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Waterborne Polyurethanes for Automobile Industries
Published in Ram K. Gupta, Ajay Kumar Mishra, Eco-Friendly Waterborne Polyurethanes, 2022
Automotive coatings have been employed to coat automobile components and outer surfaces [42,43]. In this regard, eco-friendly polyurethanes have been used. In the automotive industry, eco-friendly waterborne polyurethanes have been useful for heat resistance, flame resistance, and radiation shielding properties [44,45]. The heat and flame resistance performance of automotives can be enhanced using eco-friendly waterborne polyurethanes. Moreover, waterborne polyurethanes have shown anticorrosion properties [46,47]. These properties led to the formation of eco-friendly waterborne polyurethane-based coating materials for automobile components. Two types of coatings have been developed, i.e. flame retardant coatings and anticorrosion coatings. Pathan et al. [48] designed eco-friendly waterborne polyurethane-based thermally stable and anticorrosion coatings. Melamine formaldehyde (MF) and 3-isocynatopropyl triethoxy silane (IPTES) were used to crosslink eco-friendly waterborne polyurethane MF/IPTES. Dibutyltin dilaurate (DBTDL) was used as a catalyst to form waterborne polyurethane. The formation scheme is illustrated in Figure 23.6.
The Chemistry of Polyurethane Copolymers
Published in Nina M. K. Lamba, Kimberly A. Woodhouse, Stuart L. Cooper, Polyurethanes in Biomedical Applications, 2017
Nina M. K. Lamba, Kimberly A. Woodhouse, Stuart L. Cooper
Organotin compounds will promote the reaction of isocyanates with diol s in preference to reaction with water. Dibutyltin dilaurate and stannous octoate are widely used in polyurethane synthesis, as they are readily soluble in the reaction medium, are not very volatile, and have a low odor. Dibutyltin dilaurate and tin dicarboxylate are approximately ten times more efficient than tertiary amines at promoting the reaction between isocyanates and hydroxy groups. Catalysts with large side groups are generally less efficient, due to steric hindrance, and some latent organotin compounds exist. Organotin catalysts will also promote biuret and urea crosslinking reactions, but not isocyanurate formation. Strong bases will promote biuret, allophanate and isocyanurate reactions. A mixture of tertiary amines and organotin compounds can be used, in order to gain a balance between the chain extension and crosslinking steps of polyurethane formation.
The Art and Science of Formulating
Published in Ralph D. Hermansen, Polymeric Thermosetting Compounds, 2017
Next, we shall discuss epoxy resin formulating. As we end our discussion of polyurethane formulating, I want to point out some of the important differences between these polymer families:The presence of water in polyurethane compounds is a big problem, if we do not want to make foam. The problem also affects the environment where we use the polyurethane compound. Some substrates, like wood, have water content that can cause foaming at those surfaces. The problem virtually disappears when we work with epoxies.The reaction rate of polyurethane compounds can be fine-tuned using catalysts. There are numerous different catalysts available. The catalyst that I used in the polyurethane compounds discussed in this book was dibutyltin dilaurate (DBTDL).The available epoxy resins and curing agents are very useful if you want to make a hard, somewhat brittle plastic. The available polyols and isocyanates are very useful if you want to make a rigid or flexible foam or a rubbery product. However, if you want to make a rubbery epoxy or a hard polyurethane plastic, you are more or less on your own. Strangely enough, I found myself needing to do both of those things.
Synthesis and application of cationic fluorocarbon surfactants
Published in Journal of Dispersion Science and Technology, 2023
Saipeng Zhang, Mingxin Zhang, Xingjiang Liu, Liuhe Wei
Add 0.01 mol of hexamethylene diisocyanate and 10 mL of anhydrous dichloromethane solvent to a 50 mL three-necked flask, add two drops of dibutyltin dilaurate as catalyst, and heat to 40 °C in an oil bath with magnetic stirring. Then 0.01 mol of 2-(dimethylamino) ethanol was added for one hour and 0.01 mol of 1H, 1H, 2H, 2H-tridecafluoro-1-octanol was added slowly dropwise to the reaction flask for another hour, and finally 0.01 mol of iodomethane was weighed and added slowly dropwise to the reaction system for twenty minutes to end the reaction. The resulting product was washed with petroleum ether for 3 × 30 mL and dried in an oven at 80 °C for one hour to obtain a white powder solid. 4,4′ -dicyclohexyl methane diisocyanate and isophorone diisocyanate were reacted under the same conditions as above.
Turning a linear waterborne polyurethane into a crosslinked counterpart with improved water resistance and mechanical strength through a fast post metal-organic crosslinking
Published in Soft Materials, 2022
Guotong Du, Na Li, Qiwen Yong, Feng Jiang, Rui Wang, Yulong Li, Yao Xiao, Jinming Chang
Forty grams of PTMG-1000, 21 g of IPDI, and 0.03 g of Dibutyltin dilaurate (the catalyst) were reacted at 80°C for 2 h in a three-neck flask, obtaining an isocyanate-terminated prepolymer. Then 4 g of DMPA accompanied with 4 g of DMF was added into the flask to react with the prepolymer for 3 h. After the reaction mixture was cooled down to 45°C, 2.7 g of TEA and 8 g of DMF were added into the flask to neutralize the carboxyl groups of DMPA at 45°C for 20 min. As the reaction mixture was cooled down to 25°C, 100 g of DI water was added into the flask to disperse the reaction mixture under high-speed stirring. Then 0.84 g of EDA that dissolved in 94 g of DI water was added into the flask dropwise, and reacted with the mixture for 30 min, acquiring the linear WPU emulsion with a solid content of 25.0%. The content of DMF in the emulsion was 4.4%.
Preparation of new low viscosity urethane dimethacrylates for dental composites
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Yuling Xu, Haibo Wang, Dong Xie
Isophorone diisocyanate (IDI, mixture of isomers), 4,4′-methylenebis(phenyl isocyanate) (MPI), 4,4′-methylenebis(cyclohexyl isocyanate) (MCI, mixture of isomers), 1,3-bis(1-isocyanato-1-methylethyl)benzene (BIMB), hexamethylene diisocyanate (HDI), hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), triethylene glycol dimethacrylate (TEGDMA), dibutyltin dilaurate (DBTL), camphorquinone (CQ), N,N-dimethylaminoethyl methacrylate (DMAEMA), Hydroquinone monomethyl ether (MEHQ), acetone and diethyl ether were used as received from Sigma-Aldrich Chemical Co (Milwaukee, WI, U.S.A). The untreated barium borosilicate glass fillers (Herculite XRV, 0.7 microns) were supplied by Kerr Dental Corp (Orange, CA, U.S.A). BisGMA and UDMA were used as received from Esstech Inc (Essington, PA, U.S.A).