Papers by Keyword: Polyurethane

Abstract: The polyurethane coatings containing different concentration of graphene oxide were prepared. Their physicochemical properties were characterized by XRD and SEM. The tribological behaviors were also investigated by ring-on-block tests. Results revealed that the TDI adsorb on the surface of GO through reaction with O-H. The COF were extremely sensitive to the GO concentration of PU coatings filled. The COF of pure PU coating was 0.185, whereas it is sharply decreased when 1.0 wt% GO was added. Smaller COF was obtained as the GO concentration increase and to minimize when GO concentration is 2.0 wt%. Friction reduced mechanism of GO was further investigated. Two reasons were responsible for this phenomenon. The one was that the GO itself possessed the capacity of anti-wear and friction reduction. Another one was the GO dispersed in the PU coatings could increase the strength of the coatings by the mean, which was similar to dispersion strengthening.

Abstract: Currently, composites with a polymer matrix are most widely used in various industries, including the oil and gas sector, as an alternative to traditional metal materials. The most widespread of non-metallic pipes in the Russian Federation are pipelines made of fiberglass. One of the clear advantages of polymeric materials over metal products is their corrosion resistance. At the same time, upon contact with liquids containing abrasive particles, composites with a polymer matrix can degrade with varying degrees of intensity. Such as type of degradation like hydroabrasive wear of pipelines is common and can lead to equipment failure. Various linings are applied to the inner surface of fiberglass pipes to minimize hydroabrasive wear. This study attempts to assess the durability of coated and uncoated composite polymer materials under conditions of hydroabrasive wear, as well as to compare the properties with other materials currently used in industry.

Abstract: Conventional steel springs have gradually been replaced with composite materials due to their inherit properties like high strength-to-weight ratio, relatively inexpensive ratio, and resistance against corrosion. Also, fiberglass reinforced plastic usages and its implementation is subjected in variety of fields such as vehicle and locomotive bogies, heavy commercial vehicles like vans and trucks. The current study looks at a composite material that can be used in the composite leaf spring suspension system. In this particular research, several blends of interpenetrating polymer networks (IPNs) have been used as the matrix material with the reinforcement of E-Glass fiber. The implemented combination blends are epoxy with polyurethane (EP), vinyl ester with polyurethane (VP) and epoxy and vinyl ester (EV). However, this research work also examines the characterisation and physical properties of the composite material leaf spring (CMLS) in narrow manner. Consecutively, tests were carried out for three types of composites by varying the various blend ratios of IPNs with the standard reinforcement of E-Glass fiber. Besides, to evaluate and compare their individual uniqueness, their physical characteristics tests like compression test, hardness test, tension and cyclic load parameters are found and their corresponding results were compared with each other.

Abstract: The microcapsules with inorganic/organic composites as capsule wall were prepared to optimize the performance of microcapsules. The MMT stabilized Pickering emulsion was used as template in the interfacial polymerization. TDI and EDA were polymerized at the oil-water interface to form MMT/PU composite as the capsule wall to encapsulate clove oil. Under the process condition of the dosage ratio of clove oil to TDI 5:1, the content of MMT 2%, and the reaction temperature 70 °C, the embedding rate of microcapsule could reach 92.31%. The average volume diameter of microcapsules was 49.4 μm. The microcapsules were regular and basically spherical shape, smooth surface and high elasticity. TGA showed that the thermal stability of essential oil was improved. The retention rates of clove oil in microcapsules after 40 days storage at 4 °C and 25 °C were more than 80%, indicating that clove oil microcapsules were relatively stable. The relative content of eugenol, the main component in clove oil decreased after storage, while the relative content of secondary components increased.

Abstract: High-performance plastics or engineering polymers have been actively studied for various microelectronic applications as the demand for faster processing speeds increases. Taking advantage of its high Young’s modulus ideal for inter-layer dielectric applications, polyurethane (PU), a class of linearly-segmented polymer primarily made by reacting isocyanate and polyol, were deposited on borosilicate glass and p-type Si (100) substrates via spin coating method utilizing epoxidized soybean oil as a bio-polyol replacement. Optical micrographs showed that 100% ESBO-based PU coatings exhibited homogeneous and superior quality coatings in contrast to 50% ESBO-and 100% petroleum-based PU coatings as confirmed by scanning electron micrographs and EDX analysis. Based on the surface profilometry data, we found out that PU coatings with film thickness ranging from 6 μm to 28.5 μm can be achieved. FTIR-ATR analysis revealed that maintaining the stoichiometric ratio between O–H and N–C–O vibrational modes closer to unity is a vital factor to produce a high-quality PU coating regardless of the choice of substrate. The average bandgap energy of 4.35 ± 0.03 eV was estimated from the UV-vis reflectance spectra, and the electrical resistance of 10⁷–10¹⁰ orders of magnitude was measured using a two-probe method which are typical for dielectric materials. Preliminary insights about the dielectric response of the fabricated PU coatings were investigated using electrochemical impedance spectroscopy and a low κ-value of 2.749 was calculated from the Nyquist plot of the 7.9-μm thick 100% ESBO-based PU coating deposited at 6000 rpm for 45 seconds. These promising results proved that PU coatings from bio-polyols can be tailored to achieve desired coating properties that are amenable for next-generation microelectronic packaging and curable photoresists.

Abstract: Earthquakes are highly dangerous for all masonry structures, as they force high deformations that brittle building materials cannot withstand. The solution to such problems may be the use of flexible polyurethane-based technologies (composite strengthening, adhesives etc.). On the other hand, these technologies are relatively new and demand experimental prove, whether they would not lose their properties after being subjected to environmental conditions i.e. temperature fluctuations, humidity, chemically aggressive mortars, solar radiation etc. Herein, we discuss the aspect of durability of Sika PS polyurethane – the polymer used as both composite matrix and an adhesive in flexible protective technologies for masonry.

Abstract: Although rigid foam core structures have gotten a lot of attention, there have only been a few researches on foam reinforced sandwich panels with aluminum alloy A6061 sheets as face-sheets. In this research, the sandwich concept was applied to develop lightweight panels for roofing system. Analysis on the influences of core thickness, density, and foam layer arrangement on energy absorption, bending strength and displacement of sandwich panel under the quasi-static three-point bending test were investigated. Sandwich panel core is made of closed-cell polyurethane foam with densities of 40 kg/m³, 60 kg/m³, and 80 kg/m³. The quasi-static three-point bending tests were conducted in accordance to ASTM C-393 Standard and the polyurethane foam cores are design accordingly to the guideline of National Institutes of Standards and Technology (NIST). Load–displacement curves and mechanical properties are shown using data from experimental works. Results demonstrate that increased in thickness of the sandwich panel, also increased the bending strength, energy absorption and displacement. Furthermore, the sandwich panel with 50 mm thickness and 60 kg/m³ density foam core has the maximum bending strength.

Abstract: Co-Pоly (Urethane-Imide) s (CPUI) based on pоly (diethyleneglycol) adipate diol, tolylenediisocyanate, multinucleate dianhydrides and diamines were synthesized. The films and moldings from CPUI were processed and their mechanical characteristics were evaluated. Distinctions of specifications of the films formed from polymer solutions and the moldings formed from melt polymers are indicated when using the same starting CPUI. It appears that films and moldings possess typical properties of elastomers. The reprocessing of studied copolymers by using the injection molding method allows to assign CPUI to the thermoplastic elastomers or so-called thermoelastoplasts.

Abstract: Modified reduced graphene oxide (rtgo) was prepared by using γ - isocyanate propyl triethoxysilane (IPTS) as modifier. Graphene / polyurethane nanocomposites were prepared by in-situ polymerization. Graphene / polyurethane composites were characterized by scanning electron microscopy, TGA, DIN abrasion and electronic universal testing machine. The effects of different reaction formulations and graphene addition on the wear resistance and mechanical properties of the composites were studied. The results show that the wear resistance and tear resistance of the composite can be greatly improved after the functional graphene is compounded with polyurethane.

Abstract: The objective of presented research was to verify and evaluate whether the treated hazardous waste (HW) can be used as filler in polymer coatings based on epoxy (EP) and polyurethane resin (PUR). The end product created by the incineration of municipal waste and cement dusts from cement kiln bypasses were chosen for solidification. The hazardous waste used was solidified by a homogenisation method using filter fly ash from fluidized bed combustion of lignite and silica flour as the solidifying agents. The aim was to use as much hazardous waste as possible and incorporate it into the polymer matrix of the coatings. The usability of the filler prepared in this way was verified by testing the tensile properties of polymer coatings, the surface hardness and the adhesion to the concrete. The cohesion of the coatings with concrete was observed using a digital optical microscope. It has been found that the PUR-based coatings with HW content show better properties than the coatings containing only the silica flour as a filler.