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1.
Melamine–formaldehyde resin was modified by ethylene glycol to decrease the amount of free formaldehyde and extend the storage time. The modified resin (EMF) was further used to prepare microencapsulated ammonium polyphosphate (MCAPP). The structures of both EMF and MCAPP were well characterized. Afterward, EMF and MCAPP were mixed and coated on the surface of pre‐expanded polystyrene particles to prepare flame‐retardant expandable polystyrene foams (EPS). Both water resistance and impact strength were enhanced by the presence of MCAPP, and the flammability of the samples was also significantly improved. For the sample containing 75 phr MCAPP, the limiting oxygen index value was increased to 31.4% with a V‐0 rating in the UL‐94 vertical burning test. Cone calorimeter tests showed that the peak heat release rate of the sample declined sharply to 172.7 kW/m2, which is 81.6% lower than that of neat EPS. The smoke production of EPS foams during combustion was suppressed by the presence of MCAPP, and the thermal stability was also improved. Scanning electron microscopy showed that the char layer of the flame‐retardant sample after combustion became compact with negligible voids or cracks, which could further form an isolation barrier to prevent both heat and flame transfer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46471.  相似文献   

2.
A series of UV‐curable polyurethane acrylates (PUA0, FPUA3, FPUA6, FPUA 9 FPUA12, FPUA15, where the numbers indicate the wt % of perfluoroalkyl acrylate), were prepared from a reactive oligomer [4,4 ?‐dicyclohexymethanediisocyanate(H12MDI)/ poly(tetramethylene glycol)(PTMG)/2‐hydroxyethyl methacrylate (HEMA): 2/1/2 molar ratio, prepolymer:40 wt %] and diluents [methyl methacrylate (MMA, 20 wt %)/ isobornyl acrylate (IBOA, 40–25 wt %)/heptadecafluorodecyl methacrylate (PFA, 0–15 wt), total diluents: 60 wt %]. This study examined the effect of PFA/IBOA weight ratio on the properties of the UV‐curable polyurethane acrylates for antifouling coating materials. The as‐prepared UV‐curable coating material containing a 15 wt % PFA content in diluents (MMA/IBOA/PFA) form a heterogeneous mixture, indicating that a PFA content of approximately 15 wt % was beyond the limit of the dilution capacity of diluents for the oligomer. In the wavelength range of 400–800 nm, the UV‐cured PUA0 film sample was quite transparent (transmittance%: near 100%). On the other hand, the transmittance% of the FPUA film sample decreased markedly with increasing PFA content. XPS showed that the film‐air surface of the UV‐cured polyurethane acrylate film had a higher fluorine content than the film‐glass dish interface. As the PFA content increased from 0 to 12 wt %, the surface tension of the UV‐cured urethane acrylates decreased from 26.8 to 15.6 mN/m, whereas the water/methylene iodide contact angles of the film–air surface increased from 90.1/63.6° to 120.9/87.1°. These results suggest that the UV‐curable polyurethane acrylates containing a PFA content up to 12 wt % have strong potential as fouling‐release coating materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40603.  相似文献   

3.
To obtain highly effective antifouling coatings, a series of UV‐curable polyurethane acrylates containing diluents [heptadecafluorodecyl methacrylate (PFA, 6 wt %)/isobornyl acrylate (IBOA, 34 wt %)/methyl methacrylate (MMA, 20‐5 wt %)/vinyl methacrylate (VMA, 0–15 wt %)] were prepared. This study examined the effect of bulky MMA (20‐5 wt %)/crosslinkable VMA (0–15 wt %) weight ratio on the properties of the UV‐curable polyurethane acrylates. The fluorine concentration in UV‐cured film surface increased with increasing VMA content up to 9 wt % and then decreased. The T, transparency, elasticity, and mechanical properties of the UV‐cured film samples increased with increasing VMA content. The water/methylene iodide contact angles and surface tension of samples increased from 107/79 to 121/91° and decreased from 17.8 to 12.7 mN/m with increasing VMA content up to 9 wt % and then decreased/increased, respectively. From these results, it was found that the optimum VMA content was 9 wt % to obtain a high‐performance antifouling coating. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42168.  相似文献   

4.
Hard polyurethane coatings combine several features as high flexibility and toughness, good chemical resistance, improved clarity, and spontaneous air‐drying. However, the coating design (thicknesses, interface pretreatments, substrate features, etc.) is often troublesome. In this respect, the present investigation deals with the application of high‐clarity polyurethane coatings on transparent glass and polycarbonates. In particular, the role of the coating thicknesses and, above all, of the different compliance of the substrates was investigated. Progressive mode scratch and dry sliding linear reciprocating tribological tests were carried out and scanning electron microscopy images were captured to analyze the deformation response of the polyurethane coatings. The experimental findings allow to better interpret the way to ruptures of the investigated coating systems and the mechanisms involved. Accordingly, new strategies to prevent them could be elicited. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40021.  相似文献   

5.
Nowadays, new methods for gas‐separation processes are being quickly developed. The separation of CH4/CO2 and CH4/H2 is usually the subject of most related research studies, especially in the membrane gas‐separation process, because of their important role in industry. In this study, we attempted to improve the separation properties of a polysulfone/zeolite 4A mixed‐matrix membrane by modifying the zeolite particle surface. The method included a simple ion‐exchange reaction of magnesium chloride with ammonium hydroxide that yielded the formation and precipitation of magnesium hydroxide whiskers on the surface of the zeolites. The whiskers could omit most of the nonselective voids by interlocking the polymer chains through them and, consequently, improve the permeability, selectivity, and elastic modulus of the membranes. X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and dynamic mechanical analysis proved all the changes recorded after the particle and membrane treatments. SEM images showed the petal‐like morphology of the whiskers that formed on the surface of the particles after the reaction against the smooth surface of the untreated zeolite. At a 30 wt % loading of particles in the polymeric matrix, the selectivities for H2/CH4 and CO2/CH4 increased by 69 and 56%, respectively; in contrast, the H2 and CO2 permeabilities decreased by 2.5 and 10%, respectively. The modulus of elasticity for the treated membrane also increased by 14 and 30% compared to those of the pure and untreated membranes, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44329.  相似文献   

6.
Superhydrophobic coatings were prepared using fluorosilane‐treated diatomaceous earth (DE) with either polyurethane or epoxy binders. The surface wettability and morphology of the films were analyzed using contact angle measurements and scanning electron microscopy (SEM), respectively. The water contact angles were studied as a function of the fluorocarbon fraction on DE and the particle loadings of treated DE in the coating. The contact angles exceeded 150° for coatings with at least 0.02 fluorocarbon fraction (mass of fluorosilane/mass of particle) on the DE and with 0.2 particle loadings (mass of treated particles/mass of coating). The water contact angles of the surfaces were dependent on the nature of the binder below 0.2 particle loadings of the superhydrophobic DE particles, but were independent of the binder type after attaining superhydrophobicity. The results were consistent with the superhydrophobicity resulting from the migration of the superhydrophobic DE moving to and covering the surfaces completely. It was also shown that the treatment with fluorosilanes restricted the pores in DE and reduces the specific surface area of the material. However, these changes had effectively no effect on the superhydrophobicity of the coatings. The results of this work clearly identify some important considerations relative to producing superhydrophobic coatings from inexpensive diatomaceous earth. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44072.  相似文献   

7.
Cotton fabric was successfully modified using a simple mist polymerization with polyurethane (PU) prepolymer and ethylene glycol as the monomers. Scanning electron microscope showed the presence of a very thin polymer coating on the cotton fiber surface. Martindale abrasion tests revealed that the thin PU coating imparted to the cotton fabric a doubled wearing durability compared with the original fabric. Additional experiments demonstrated that the mist polymerization has little impact on the desired cotton properties such as water absorptivity, vapor transmissibility, mechanical property, and flexibility. Considering the excellent balance between the enhanced abrasion resistance and the cotton natures, this surface modification methodology has potential to fabricate wearing durable textiles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43024.  相似文献   

8.
9.
Waterborne polydimethylsiloxane‐modified epoxy‐resin‐based polyol dispersions were synthesized by the reaction of 2,4‐toluene diisocyanate with 2,2‐bis(hydroxymethyl) propionic acid, hydroxypropyl‐terminated polydimethylsiloxane (HTPDMS), and bisphenol A epoxy resin based polyol. These HTPDMS‐modified polyol dispersions exhibited a small particle size and an excellent dispersion stability. Two‐component waterborne polyurethane (2K‐WPU) was prepared from the HTPDMS‐modified polyol dispersion and a hydrophilic‐modified polyisocyanate. The structure of the HTPDMS‐modified polyol and its crosslinked 2K‐WPU films (SEFs) were characterized with Fourier transform infrared and NMR spectroscopies. The effects of the HTPDMS content on the mechanical and thermal properties of the resulting SEFs were investigated. The results show that the thermal stability of the crosslinked SEFs was enhanced with increasing HTPDMS content, whereas the modulus, tensile strength, and pencil hardness values of the films decreased with increasing HTPDMS content. Siloxane segments migrated onto the surface during the film‐formation process. The contact angle of the films increased from 71 to 96 °, and the water absorption ratio of the films decreased from 6.6 to 5.0% when the HTPDMS content in the films increased from 0 to 10%. These results indicate that the water resistance of the films was enhanced by the introduction of HTPDMS into the 2K‐WPU networks. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44342.  相似文献   

10.
To obtain a copolymer network with low surface energy and antibacterial properties, a series of hydroxyl‐terminated poly(dimethyl siloxane)s (PDMSs) modified by a quaternary ammonium salt (QAS) side chain was synthesized via hydrolytic polycondensation and quaternization. The structures of the intermediate and final products were confirmed by Fourier transform infrared spectroscopy, 1H‐NMR, and gel permeation chromatography. The results show that each step was successfully carried out, and objective products were obtained. The modified PDMSs were crosslinked with a commercial polyisocyanate to obtain cured QAS‐modified PDMS coatings. The target functional coatings exhibited excellent antibacterial performance with a low surface energy. When the molar content of QAS in PDMS was varied from 10 to 30%, the critical surface energy of the coatings remained in the range 24.05–26.88 mN/m; this indicated that the coatings had minimal adhesion with fouling according to the Baier curve. The bactericidal tests showed that the antibacterial activity was independent of the PDMS molecular weight but was closely correlated with the QAS content in PDMS. The bactericidal rate of the coatings to Escherichia coli and Staphylococcus aureus was higher than 97% when the molar content of QAS in PDMS was above 20%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41725.  相似文献   

11.
Nano‐thin coatings of glutaraldehyde (GA)‐crosslinked polyethyleneimine (PEI) are extremely selective and effective in binding copper from seawater. Here it was demonstrated that GA‐PEI performs significantly different from PEI. The copper‐selectivity of self‐assembled PEI coatings on silicon substrates was greatly improved by GA‐crosslinking. After submersion in artificial seawater containing 200 ppb copper and equimolar amounts of 11 competing ions only copper and trace amounts of Zn were detected in the GA‐crosslinked coatings, while for non‐crosslinked PEI there was about 30% Zn present relative to copper. The coatings were demonstrated to be highly stable under acidic conditions and retained their copper‐binding selectivity after repeated cycles of binding and acid‐mediated elution. After self‐assembly of the GA‐crosslinked coating on mesoporous diatomaceous earth particles, significant amounts of copper could be extracted from 200 ppb in artificial seawater and eluted under acidic pH. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43954.  相似文献   

12.
To strengthen the interfacial interactions between waste‐printed circuit board (WPCB) nonmetals and unsaturated polyester resin (UPE) and achieve a high performance in UPE composites, a novel type of polyurethane prepolymer (pre‐PU) with dual functions was prepared by the reaction of isophorone diisocyanate with poly(ethylene glycol). We found that pre‐PU was chemically bonded to the surface of the WPCB nonmetals, and a stronger interaction between the WPCB nonmetals and UPE matrix was formed. The mechanical properties and thermal stability of the UPE/pre‐PU–WPCB nonmetal composites showed remarkable improvements compared with those of the UPE/WPCB nonmetals composites, in particular, the impact toughness, which increased threefold. We envision that this promising modification method will not only open up new opportunities for the preparation of high‐performance plastic composites but also provide a guarantee for the practical industrial application of WPCB nonmetals. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45129.  相似文献   

13.
The fluoroalkyl‐modified polyester (PE‐Fn) was synthesized by the reaction of polyester resin (PE) and fluorinated isocyanate, and the structure of the synthesized product was characterized by proton nuclear magnetic resonance (1H‐NMR) and fluorine nuclear magnetic resonance (19F‐NMR). The water and oil wettability of the cured PE coatings with PE‐Fn as additives was investigated by contact angle meter. The results showed that the introduction of an extremely low concentration of PE‐Fn into PE led to the increase in contact angle of water and diiodomethane on cured PE coatings, and the decrease in the surface free energy. The X‐ray photoelectron spectroscopic (XPS) analysis showed that the F/C molar ratio in the outer few nanometers was significantly higher than that in the bulk, indicating that the fluoroalkyl groups in PE‐Fn had enriched on the coating surface. It was also found that longer fluoroalkyl groups and fluoroalkyl groups with ? CF3 at its end had the higher tendency to aggregate on the coating surface. The topological structures of the cured coatings were recorded by an atomic force microscope under tapping mode and the results revealed that there was a strong surface segregation of fluorinated species. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39812.  相似文献   

14.
Present work concerns to the study of the dynamic mechanical and thermal responses of selected polypropylene (iPP)/mica composites with a modified interface from the matrix side by using a p‐phenylen‐bis‐maleamic acid grafted atactic polypropylene, coming from a byproduct of industrial polymerization reactors. Thus, the study is mainly focused on the 75/25 iPP/mica ratio since it was identified in previous works as providing the maximum inter mica particle distance to assure they should participate in the overall process of dissipation of the mechanical energy supplied to the composites. Hence, the present dynamic mechanical analysis discussion tries to correlate the damping responses of the injection‐molded composites with those previously obtained but over compression molded composites as the basis of further studies all along the compositional iPP/mica map. Therefore, the latter let us, on the one hand, to follow how the main values of the different dynamic mechanical analysis parameters vary because of the interfacial modifier presence, and on the other, to develop a robust correlation between them and the corresponding macroscopic mechanical parameters. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45366.  相似文献   

15.
The dynamic properties, including the dynamic mechanical properties, flex fatigue properties, dynamic compression properties, and rolling loss properties, of star‐shaped solution‐polymerized styrene–butadiene rubber (SSBR) and organically modified nanosilica powder/star‐shaped styrene–butadiene rubber cocoagulated rubber (N‐SSBR), both filled with silica/carbon black (CB), were studied. N‐SSBR was characterized by 1H‐NMR, gel permeation chromatography, energy dispersive spectrometry, and transmission electron microscopy. The results show that the silica particles were homogeneously dispersed in the N‐SSBR matrix. In addition, the N‐SSBR/SiO2/CB–rubber compounds' high bound rubber contents implied good filler–polymer interactions. Compared with SSBR filled with silica/CB, the N‐SSBR filled with these fillers exhibited better flex fatigue resistance and a lower Payne effect, internal friction loss, compression permanent set, compression heat buildup, and power loss. The nanocomposites with excellent flex fatigue resistance showed several characteristics of branched, thick, rough, homogeneously distributed cross‐sectional cracks, tortuous flex crack paths, few stress concentration points, and obscure interfaces with the matrix. Accordingly, N‐SSBR would be an ideal matrix for applications in the tread of green tires. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40348.  相似文献   

16.
An easy approach was reported to achieve the simultaneous reinforcement and toughening of polypropylene (PP) via thermally induced self‐assembly of β‐nucleating agent (TMB‐5). The results showed that the processing temperatures dictated the solubility and self‐assembly of TMB‐5 in the polymer melts to determine the subsequent morphology development of PP. At low processing temperature, TMB‐5 did not dissolve into the polymer melt but remained original shape to induce PP to crystallize into spherulites so that it only promoted the formation of β‐form crystals to enhance the toughness of the samples. At high processing temperature, TMB‐5 gradually dissolved into the polymer melts. On cooling, the dissolved nucleating agent self‐assembled into high aspect ratio fibrils through intermolecular hydrogen‐bonding interactions. Due to a favorable matching between PP and TMB‐5, PP preferred to nucleate and grow orthogonally to the fibril axis and into oriented hybrid shish‐kebab morphology with rich β‐form crystals. Compared with isotropic spherulites, the anisotropic structure exhibited excellent properties of the β‐form crystal and shish‐kebab morphology to simultaneously improve the strength and toughness of TMB‐5‐modified PP samples. With the increasing processing temperature, more dissolved TMB‐5 was involved in the self‐assembly procedure to generate longer fibrils and induce more lamellae to grow on the surface. As a consequence, the anisotropy of the PP samples increased further, bringing out more improvements of the tensile strength. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40605.  相似文献   

17.
A zwitterionic poly(vinyl alcohol‐co‐ethylene) (PVA‐co‐PE) nanofiber membrane for resistance to bacteria and protein adsorption was fabricated by the atom transfer radical polymerization of sulfobetaine methacrylate (SBMA). The PVA‐co‐PE nanofiber membrane was first surface‐activated by α‐bromoisobutyryl bromide, and then, zwitterionic SBMA was initiated to polymerize onto the surface of nanofiber membrane. The chemical structures of the functionalized PVA‐co‐PE nanofiber membranes were confirmed by attenuated total reflectance–Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The morphologies of the PVA‐co‐PE nanofiber membranes were characterized by scanning electron microscopy. The results show that the poly(sulfobetaine methacrylate) (PSBMA) was successfully grafted onto the PVA‐co‐PE nanofiber membrane, and the surface of the nanofiber membrane was more hydrophilic than that of the pristine membrane. Furthermore, the antibacterial adsorption properties and resistance to protein adsorption of the surface were investigated. This indicated that the PSBMA‐functionalized surface possessed good antibacterial adsorption activity and resistance to nonspecific protein adsorption. Therefore, this study afforded a convenient and promising method for preparing a new kind of soft and nonwoven dressing material with antibacterial adsorption and antifouling properties that has potential use in the medical field. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44169.  相似文献   

18.
Surface grafting of functional polymers is an effective method to alter material properties and degradation behavior. Two different substrate shapes of poly(l ‐lactide) (PLLA), i.e., films and microparticles, were surface‐grafted with hydrophilic monomers, and their surface degradation was monitored. Surface grafting with a hydrophilic and acidic polymer graft [acrylic acid (AA)] induced large alterations in the surface morphology and topography of the films. In contrast, hydrophilic and neutral polymer grafts [acrylamide (AAm)] had no significant effect on the surface degradation behavior, while the PLLA reference and co‐monomeric (AA/AAm) polymer‐grafted samples exhibited intermediate surface degradation rates. The grafted PAA chains induced a local acidic environment on the surface of the substrates, which in turn catalyzed the surface degradation process. This effect was more pronounced in the films than in the microparticles. Thus, the nature of the grafted chains and substrate geometry were shown to affect the surface degradation behavior of PLLA substrates. © 2015 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42736.  相似文献   

19.
Modified hollow glass microsphere (HGM) particles have been prepared by surface treatment. Coupling agents such as γ‐aminopropyltriethoxysilane (APTES), di(dioctylpyrophosphato) ethylene titanate (NDZ‐311), and glutaraldehyde (GA) were used as modifiers to improve the hydrophobicity of HGM. Compared with pristine HGM, the modified HGM, especially the particles coupled with APTES‐GA, show better properties on flexural strength, fracture toughness, and dynamic mechanical properties of phenolic syntactic foams. It is revealed that the coupling agent coating layer grafted onto the surface of HGM reduces the polarity of particles, avoiding agglomeration of HGM in phenolic matrix and exhibiting good interfacial interaction between HGM and phenolic matrix. The remarkable improvement of interfacial adhesion between APTES‐GA modified HGM and phenolic matrix is mainly due to the covalent linkage with phenolic resin while the physical entanglement of molecular chains dominates the linkage between other modified HGM and phenolic matrix. APTES‐GA treatment is a more appropriate surface modification method for inorganic particle reinforced phenolic matrix composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44415.  相似文献   

20.
On the basis of the short‐chained modifier of stearyl‐alcohol poly(ethylene oxide) ether (AEO), an entrapping modification was carried out on the polypropylene (PP) surface for hydrophilic improvement. A swelling layer was confirmed locating in the amorphous region on the PP surface, from which the modifiers could penetrate into the surface. The AEO‐8 modifier achieved the optimal hydrophilic modification on the surface with a contact angle of 20.6° and modifier coverage of 19.2%. A microphase separation was speculated to occur between the poly(ethylene oxide) (PEO) chain of AEO and the PP substrate in the entrapping surface, after which surface‐enriched PEO chains could improve surface hydrophilicity, simultaneously, reserved stearyl chains in the surface could approach modifier fixation. Water immersion durability of the modified surface could be improved by establishing a covalent linkage in the surface‐fixed structure. This work gives more comprehensive insights in the entrapping modification on the semi‐crystalline PP surface based on the short‐chained and block modifier. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43607.  相似文献   

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