform infrared (FT-IR) spectroscopy. The reaction of the isocyanate groups followed pseudo-first-order kinetics with a half-life of 11 to 14 h.

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“…The USA Environmental Protection Agency and air quality regulators devote significant time and resources to decrease or eliminate industrial products that contain VOCs and encourage the development of new environment-friendly, alternative products with a similar performance for industrial applications. Aqueous PUDs are important alternatives to the organic solventborne polyurethanes with minimal or even no VOCs and can be used in many industrial applications with no health or environmental issues. − For aqueous PUDs, water is used to disperse PU instead of the harmful and expensive volatile organic solvents, such as N -methyl-2-pyrrolidone, acetone, methylene chloride, and methyl ethyl ketone (MEK), which are typically used for the formulation of solvent-based polyurethanes. Because of the major advantages of aqueous PUDs (being environment-friendly and of low cost) over solvent-based counterparts, the aqueous PUDs are among the most rapidly developed areas of PU chemistry.…”

Section: Introductionmentioning

confidence: 99%

Sustainable Polyurethane–Lignin Aqueous Dispersions and Thin Films: Rheological Behavior and Thermomechanical Properties

Madbouly

Xia

Kessler

2020

ACS Appl. Polym. Mater.

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Sustainable aqueous polyurethane (PU) dispersions derived from castor oil and lignosulfonate (LS) have been successfully synthesized with stable nanoscale morphology and average particle sizes as small as 35 nm with no organic solvent. Incorporation of a rigid structure of LS into the castor oil-based PU reinforces the resulting cast films of the PU−LS nanocomposites and increases the cross-link density, as determined by dynamic mechanical analysis measurements and the theory of rubber elasticity. In addition, the LS plays a significant role in enhancing the ultimate mechanical and thermal properties of the resulting nanocomposite films. The TEM morphologies of the PU−LS dispersions confirmed that the average particle sizes are constant (approximately 35 nm) for all different LS concentrations. The effect of LS on the dynamic viscosity of PU−LS aqueous dispersions at different angular frequencies in the linear viscoelastic regime has also been investigated, and the experimental data were analyzed based on the Cross model. The dynamic viscosity increases significantly with increasing LS content while holding a constant 15 wt % of the solid content in all dispersions. The nature of LS as a water-soluble material suggests that PU−LS nanoparticles adsorb more water onto the particle surface with increasing LS content, which leads to a considerable decrease in the concentration of free water in the dispersion, and consequently, the viscosity increases dramatically. The influence of different concentrations of LS on the reduced viscosity of the dispersions was investigated using the Krieger−Dougherty viscosity model with a critical concentration of LS (ϕ c = 0.08) above which the viscosity of the dispersions increased strongly. The current study provides an effective and promising approach to synthesize high-performance, biorenewable nanocomposites for coatings and adhesives.

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Effective role of eco-friendly acetyl tributyl citrate in large-scale catalyst-free synthesis of waterborne polyurethanes without volatile organic compounds

Cited by 32 publications

References 61 publications

Conventionally facile fabrication of mechanically robust waterborne polyurethane with self‐healing and photoluminescence

Conventionally facile fabrication of mechanically robust waterborne polyurethane with self‐healing and photoluminescence

Characterization of an Aqueous Dispersion of a Hydrophilic Polyisocyanate for Waterborne Two-Pack Polyurethane Coatings

Sustainable Polyurethane–Lignin Aqueous Dispersions and Thin Films: Rheological Behavior and Thermomechanical Properties

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