Reaction kinetics and properties of MDI base poly (urethane-isocyanurate) network polymers

Li, Juan; Jiang, Shilong; Ding, Liang; Wang, Lingfang

doi:10.1080/15685551.2021.1971858

Cited by 9 publications

(7 citation statements)

References 18 publications

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“…The C=C bonds related to the aromatic groups in the MDI monomer were found at 1660 cm −1 [ 26 ]. For comparison, the isocyanate (NCO) group was reported at 2278 cm −1 [ 27 ], which showed very weak peaks in three RPUFs, suggesting that almost all of the polymeric MDI was reacted in the polymerization to form the crosslinking polyurethane foams. Another key monomer of poly(ether polyol) had a strong C-O-C stretching peak at 1089 cm −1 [ 28 ], which was also found in the as-prepared polyurethane materials.…”

Section: Resultsmentioning

confidence: 99%

Long-Service-Life Rigid Polyurethane Foam Fillings for Spent Fuel Transportation Casks

Zhang,

Shen,

et al. 2024

Polymers

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Soft materials bearing rigid, lightweight, and vibration-dampening properties offer distinct advantages over traditional wooden and metal-based fillings for spent fuel transport casks, due to their low density, tunable structure, excellent mechanical properties, and ease of processing. In this study, a novel type of rigid polyurethane foam is prepared using a conventional polycondensation reaction between isocyanate and hydroxy groups. Moreover, the density and size of the pores in these foams are precisely controlled through simultaneous gas generation. The as-prepared polyurethane exhibits high thermal stability exceeding 185 °C. Lifetime predictions based on thermal testing indicate that these polyurethane foams could last up to over 60 years, which is double the lifetime of conventional materials of about 30 years. Due to their occlusive structure, the mechanical properties of these polymeric materials meet the design standards for spent fuel transport casks, with maximum compression and tensile stresses of 6.89 and 1.37 MPa, respectively, at a testing temperature of −40 °C. In addition, these polymers exhibit effective flame retardancy; combustion ceased within 2 s after removal of the ignition source. All in all, this study provides a simple strategy for preparing rigid polymeric foams, presenting them as promising prospects for application in spent fuel transport casks.

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Section: Resultsmentioning

confidence: 99%

Long-Service-Life Rigid Polyurethane Foam Fillings for Spent Fuel Transportation Casks

Zhang,

Shen,

et al. 2024

Polymers

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“…This is the characteristic adsorption signal of -NCO(Shao et al, 2021; Stuart, 2021;Zhao et al, 2011), and signi es that MDI involved in the curing process. Besides that, the 755 and 1408 cm − 1 peaks are novel signals of cured SDTM20 adhesive, re ecting the isocyanurate rings and C-N stretching vibration of isocyanurate rings(Gao et al, 2011;Li et al, 2021;Reignier et al, 2021). With the addition of TsOH/MDI, the signals of 1506 and 1202 cm − 1 peaks were progressively strengthened, con rming that the SDTM20 adhesives formed more 5-HMF or its derivatives and dimethyl ether bridges after curing(Adina et al, 2011;Beta et al, 2001).…”

mentioning

confidence: 82%

A high curing efficiency sucrose-based adhesive via two-step modification by toluene-4-sulfonic acid and methylenediphenyl diisocyanate

Lin,

Cai,

Zhang

et al. 2023

Eur. J. Wood Prod.

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Sucrose-based adhesives utilize renewable biomass material sucrose as the main ingredient, which are ecofriendly and non-toxic, making them attractive potential substitutes for formaldehyde-based wood adhesives. However, wood-based panel processing using sucrose-based adhesives requires extraordinary harsh conditions with high hot-pressing temperatures (≥170 ℃), limiting practical applications. In this study, the sucrose-based adhesive (SD adhesive) was modi ed by toluene-4-sulfonic acid (TsOH) and methylenediphenyl diisocyanate (MDI) in two steps. The sucrose-based solution (SS) of the optimal adhesive in the study (SDTM20 adhesive) was synthesized with 5%TsOH catalyst at 100 ℃ for 3h, and then 20%MDI curing agent was added, followed by mixing. After that, the curing behavior, curing mechanism and microscopic characterization was used to analyze the optimal prepared materials. The wet shear strength (0.80 MPa) of the prepared adhesive meets the GB/T 9846-2015 China National Standard (≥0.7 MPa). 13 C NMR showed that the TsOH catalyst promoted the formation of aromatic compounds, oligosaccharides and carbonyls, and the 5-HMF content of the SS in SDTM20 adhesive (44.0 g/L) was 158.8% higher than that of SD adhesive. In addition, the thermal curing behavior of SDTM20 adhesive was explained by changes in insoluble mass proportion (IMP) and TG-DSC thermal analysis. From the IMP measurement, SDTM20 adhesive (61.2%) increased by 141.9% compared with the SD adhesive.Additionally, in TG-DTG and DSC curves, the rapid weight loss temperature (145.1 ℃) corresponded to the endothermic reaction temperature (135.3 ℃), implying that the main curing reaction occurred at approximately 140 ℃, indicating that it is possible to improve curing e ciency of SD adhesive. ATR-FTIR was used to evaluate the curing mechanism of the SDTM20 adhesive. After adding TsOH/MDI, the dehydration reaction of sucrose, caramelization reaction, and Maillard reaction were accelerated to improve the curing e ciency. A complex polymeric cross-linking network structure with isocyanurate rings was generated, mainly connected by dimethyl ether bridges. SEM analysis of the microstructure of the adhesive revealed unknown crystal substances and small bubble pores on the fracture surface of the modi ed SDTM adhesive, showing that a novel cross-linking reaction had occurred.

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mentioning

confidence: 95%

A High Curing Efficiency Sucrose-based Adhesive via two-step modification by Toluene-4-sulfonic Acid and Methylenediphenyl Diisocyanate

Lin

Cai

Xue

et al. 2023

Preprint

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Sucrose-based adhesives utilize renewable biomass material sucrose as the main ingredient, which are eco-friendly and non-toxic, making them attractive potential substitutes for formaldehyde-based wood adhesives. However, wood-based panel processing using sucrose-based adhesives requires extraordinary harsh conditions with high hot-pressing temperatures (≥170 ℃), limiting practical applications. In this study, the sucrose-based adhesive (SD adhesive) was modified by toluene-4-sulfonic acid (TsOH) and methylenediphenyl diisocyanate (MDI) in two steps. The sucrose-based solution (SS) of the optimal adhesive in the study (SDTM20 adhesive) was synthesized with 5%TsOH catalyst at 100 ℃ for 3h, and then 20%MDI curing agent was added, followed by mixing. After that, the curing behavior, curing mechanism and microscopic characterization was used to analyze the optimal prepared materials. The wet shear strength (0.80 MPa) of the prepared adhesive meets the GB/T 9846-2015 China National Standard (≥0.7 MPa). 13C NMR showed that the TsOH catalyst promoted the formation of aromatic compounds, oligosaccharides and carbonyls, and the 5-HMF content of the SS in SDTM20 adhesive (44.0 g/L) was 158.8% higher than that of SD adhesive. In addition, the thermal curing behavior of SDTM20 adhesive was explained by changes in insoluble mass proportion (IMP) and TG-DSC thermal analysis. From the IMP measurement, SDTM20 adhesive (61.2%) increased by 141.9% compared with the SD adhesive. Additionally, in TG-DTG and DSC curves, the rapid weight loss temperature (145.1 ℃) corresponded to the endothermic reaction temperature (135.3 ℃), implying that the main curing reaction occurred at approximately 140 ℃, indicating that it is possible to improve curing efficiency of SD adhesive. ATR-FTIR was used to evaluate the curing mechanism of the SDTM20 adhesive. After adding TsOH/MDI, the dehydration reaction of sucrose, caramelization reaction, and Maillard reaction were accelerated to improve the curing efficiency. A complex polymeric cross-linking network structure with isocyanurate rings was generated, mainly connected by dimethyl ether bridges. SEM analysis of the microstructure of the adhesive revealed unknown crystal substances and small bubble pores on the fracture surface of the modified SDTM adhesive, showing that a novel cross-linking reaction had occurred.

show abstract

Reaction kinetics and properties of MDI base poly (urethane-isocyanurate) network polymers

Cited by 9 publications

References 18 publications

Long-Service-Life Rigid Polyurethane Foam Fillings for Spent Fuel Transportation Casks

Long-Service-Life Rigid Polyurethane Foam Fillings for Spent Fuel Transportation Casks

A high curing efficiency sucrose-based adhesive via two-step modification by toluene-4-sulfonic acid and methylenediphenyl diisocyanate

A High Curing Efficiency Sucrose-based Adhesive via two-step modification by Toluene-4-sulfonic Acid and Methylenediphenyl Diisocyanate

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