喷涂缠绕保温管用全水发泡聚氨酯组合聚醚的研制

用聚醚多元醇A、聚醚二醇B、聚酯多元醇PS-2915、三乙醇胺、水和其他助剂制备了喷涂管道用全水发泡聚氨酯硬泡组合聚醚,并对其反应性能、黏度进行评价,对使用该组合聚醚和多异氰酸酯PM-200制得的聚氨酯泡沫材料的性能进行研究。结果表明,在合适的原料用量时,制得的组合聚醚黏度较低,与多异氰酸酯PM-200的反应速度满足喷涂管道生产工艺要求。当喷涂制得的聚氨酯泡沫单层厚度7 mm左右,泡沫体具有较高的粘接强度、较好的韧性和较低的导热系数,密度61 kg/m^3的泡沫压缩强度达到526 kPa。制得的喷涂管道产品满足GB/T 34611—2017要求。     

Specialty polyurethane soft segments. III. Synthesis and characterization of N-isopropyl polyether polyamine oligomers containing backbone urea or amide moieties

Primary polyether polyamine oligomers containing preformed urea or amide moieties in their backbones were converted to the corresponding N-isopropyl polyether polyamine oligomers (secondary amines) by reaction with acetone and hydrogen in the presence of a catalyst. The best results were from reactions carried out at about 150°C using a supported platinium or palladium catalyst in a fixed bed. Reactants and products were monitored by quantitative carbon-13 NMR, size exclusion chromatography, and amine titration. Perchloric acid titration was used to quantify the number of urea moleties per molecule. Amide backbone materials gave very little backbone degradation. However, some backbone degradation was observed with urea backbone materials, leading to products with lower molecular weights. These polyether polyamine oligomers, containing urea or amide moieties in their backbones, are useful in urethane/urea polymer systems. The lower reactivity of these secondary amines (toward polyisocyanates) results in their utility in a broader range of polyurethane fabrication technologies. © 1992 John Wiley & Sons, Inc.     

Influence of PEPA-containing polyether structure on fire protection of transparent fire-resistant coatings

Three kinds of novel PEPA-containing polyether flame retardants were synthesized by 1-oxo-4-hydroxymethyl-2,6,7-trioxa-l-phosphabicyclo [2.2.2] octane (PEPA), phosphorus oxychloride (POCl₃), and polyether with different structures (PEG, PPG, and PTMG). Their structures were confirmed by ¹H nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR). The solubility test showed that PEPA modified by polyethylene glycol (PEG) and polypropylene glycol (PPG) had better water solubility than that modified by poly(tetrahydrofuran) (PTMG). The decomposition process of PEPA-containing polyether flame retardants (PCPE) was studied by thermogravimetric analysis (TG) and derivative thermogravimetry. A possible mechanism was proposed to analyze the influence of polyether structure on the thermal degradation process of PCPEs. Afterward, the PEPA-containing polyether flame retardants were mixed with melamine formaldehyde resin to prepare the transparent fire-resistant coatings. The influences of polyether structure on the properties of the coatings were investigated in detail by fire protection test, TG, FTIR, X-ray photoelectron spectroscopy (XPS), and scanning electron microscope. It was found that the fire protection of the coating and foam structure of char layer were significantly improved when the number of carbon atoms in a unit of polyether chain was less. TG results showed that the chain unit of polyether with less carbon atom number could increase the residue weights of the coatings. FTIR and XPS result illustrated that the char layers were mainly composed of aromatic rings and phosphorus oxide, and the antioxidation and char-forming ability of coatings were enhanced effectively with the decrease in the number of carbon atoms in a unit of polyether chain.     

Degradation process of an industrial thermoplastic elastomer polyurethane-coated fabric in artificial weathering conditions

The aging of an industrial thermoplastic elastomer polyurethane (TPU)-coated fabric, based on a polyether diol and an aromatic diisocyanate, is studied in artificial weathering tests. It is noticed that the degradation of this TPU-coated fabric leads to a weight loss, to the formation of a reticulated layer in sample surface, and to a change of surface relief. The degradation layer and the surface relief have been observed by optical microscopy. The weight loss has been followed with aging time. The main degradation products causing weight loss are volatile. Therefore, they have been analyzed by gas chromatography–mass spectroscopy. The weight loss degradation takes place in the exposed part of the reticulated layer by volatile products emission, which implies the urethane and the polyether bonds. Water is involved in degradation process: without external water supply, weight loss is limited; with a permanent contact of vapor or liquid water, the weight loss rate is constant and depends on aging conditions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2525–2534, 1999     

Effect of crosslinking density on resilient performance of low‐resilience flexible polyurethane foams

Low‐resilience flexible polyurethane foams (FPUFs) with varying crosslinking densities, were synthesized from polyols, 4, 4′‐diphenyl methane diisocyanate (MDI‐100), and water. The effects of crosslinking agent content, the molecular weight (M_w) of polyether diol, and the ratio of (polyether triol)/(polyether diol) on the resilience performance of FPUFs were investigated. Results indicate that higher crosslinking density was beneficial to the increasing of recovery time. The recovery time of the FPUF using polyether diol with M_w of 400 was 24.3 s. It was 3.2 times longer compared with FPUF using polyether diol with M_w of 3000. Dynamic mechanical analysis (DMA) results showed that, FPUFs with high crosslinking density displayed viscoelasticity in a wider range of temperature. However, when molecular chains were longer enough, FPUFs with low crosslinking density also demonstrated significant viscoelasticity, which is owing to the excess of physical crosslinking points. The results in stress–strain cycling and recovery time experiments were consistent with the results of DMA. POLYM. ENG. SCI., 55:308–315, 2015. © 2014 Society of Plastics Engineers     

Effect of urea groups on reaction kinetics of polyurethane formation

Urea-containing polyurethane reaction systems, based on ethylene oxide-capped poly(propylene oxide) polyether diol, 1,4-butyldiol, uretonimine liquefied 4,4′-diphenyl-methane diisocyanate, and a biurea compound, were used to investigate the effect of urea groups on polyurethane bulk polymerization by using Fourier transform infrared spectroscopy. The biurea compound was a liquid biurea-capped poly(propylene oxide) polyether, which can mix well with the polyurethane systems. Catalysis of urea groups was observed clearly regardless of whether organotin catalyst was used. A catalytic mechanism was presented in this paper. © 1996 John Wiley & Sons, Inc.     

The influence of different glycerine purities on chemical recycling process of polyurethane waste and resulting semi‐products

Chemical recycling is the most favourable recycling method due to the possibility of polyol recovery. This work is dedicated to the utilisation of crude glycerine and polyurethane waste. It aims at determining the impact of the use of glycerine from the production of biodiesel with various degrees of purity as a cleavage agent on the decomposition process of polyurethane foam. The influence of glycerine purity on the chemical structure of recycling products was analysed using Fourier transform infrared and ¹H NMR spectroscopies and gel permeation chromatography. Hydroxyl and amine values were determined, and rheological measurements were performed. Glycerolysates showed minor structural differences due to the presence of amine groups and exhibited heterogeneous structure compared to original polyols. The ones obtained in decomposition using 84 and 99.5% glycerine had a lower viscosity below 0.45 Pa s at 50 °C and higher hydroxyl number of 183 and 220 mg KOH g^?1, respectively, compared to the ones obtained with glycerine purity of 40 and 62% due to a different chemical structure. All of the products of decomposition were defined as non‐Newtonian fluids, where viscosity depended on the shear rate. Selected glycerolysates were used in the production of cast polyurethanes with satisfactory mechanical properties. © 2018 Society of Chemical Industry     

Intercalation and exfoliation behaviour of clay layers in branched polyol and polyurethane/clay nanocomposites

The exfoliation of clay layers was realized in a tri‐hydroxyl branched polyether polyol by direct mixing and the corresponding exfoliated polyurethane/clay nanocomposite was prepared by further in situ curing. The effects of various surface‐modified organoclays and various polyol types on the intercalation and exfoliation behaviour of clay layers were investigated. The interaction between the polyol and clay and the mixing temperature plays an important role in the occurrence of exfoliation and intercalation. The relationship between rheological data of polyol/clay dispersion and the intercalation or exfoliation state of the clay was established. This provides a convenient and efficient way to evaluate the dispersion state of the clay. Based on the experimental results, a possible layer‐by‐layer exfoliation mechanism is proposed. Copyright © 2006 Society of Chemical Industry     

Kinetic Study of Polyurethane Reaction between Castor Oil/TMP Polyol and Diphenyl Methane Diisocyanate in Bulk

Polyols as precursors of crosslinked polyurethanes were prepared by alcoholysis between castor oil (CO) and Trimethylol propane (TMP). The alcoholysis reaction produced an equilibrium mixture of monoglycerides, diglycerides, and triglycerides of TMP and some free TMP. The polyol thus prepared was characterized using FTIR, Atmospheric Pressure Chemical Ionization (APCI) under positive ion mode and various analytical techniques. A series of bulk polyurethane polymerization reactions were then carried out using the polyol and Diphenyl methane diisocyanate (MDI) at 25°C, and were investigated using Fourier transform Infrared (FTIR) spectroscopy with different NCO/OH ratios, that is, 0.75, 1.0, and 1.25. All the reactions obeyed second order kinetics. Second order rate constants were calculated and found to be 2.49 × 10^?4 lit/eq. sec., 3.4 × 10^?4 lit/eq. sec. and 2.38 × 10^?4 lit/eq. sec. for NCO/OH ratio 1.25, 1.0, and 0.75, respectively.     

Development of a rigid polyurethane foam from palm oil

The reactions between polymeric diphenyl methane diisocyanate (polymeric MDI) and conventional polyols to produce foamed polyurethane products are well documented and published. Current polyurethane foams are predominantly produced from these reactions whereby the polyol components are usually obtained from petrochemical processes. This article describes a new development in polyurethane foam technology whereby a renewable source of polyol derived from refined–bleached–deodorized (RBD) palm oil is used to produce polyurethane foams. Using very basic foam formulation, rigid polyurethane foams were produced with carbon dioxide as the blowing agent generated from the reaction between excess polymeric MDI with water. The foams produced from this derivatized RBD palm oil have densities in excess of 200 kg/m³ and with compression strengths greater than 1 MPa. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 509–515, 1998     

Synthesis of palm oil‐based polyester polyol for polyurethane adhesive production

Palm oil‐based polyester polyol is synthesized by ring opening reaction on epoxidized palm olein by phthalic acid. The reaction is carried out in a solvent free and noncatalyzed condition with the optimal reaction condition at 175°C for 5 h reaction time. The physical state of the product is a clear bright yellowish liquid with low viscosity value of 5700–6700 cP at 25°C and pour point of 15°C. The chemical structure and molecular weight of the polyester polyol were characterized by FTIR, ¹H‐NMR, ¹³C‐NMR, and GPC. The optimal polyol with molecular weight of 36,308 dalton and hydroxyl value of 78.17 mg KOH/g sample was reacted with polymeric 4,4′‐methylene diphenyl diisocyanate (pMDI) at isocyanate index of 1.3 to produce polyurethane adhesive. The lap shear strength of the polyurethane adhesive showed two times higher than the commercial wood adhesives. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39967.     

Polydopamine functional reduced graphene oxide for enhanced mechanical and electrical properties of waterborne polyurethane nanocomposites

Waterborne polyurethane/polydopamine (PDA) functional reduced graphene oxide (WPU/PDRGO) nanocomposites were prepared by in situ emulsification method. The presence of a PDA layer and the partial reduction of GO by PDA were confirmed by FTIR, XRD, Raman spectra, and TGA. It was found that the interfacial PDA layers facilitated the dispersion of the PDRGO sheets in the WPU matrix and enhanced mechanical properties of the WPU matrix. The resulting WPU/PDRGO nanocomposite coatings show excellent electrical conductivity (9.9?×?10^?6–1.1?×?10^?4 S cm^?1) corresponding to a PDRGO content of 1–16 wt%. The obtained waterborne polyurethane/graphene nanocomposite dispersions are promising for anticorrosion, antistatic, conductive, and electromagnetic interference shielding coatings.     

异氰脲酸酯改性聚氨酯弹性体包覆层研究

为改进固体推进剂包覆层的耐烧蚀性能.以端羟基碳氮杂环氯化聚醚多元醇和改性液体,4,4'-二苯基甲烷二异氰酸酯(L-MDI)为主要原料,设计合成异氰脲酸酯改性聚氨酯弹性体(IMPUE),用于固体推进剂包覆层粘接体系.结果表明,IMPUE具有良好的力学性能,与普通聚氨酯弹性体相比,其热性能、阻燃性能及耐烧蚀性能明显提高,是...     

Synthesis and thermal properties of polyurethane–polysiloxane crosslinked polymer networks

Polysiloxane–polyurethane crosslinked polymer networks (PSI–PU) were synthesized in solution by polymerization of oligosiloxanes containing γ‐hydroxy propyl groups with polymethane polyphenyl polyisocyanate. Polyether‐based polyurethane and polyester‐based polyurethane were also prepared by a “one‐shot” method. Their thermal properties were studied by thermogravimetric analysis. It was observed that the thermal stability of PSI–PU was better than that of polyether‐based polyurethane and polyester‐based polyurethane, and an inert atmosphere had no effect on decomposition of polyurethanes below 350°C. It was found that polyurethane–polysiloxane crosslinked polymer networks decomposed slower in oxygen than in nitrogen in the temperature range of 350–550°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 310–315, 2003     

醇溶性聚氨酯胶粘剂的合成与性能研究

醇溶性聚氨酯(APU)胶粘剂是一种新型、环保的胶粘剂,它既克服了溶剂型聚氨酯(PU)胶粘剂毒性大的缺点,又克服了水性PU水挥发慢、影响生产效率和能耗大的缺点,是目前综合性能优良的新品种胶粘剂。采用聚醚二醇、甲苯二异氰酸酯、二羟甲基丙酸和三羟甲基丙烷为基本原料,用丙酮为溶剂合成了聚醚型阴离子APU胶粘剂。讨论了预聚反应-NCO/-OH的配比、交联体系、硅烷偶联剂KH-550的加料方式和扩链反应温度等因素对APU胶粘剂性能的影响。当初聚n(-NCO)/n(-OH)比值为6,扩链剂反应温度控制在(60±2)℃时,合成的聚醚型阴离子APU具有较好的力学性能和耐水性,而且贮存稳定性较好。     

A review of the literature on the gaseous products and toxicity generated from the pyrolysis and combustion of rigid polyurethane foams

The literature on rigid polyurethane foam has been reviewed with an emphasis on the gaseous products generated under various thermal decomposition conditions and the toxicity of those products. This review is limited to publications in English through 1984. Carbon monoxide (CO) and hydrogen cyanide (HCN) were the predominant toxicants found among more than a hundred other gaseous products. The generation of CO and HCN was found to increase with increasing combustion products from various rigid polyurethane foams. Lethality, incapacitation, physiological and biochemical parameters were employ as biological end points. In general, the combustion products generated from rigid polyurethane foam in the flaming mode appear from to be more toxic than those produced in the non-flaming mode. The LC₅₀ values for 30-min exposures ranged from 10 to 17 mg l^?1 in the flaming mode and were greater then 34 mg l^?1 in the non-flaming mode. With the exception of one case, in which a reactive type phosphorus containing fire retardant was used, the addition of fire retardants to rigid polyurethane foams does not appear to generate unusual toxic combustion products.     

Synthesis and electrochemical properties of redox active polyurethanes with ferrocene units in polyether soft segments

Electrochemical active segmented polyurethane with ferrocene units in polyether soft segments (PU‐S‐Fc) has been originally synthesized and identified by ¹H‐NMR spectra. Electrochemical behaviors of PU‐S‐Fc blending with lithium perchlorates were investigated by cyclic voltammetry. In N,N′‐dimethyl formide solution, PU‐S‐Fc exhibited normal cathodic and anodic peaks of the ferrocene/ferricinium (Fc/Fc⁺) couple. Compared with that of ferrocene molecules blended in ordinary polyurethane (PU‐B‐Fc), redox peaks of ferrocene units in PU‐S‐Fc were found to be broader, which may be ascribed to the weak adsorption of the polyurethane on the electrode surface. The influence of lithium perchlorate concentration on peak potentials indicated that supporting electrolytes played an important role in electrochemical redox of PU‐S‐Fc. In the solid state, PU‐S‐Fc/Li⁺ showed discernible redox peaks at temperatures higher than 60°C, and an exponential increase curve of electrochemical response with an increase of temperature was found. Temperature variations of the solid‐state ionic conductivity for PU‐S‐Fc/Li⁺ can be interpreted by the Arrhenius equation. The similarity between the temperature dependence of ionic conductivity and electrochemical response revealed that transport mechanism of ionic and redox species in the polyurethane matrix was controlled by the mobility of polyether chains. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2674–2680, 1999     

酚醛树脂改性聚氨酯/聚脲涂料的制备及其性能研究

通过二苯基甲烷二异氰酸酯(MDI50)与聚醚多元醇(1000D)合成异氰酸酯基封端聚醚多元醇预聚体(A组分),再与含有聚醚多元醇、端氨基聚醚、酚醛树脂和扩链剂的R组分反应,制备酚醛树脂改性聚氨酯/聚脲涂料。对其凝胶时间、表干时间、硬度、柔韧性、附着力及耐强酸性、耐强碱性、热性能和阻尼性能进行了测试。结果表明:当R组分中酚醛树脂含量为50%左右时,其涂膜拉伸强度由8.9 MPa提升至13.2 MPa,耐强酸性和阻尼性能得到提升,玻璃化转变温度由12 ℃提升至106 ℃;通过动态热机械分析仪预测了在较高频率下产物仍具有较高储能模量及损耗因子的变化趋势。     

Bituminous polyurethane network: Preparation,properties, and end use

Industrial‐grade bitumen (85:25) was treated with 4,4′‐diphenyl methane diisocyanate as a blocking agent to make it compatible with polyurethane resin. Optimization of treatment conditions for the bitumen such as isocyanate dose (～3 wt % of bitumen), reaction temperature (180°C), and treatment time (120 min) was done on the basis of estimating its residual acid value and unreacted ? NCO groups. Formation of the urethanized bituminous species after treatment resulted in a reduction in the glass‐transition temperature of the base bitumen from ?9.63°C to ?17.09°C and in moisture vapor transmission from 16.95 to 12.21 g 24 h^?1 m^?2. The bituminous networks were prepared from these treated/SBS‐modified treated bitumen and polyurethane prepolymers by in situ and conventional liquid blending methods. Lack of low‐temperature flexibility in the bituminous network made from the blending method restricted its use for waterproofing/sealing purposes. Modulated differential scanning calorimetry showed the presence of two overlapping glass‐transition temperatures and an endothermic peak in the in situ prepared networks similar to the base bitumen, evidence of a close intermixing of the bitumen constituents with the polyurethane phases. Rheological studies revealed that the SBS‐modified bituminous polyurethane network exhibited superior behavior than that of other systems in terms of stiffness and elasticity over a wide range of frequencies. The compounded bituminous networks satisfied the requirements of standard specifications and can be suitably used for waterproofing purpose and sealing of concrete joints. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 217–226, 2006     

Synthesis of Carbon‐Rich Hybrid Foam from GAP‐Modified Polyurethane

4,4′‐Diisocyanato diphenylmethane (MDI)‐based polyurethanes melt and start to burn at 150–200 °C. Mainly H₂O, CO₂, CO, HCN, and N₂ are formed. The new modified polyurethane shows a different pyrolysis behavior. GAP‐diol (glycidyl azide polymer), which was used as a modifying agent, is a well‐known energetic binder with a high burning velocity and a very low adiabatic flame temperature. The modified polyurethane starts to burn at approximately 190 °C because of the emitted burnable gases, but it does not melt. The PU foam shrinks slightly and a black, solid, carbon‐rich hybrid foam remains. TGA and EGA‐FTIR revealed a three‐step decomposition mechanism of pure GAP‐diol, the isocyanate‐GAP‐diol, and PU‐GAP‐diol formulations. The first decomposition step is caused by an exothermic reaction of the azido group of the GAP‐diol. This decomposition reaction is independent of the oxygen content in the atmosphere. In the range of 190–240 °C the azido group spontaneously decomposes to nitrogen and ammonia. This decomposition is assumed to take place partly via the intermediate hydrogen azide that decomposes spontaneously to nitrogen and ammonia in the range of 190–240 °C. The second decomposition step was attributed to the depolymerization of the urethane and bisubstituted urea groups. The third decomposition step in the range of 500–750 °C was attributed to the carbonization process of the polymer backbone, which yielded solid, carbon‐rich hybrid foams at 900 °C. In air, the second and the third decomposition step shifted to lower temperatures while no solid carbon hybrid foam was left. Samples of PU‐GAP‐diol, which were not heated by a temperature program but ignited by a bunsen burner, formed a similar carbon‐rich hybrid foam. It was therefore concluded that the decomposition products of the hydrogen azide, ammonia and mainly nitrogen act as an inert atmosphere. FTIR, solid‐state ¹³C‐NMR, XRD, and heat conductivity measurements revealed a high content of sp²‐hybridized, aromatic structures in the hybrid foam. The carbon‐rich foam shows a considerable hardness coupled with high temperature resistance and large specific surface area of 2.1 m²⋅g⁻¹.