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61.
先用逐步聚合反应法以聚乙二醇(PEG)、甲苯二异氰酸酯(TDI)、甲基丙烯酸羟乙酯(HEMA)等为原料制备出吸水性聚氨酯大分子反应型树脂(PU)。该树脂与丁腈橡胶(NBR)混合,制备出PEG接枝NBR主链的新型耐盐型遇水膨胀橡胶(WSR)。论文研究了PU用量、聚丙烯酸钠(SAP)用量、过氧化二异丙苯(DCP)用量及循环浸泡次数对WSR力学性能和最大质量膨胀倍率(ΔWe)的影响。研究结果表明,随着吸水树脂中PU树脂相对含量的升高,WSR力学性能提高,ΔWe增大。当PU完全代替SAP时,DCP含量越高其力学性能及ΔWe越低,当DCP含量为2份时ΔWe保持在2.04倍以上,WSR的重复吸水膨胀倍率保持在98%以上。 相似文献
62.
An experimental study was conducted to investigate the effect of pressure-cycling on adhesive bond fracture energy of polyurethane/aluminum adhesive bond joints. Initially, two types of peel tests were conducted to characterize adhesive bond strength and challenges associated with pre-mature polyurethane cracking and failure during these tests are discussed. A modified double cantilever beam (MDCB) specimen configuration was specially designed and opening-mode loading conditions were employed to determine the interfacial adhesive bond energy (GC). The test specimens were pressure-cycled in water-filled tanks for 1 to 4 weeks with an increment of 1 week. The GC of pressure-cycled specimens was compared with both control and water-soaked samples (without pressure-cycling). The results indicated that pressure-cycling decreased GC values to those of the control and water-soaked samples: hence, prolonged pressure-cycling could be problematic to polymer/metal adhesive bonds of hardware installed outboard of submarine pressure hulls. 相似文献
63.
Shishan Wu Aimin Cheng Hongyan Hua Jian Shen 《Polymer-Plastics Technology and Engineering》2013,52(6):685-689
The intercalated nanocomposites of polyurethane (PU) with organic-montmorillonite (OMMT) treated by cetryltrimethyl ammonium bromide was prepared. The interlayer spacing of PU/OMMT nanocomposites was 3–4 nm. The interface interaction of PU/OMMT nanocomposites was improved compared to that of PU/montmorillonite (MMT) composites. The orderly arrangement of the PU chains was hindered because of strong interface interaction between the silicate layers dispersed in the nanometer and PU chains. By adding 2 wt% OMMT to PU, tensile strength and tear strength of the PU/OMMT composites were increased from 10.5 MPa and 36.4 KN/m to 13.8 MPa and 42.2 KN/m, respectively. The tensile strength and tear strength increased with OMMT content firstly, reaching its maximum when the OMMT content was 8 wt%. After that, the tensile strength and tear strength decreased with the further increase of the OMMT content. Compared to that of PU, the elongation at break of the PU/OMMT nanocomposites increased, indicating that the stretch of PU/OMMT nanocomposites increased. 相似文献
64.
Mir Mohammad Alavi Nikje Amir Bagheri Garmarudi 《Polymer-Plastics Technology and Engineering》2013,52(10):1101-1107
Waste polyurethane rigid foam (PUF) is recycled by the glycolysis process. The recycled product is used in a polyol blend, applied in a new foam formulation. Polyurethane rigid foams formulated by recycled polyols are highly dense compared to rigid foams formulated by virgin polyols. As these foams are mostly used in insulation, they make an extra mass to the main product or system that is insulated. Therefore, it is important to decrease their density as much as possible. Some density modifiers such as starch, sucrose, and REZOL® IL800 were investigated to recognize their effect on PUF's density. 相似文献
65.
Mir Mohammad Alavi Nikje Amir Bagheri Garmarudi Moslem Haghshenas 《Polymer-Plastics Technology and Engineering》2013,52(11):1213-1217
This article reports on the properties of polyurethane rigid foams, which are used as insulating materials. Most polyurethane rigid foams, derived from cellular polymers, are unstable and tend to crack when acted upon by external forces. These foams are classified as a subgroup of cellular polymers, and thus their low stabilization levels can be partly explained by the fact that they contain cells. In these experiments, we attempted to add talc, to polyurethane rigid foams, as a filler, in an attempt to investigate its effect on the physical properties of the constructed foams in both horizontal and vertical directions. Physical and comparative tests were performed on various compositions of polyurethane foam to chart their insulating capabilities, and our comparative analysis indicated that advances had been achieved with respect to some of its properties. 相似文献
66.
Rati Ranjan Nayak Gyanjit Ray Subasini Lenka 《Polymer-Plastics Technology and Engineering》2013,52(5):503-508
The mixed ester polyol (MEP) is obtained from refined soybean oil on treatment with glycerol at 210°C in presence of lithrage. The probable structure of MEP was established by IR spectra. The polyurethane synthesized from MEP and diphenyl methane diisocyanate (DPMDI) with varying NCO:OH ratios were reacted with cardanol-o-aminophenol dye using ethyleneglycol dimethacrylate (EGDM) as a cross-linking agent and benzoyl peroxide as initiator. The PU was thoroughly characterized by IR spectroscopy. The thermal behavior of the Interpenetrating polymer networks was characterized by TG and the Morphology was studied by XRD studies. 相似文献
67.
Mir Mohammad Alavi Nikje Fatemeh Haji Agha Mohammadi 《Polymer-Plastics Technology and Engineering》2013,52(8):818-821
Microwave-assisted (MW-assisted) glycolysis of waste-flexible polyurethane (PU) foams using pentaerythritol in combination with glycerin and sodium hydroxide as a PU bond degradation reagent is reported. Split phases appeared after complete foam digestion. The upper phase contained recycled polyol, and the lower phase was a brown liquid with highly functionalized oligomers, amines and unreacted degradation reagents and showed potential for application in rigid polyurethane foam formulation. Our studies showed the dependence of recovered polyol assay to the additional MW irradiation and amine-free polyol were achieved in high yields and purities. 相似文献
68.
Jian Guo 《Polymer-Plastics Technology and Engineering》2013,52(12):1266-1272
Nanosilica particles were dispersed into polymer diols by high pressure shearing homogenizer (HPSH), then polyurethane nanocomposites were prepared via in-situ polymerization of diphenylmethane diisocyanate (MDI) and polymer diols. FTIR analysis indicated that the -NCO groups of MDI had reacted with the hydroxy on the surface of nanosilica during in-situ polymerization. TGA suggested that polyurethane/nanosilica composites obtained by in-situ polymerization had better thermal stability than pure polyurethane. Meanwhile, the tensile and dynamic mechanical properties of the samples prepared by HPSH were superior to those by directly ultrasonic dispersing nanosilica, accompanied by more homogeneous dispersion of nanosilica particles in the polymer matrix. 相似文献
69.
S. Manjunath Yadav K. V. Arun S. Basavarajappa Narendranath S. Santosh Kumar 《Polymer-Plastics Technology and Engineering》2013,52(13):1351-1356
In this work the moisture absorption capability, compressive properties, collapse modes of various types of composite sandwich structures are reported. The tested sandwich structures were constructed with varieties of hybridized skin materials and different compositions of the core materials. The moisture absorption, Flatwise compression and Edgewise compression tests are conducted for core as well as sandwich structures. Comparisons of results have been between the hybridized and non-hybridized sandwich structures. Two modes of collapse were noticed in the Edgewise compressive test, one of which being progressive end-crushing of the sandwich structure featured by significant crash energy absorption. This feature was highly desired for the parts of transportation vehicles. Microscopic analysis has been carried out to know the nature of failure under compressive loads. It has been observed that with increasing the debonding strength of the core–face interface, the failure mode changes from unstable collapse mode stable progressive crushing. 相似文献
70.
A new disk-type viscous pump, with radial pumping grooves on its stator, is described and its performance analyzed. Its flow rate and discharge pressure relationship is found to be linear. Two proposed viscous pumps of this new design having slightly different dimensions are considered and compared to the recently reported design utilizing multilobes. Analyses on these two proposed pumps show that this new design exhibits higher flow rate characteristics than the recent multilobe design for the same pump size and rotor–stator clearances. 相似文献