Papers by Keyword: Waterborne Polyurethane (WPU)

Abstract: Waterborne polyurethane and chitosan were mixed in different volume ratio, and finished on the cotton of plasma pre-treatment and non-plasma pre-treatment to discuss the influence of plasma pretreatment on the properties of the fabric. Firstly, the mixed aqueous emulsion was made into film and analyzed by FTIR. Secondly, the relationship between the properties of whiteness, wrinkle recovery performance and water vapor permeability of the fabric that finished by the only blended solution and the mixed ratio was studied. Finally, the property changes between the pretreatment with and without plasma was compared. The results showed that, the blended film not only had both polyurethane and chitosan characteristic peaks, but also generated the new characteristic peaks; the three properties of the fabric that finished by the only blended solution changed with the mixed ratio; the plasma pre-treatment would increase the fabric’s whiteness, decrease wrinkle recovery performance, but the water vapor permeability would improve obviously.

Abstract: Waterborne polyurethane (WPU) has its main applications in coatings and adhesives. Compared with the competing PU products from solvent-based processes, it has a more environmentally friendly manufacturing process. Its economic competitiveness could also be improved by the use of aromatic isocyanates that are widely available and cheaper than the currently used aliphatic isocyanates. We report on the synthesis and properties of WPU, based on natural rubber (NR) whose molecular structure has been altered, in combination with an aromatic isocyanate. The NR modification is by hydroxyl termination, with experiments using two chain lengths (HT600 and HT1000, named after molecular weight). The aromatic isocyanates used are 4,4’-Methylene bis (phenyl isocyanate) (MDI) and polymethylene polyphenyl polyisocyanate (p-MDI). The synthesized chemical structure is characterized using ATR-FTIR, while the key material properties reported here are the pH value, mean particle size and size distribution, and glass transition temperature. The WPU achieved suitable material properties, with small particles sizes and good dispersion, for applications in coatings.

Abstract: TDI as main isocyanate, IPDI as end-capping reagent, waterborne polyurethane (WPU) surface-sizing agent have been obtained by a pre–polymerization process. WPU were mixed with starch SSA in different proportion and a composite sizing agent obtained. It is indicated the water resistance, gloss and folding resistance of WPU/starch sized papers are much higher than starch sized papers. The ink absorption obviously decreases and the mechanical properties wholly increase. WPU/starch composite emulsions is a new kind of surface sizing agent having broad development prospects.

Abstract: Waterborne polyurethane emulsions were synthesized with isophorone diisocyanate(IPDI), dihydromethyl propionic acid(DMPA) and poly-ε-caprolactone glycol(PCL), and then reacted with hydroxy-ethyl acrylate(HEA) and 3-aminopropyltriethoxylsilane(APTES) to cap the terminal -NCO groups. The polyurethane emulsions were used to copolymerize with acrylates to synthesize the modified waterborne polyurethane-acrylate hybrid emulsions. The structure, thermal stability and crystallinity of modified polyurethane were studied by FTIR, TG, XRD and the mechanical properties of modified polyurethane films was also investigated. The results show that crystallization of the modified waterborne polyurethane decreases and thermal stability is improved. When the mass fraction of acrylate is 20% and APTES content is 15%, tensile strength of the modified polyurethane films can reach 23.9MPa and elongation at break is 247%.

Abstract: Waterborne cationic fluorinated polyurethane (WCFPU) was prepared by the reaction of isophorone isocyanate (IPDI), polyether polyol (PTMG1000), N-methyldiethanolamine (MDEA), trimethylol propane (TMP) and 2-(perfluorooctyl) ethyl alcohol (FEOH) and then the films of the WCFPU were prepared. Their structure, surface property, mechanical properties, thermal performance and chemical resistance of their membrane were characterized by fourier transform infared spectrometer (FT-IR), interfacial tension instrument (IT), contact angle (CA), thermogravimetry (TG) and spot test. The results revealed that WCFPU was endowed with good mechanical properties and low surface energy of its film. TG diagrams also revealed that the application range of product was enlarged. It was also found that the fluorinated polyurethane had outstanding chemical resistance.

Abstract: The waterborne polyurethane coatings modified by linseed oil were prepared in a method of ammonolysis. The influence of reaction time and temperature of the linseed oil ammonolysis on structure and properties of the waterborne polyurethane coatings was investigated and discussed. It has been shown in this work that the preferred ammonolysis temperature would be 102~118°C, the reaction time could be about 80 min, and structure of the modified waterborne polyurethane was analysed by FTIR. The touch-dry time of the modified waterborne polyurethane with drier would be shorter than that of non-modified waterborne polyurethane, normally in a week, and the stability of the modified waterborne polyurethane coating in water could stand for 3 months under room temperature. The TGA results of the coatings showed that the weight loss started at about 294°C.

Abstract: A series of polyols (GSOLs) with a range of hydroxyl numbers based on epoxidized soybean oil (ESO) were prepared by ring opening with glycol. These Polyols of hydroxyl (OH) numbers ranging from 111 to 162 mg KOH/g were obtained. The environmentally friendly soybean-oil-based waterborne polyurethane dispersions (SPU) with very promising properties have been successfully synthesized from a series of soybean-oil-based polyols (GSOLs) with different hydroxyl numbers by a polyaddition reaction with toluene 2,4-diisocyanate (2,4-TDI). The structure and thermophysical properties of the resulting SPU films have been studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and hardness testing. The experimental results showed that the functionality of the GSOLs and the hard segment content play a key role in controlling the structure and the thermophysical properties of the SPU films.

Abstract: The waterborne polyurethane (WPU) was synthesized from isophorone diisocyanate (IPDI), polypropylene glycol (PPG), dimethylolpropionic acid (DMPA) and 1,4-butanediol (BDO) under acetone reflux. The cast films obtained from it were characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (¹H NMR) and differential scanning calorimetry (DSC). The curve of DSC presented a bimodal profile. It showed that the waterborne polyurethane resin degraded obviously at about 305°C and 381°C, which was an endothermic course. The scanning electron microscopy (SEM) micrographs revealed that hexanitrohexaazaisowurtzitane (HNIW) was coated with waterborne polyurethane by means of water volatilization. The impact sensitivity experimental results indicated that the characteristic height H₅₀ of HNIW coated with waterborne polyurethane increased from 25.1cm to 34.2cm. That is, the waterborne polyurethane can decrease the impact sensitivity of HNIW.

Abstract: In the present study, a kind of bio-based waterborne polyurethane (BWPU) /ZnO was prepared with BWPU and different concentrations of nanometer ZnO emulsion by incorporated into the BWPU matrix. The prepared BWPU/ZnO hybrid dispersions were casted in a Teflon petridish and the dried films were used for XRD, SEM, FT-IR and antibacterial tests. The results suggest that the BWPU/ZnO hold the potential applications as new materials.

Abstract: UV-curable waterborne polyurethane/acrylate (WPUA) composite resin was prepared, and its properties were compared with those of waterborne polyurethane resin. Results showed that the particle size distribution of the compounding resin was broader, and the compatibility of two phases in resin system became better after adding the acrylate into polyurethane. Moreover, water and alcohol resistances, and mechanical properties of composite resin were superior to those of waterborne polyurethane resin. Comprehensive properties of resin film were the best when photoinitiator amount is 3% of resin.