In order to improve the adhesion of the middle frequency magnetic sputtered zirconium coating on a polyurethane film,an anode layer source was used to pretreat the polyurethane film with nitrogen and oxygen ions.SEMs ...In order to improve the adhesion of the middle frequency magnetic sputtered zirconium coating on a polyurethane film,an anode layer source was used to pretreat the polyurethane film with nitrogen and oxygen ions.SEMs and AFM roughness profiles of treated samples and the contrast groups were obtained.Besides,XPS survey spectrums and high resolution spectrums were also investigated.The adhesion test revealed that ion bombardment could improve the adhesion to the polyurethane coating substrate.A better etching result of oxygen ions versus nitrogen predicts a higher bonding strength of zirconium coating on polyurethane and,indeed,the highest bonding strengths are for oxygen ion bombardment upto 13.3 MPa.As demonstrated in X-ray photoelectron spectroscopy,the oxygen ion also helps to introduce more active groups,and,therefore,it achieves a high value of adhesion strength.展开更多
UV-curable polyurethane prepolymer and photoinitiator 1173 were facilely encapsulated in a poly（urea-formaldehyde） shell, which was in situ formed by the polymerization of formalde-hyde and urea in an oil-in-water e...UV-curable polyurethane prepolymer and photoinitiator 1173 were facilely encapsulated in a poly（urea-formaldehyde） shell, which was in situ formed by the polymerization of formalde-hyde and urea in an oil-in-water emulsion. The diameters of the microcapsules ranged from 118 μm to 663 μm depending on agitation speed, and were obtained via optical mi-croscopy and scanning electron microscopy analyses. The encapsulation percent and the yield of microcapsules prepared at the agitation speed of 600 r/min can reach 97.52wt% and 65.23wt%, respectively. When the water-borne polyurethane （WPU） coating embedded with the prepared microcapsules were scratched, the healing agent could be released from rup-tured microcapsules and lled the scribed region. The excellent anticorrosion properties of the WPU coating embedded with the prepared microcapsules were con rmed by the results obtained from both electrochemical impedance spectroscopy and Tafel curves.展开更多
MoS2-multi-walled-carbon-nanotube(MWCNT)hybrids containing two-dimensional MoS2 and one-dimensional MWCNTs were synthesized through a one-step hydrothermal reaction.X-ray-diffraction and transmission-electron-microsco...MoS2-multi-walled-carbon-nanotube(MWCNT)hybrids containing two-dimensional MoS2 and one-dimensional MWCNTs were synthesized through a one-step hydrothermal reaction.X-ray-diffraction and transmission-electron-microscopy results demonstrated that MoS2 nanosheets were successfully synthesized,and uniformly anchored on the MWCNTs’surfaces.Furthermore,the effects of the Mo S2-MWCNT hybrids on the tribological performances of polyurethane composite coatings were investigated using a UMT-2MT tribo-tester.Friction and wear test results revealed that the friction coefficient and wear rate of a 3 wt%Mo S2-MWCNT-1 filled polyurethane composite coating were reduced by 25.6% and 65.5%,respectively.The outstanding tribological performance of the MoS2-MWCNT-1 reinforced polyurethane composite coating was attributed to the excellent load-carrying capacity of the MWCNTs and good lubricant ability of MoS2.The surface morphologies of the worn surfaces and counterpart ball surfaces were investigated to reveal the wear mechanisms.展开更多
The increasing pressure from consumers and policy makers to reduce the use of synthetic polymers,whose production contributes to the depletion of non-renewable resources and are usually non-biodegradable,has prompted ...The increasing pressure from consumers and policy makers to reduce the use of synthetic polymers,whose production contributes to the depletion of non-renewable resources and are usually non-biodegradable,has prompted the efforts to find suitable bio-based sources for the production of polymers.Vegetable oils have been a frequently spotted in this search because they are versatile,highly available and a low cost liquid biosource,which can be used in the synthesis of a wide plethora of different polymers and reactive monomers.Following the same idea of reducing the environmental stress,the traditional polyurethanes that are soluble in organic solvents have been targeted for replacement,particularly in applications such as adhesives and coatings,in which the solvent is released to the atmosphere increasing the air pollution.Instead,waterborne polyurethanes(WBPU),which are polyurethane dispersions(PUD)prepared in aqueous media,release benign water to the atmosphere during use as supported or self-standing films for different applications.In this brief review,the contributions to the development of WBPUs based on vegetable oils are discussed,focusing mainly on the contributions of the last decade.The synthesis of ionic and nonionic PUDs,their characterization and the properties of the resulting dried materials,as well as derived composite materials are considered.展开更多
Silane terminated prepolymers for adhesives, sealants and coatings are of </span></span><span><span><span style="font-family:"">great <span>industrial importance. The...Silane terminated prepolymers for adhesives, sealants and coatings are of </span></span><span><span><span style="font-family:"">great <span>industrial importance. They are very important because of their low toxicity</span><span> over polyurethanes, silicones, and solvent-based products. Hence</span>, many pieces of literature which deal with the synthesis, properties and applications of this Si<span>lane terminated polymers hybrid system exist. Silylated polyether (MS polymers) </span>and Silylated Polyurethane Polymers (SPUR) are the bases for nu<span>merous sealants, adhesives and coatings used worldwide. A hybrid system mixed with </span><span>organic-polyurethane proportion and inorganic-alkoxysilane proportion</span> <span>com</span>bines the benefits of conventional polyurethane and silicone-based products.<span> This article reviews the chemistry of MS polymers and SPUR and their</span> <span>ad</span><span>vantages and disadvantages in silyl terminated prepolymer-based adhesives</span>, sea<span>lants and coatings as well as provides information on different end applications.展开更多
Surfaces with hydrophilic and antimicrobial properties are very attractive for cardio-vascular device-associated applications.The aim of this study was to prepare and coat a hydrophilic polymer containing a functional...Surfaces with hydrophilic and antimicrobial properties are very attractive for cardio-vascular device-associated applications.The aim of this study was to prepare and coat a hydrophilic polymer containing a functional group capable of forming triazole functionality onto the surface of polyurethane(PU).The modified surfaces were assessed with cell adhesion,bacterial adhesion and bacterial viability.Mouse fibroblast cells(NIH-3T3)and three bacterial species were used for assessment.The results showed that the modified surface not only exhibited a significant reduction in cell adhesion with a 25%-59%decrease to mouse fibroblast but also showed a sig-nificant reduction in bacterial attachment with 26%-67%,24%-61%and 23%-57%decrease to Staphylococcus aureus,Escherichia coli and Pseudomonas aeruginosa,respectively,as compared with original PU.Furthermore,the polymer-modified surface exhibited a significant antibacterial function by inhibiting bacterial growth with reduction of 49%-84%,44%-79%and 53%-79%to S.aureus,E.coli and P.aeru-ginosa,respectively,as compared with original PU.These results indicate that covalent polymer attachment enhanced the antibacterial and antifouling properties of the PU surface.展开更多
文摘In order to improve the adhesion of the middle frequency magnetic sputtered zirconium coating on a polyurethane film,an anode layer source was used to pretreat the polyurethane film with nitrogen and oxygen ions.SEMs and AFM roughness profiles of treated samples and the contrast groups were obtained.Besides,XPS survey spectrums and high resolution spectrums were also investigated.The adhesion test revealed that ion bombardment could improve the adhesion to the polyurethane coating substrate.A better etching result of oxygen ions versus nitrogen predicts a higher bonding strength of zirconium coating on polyurethane and,indeed,the highest bonding strengths are for oxygen ion bombardment upto 13.3 MPa.As demonstrated in X-ray photoelectron spectroscopy,the oxygen ion also helps to introduce more active groups,and,therefore,it achieves a high value of adhesion strength.
文摘UV-curable polyurethane prepolymer and photoinitiator 1173 were facilely encapsulated in a poly（urea-formaldehyde） shell, which was in situ formed by the polymerization of formalde-hyde and urea in an oil-in-water emulsion. The diameters of the microcapsules ranged from 118 μm to 663 μm depending on agitation speed, and were obtained via optical mi-croscopy and scanning electron microscopy analyses. The encapsulation percent and the yield of microcapsules prepared at the agitation speed of 600 r/min can reach 97.52wt% and 65.23wt%, respectively. When the water-borne polyurethane （WPU） coating embedded with the prepared microcapsules were scratched, the healing agent could be released from rup-tured microcapsules and lled the scribed region. The excellent anticorrosion properties of the WPU coating embedded with the prepared microcapsules were con rmed by the results obtained from both electrochemical impedance spectroscopy and Tafel curves.
基金financial support of the National Natural Science Foundation of China (Grant Nos. 51375472 and 51675252)
文摘MoS2-multi-walled-carbon-nanotube(MWCNT)hybrids containing two-dimensional MoS2 and one-dimensional MWCNTs were synthesized through a one-step hydrothermal reaction.X-ray-diffraction and transmission-electron-microscopy results demonstrated that MoS2 nanosheets were successfully synthesized,and uniformly anchored on the MWCNTs’surfaces.Furthermore,the effects of the Mo S2-MWCNT hybrids on the tribological performances of polyurethane composite coatings were investigated using a UMT-2MT tribo-tester.Friction and wear test results revealed that the friction coefficient and wear rate of a 3 wt%Mo S2-MWCNT-1 filled polyurethane composite coating were reduced by 25.6% and 65.5%,respectively.The outstanding tribological performance of the MoS2-MWCNT-1 reinforced polyurethane composite coating was attributed to the excellent load-carrying capacity of the MWCNTs and good lubricant ability of MoS2.The surface morphologies of the worn surfaces and counterpart ball surfaces were investigated to reveal the wear mechanisms.
基金the Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET,Argentina)(PIP 20170100677)the Fondo para la Investigación Científica y Tecnológica(FONCYT)(PICT-2017-1318)the Universidad Nacional de Mar del Plata(UNMdP,15/G557,ING561/19)and to the Comisión de Investigaciones Científicas de la Provincia de Buenos Aires(CIC)and the Universidad Tecnológica Nacional(UTN)for their financial support.
文摘The increasing pressure from consumers and policy makers to reduce the use of synthetic polymers,whose production contributes to the depletion of non-renewable resources and are usually non-biodegradable,has prompted the efforts to find suitable bio-based sources for the production of polymers.Vegetable oils have been a frequently spotted in this search because they are versatile,highly available and a low cost liquid biosource,which can be used in the synthesis of a wide plethora of different polymers and reactive monomers.Following the same idea of reducing the environmental stress,the traditional polyurethanes that are soluble in organic solvents have been targeted for replacement,particularly in applications such as adhesives and coatings,in which the solvent is released to the atmosphere increasing the air pollution.Instead,waterborne polyurethanes(WBPU),which are polyurethane dispersions(PUD)prepared in aqueous media,release benign water to the atmosphere during use as supported or self-standing films for different applications.In this brief review,the contributions to the development of WBPUs based on vegetable oils are discussed,focusing mainly on the contributions of the last decade.The synthesis of ionic and nonionic PUDs,their characterization and the properties of the resulting dried materials,as well as derived composite materials are considered.
文摘Silane terminated prepolymers for adhesives, sealants and coatings are of </span></span><span><span><span style="font-family:"">great <span>industrial importance. They are very important because of their low toxicity</span><span> over polyurethanes, silicones, and solvent-based products. Hence</span>, many pieces of literature which deal with the synthesis, properties and applications of this Si<span>lane terminated polymers hybrid system exist. Silylated polyether (MS polymers) </span>and Silylated Polyurethane Polymers (SPUR) are the bases for nu<span>merous sealants, adhesives and coatings used worldwide. A hybrid system mixed with </span><span>organic-polyurethane proportion and inorganic-alkoxysilane proportion</span> <span>com</span>bines the benefits of conventional polyurethane and silicone-based products.<span> This article reviews the chemistry of MS polymers and SPUR and their</span> <span>ad</span><span>vantages and disadvantages in silyl terminated prepolymer-based adhesives</span>, sea<span>lants and coatings as well as provides information on different end applications.
基金Indiana University-Purdue University IndianapolisMajmaah University。
文摘Surfaces with hydrophilic and antimicrobial properties are very attractive for cardio-vascular device-associated applications.The aim of this study was to prepare and coat a hydrophilic polymer containing a functional group capable of forming triazole functionality onto the surface of polyurethane(PU).The modified surfaces were assessed with cell adhesion,bacterial adhesion and bacterial viability.Mouse fibroblast cells(NIH-3T3)and three bacterial species were used for assessment.The results showed that the modified surface not only exhibited a significant reduction in cell adhesion with a 25%-59%decrease to mouse fibroblast but also showed a sig-nificant reduction in bacterial attachment with 26%-67%,24%-61%and 23%-57%decrease to Staphylococcus aureus,Escherichia coli and Pseudomonas aeruginosa,respectively,as compared with original PU.Furthermore,the polymer-modified surface exhibited a significant antibacterial function by inhibiting bacterial growth with reduction of 49%-84%,44%-79%and 53%-79%to S.aureus,E.coli and P.aeru-ginosa,respectively,as compared with original PU.These results indicate that covalent polymer attachment enhanced the antibacterial and antifouling properties of the PU surface.
