Preparation and properties of polymide foams

Catalysts for the raction of aromatic isocyanates with aromatic anhydrides to form imides were investigated using a model reaction. Alkali metal acetylacetone chelate compounds exhibited good catalytic efficiency and selectivity in dimethyl sulfoxide (DMSO). These catalysts were used for the preparation of polymide foams. The resulting foams exhibited excellent fire resistance and thermal stability. © 1994 John Wiley & Sons, Inc.     

Effect of different isocyanates on the properties of soy‐based polyurethanes

New types of polyurethanes were prepared by reacting soybean oil‐based polyol and different isocyanates. The polyurethanes can be used as foams, elastomers, coatings, adhesives, etc. Their properties strongly depend on crosslinking density and the structure of isocyanates. Aromatic triisocyanates impart the highest density, glass transition, modulus, and tensile strength, but have the lowest elongation at break, swelling in toluene, and impact resistance. Aliphatic triisocyanates and diisocyanates give rubbery materials with the highest elongation at break, highest swelling, and the lowest tensile strength. Polyurethanes with aromatic and cycloaliphatic diisocyanates were similar in properties, with values between those of the two groups. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2912–2916, 2003     

液压支架柱窝填充物用自结皮型聚氨酯材料的开发研究

以三官能度聚醚多元醇和混合异氰酸酯为主要原料,制备了适用于目前矿用液压支架柱窝填充物的自结皮型聚氨酯材料,讨论了小分子交联剂、泡沫稳定剂、催化剂、阻燃剂等助剂对材料性能的影响。结果表明,通过不同小分子交联剂搭配使用,可使自结皮表面具备良好的力学性能;通过合适的泡沫稳定剂的选择,可使制品表面达到光滑无气泡;采用自制复合催化剂调控发泡速率,可使制品达到3 min开模要求;通过固体阻燃剂与液体阻燃剂搭配使用,可使泡沫达到离火自熄。     

Physical properties of water‐blown rigid polyurethane foams from vegetable oil‐based polyols

Fifty vegetable oil‐based polyols were characterized in terms of their hydroxyl number and their potential of replacing up to 50% of the petroleum‐based polyol in waterborne rigid polyurethane foam applications was evaluated. Polyurethane foams were prepared by reacting isocyanates with polyols containing 50% of vegetable oil‐based polyols and 50% of petroleum‐based polyol and their thermal conductivity, density, and compressive strength were determined. The vegetable oil‐based polyols included epoxidized soybean oil reacted with acetol, commercial soybean oil polyols (soyoils), polyols derived from epoxidized soybean oil and diglycerides, etc. Most of the foams made with polyols containing 50% of vegetable oil‐based polyols were inferior to foams made from 100% petroleum‐based polyol. However, foams made with polyols containing 50% hydroxy soybean oil, epoxidized soybean oil reacted with acetol, and oxidized epoxidized diglyceride of soybean oil not only had superior thermal conductivity, but also better density and compressive strength properties than had foams made from 100% petroleum polyol. Although the epoxidized soybean oil did not have any hydroxyl functional group to react with isocyanate, when used in 50 : 50 blend with the petroleum‐based polyol the resulting polyurethane foams had density versus compressive properties similar to polyurethane foams made from 100% petroleum‐based polyol. The density and compressive strength of foams were affected by the hydroxyl number of polyols, but the thermal conductivity of foams was not. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

IPDI及MDI型聚氨酯预聚体中游离二异氰酸酯含量测定

合成了异佛尔酮二异氰酸酯（IPDI）型及二苯基甲烷二异氰酸酯（MDI）型无溶剂聚氨酯（PU）预聚体。利用高效液相色谱仪，建立了IPDI型及MDI型PU预聚体中游离二异氰酸酯单体含量的检测方法，并用在所合成PU预聚体中游离二异氰酸酯单体测定。结果表明，该方法能定量测定出IPDI型及MDI型PU预聚体中游离二异氰酸酯的含量，且具有良好的稳定性和线性，相关性系数均达到0．9999。     

2-芳氧基-噻吩并[2,3-d]嘧啶-4（3H）-酮衍生物的合成

采用串联氮杂Wittig反应,合成了5种未见文献报道的2-芳氧基-噻吩并[2,3-d]嘧啶-4（3 H）-酮衍生物。首先由膦亚胺与芳基异氰酸酯反应得到碳二亚胺,再与取代酚在碳酸钾的催化下反应得到目标化合物,收率为62%～85%,并采用元素分析、IR、MS、1 HNMR等手段对目标化合物的结构进行了确证。     

汽车隔音垫用聚氨酯软质高回弹泡沫的吸音性能研究

通过驻波管法测试不同隔音垫聚氨酯软质高回弹泡沫的吸声系数,结合显微镜对泡沫的力学特性和形态进行观察和分析。研究结果表明,泡沫在低频区的吸声系数随厚度的增加而提高,而在高频区则有所减弱;泡沫的吸声系数随密度增加而提高;泡孔形态对泡沫的吸声性能有显著影响,细密而均一的泡孔有利于声能的吸收;不同异氰酸酯由于反应性和结构上的差异,泡沫也表现出不同的吸声特性;高压发泡生产的泡沫峰值吸声频率稍向高频区移动,复合乙烯–醋酸乙烯共聚弹性体（EVA）后泡沫的峰值吸声频率稍向低频区移动。     

Glycolysis of Waste Polyurethane Integral Skin Foams from Steering Wheel

As polyurethane integral skin foams are widely used in the automotive industry, in order to decrease the amount of waste disposal of these foams, chemical recycling is preferred as a useful method to achieve both targets: 1) making the industry more compatible with the environment, and 2) defining an economic progress. In this research it has been tried to reconvert integral skin PUF to raw materials by glycolysis. A mixture of diethylene glycol and diethanol amine was used as a solvent system. The product's specifications were analyzed and an amount of recycled polyol usable in foam formulation was adjusted.     

Highly flame‐retardant bio‐based polyurethanes using novel reactive polyols

Poor flame retardancy of polyurethanes (PU) is a global issue as it limits their applications particularly in construction, automobile, and household appliances industries. The global challenge of high flammability of PU can be addressed by incorporating flame‐retardant materials. However, additive flame‐retardants are non‐compatible and depreciate the properties of PU. Hence, reactive flame‐retardants (RFR) based on aliphatic (Ali‐1 and Ali‐2) and aromatic (Ar‐1 and Ar‐2) structured bromine compounds were synthesized and used to prepare bio‐based PU using limonene dimercaptan. The aromatic bromine containing foams showed higher close cell content (average 97 and 100%) and compressive strength (230 and 325 kPa) to that of aliphatic bromine containing foams. Similar behavior was observed for a horizontal burning test where with a low concentration of bromine (5 wt %) in the foams for Ar‐1 and Ar‐2 displayed a burning time of 12.5 and 11.8 s while, Ali‐1 and Ali‐2 displayed burning time of 25.7 and 37 s, respectively. Neat foam showed a burning time of 74 s. The percentage weight loss for neat PU foam was 26.5%, while foams containing 5 wt % bromine in Ali‐1, Ali‐2, Ar‐1, and Ar‐2 foams displayed weight loss of 11.3, 14, 7.9, and 14%, respectively. Our results suggest that flame retardant PU foams could be prepared effectively by using RFR materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46027.     

Conducting polymerized high‐internal‐phase emulsion/single‐walled carbon nanotube nanocomposite foams: Effect of the aqueous‐phase surfactant type on the morphology and conductivity

Poly(styrene‐co‐divinylbenzene)/single‐walled carbon nanotubes (SWCNTs) polymerized high‐internal‐phase emulsion (polyHIPE) nanocomposite foams were successfully synthesized with various types of aqueous‐phase surfactants. The effects of anionic, cationic, nonionic, and mixed surfactants on the morphology and electrical conductivity of the resulting nanocomposite foams were investigated. The use of an anionic surfactant, sodium dodecylbenzesulfonate (SDBS), did not completely result in the typical polyHIPE nanocomposite foam microstructure because of the partial instability of the high‐internal‐phase emulsion. The nanocomposite foams synthesized by nonionic surfactants, that is, Pluronic F127 and Triton X‐100, and the cationic/anionic mixture, cetyltrimethylammonium bromide/SDBS, exhibited the proper morphology, but the resulting nanocomposite foams were electrically insulators. Interestingly, the use of a Gemini‐like surfactant, sodium dioctylsulfosuccinate (SDOSS), significantly improved both the typical morphology and electrical properties of the resulting nanocomposite foams because of the probable stronger interactions of SDOSS molecules with SWCNTs. The typical morphology of the nanocomposite foam synthesized with the SDOSS/F127 mixed surfactant was significantly improved, but the electrical conductivity decreased to some extent compared with the SDOSS‐synthesized nanocomposite foams. This behavior was attributed to an increase in the tunneling length of the electrons between adjacent SWCNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43883.     

阻燃剂在聚氨酯自结皮泡沫塑料中的应用

分别采用三（氯异丙基）磷酸酯（TCPP）、膨胀石墨（EG）和阻燃聚合物聚醚多元醇（POP）三种阻燃剂制备聚氨酯自结皮泡沫（ISF）塑料。探讨了TCPP,EG和POP对聚氨酯ISF塑料的力学性能和阻燃性能的影响。结果表明：以POP为阻燃剂制备的聚氨酯ISF塑料,力学性能较好,工艺稳定性及综合性能优于其他两种阻燃剂制备的聚氨酯ISF塑料。当POP与聚醚EP-330N的质量比为70∶30时,制品的拉伸强度为17MPa,伸长率为125%,压陷硬度为76.5 shao A,氧指数为25%。因此,POP可广泛应用于聚氨酯ISF塑料。     

The analysis of rigid polyurethanes by chemical ionization mass spectrometry

Methods for the elucidation of the chemical components of polyurethane foams are described. Foam samples of 50 mg were hydrolyzed in aqueous base and the resulting mixture of polyols and polyamines was analyzed by chemical ionization mass spectrometry (CI-MS) and high-pressure liquid chromatography (HPLC). The aromatic polyamines, which were separated by HPLC, produced few fragment ions under methane chemical ionization and were identified without difficulty. Each propoxylated homolog in the mixture of polyols was detected by CI-MS techniques, and approximate molecular weight profiles are presented for each polyol studied. Chemical ionization spectra are listed for samples of standard polyols and of base-hydrolyzed isocyanates. The hydrolysis products from urethane foam formulations were easily related to the standard compounds via CI-MS. These methods should be applicable to polymeric materials containing urethane, urea, and ester link-ages.     

蓖麻油酸镧对聚氨酯自结皮泡沫性能的影响

采用硝酸镧、蓖麻油酸为原料, 利用复分解法制备了蓖麻油酸镧。以蓖麻油酸镧作为催化剂, 作用于全水发泡聚氨酯自结皮泡沫材料, 考察了蓖麻油酸镧对全水发泡聚氨酯自结皮泡沫材料性能的影响。采用傅里叶红外光谱仪、紫外可见分光光度计、生物显微镜、电子万能试验机等进行表征, 结果表明蓖麻油酸镧对全水发泡聚氨酯自结皮泡沫材料的影响作用明显, 稀土元素的加入使泡沫材料的体系结构发生变化。加入蓖麻油酸镧后可明显缩短泡沫的脱模时间, 改善了泡沫强度和表皮硬度, 对形成稳定良好的泡孔结构有一定的促进作用, 添加0.3份和0.6份的蓖麻油酸镧制取的泡沫泡孔形态较好。     

双[(N-芳基脲基)苯基]二硫化物的合成与生物活性

由双（4-氨基-2-氯苯基）二硫醚与芳基异氰酸酯反应,合成了11个不同取代的双[（N-芳基脲基）苯基]二硫化物,结构经IR、MS和^1H NMR确定。初步的生测结果表明目标化合物3f、3k具有一定的除草活性．3i对南方粘虫具有杀虫和拒食活性,3f和3h对黄瓜白粉病有一定的抑制作用。     

Reaction behaviour of monomeric β-ketoesters

Summary The addition of 2-acetoacetoxyethyl methacrylate (AAEMA) to aromatic isocyanate such as phenyl isocyanate or tolylene 2,4-diisocyanate, and the Knoevenagel condensation of AAEMA with aromatic aldehydes, respectively, yield polymerizable products. These monomers were characterized by elemental analyses, IR, ¹H NMR and partially by ¹³C NMR spectroscopy. The radical polymerization of synthesized AAEMA-isocyanates adducts forms polymeric blocked isocyanates. The Knoevenagel condensate of AAEMA with benzaldehyde is radically polymerizable and tends to crosslink during its homopolymerization.     

Physical Properties of Polyurethanes Produced from Polyols from Seed Oils: II. Foams

Rigid polyurethane (PU) foams were prepared using three North American seed oil starting materials. Polyol with terminal primary hydroxyl groups synthesized from canola oil by ozonolysis and hydrogenation based technology, commercially available soybean based polyol and crude castor oil were reacted with aromatic diphenylmethane diisocyanate to prepare the foams. Their physical and thermal properties were studied and compared using dynamic mechanical analysis and thermogravimetric analysis techniques, and their cellular structures were investigated by scanning electron microscope. The chemical diversity of the starting materials allowed the evaluation of the effect of dangling chain on the properties of the foams. The reactivity of soybean oil-derived polyols and of unrefined crude castor oil were found to be lower than that of the canola based polyol as shown by their processing parameters (cream, rising and gel times) and FTIR. Canola-PU foam demonstrated better compressive properties than Soybean-PU foam but less than Castor-PU foam. The differences in performance were found to be related to the differences in the number and position of OH-groups and dangling chains in the starting materials, and to the differences in cellular structure.     

硬质自结皮聚氨酯泡沫

介绍了用于家具的硬质自结皮聚氨酯泡沫,包括原料配方、成型工艺及制品性能。     

Branched polyols based on oleic acid for production of polyurethane foams reinforced with bamboo fiber

Fatty acids and bamboo fiber (BF) are abundant and renewable materials that have great potential application in the production of high-valued chemical products. In this work, polyurethane foams (PUFs) with remarkable mechanical and thermal properties were synthesized using OAPs (polyols-based on oleic acid (OA), an important fatty acid) and polymeric isocyanates. PUFs were reinforced with BF. Novel OAPs were prepared from OA through a process consisting of hydroxylation, carboxylation, and esterification. The strategy afforded branched polyols with high content of primary hydroxyls. Phthalic anhydride was used as a modifying agent to improve the properties of OAPs. Physicochemical properties of the polyols were characterized by standard methods (analyses of hydroxyl number, viscosity, acid value, density, and water content) and instrumental analysis (gel permeation chromatography, Fourier transform infrared spectroscopy, and thermogravimetry). The mechanical properties of polyurethane foams made from the OAPs were improved by applying modified BF as filler. With BF having particle sizes of 250–500 μm, the compressive strength of composite foams increased from 0.45 to 0.66 MPa, and the flexural strength increased from 0.66 to 0.77 MPa. Surface modification of BF by alkali could enhance the interfacial interaction between the reinforcing fibers and foam matrix, resulting in greater mechanical strength of the PUFs. It also improved the thermal stability and dynamic thermomechanical properties of PUFs.     

New Intermediates and Dyes for Synthetic-polymer Fibres Derivatives of 2-Chloro-4-nitro-4‘-(N-β-hydroxyethyl-N- β-cyanoethylamino)azobenzene

Condensation of 2-chloro-4-nitro-4^t-(N-(β-hydroxyethyl-N-β-cy anoethylamino)azobenzene with various acid chlorides, chloroformates, isocyanates, isothiocyanates and reactive halogeno compounds gives dyes of excellent fastness to light and sublimation on polyester fibres.     

Desaminated glycolysis of water‐blown rigid polyurethane foams

Glycolysis reaction kinetics of methylene diphenyl diisocyanate‐based water‐blown polyurethane foams was examined by gel permeation chromatography. Glycolysates were reacted with butyl glycidyl ether to convert toxic aromatic amines to polyols, and their products were identified by ¹H‐NMR spectroscopy. To examine the quality of recycled polyol, polyurethane foams were reprepared using the virgin and recycled polyol mixtures with varying compositions. Cell structures and sizes of reprepared foams were similar to those of original ones when the recycled polyols were mixed up to 30 wt %. Density, thermal conductivity, and flexural strength of the reprepared foams were compared with those of the original ones, and no difference was observed below the recycled polyol concentration of 30 wt %. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2646–2656, 2000