Properties of isocyanate‐reactive waterborne polyurethane adhesives: Effect of cure reaction with various polyol and chain extender content

Three series of isocyanate‐reactive waterborne polyurethane adhesives were prepared with various contents of chain extender (4.25/8.25/12.50 mol %) and polyol (20.75/16.75/12.50 mol %). Each series had a fixed amount of excess (residual) NCO group (0.50–2.00 mol %). FTIR and ¹H‐NMR spectroscopy identified the formation of urea crosslink structure mainly above 80°C of various cure temperatures (20–120°C) with excess diisocyanate. The molecular weight, tensile strength, Young's modulus, and adhesive strength depend on excess NCO content and cure temperature and also varied with polyol and chain extender content. The optimum cure temperature was 100°C for all the samples. The tensile strength, Young's modulus, and adhesive strength increased with increasing cure temperature above 60°C up to the optimum temperature) (100°C) and then almost leveled off. Among all the samples, the maximum values of tensile strength, Young's modulus, and adhesive strength were found with 63.22 wt % polyol, 0.93 wt % chain extender, and 1.50 mol % excess (residual) NCO content at 100°C optimum cure temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Chemical degradation of polyurethanes. II. Degradation of microporous polyurethane elastomer by phosphoric acid esters

Microporous polyurethane elastomer, based on 4,4′‐diphenylmethane diisocyanate and polyester polyol Bayflex 2003 (Bayer AG), was degraded by phosphoric acid esters  (CH₃CH₂O)₃P(O) and (ClCH₂CH₂O)₃P(O) at 180°C. Structure of degraded products was investigated by means of ¹H‐, ¹³C‐, and ³¹P‐NMR spectroscopy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 886–893, 2000     

Chemical degradation of polyurethanes: Degradation of flexible polyester polyurethane foam by phosphonic acid dialkyl esters

Flexible polyurethane foam based on toluene diisocyanate and polyester polyol has been liquefied by treatment with either dimethyl phosphonate (CH₃O)₂P(O)H or diethyl phosphonate (C₂H₅O)₂P(O)H at 160°C. The product degraded has been studies by ¹H, ¹³C, and ³¹P nuclear magnetic resonance (NMR) spectroscopy. The likely reaction mechanism is presented. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2565–2573, 2000     

Production of a high‐functionality RBD palm kernel oil‐based polyester polyol

A diol‐based refined, bleached, and deodorized (RBD) palm kernel oil polyol was prepared. It was found that the polyurethane foam produced only gives a good compressive strength property at a 45 kg/m³ molded density. The combination of sorbitol into the polyol system resulted in a better dimensional stability and improved thermal conductivity as well as enhanced compressive strength. These were obtained by increasing the functionality of the polyol (functionality of 4.5) through introduction of a high molecular weight and branching polyhidric compound. Direct polycondensation and transesterification methods were used for the syntheses. The hydroxyl value, TLC, and FTIR were used to study the completion of the reaction. A comparative study of the mechanical properties and morphological behavior was carried out with a diol‐based polyol. From the water‐blown molded foam (zero ODP) with a density of about 44.2 kg/m³ and a closed‐cell content of 93%, a compressive strength of 222 kPa and a dimensional stability of 0.09, 0.10, and 0.12% at the length, width, and thickness of the foam, respectively, conditioned at ?15°C for 24 h, were obtained. The thermal conductivity improved to an initial value of 0.00198 W/mK, tested at 0°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 384–389, 2001     

Influence of diisocyanate,glycidol and polyol molar ratios on the mechanical and thermal properties of glycidyl‐terminated biobased polyurethanes

A series of epoxy‐terminated polyurethanes (EPUs) were synthesized from castor oil, 4,4′‐methylenebis(cyclohexyl isocyanate) (H₁₂MDI) and 2,3‐epoxy‐1‐propanol (glycidol) by changing the molar ratio of H₁₂MDI to glycidol to polyol. Fourier transform infrared, ¹H NMR and solid‐state CP/MAS ¹³C NMR spectroscopic analyses revealed the presence of epoxy linkages within the polyurethane backbone. Thermogravimetric analysis showed that EPU4 with a polyol:diisocyanate:glycidol molar ratio of 1:6:6 exhibited an initial decomposition temperature of 128 °C, which was 26 °C higher than that of EPU1 (1:3:3 molar ratio). Differential scanning calorimetry showed an upward shift in the glass transition temperature with increasing molar ratio. Mechanical analysis demonstrated that the tensile modulus of EPU4 was 7.8 times greater than that of EPU1. The crosslinking densities of EPUs were determined using swelling studies which revealed a gradual increase in crosslinking density with increasing epoxy content within the polyurethane. The morphologies of cryo‐fractured surfaces of EPUs were determined through scanning electron microscopy to analyse the phase dispersion of epoxy and polyurethane. © 2017 Society of Chemical Industry     

PP或PE用双组分PU胶粘剂的制备与性能研究

以聚酯多元醇、混合异氰酸酯(MDI/TDI)、扩链剂(1,2-丙二醇)、异氰酸酯固化剂(TMP-TDI)和溶剂(乙酸乙酯)等为主要原料,制备了PP(聚丙烯)、PE(聚乙烯)粘接用双组分PU(聚氨酯)胶粘剂。研究结果表明:当m(结晶性聚酯多元醇)∶m(非结晶性聚酯多元醇)=80∶20~60∶40、R=n(-NCO)/n(-OH)=0.95~0.97、m(MDI)∶m(TDI)=90∶10~60∶40和w(功能性聚酯多元醇XCP-2325)=2%时,PU预聚体的相对分子质量为(9~11)×104,其常温固化12 h后的邵A硬度(76)有利于PU预聚体的破碎;当PU预聚体/乙酸乙酯溶液的固含量为12%时,双组分PU胶粘剂的操作性能(黏度为22 mPa.s)、180°剥离强度(初始2.3 N/25 mm、最终41.0 N/25 mm)俱佳。     

Structure and mechanical properties of fluorine‐containing glycidyl azide polymer‐based energetic binders

A novel energetic polymer, fluorine‐containing glycidyl azide polymer (FGAP ), was developed via an initial cationic copolymerization of epichlorohydrin and 1,1,1‐trifluoro‐2,3‐epoxypropane, followed by azidation. The structure of FGAP was confirmed using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopies. The molecular weight and the thermal behavior of FGAP were characterized using gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis. FGAP had a molecular weight of 2845 g mol^?1, and the glass transition temperature and decomposition temperature were found to be ?47.8 and 253 °C, respectively. FGAP ‐based polyurethane networks were further prepared using triphenylmethane‐4,4,4‐triisocyanate as the crosslinking agent. In comparison with GAP , FGAP ‐based polyurethane networks exhibited better mechanical behaviors (a tensile strength of 1.5 MPa and an elongation at break of 81.6%). The results demonstrated that FGAP might be a promising polymeric binder for future propellant formulations. © 2017 Society of Chemical Industry     

Synthesis of bio‐based polyurethanes from epoxidized soybean oil and isopropanolamine

Epoxidized soybean oil (ESO) and isopropanolamine were used to synthesize a new polyol mixture for preparation of bio‐based polyurethanes. The chemical synthetic route for reaction of ESO with isopropanolamine was analyzed by ¹H‐NMR. The results suggested that both ester groups and epoxy groups in ESO had reacted with amino group of isopropanolamine through simultaneous ring‐opening and amidation reactions. Epoxy groups in various situations exhibited different reactivity, and the unreacted epoxy groups were further opened by hydrochloric acid. The synthesized polyol mixture had high hydroxyl number of 317.0 mg KOH/g. A series of polyurethanes were prepared by curing the synthesized polyol mixture with 1,6‐diisocyanatohexance along with different amount of 1,3‐propanediol (PDO) as chain extender. Tensile tests showed that yield strengths of the polyurethanes ranged from 2.74 to 27.76 MPa depending on the content of PDO. Differential scanning calorimetry analysis displayed one glass transition temperature in the range of 24.4–28.7°C for all of the polyurethane samples, and one melt peak at high content of PDO. Thermogravimetric analysis showed that thermal degradations of the polyurethanes started at 240–255°C. In consideration of simple preparation process and renewable property of ESO, the bio‐based polyurethane would have wide range of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and properties of polydimethylsiloxane (PDMS)/polytetramethyleneadipate glycol (PTAd)-based waterborne polyurethane adhesives: Effect of PDMS molecular weight and content

Waterborne polyurethane (WBPU) dispersions were prepared by pre-polymer process using siloxane polyol, namely polydimethylsiloxane (PDMS), and polyester polyol, namely poly(tetramethyleneadipate glycol) (PTAd), as a soft segment. Three different molecular weights (M_n = 550, 6000, 110,000) of PDMS and one fixed molecular weight of PTAd (M_n = 2000) was used during preparation of WBPU dispersions. This research aims to explore the potential use of PDMS in complementing WBPU by boosting flexibility, water resistance, and adhesive strength. The water swelling (%), tensile strength, and adhesive strength of WBPUs were investigated with respect to PDMS molecular weight and PDMS content (PDMS mol %). The water swelling (%) and tensile strength decreased with increasing PDMS molecular weight at a fixed PDMS content (mol %) in mixed polyol of WBPU films. By contrast, the peel adhesive strength peaked at 6.64 mol % and 4.43 mol % with molecular weight of PDMS at 550 and 6000, respectively, while it only decreased when the molecular weight of PDMS stood at 110,000. The adhesive strength was almost unaffected with optimum content (6.64 mol %) of lower PDMS molecular weight (M_n = 550) in mixed polyol-based WBPU after immersing the adhesive bonded nylon fabrics in water for 48 h among all of the samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

二异氰酸酯封端聚酯多元醇型固化剂合成反应动力学的研究

以低分子聚酯多元醇与二异氰酸酯合成新型聚氨酯固化剂,分别研究了甲苯二异氰酸酯（TD I）、二苯基甲烷二异氰酸酯（MD I）与低分子聚酯多元醇的反应动力学。结果表明,TD I封端低分子聚酯多元醇的反应为二级反应,反应活化能为51.7 kJ/mol;MD I封端低分子聚酯多元醇的反应在反应温度低于70℃时也为二级反应,反应活化能为27.6 kJ/mol。     

Synthesis of hyperbranched polyester‐amides and their application as crosslinkers for polyurethane curing systems

A series of hyperbranched polyester‐amides (S1, S2, S3) with trimethylolpropane as a core molecule were synthesized using core‐dilution/slow monomer addition strategy. The products were characterized by FTIR, ¹³C NMR, GPC, TGA, hydroxyl value measurement, and viscosity measurement. The result showed that the hyperbranched polyester‐amides synthesized had narrow molecular weight distribution and high degree of branching (DB). The hyperbranched polyester‐amides synthesized were used as crosslinkers for polyurethane curing systems and the mechanical properties of the polyurethane curing systems were investigated. It was found that the best tensile property and tear strength were obtained when the S2 were used as crosslinkers and the molar ratio of  OH and  NCO was 1 : 1. It was also found that the polyurethane curing systems had the highest hardness and T_g when the S3 were used as crosslinkers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Biopolyol preparation from liquefaction of grape seeds

The feasibility of liquefying grape seeds (GS) in the blended solvents of PEG 400 and glycerol for the production of biopolyol was investigated. Different liquefaction conditions have great influences on the residue ratio of GS. The influences of the liquefaction condition such as temperature, time, catalyst percentage, and liquid–solid ratio on the residue ratio were discussed. The optimal conditions obtained were 180 °C, 120 min, catalyst percentage (percentage of solvent mass) of 3.5%, and liquid–solid ratio of 4. The FTIR showed that the lignin, cellulose, and hemicellulose in the GS were effectively decomposed in the liquefaction process. The characteristic parameters of the biopolyol were as follows: hydroxyl number of 397.46 mg KOH/g, acid number of 1.85 mg KOH/g, viscosity of 2960 mPa·s, weight‐average molecular weight of 5.18 × 10³ g mol⁻¹, and polydispersity of 3.64. These results suggest that the GS‐based polyol was suitable for the production of polyurethane foams. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43835.     

Synthesis of Transesterified Palm Olein‐Based Polyol and Rigid Polyurethanes from this Polyol

Transesterification of palm olein with glycerol can increase the functionality by introducing additional hydroxyl groups to the triglyceride structure, an advantage compared to using palm olein directly as feedstock for producing palm‐based polyol. The objective of this study was to synthesize transesterified palm olein‐based polyol via a three‐step reaction: (1) transesterification of palm olein, (2) epoxidation and (3) epoxide ring opening. Transesterification of palm olein yielded approximately 78 % monoglyceride and has an hydroxyl value of approximately 164 mg KOH g^?1. The effect of formic acid and hydrogen peroxide concentrations on the epoxidation reaction was studied. The relationships between epoxide ring‐opening reaction time and residual oxirane oxygen content and hydroxyl value were monitored. The synthesized transesterified palm olein‐based polyol has hydroxyl value between 300 and 330 mg KOH g^?1 and average molecular weight between 1,000 and 1,100 Da. On the basis of the hydroxyl value and average molecular weight of the polyol, the transesterified palm olein‐based polyol is suitable for producing rigid polyurethane foam, which can be designed to exhibit desirable properties. Rigid polyurethane foams were synthesized by substituting a portion of petroleum‐based polyol with the transesterified palm olein‐based polyol. It was observed that by increasing the amount of transesterified palm olein‐based polyol, the core density and compressive strength were reduced but at the same time the insulation properties of the rigid polyurethane foam were improved.     

油墨连接料用聚氨酯胶粘剂的研制

简单介绍了聚氨酯油墨连接料的使用性能要求，合成了一种油墨连接料用聚氨酯胶粘剂。讨论了聚酯多元醇的相对分子质量、扩链剂、异氰酸酯指数、水分等对聚氨酯油墨连接料性能的影响。确定了聚氨酯油墨连接料的各项性能指标。     

Preparation and properties of waterborne polyurethane adhesives modified by polystyrene

Waterborne polyurethane (WPU) adhesives modified by polystyrene (PS) were prepared through a prepolymer mixing process from diisocyanates, an anionic polyester, internal emulsifiers, a neutralizer, a chain extender, and PS dispersions. The latter was preformed via the in situ polymerization of styrene in poly(1,4‐butanediol adipate) diol. Transmission electron microscopy, Fourier transform infrared spectroscopy, and ¹H‐NMR techniques were used to characterize the PS dispersions and polyurethane (PU)–PS prepolymer. Experimental results with respect to the performance of the PU–PS adhesives indicate that suitable PS/polyester diol weight ratios improved the mechanical properties, thermal stability, water resistance, and initial adhesive strength of the pristine WPU adhesives. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Bis(nitrone) as crosslinking agent for unsaturated polyesters via 1,3‐dipolaric cycloaddition

The microwave‐assisted polycondensation of maleic anhydride and 1,6‐hexanediol was carried out using p‐toluenesulfonic acid as catalyst. The resulting unsaturated polyester was characterized using Fourier transform infrared (FTIR) and ¹H NMR spectroscopy, and the molecular weight determined using gel permeation chromatography. 4,4′‐Decanediyldioxydi(N‐methyl‐p‐phenylenenitrone) was chosen as a model compound for the crosslinking of the unsaturated polyester. The crosslinking, which is known to proceed via 1,3‐dipolaric cycloaddition, was followed using differential scanning calorimetry. Additionally, the kinetics of the cycloaddition was evaluated at 120 °C using FTIR spectroscopy. Copyright © 2012 Society of Chemical Industry     

Glycolyzed poly(ethylene terephthalate) waste and castor oil-based polyols for waterborne polyurethane adhesives containing hexamethoxymethyl melamine

Glycolysis of poly(ethylene terephthalate) (PET) waste using different molar ratio of poly(ethylene glycol) (PEG400), was used to produce saturated hydroxyl-functional polyester polyols with castor oil (CO) by transesterification process. The waterborne polyurethane (WBPU) adhesives were synthesized from these saturated polyester polyols, isophorone diisocyanate (IPDI), dimethylolpropionic acid (DMPA), and hexamethoxymethyl melamine (HMMM) as cross-linking agent by a conventional prepolymer process. The glycolyzed polyols and polyester polyos formations were characterized using Fourier transform infrared spectroscopy (FTIR) and the molecular weights were determined using gel permeation chromatography (GPC). The cross-linking reaction between WBPU and HMMM was verified using FTIR and ¹H NMR analysis. Thermal properties were investigated by thermogravimetric analysis (TG). Thermal stability of cross-linked WBPU significantly increased with decreasing castor oil content in the process of transesterification to obtain polyester polyol as a soft segment. The T_15% and T_50% (the temperature where 15 and 50% weight loss occurred) of WBPU increased with the decreasing of castor oil content in the obtained polyester polyols, caused by the steric hindrance of polyester polyol with higher castor oil content, in the process of cross-linking reactions with HMMM. The physico-mechanical properties of WBPU, such as hardness, adhesion test, and gloss of the dried films were also determined considering the effect of participation of HMMM in cross-linking reactions with polyurethane, on coating properties.     

Synthesis and Application of a Hyperbranched Polyester Quaternary Ammonium Surfactant

In the presence of the alkaline catalyst sodium hydroxide, the intermediate of hyperbranched polyester (H20Cl) was prepared by the modification of the hyperbranched polyester Boltorn H20 with epichlorohydrin. Then a new kind of quaternary ammonium functionalized hyperbranched polyester (H20C16 N) was synthesized by the reaction of H20Cl and hexadecyldimethylamine. The characteristics of H20C16 N were determined by FT‐IR, ¹H NMR and TGA. The molecular and molecular weight distribution of H20C16 N were determined by Gel Permeation Chromatography (GPC) and the surface activities of H20C16 N including surface tension (γ) and the critical micelle concentration (CMC) were measured at 25 °C. The H20C16 N reduced the surface tension of water to 30.81 mN/m at concentration levels of 7.94 × 10^?5 mol L^?1 and micellization free energies of the quaternary ammonium salt in its solution showed a good tendency towards adsorption at interfaces. The H20C16 N was applied to the silk fabric. An antimicrobial test of the treated fabrics against Escherichia coli and Staphylococcus aureus was carried out. SEM and XPS analysis were performed to study the dispersion of H20C16 N onto the fabric. All results exhibited excellent antibacterial properties of the hyperbranched polyester quaternary ammonium salt.     

Moisture-cured polyurethane based on polyester and polycarbonate polyols

Moisture-cured polyurethanes were prepared by reacting toluene diisocyanate and sebacic acid-based hydroxy esters such as ethylene glycol sebacate, propylene glycol sebacate, diethylene glycol sebacate, and polyester polyols such as poly(ethylene glycol sebacate), poly(propylene glycol sebacate), poly(diethylene glycol sebacate), and poly(butane diol sebacate). The effect of molecular weight of the esters on film properties and the catalytic effect of 3–5% triethylamine, triethanolamine, and 2-diethylaminoethanol on curing of such films were investigated. Polyurethanes were also prepared using a blend of poly(butane diol carbonate) polyol with polyester polyols. Best polyurethane compositions were obtained when sebacic acid-based polyester polyols were blended with poly(butane diol carbonate) polyol in the ratio of 3:2. These polyurethanes show good tensile strength (120–215 kg/cm²) and elongation (340–460%) properties, having high melting points (247–268°C) and good resistance to solvents and chemicals. Moreover, they are colorless and transparent.     

Novel heat resistant methyl‐tri(phenylethynyl)silane resin: Synthesis,characterization and thermal properties

Methyl‐tri(phenylethynyl)silane (MTPES) was successfully synthesized by the reaction of lithium phenylacetylide with methyltrichlorosilane. The structure was characterized by HRMS, FTIR, ¹H‐NMR, ¹³C‐NMR, ²⁹Si‐NMR, and elementary analysis. Thermal cure process was monitored by DSC, DMA, and FTIR. MTPES was heated to free flowing liquid around 130°C and thermally polymerized at 327–377°C to form thermoset. Thermal and oxidative properties were evaluated by TGA analysis. Thermoset exhibits extremely high heat‐resistance and TGA curve in nitrogen shows the temperature of 5% weight loss (Td₅) of 695°C and total weight loss at 800°C of 7.1%. TGA shows a high Td₅ of 565°C even in air, although the total weight loss at 800°C was 56.1% of the initial weight, much higher than that in nitrogen. The high heat resistance of MTPES was ascribed to crosslinking reaction concerning ethynyl groups. Aging studies performed at elevated temperatures in air on a thermoset showed that MTPES is oxidatively stable to 300°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2488–2492, 2006