Process investigating and modelling for the self-polymerization of toluene diisocyanate (TDI)-based polyurethane prepolymer

Guo, Jishuai; He, Yong; Xie, Delong; Zhang, Xinya

doi:10.1007/s10853-015-9134-6

Cited by 20 publications

(18 citation statements)

References 66 publications

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“…Even though the difference in the degradation pattern is clear evidence of a chemistry change during excessive heating in the case of TDIprep_G prepolymer, the reason why this change only occurred for the prepolymer TDIprep_G and not for the other linear prepolymers remains unclear, since all three prepolymers contain identical starting functional groups. Apparently, the presence of glycerol contributes towards higher reactivity of possible reactions taking place at higher temperatures in polyurethane/isocyanate mixture [ 28 , 29 , 30 ]. Nevertheless, this explanation remains elusive and is beyond the scope of this work.…”

Section: Resultsmentioning

confidence: 99%

Influence of the Prepolymer Type and Synthesis Parameters on Self-Healing Anticorrosion Properties of Composite Coatings Containing Isophorone Diisocyanate-Loaded Polyurethane Microcapsules

et al. 2021

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Self-healing anticorrosion composite coatings containing isophorone diisocyanate-loaded polyurethane microcapsules were developed, and comprehensive research on prepolymer and microcapsules synthesis, as well as functional composite coatings preparation and characterization, was performed. The influence of the prepolymer type and the concentration of the stabilizing agent used in the synthesis procedure on the properties of the microcapsules was studied in detail. For this purpose, three different prepolymers were prepared from toluene-2,4-diisocyanate (TDI) and either glycerol, 1,4-butanediol, or 1,6-hexanediol, and their chemical properties were investigated. Microcapsules were synthesized from the obtained prepolymers, according to the oil-in-water polymerization method, where 1,6-hexanediol was used as a chain extender, while the concentration of the stabilizing agent in the synthesis procedure was varied. Microcapsules prepared from TDI-glycerol prepolymer, synthesized in the presence of 10 wt% of the stabilizing agent, showed superior chemical, morphological, and thermo-gravimetrical properties; thus, they were incorporated into the coating in the concentration of 20 wt%. The prepared composite coatings demonstrated self-healing and anticorrosion properties, and thus the developed microcapsules show great potential for the incorporation into the composite anticorrosion coatings at critical points where damage can easily occur, providing longer and more efficient anticorrosion protection.

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Section: Resultsmentioning

confidence: 99%

Influence of the Prepolymer Type and Synthesis Parameters on Self-Healing Anticorrosion Properties of Composite Coatings Containing Isophorone Diisocyanate-Loaded Polyurethane Microcapsules

et al. 2021

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“…Such side reaction could possibly lead to the formation of the dimers: uretidinedione and carbodiimide. It is unlikely that trimers and higher oligomers would form on the CNC surface due to steric and structural hindrances [42]. Despite of the possibility of self-polymerization to happen, it does not seem as a major side reaction as the amount of dimers is not significant enough to be detected using spectroscopic methods such as Fourier-transform infrared spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

On the Para/Ortho Reactivity of Isocyanate Groups during the Carbamation of Cellulose Nanocrystals Using 2,4-Toluene Diisocyanate

Abushammala

2019

Polymers

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2,4-toluene diisocyanate (TDI) has been commonly used to bind molecules and polymers onto the surface of cellulose nanocrystals (CNCs). Such a process usually involves two steps: (1) the more reactive para-isocyanates (p-NCOs) of TDI are reacted with the surface hydroxyl groups of CNCs then (2) the ortho-isocyanates (o-NCOs) are reacted with certain desired molecules. During the first reaction, an ideal para/ortho selectivity could be impossible to achieve, as o-NCOs are not fully unreactive. Therefore, there is a need to better understand the reaction between CNCs and TDI towards a maximum para/ortho selectivity. For that goal, CNCs were reacted with TDI under varying temperatures (35–75 °C) and TDI/CNCs molar ratios (1–5). The amount of the reacted TDI was estimated using elemental analysis while the free o-NCO groups were quantified following the hydrolysis method of Abushammala. The results showed that temperature had a negative impact on para/ortho selectivity while TDI/CNCs molar ratio improved it. A maximum selectivity of 93% was achieved using a temperature of 35 °C and a molar ratio of 3. This is a three-fold improvement to that using the traditional reaction conditions (75 °C and molar ratio of 1).

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“…Isocyanates, in the presence of a catalyst and heat, can dimerize to uretidinediones and carbodiimides, or trimerize to isocyanurates, or even form larger oligomers. These many possibilities of isocyanates to self-polymerize have a negative impact on the efficiency of nanocellulose modification [132,133,134].…”

Section: Challengesmentioning

confidence: 99%

A Review of the Surface Modification of Cellulose and Nanocellulose Using Aliphatic and Aromatic Mono- and Di-Isocyanates

2019

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Nanocellulose has been subjected to a wide range of chemical modifications towards increasing its potential in certain fields of interest. These modifications either modulated the chemistry of the nanocellulose itself or introduced certain functional groups onto its surface, which varied from simple molecules to polymers. Among many, aliphatic and aromatic mono- and di-isocyanates are a group of chemicals that have been used for a century to modify cellulose. Despite only being used recently with nanocellulose, they have shown great potential as surface modifiers and chemical linkers to graft certain functional chemicals and polymers onto the nanocellulose surface. This review discusses the modification of cellulose and nanocellulose using isocyanates including phenyl isocyanate (PI), octadecyl isocyanate (OI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), and their derivatives and polymers. It also presents the most commonly used nanocellulose modification strategies including their advantages and disadvantages. It finally discusses the challenges of using isocyanates, in general, for nanocellulose modification.

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Process investigating and modelling for the self-polymerization of toluene diisocyanate (TDI)-based polyurethane prepolymer

Cited by 20 publications

References 66 publications

Influence of the Prepolymer Type and Synthesis Parameters on Self-Healing Anticorrosion Properties of Composite Coatings Containing Isophorone Diisocyanate-Loaded Polyurethane Microcapsules

Influence of the Prepolymer Type and Synthesis Parameters on Self-Healing Anticorrosion Properties of Composite Coatings Containing Isophorone Diisocyanate-Loaded Polyurethane Microcapsules

On the Para/Ortho Reactivity of Isocyanate Groups during the Carbamation of Cellulose Nanocrystals Using 2,4-Toluene Diisocyanate

A Review of the Surface Modification of Cellulose and Nanocellulose Using Aliphatic and Aromatic Mono- and Di-Isocyanates

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