Search

Copyright of Journal of Sichuan University (Medical Science Edition) is the property of Editorial Board of Journal of Sichuan University (Medical Sciences) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to the increasingly serious harm caused by marine fouling to humans, marine antifouling has become an urgent issue in the development of marine resources. Many antifouling countermeasures have been explored, among which applying antifouling coatings is the most economical and effective method and is currently the most widely used approach. Given the significant harm of traditional marine antifouling coatings to the ecological environment, focusing on green, efficient and environment-friendly marine antifouling coatings, the development status and research progress of modified polyurethane in marine antifouling were summarized. Polyurethane coatings are divided into solvent-based and water-based types, both of which exhibit good properties such as solvent resistance. Water-based polyurethane coatings are more environmentally friendly, while solvent-based polyurethane coatings have superior water resistance. These coatings can serve as substrate resins in the field of marine antifouling, helping to reduce biological pollution on the surface of marine structures. By modifying polyurethane coating, its antifouling performance can be further enhanced. In this paper, the application of modified polyurethane in marine antifouling coatings was reviewed, and the existing problems and improvement schemes were analyzed to provide references and suggestions for the research and development of marine antifouling coatings.

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to enhance the physical barrier performance of polyaniline(PANI)/polyurethane(PU) coating against corrosive medium, the introduction of two-dimensional material in the coating is one of the effective methods. PU coating matrix was synthesized from 2, 4-diisocyanate (TDI) and 3, 3′-dichloro-4, 4′-diamino diphenylmethane(MOCA), and MXene@PANI was synthesized by intercalation reaction of PANI with Ti3C2Tx.Then protective coating of MXene@PANI/PU was obtained by adding MXene@PANI into PU. The results show that when the mass ratio of MXene/PANI is 1∶1, no obvious corrosion occurs on the surface of the MXene@PANI/PU coating after 60 days of salt spraying. The corrosion current is 3.709×10-9 A·cm-2, and the impedance modulus is 1.93×108 Ω·cm2. The reason is that MXene improves the electrochemical activity of PANI and thus enhances the electrochemical anticorrosion performance of PANI. On the other hand, MXene nanoplates as a two-dimensional barrier can prevent the corrosive medium from entering into the coating, which improves the long-term protective performance of the coating.

During operation， hydraulic turbines are continuously subjected to long-term impact from sediment-laden water flows.The combined damage from sediment erosion and cavitationerosion significantly impairs the flow components，compromising the safe and stable operation of the unit.Surface protection of the flow components by means of high-elastic polymer coatings is an economical and practical strategy.In this paper，firstly， the anti-cavitation protective polymer coatings on the surfaces of flow components were reviewed， especially research progress on polyurethane and epoxy resin coatings.Considering the important influence of the erosive and abrasive effects of sediment-laden water flows in the damage of hydraulic turbines，the research progress of polymer/ceramic composite coatings in the synergistic resistance to cavitation and erosion was reviewed； finally， the problems of polymer coatings in the protection of hydraulic turbine flow components were described.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polyurethane is a unique polymer with excellent flexibility, elasticity, controllable hardness, fine tensile strength, abrasion and medium resistant, and stable in both low and high temperature. Since it is suitable for use as a gas barrier material, so it has a wide range of applications in fuel gas isolation, food packing, tire repairing, hot balloon, and flame retardance. The copolymerization of soft segments and hard segments formulated polyurethane, and its gas barrier properties depends on phase separation caused by two thermodynamically incompatible segments. Adjustment of molecular structure and fabrication of nano composites are effective approaches to enhance gas barrier properties. Nanoclay and graphene are widely studied as nano fillers for polyurethane, they improve the barrier ability of polyurethane to water vapor, oxygen, and carbon dioxide and other gases by blocking mechanism of which is reported to be layer stack and hydrogen bonding. In this article, mechanism of gas transport and barrier, intrinsic polyurethane, polyurethane nanocomposites is discussed. Finally, the development direction of polyurethane for gas barrier application is prospected.

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A thin-walled sandwich structure filled with polyurethane is introduced. Based on the hyperelastic constitutive model of polyurethane, the energy absorption characteristics of the structure are studied and compared with single-layer and double-layer thin-walled steel circular tubes. Applying quasi-static load and dynamic load to the three structures, the deformation mode, energy absorption characteristic parameters, crushing force and stroke efficiency of the three structures are obtained. The results show that under quasi-static loading, the thin-walled circular tube filled with polyurethane produces axisymmetric deformation, and the average load and specific energy absorption are higher than the other two structures. Under dynamic loading, the stroke efficiency of thin-walled circular tube filled with polyurethane is small, but the average load and specific energy absorption are higher than the other two structures.

To obtain the filling material with good compression mechanical properties, two kinds of orthogonal trapezoidal honeycomb aluminum with different structures were manufactured（90°orthogonal trapezoidal honeycomb aluminum and 45° orthogonal trapezoidal honeycomb aluminum）, the mechanical properties of the material under quasi-static axial loading was analyzed. Two kinds of orthogonal trapezoidal honeycomb aluminum were filled with polyurethane foam, and the effect of polyurethane filling on the orthogonal trapezoidal honeycomb aluminum was analyzed. The results show that compared with 45° orthogonal trapezoidal aluminum honeycomb, the performance of 90° orthogonal trapezoidal honeycomb aluminum is better, and the peak stress, plateau stress and unit volume absorption energy of the two kinds of orthogonal trapezoidal honeycomb aluminum are improved after polyurethane filling. However, the energy absorption efficiency is not significantly improved after being filled with polyurethane, and the strain corresponding to the maximum energy absorption efficiency decreases.

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The causes and protective measures of cavitation erosion were summarized. The cavitation corrosion resistance of different kinds of metal coatings prepared by thermal spraying, surfacing, electroless plating and plasma surface technology was introduced. Then, the research progress of organic coating such as epoxy resin series, polyurethane series, ultra high molecular-weight polyethylene coatings in the field of cavitation resistance was reviewed emphatically and compared with metal coatings. The anti-cavitation effect of ceramic organic composite coatings was reviewed. The advantages and disadvantages of several kinds of coatings were compared. Finally, the future research direction was prospected.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Medical polyurethanes have emerged as a leading choice for biomedical applications owing to their exceptional biocompatibility and good physical and mechanical properties. Catalysts play a crucial role as additives in the synthesis of medical polyurethanes, enhancing synthesis efficiency and material properties. However, the catalysts used may affect the biocompatibility of polyurethanes and pose potential harm to human health. This review encapsulates the latest findings regarding the catalysts employed in the synthesis of medical polyurethane materials and their biotoxicity. Initially, we reviewed the prevalent types of catalysts used in the synthesis of medical polyurethane materials and described their distinctive characteristics. Subsequently, our focus shifted to exploring the potential biotoxicity associated with these catalysts. Finally, we provided a forward-looking perspective and recommendations for the future trajectory of catalyst selection in the synthesis of medical polyurethane materials. By acquiring a more profound understanding of the properties and biotoxicity of catalysts used in the synthesis of medical polyurethane materials, and by uncovering existing issues and challenges, we can better guide the design of medical polyurethane materials. This, in turn, enables us to chart the course for future development and ultimately enhance the biocompatibility and safety profiles of medical polyurethane materials. Such advancements will promote the continued development and application of medical polyurethane materials in clinical settings., Competing Interests: 利益冲突　所有作者均声明不存在利益冲突, (© 2024《四川大学学报（医学版）》编辑部 版权所有Copyright ©2024 Editorial Office of Journal of Sichuan University (Medical Sciences).)

In order to deeply analyze the microstructure of silicate modified polyurethane grouting reinforcement materials for mining and understand the influence of microstructure on the macro strength, firstly, the main reactions and reaction processes involved in this system are deduced. Secondly, the phase distribution of the composite system is characterized by scanning electron microscopy（ＳＥＭ）. The enrichment state of elements is qualitatively characterized by surface scan method and the percentage of main elements and atoms in each phase is quantitatively characterized by point scan method. Finally, the influence of microstructure on the macro strength is studied. As a result, there are three phases in silicate modified polyurethane grouting reinforcement materials, which are polymer continuous phase, silica polymer microsphere phase and sodium carbonate acicular phase. The disordered distribution of phases in microstructure is easy to cause stress concentration, which is manifested in the decrease of mechanical strength of materials.

In view of the problems existing in the ecological restoration of rock slope, such as the slide of the soil substrate, the serious loss of the surface soil and the poor growth of vegetation, etc., in this paper, polyurethane organic polymer materials and soil are used to form a polyurethane composite substrate. The strength, erosion resistance and vegetation growth of the composite substrate are studied through laboratory tests. In addition, a suitable site is chosen for field test to verify the effectiveness of the polyurethane composite substrate. The specific research results show that the existence of the polyurethane organic polymer has a significant effect on the strength and anti-scour of the composite substrate, and with the increasing concentration of the polyurethane organic polymer, the strength and anti-scour of the polyurethane composite substrate also increase. Compared with the specimens not added, the strength of 1% polyurethane composite substrate is 113.63 kPa, with an increasing rate of about 95.45%. The peak scouring amount of 20% polyurethane composite substrate is 28.8 g, with a decreasing rate of about 71.2%. The polyurethane organic polymer can effectively improve the germination and growth of vegetation seeds. When the concentration of polyurethane increases from 0% to 10%, the germination rate of seeds increases from 12% to 68%. When the concentration of the polyurethane organic polymer is too high, it will inhibit the germination and growth of vegetation. The polyurethane composite substrate can effectively repair the rock slope, and the effect is significant. The research results may provide some references for the ecological protection of rock slope, and are of important theoretical and practical significance.

In this paper, organosilicone-modified polyurethane was synthesized by the prepolymerization method by using polypropylene glycol and isophorone diisocyanate as the synthetic monomers, and γ-aminopropyltriethoxysilane (KH550) as the silicone source. The modified polyurethane was used as the interlayer to prepare the organic-inorganic glass laminates. The effects of silicone contents on the optical properties, thermomechanical properties, and interfacial adhesion property of the glass laminates were investigated. With the KH550 content increasing, the polymerization degree of polyurethane is decreased, resulting in lower transparency, higher haze and lower surface hardness. The storage modulus of the modified polyurethane is increased at first and then decreased, and the glass transition temperature of hard segments is firstly increased and then decreased. Both reached the maximum value when the additive amount of KH550 is 1%. Using polyurethane adhesive layer as the interlayer of glass laminates, the interfacial shear strength of the unmodified glass laminates is 6.7 MPa, while the interfacial shear strength of glass laminates containing 0.5% KH550 is 7.7 MPa.

In order to evaluate the effect of the complicated working conditions in small diameter pipeline on the passing capacity of all-polyurethane pig, the possible causes for the whole fracture of all-polyurethane pig were analyzed. 3 D explicit dynamics simulation analysis models for all-polyurethane pig with diameter of 323.9 mm passing through a straight pipeline with single-sided deformation and scaled pipeline were established respectively with the Scan To 3 D technology and the mechanical property test of polyurethane material based on the actually-deformed pipeline with diameter of 323.9 mm on site. Through simulation model solution and result analysis, it is found that the all-polyurethane pig has high passing capacity and good pigging effect under the conditions of single-sided dent deformation and internal wall scaling of straight pipeline. The bending stress and contact stress generated when the all-polyurethane pig passing through a single-sided dent deformation of pipeline are not sufficient to cause serious scratches on the surface, cup tearing or whole fracture of the polyurethane pig. In the process of pig passing through the scaled section of the pipeline, large axial compression deformation is generated on the barrel between the front and rear cups, and serious radial outward expansion and tearing is the main reason for the whole tearing fracture of the pig barrel. Generally, the above research conclusions have profound practical significance for improving the schematic design level and promoting the engineering application of small-diameter all-polyurethane pig in China.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to prepare a type of lightweight foaming material well-suited for vertical greening, this study adopted a green and environmentally friendly full-water foaming approach based on the one-step foaming and synthesis of polyurethane foam technology to form a composite of polyurethane foam and organic peat soil. The polyurethane-peat soil lightweight foaming material was prepared from the following lightweight raw materials: polyether polyols, polypropylene glycol, isocyanate, silicone oil, and peat soil with a particular moisture content. The influence of the amount of peat soil, the moisture content of the peat soil, and the mixing time during the preparation process on the resilience performance, apparent shape, density (volume density, apparent density, and wet density), open porosity, and water absorption of the polyurethane-peat soil lightweight foaming material is discussed. The results showed that when the amount of peat soil was 60%, 70%, and 80%, the resilience of the lightweight foam material remained relatively stable; when the amount of peat soil was fixed, the moisture content (60%, 70%, and 80%) of the peat soil changed, and the performance data of the lightweight foam material could be obtained. When the amount of peat soil was 70%, the mixing time was 180s and the moisture content of the peat soil was 80%. The main performance of the polyurethane-peat soil lightweight foaming material was better than that of other greening matrix materials, with a bulk density of 0.101 g em, an open porosity of 66.87%, and a water absorption rate of 656%. According to observations with a microscope and scanning electron microscope (SEM), the addition of peat soil did not affect the three-dimensional interior of the polyurethane foam net structure: however, it improved the pore structure of the polyurethane foam and enhanced its water absorption performance, and its internal structure was good [ABSTRACT FROM AUTHOR]

Copyright of Journal of Aeronautical Materials is the property of Editorial Board of Journal of Aeronautical Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to investigate the structure and property relationships of intrinsic self-healing polyurethane and balance the seemly contradictory forces between its self-healing efficiency and mechanical strength, the reversible disulfide bonds were introduced into polyester-polyurethane by taking hexamethylene diisocyanate (HDI) trimers as the cross-linker and 4,4-diamino diphenyl disulfide as the chain-extender. The results show that the optimal self-healing elastomer exhibits a tensile strength of 7.7MPa and a maximum self-healing efficiency of 97.4% at 60℃after 24 hours, whereas the common elastomer synthesized without disulfide bonds (via H-bonding interactions) only exhibits a tensile strength of 9.3MPa and a maximum self-healing efficiency of 58.0% under the same condition, indicating that the existence of disulfide bonds helps to increase the self-healing efficiency by 67.9%. The prepared elastomer is found to have multi time self-healing capabilities and the second time self-healing efficiency is 62.3%.

Shape memory polymers(SMPs) are a class of functional "smart" materials that have shown bright prospects in the area of biomedical applications. The novel smart materials with multifunction of biodegradability and biocompatibility can be designed based on their general principle, composition and structure. In this review, the latest process of three typical biodegradable SMPs(poly(lactide acide), poly(ε-caprolactone), polyurethane) was summarized. These three SMPs were classified in different structures and discussed, and shape-memory mechanism, recovery rate and fixed rate, response speed was analysed in detail, also, some biomedical applications were presented. Finally, the future development and applications of SMPs are prospected: two-way SMPs and body temperature induced SMPs will be the focus attension by researchers.

This paper summarizes the latest progress for vegetable oil-based polyurethanes mainly from the view of thermoset and thermoplastic. Firstly, the modification methods for traditional thermoset polyurethane are introduced, including physical modification methods (filling and alloying) and chemical modification methods (copolymerization grafting, crosslinking and interpenetrating polymer network). Materials used for physical modification mainly contain inorganic materials such as SiO2 and organic substances such as cellulose. Grafting copolymerization of styrene, acrylate and other monomers with polyurethane is the main method of chemical modification. The characteristics, preparations and application fields of thermoplastic polyurethane are reviewed, and the preparations, performances and applications of oleic acid-based thermoplastic polyurethane are chiefly presented. The development prospects of vegetable oil-based polyurethane are put forward. Surface-initiated living polymerization and other methods are used to controllable chemical modification of the traditional thermoset polyurethane and click chemistry method is uesd to promote multi-functionalization of the thermoplastic polyurethane.

Objective • To investigate the mechanical properties of polyurethane composite containing polyphosphazene nanospheres. Methods • Test specimens were prepared with different materials, including polyurethane (the PU group), polyurethane containing 1% polyphosphazene nanospheres (the 1% PSZ group), polyurethane containing 5% polyphosphazene nanospheres (the 5% PSZ group), and selfcuring silicone rubber soft liner material Sofreliner (the Sofreliner group). The microstructure of test specimens was observed using the scanning electron microscope (SEM). The tensile strength and tearing strength of test specimens were calculated after 0，1 000，and 3 000 hot and cold cycles. Results • SEM observation showed that there were no nanoparticles aggregating on the surface of test specimens in the 1% PSZ and 5% PSZ groups. Depressions on the surface of test specimens were shallower in the 5% PSZ group than those in the 1% PSZ and PU groups. Before hot and cold cycling tests, the differences in tensile strength and tearing strength among the PU, 1% PSZ and 5% PSZ groups were not statistically significant, but tensile strength and tearing strength were significantly higher in the PU, 1% PSZ and 5% PSZ groups than those in the Sofreliner group (P<0.05). After hot and cold cycling tests, the tensile strength in the PU, 1% PSZ and 5% PSZ groups was slightly decreased, while the tearing strength was not significantly changed. Conclusion • The tensile strength and tearing strength of polyurethane composite are higher than those of Sofreliner and meet the clinical application standard. The surface properties of materials were improved by adding 5% polyphosphazene nanospheres to polyurethane compared with adding 1% polyphosphazene nanospheres, but the tensile strength and tearing strength were not significantly improved. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Given ordinary polyurethane grouting reinforced materials releases amount of heat when curing reaction happens, it will cause fuming or catching fire when applying in underground coal mine, so a kind of novel self-controlling temperature polyurethane (SCT-PU) grouting materials, which with Na2Si03 and NaCl aqueous solution as self-limiting additives and blending with polyether polyol as white material, with isocyanate as a black material, was prepared. Its composition, structure, properties and self-limiting temperature heat storage mechanism was studied. The results show that,maximum storage temperature of self-limiting polyurethane grouting material is 101.5 °C, significantly lower. There are many sections of grouting material foam, hole contains solid microspheres, there is an annular gap between the two. Na2Si03 in Self-limiting additives absorp C02 producting in the reaction of isocyanate and water, generated Si (OH) 4 microspheres. Si(OH) 4 endothermic dehydration is the main reason of the system to limit temperature increase. Water present in the annular gap vaporization is the final barrier of the system to limit the heat rise. Combination properties testing and mine grouting industrial experiment show that the production properties reach or exceed coal national industry standard of polyurethane grouting reinforced materials, especially have outstanding advantages in stored temperature. [ABSTRACT FROM AUTHOR]

The paper introduced that the shape memory polyurethane was prepared by the quasi-prepolymer method using PCL (polycaprolactone glycol) of different molecular weights' liquefied MDI (4,4 - diphenyl methane diisocyanate) and BOD (1,4 -- butanediol) as raw materials. The effect of different molecular weights PCL on some properties of polyurethane materials was discussed such as mechanical property' thermal property and shape memory property and so on. The research results show that the shore A hardness' the tensile strength' the elongation at break' the hot deformation temperature and the vicat softening point are increased with the increase of PCL molecular weight' the shape fixed rate and the shape recovery ratio are almost enlarged to be over 95 % with the increase of molecular weight' thereby. [ABSTRACT FROM AUTHOR]