纳米二氧化硅/聚氨酯酰亚胺复合泡沫材料的制备与性能

采用预分散法和一步法制备了纳米SiO2/聚氨酯酰亚胺(PUI)复合泡沫材料,考察了纳米SiO2对PUI发泡过程的影响,研究了纳米SiO2/PUI复合泡沫材料的泡孔结构及性能。结果表明,在PUI发泡过程中,随着纳米SiO2用量的增加,复合泡沫材料的开孔率增大,可有效防止泡沫收缩,且密度也减小;当纳米SiO2用量为10份时,纳米SiO2/PUI复合泡沫材料具有比较均匀的泡孔结构,且具有较高的开孔率、良好的阻燃性和热稳定性;柔软性泡沫还具有较好的吸声性能     

异氰酸指数对聚氨酯酰亚胺泡沫结构与性能的影响

采用一步法制备了结合聚氨酯泡沫和聚酰亚胺泡沫优点于一体的聚氨酯酰亚胺(PUI)泡沫,研究了异氰酸指数对聚氨酯酰亚胺泡沫微观形貌、力学性能、热稳定性及阻燃性能的影响。结果表明,当异氰酸指数为1. 25时,聚氨酯酰亚胺泡沫的泡孔形态更为规整均匀,并且压缩强度、热稳定性以及阻燃性能均达到最佳。通过调节异氰酸指数得到的性能优异的PUI泡沫将在建筑保温领域有着良好的应用前景。     

HCFC-141b对聚氨酯酰亚胺泡沫材料结构与性能的影响

以多异氰酸酯、芳香二酐和蓖麻油为原料,采用聚氨酯预聚体法制备聚氨酯酰亚胺（PUI）泡沫材料,分析了物理发泡剂1,1二氯1一氟乙烷（HCFC-141b）对泡沫材料的化学结构、泡孔结构、开闭孔率、表观密度、体积膨胀率、力学性能和热性能的影响。结果表明,HCFC-141b的添加量并不改变PUI泡沫材料的化学结构和热性能;当HCFC-141b添加量从零增加到10 %时,材料的平均泡孔直径、开闭孔率和体积膨胀率增加;而表观密度和压缩强度降低。     

APP对硬质聚氨酯-酰亚胺泡沫泡孔结构及力学性能的影响

采用聚酰亚胺(PI)预聚法,合成由聚磷酸铵(APP)阻燃的硬质聚氨酯-酰亚胺泡沫塑料。分析了APP添加量对泡孔结构、泡沫结构参数、力学性能的影响以及三者之间的关系,并通过幂次法则建立起压缩性能、冲击性能与泡沫密度之间的关系。结果表明:随着APP添加量的增加,硬质聚氨酯-酰亚胺泡沫塑料的泡孔孔径和冲击强度减小,而泡沫密度、压缩强度和压缩模量均增大;冲击强度、压缩强度、压缩模量与泡沫密度之间的密度指数分别为-1.688、1.062和0.934;冲击性能和压缩性能与泡孔结构和孔隙率有密切关系。     

笼状硫代磷酸酯对聚氨酯泡沫性能的影响

以多异氰酸酯、硫代笼状季戊四醇磷酸酯(SPEPA)、聚醚多元醇为主要原料,采用一步法和自由发泡工艺制备SPEPA阻燃硬质聚氨酯泡沫塑料(RPUF)。通过电子扫描显微镜(SEM)、氧指数、冲击强度、压缩强度、热稳定性等测试,研究了SPEPA对泡沫的泡孔结构、阻燃性能、力学性能及热稳定性的影响。结果表明:随SPEPA含量的增加,SPEPA改性RPUF的平均泡孔直径减小,且SPEPA在一定程度上提高了RPUF的阻燃性能。阻燃RPUF的力学性能呈先上升后下降趋势,当SPEPA质量分数为5%时,力学性能最好。SPEPA阻燃RPUF获得了较高的热稳定性,残炭量从9.3%增加至33.1%。     

医用聚氨酯亲水泡沫的制备工艺研究

分别采用聚醚多元醇(PPG)与二苯基甲烷二异氰酸酯(MDI)一步法、PPG与2,4-甲苯二异氰酸酯(TDI)一步法、TDI亲水预聚体二步法等3种反应体系制备聚氨酯亲水泡沫。通过吸液倍率、亲水性、保水倍率、溶胀率、硬度及孔结构等性能对比了3种体系泡沫,得到了二步法制备工艺最适合用作制备聚氨酯亲水软泡的结论,为实现聚氨酯泡沫敷料国产化奠定基础。     

医用聚氨酯亲水泡沫的制备工艺研究

分别采用聚醚多元醇(PPG)与二苯基甲烷二异氰酸酯(MDI)一步法、PPG与2,4-甲苯二异氰酸酯(TDI)一步法、TDI亲水预聚体二步法等3种反应体系制备聚氨酯亲水泡沫。通过吸液倍率、亲水性、保水倍率、溶胀率、硬度及孔结构等性能对比了3种体系泡沫,得到了二步法制备工艺最适合用作制备聚氨酯亲水软泡的结论,为实现聚氨酯泡沫敷料国产化奠定基础。     

发泡剂对合成革用复合泡沫材料性能的影响

选用聚四氢呋喃醚二醇(PTMG-1000)和异佛尔酮二异氰酸酯(IPDI)等为原材料制备了聚氨酯预聚体,并与匀泡剂、扩链剂和催化剂等混合制备了聚氨酯发泡浆料。将特殊处理的PP无纺毡浸渍于聚氨酯发泡浆料中,通过改变发泡剂水的质量分数制备了合成革用系列复合泡沫材料,并研究了泡孔结构、力学性能、热稳定性和动态力学性能。结果表明,随着发泡剂用量的增大,材料拉伸强度、撕裂强度、回弹性、剥离强度和热稳定性等均出现最佳值;硬度和密度等均下降;阻尼峰向高温方向移动;泡孔尺寸增大,尺寸均匀性变差。     

环境友好型阻燃高回弹聚氨酯软泡性能

开发环境友好型聚氨酯是目前聚氨酯（polyurethane,PU）泡沫塑料领域的热点课题。在PU中引入大豆分离蛋白质（soy protein isolate,SPI）,采用阻燃聚醚制备了环境友好型阻燃高回弹聚氨酯软泡。研究了SPI的不同添加方式及用量对聚氨酯软泡物理、力学、阻燃和生物降解性能的影响。结果表明,SPI以添加的方式而不是替代聚醚的方式加入软泡性能更好;少量添加SPI可以提高PU软泡的开孔率、密度、压陷硬度、舒适因子、回弹率和断裂伸长率,对压缩永久变形率、拉伸强度和极限氧指数影响不大。SPI改变了PU的硬段结构,可以有效促进聚氨酯泡沫的生物降解。     

聚氨酯-酰亚胺泡沫的制备及性能表征

以3,3′,4,4′-二苯甲酮四酸二酐(BTDA)、多亚甲基多苯基异氰酸酯(PAPI)、聚醚多元醇4110(P-4110)为单体,采用PI预聚体法制备了聚氨酯-酰亚胺泡沫。采用化学滴定法研究了反应时间和反应温度对预聚体合成反应的影响,并通过红外光谱、电子万能试验机和热重对产物的结构、力学性能和热稳定性进行了表征。结果表明当预聚反应时间为60min,反应温度为70℃时,BTDA的转化率最佳;聚氨酯-酰亚胺泡沫的力学性能和热稳定性优于聚氨酯泡沫。     

Effect of Dibutyltin Dilaurate and Triethanolamine Catalysts on Structure and Properties of Polyimide Foams

A series of rigid polyimide (PI) foams were prepared by the prepolymer method with pyromellitic dianhydride and polyaryl polymethylene isocyanate as the starting materials and dibutyltin dilaurate (DBTDL), and triethanolamine (TEOA) as catalysts. The effect of the two kinds of catalysts on the structure and properties such as molecular structure, cell morphology, density, mechanical properties, thermal properties, and flame retardancy of the resulting foams were characterized in detail. The experimental results showed that the PI foams prepared in this work possessed low density, good mechanical properties, outstanding thermal stability, and excellent flame retardancy. The thermal stability and flame retardancy were improved obviously with the increase of DBTDL content. While with the increase of the content of TEOA, the mechanical strength and apparent density of PI foams increased significantly. Therefore, different structure and performance of PI foams can be prepared by adjusting the content of these two catalysts. J. VINYL ADDIT. TECHNOL., 25:385–395, 2019. © 2019 Society of Plastics Engineers     

Mechanical and flame-resistance properties of polyurethane-imide foams with different-sized expandable graphite

Polyurethane-imide (PUI) composite foams with expandable graphite (EG) of different sizes were prepared by a polyimide prepolymer method. EG particles were treated with a silane coupling agent to improve compatibility with the foam. The effect of EG particle size on cell morphology, thermal degradation, flame-resistance and mechanical properties of PUI foams was investigated. Results showed that the mean cellular diameter of foams with EG particle was much higher than that of foams with surface-modified EG particle at the same filler loading. When filler particle diameter increased from 20 to 90 μm, the compressive strength, density and closed-cell ratio of foams increased, and then decreased when filler particle diameter further increased from 90 to 150 μm. Thermal stability of foams increased with the increasing filler particle diameter from 20 to 50 μm, and decreased with the increasing filler particle diameter from 50 to 90 μm. The limited oxygen index (LOI) value of foams with surface-modified EG increased from 24.8% to 32.1% when EG particle diameter was below 90 μm. Foams with surface-modified EG exhibited enhanced mechanical properties, thermal stability and flame resistance than foams with neat EG at the same loading.     

Thermal Stability and Flame Retardancy of Rigid Polyurethane Foams/Organoclay Nanocomposites

The thermal stability and flame retardancy of a new kind of rigid polyurethane (PU) foams/organoclay nanocomposites developed by our research group were investigated by using thermogravimetry analysis (TGA) and cone calorimeter test. Results indicate that compared with pure PU foams, rigid PU foams/organoclay composites show significantly enhanced thermal stability and flame retardancy. The reasons leading to the results were discussed in detail by relating with the morphology of the composites. The discussion suggests that the enhancement degree of thermal stability and flame retardancy of composites compared with that of PU foams coincides well with the sequences of gallery spacing of organoclay in the PU matrix.     

Preparation and Characterization of Sustainable Polyurethane Foams from Soybean Oils

Polyol derived from soybean oil was made from crude soybean oil by epoxidization and hydroxylation. Soy-based polyurethane (PU) foams were prepared by the in-situ reaction of methylene diphenyl diisocyanate (MDI) polyurea prepolymer and soy-based polyol. A free-rise method was developed to prepare the sustainable PU foams for use in automotive and bedding cushions. In this study, three petroleum-based PU foams were compared with two soy-based PU foams in terms of their foam characterizations and properties. Soy-based PU foams were made with soy-based polyols with different hydroxyl values. Soy-based PU foams had higher T _g (glass transition temperature) and worse cryogenic properties than petroleum-based PU foams. Bio-foams had lower thermal degradation temperatures in the urethane degradation due to natural molecular chains with lower thermal stability than petroleum skeletons. However, these foams had good thermal degradation at a high temperature stage because of MDI polyurea prepolymer, which had superior thermal stability than toluene diisocyanate adducts in petroleum-based PU foams. In addition, soy-based polyol, with high hydroxyl value, contributed PU foam with superior tensile and higher elongation, but lower compressive strength and modulus. Nonetheless, bio-foam made with high hydroxyl valued soy-based polyol had smaller and better distributed cell size than that using low hydroxyl soy-based polyol. Soy-based polyol with high hydroxyl value also contributed the bio-foam with thinner cell walls compared to that with low hydroxyl value, whereas, petroleum-based PU foams had no variations in cell thickness and cell distributions.     

Synthesis and properties of novel poly(urethane‐imide) dispersions based on 2,2‐bis[N‐(3‐hydroxyphenyl)phthalimidyl]hexafluoropropane

Imide units are incorporated into thermoplastic and solvent‐based polyurethane (PU) chains to improve the thermal stability of PU. However, these poly(urethane‐imide) (PUI) materials have poor processablity and suffer from solvent emission. To prepare easily processable and environmentally friendly PUI products, some waterborne PUIs are synthesized using a prepolymer process. A series of PUI dispersions with 25 wt % solid content, viscosities of 7.5–11.5 cps, and particle sizes of 63–207 nm was prepared. The composition–property relationship of PUIs, including the solubility behavior of PUI cast films, and their thermal and mechanical properties were established. The solvent resistance and tensile strength of PUI film increased with the number of imide groups. All PUIs exhibited improved thermal stability but not char yield as the temperature increased. The inclusion of a little imide increased the decomposition temperature of PUI while maintaining the elasticity of the polymer, revealing successful translation of PUI into the water‐based form. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of a green reactive flame-retardant polyether polyol and its application

The low-flame retardancy properties of pure rigid polyurethane (PU) foams hindered its practical application in many cases for the safety and environmental concern. Although rigid PU foams with flame retardants can achieve standard of fire resistance, addition of flame retardants in PU can worsen its mechanical properties, enlarge production cost, and induce safety problems. Therefore, green reactive flame-retardant polyether polyols (GPP) have been considered as one of the best solutions. In this work, the GPP by the ring-opening polymerization of the self-made environmentally friendly melamine resin (EFMR) with propylene oxide are synthesized with their hydroxyl number of 390 ~ 420 mg KOH/g, and the structure of GPP product was identified by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The flame-retardant rigid polyurethane foams (RPUFs) were successfully prepared with GPP as the polyol, the results showed that the addition of GPP can greatly improve the thermal stability and flame retardancy of the RPUFs prepared. The RPUF were prepared by fully GPP with 30.4% of limiting oxygen index and 350 kpa of compressive strength. These properties are qualified for commercial utilization. Therefore, this GPP provides great prospect in the development of specified flame-retardant PU materials.     

Preparation and characterization of microencapsulated ammonium polyphosphate and its synergistic flame‐retarded polyurethane rigid foams with expandable graphite

A facile and effective method for the preparation of microencapsulated ammonium polyphosphate (MAPP) by in situ surface polymerization was introduced. The ‘polyurethane‐like’ shell structure on the surface of MAPP was characterized by using Fourier transform infrared spectroscopy. The hydrophobicity and thermal behavior of MAPP were studied by using water contact angle tests and thermogravimetric analysis. The foam density and mechanical properties of polyurethane (PU) rigid foams were investigated. The flame retardancy of PU rigid foams formulated with MAPP was evaluated by using limiting oxygen index and cone calorimetry. The results show that MAPP can greatly increase the flame retardancy of PU materials. Also, there is a synergistic effect between MAPP and expandable graphite in flame retarding PU rigid foams. Moreover, the water resistance property of PU/MAPP composites is better than that of PU/ammonium polyphosphate. The morphology and chemical structure of PU/MAPP rigid foams after burning were systematically investigated. © 2013 Society of Chemical Industry     

Thermal and mechanical properties of poly(urethane‐imide)/epoxy/silica hybrids

Improving properties of polyurethane (PU) elastomers have drawn much attention. To extend the properties of the modified PU composite, here a new method via the reaction of poly(urethane‐imide) diacid (PUI) and silane‐modified epoxy resin (diglycidyl ether of bisphenol A) was developed to prepare crosslinked poly (urethane‐ imide)/epoxy/silica (PUI/epoxy/SiO₂) hybrids with enhanced thermal stability. PUI was synthesized from the reaction of trimellitic anhydride with isocyanate‐terminated PU prepolymer, which was prepared from reaction of polytetramethylene ether glycol and 4,4′‐diphenylmethane diisocyanate. Thermal and mechanical properties of the PUI/epoxy/SiO₂ hybrids were investigated to study the effect of incorporating in situ SiO₂ from silane‐modified epoxy resin. All experimental data indicated that the properties of PUI/epoxy/SiO₂ hybrids, such as thermal stability, mechanical properties, were improved due to the existence of epoxy resin and SiO₂. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Highly reinforcing and thermal stabilizing effect of imide structure on polyurethane foam

In order to improve the heat‐resistant property of polyurethane foams, a series of polyurethane‐imide foams (PUIFs) with different contents of the imide group were fabricated via the prepolymer foaming method. It was found that the PUIFs showed a closed cellular structure with almost circular cell shapes. With increasing content of imide groups, the cell wall thickness and apparent density of the foams gradually increased, and the cell size showed a trend of first increasing and then decreasing. All foams exhibited a multistage deformation response when subjected to compressive loading, and the compressive strength and modulus of the PUIFs were significantly improved by incorporation of the imide group, increasing by roughly 5500% and 6400% for the PUIF with 34.25 wt% imide groups, indicating the remarkable reinforcing effect of the imide group on the PUIF. TGA and dynamic mechanical analysis showed that with increase of the imide group content the thermal degradation temperatures, the char yield and the degradation activation energy for the PUIFs sharply increased, while the storage modulus (G′) and T_g were obviously improved, reaching 575 MPa and 283 °C respectively, much higher than that of most reported PU foams, indicating the remarkable enhancement of the thermal mechanical stability of the PUIF. The heat insulation of the PUI system was also enhanced by the incorporation of imide groups. Such PUIFs showed potential applications for use in high temperature environments. © 2018 Society of Chemical Industry     

Flame retardant,thermal, and mechanical properties of glass fiber/nanoclay reinforced phenol–urea–formaldehyde foam

To increase the toughness, flame retardancy, and compression strength of phenolic foams, glass fiber/nanoclay composites were prepared, and their mechanical property, cellular structure, thermal stability, and flame retardancy were investigated. The results show that the pulverization rate of phenolic foam decreases significantly by adding glass fibers and nanoclay. The impact strength of the composite foam significantly increases with increasing quantities of glass fiber and nanoclay, while the compression strength of the composite foam first increases and then decreases. The microstructure of the composite foam indicates that excessive glass fiber increases the number of open cells, while an appropriate quantity of nanoclay can control the cell size. Further, excessive clay increases the thickness of cell walls and the percentage of open cells. Nanoclay increases the thermal stability of the composite foam; this decreases the maximum heat release rate, total heat release, and total smoke release of the foam, thus reducing its fire hazards. Glass fiber and nanoclay demonstrate good synergistic effects and significantly increase the compression strength, thermal stability, and flame retardancy of the foam. Moreover, the addition of nanoclay and glass fiber–nanoclay decreases the average aperture of the cells. POLYM. COMPOS., 37:2323–2332, 2016. © 2015 Society of Plastics Engineers