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1.
A series of the surface‐functionalized nano‐SiO 2/polybenzoxazine (PBOZ) composites was produced, and an attempt was made to improve the toughness of PBOZ material, without sacrificing other mechanical and thermal properties. A benzoxazine functional silane coupling agent was synthesized to modify the surface of nano‐SiO 2 particles, which were then mixed with benzoxazine monomers to produce the nano‐SiO 2‐PBOZ nanocomposites. The notched impact strength and the bending strength of the nano‐SiO 2‐PBOZ nanocomposites increase 40% and 50%, respectively, only with the addition of 3 wt % nano‐SiO 2. At the same load of nano‐SiO 2, the nano‐SiO 2‐PBOZ nanocomposites exhibit the highest storage modulus and glass‐transition temperature by dynamic viscoelastic analysis. Moreover, the thermal stability of the SiO 2/PBOZ nanocomposites was enhanced, as explored by the thermogravimetric analysis. The 5% weight loss temperatures increased with the nano‐SiO 2 content and were from 368°C (of the neat PBOZ) to 379°C or 405°C (of the neat PBOZ) to 426°C in air or nitrogen with additional 3 wt % nano‐SiO 2. The weight residue of the same nanocomposite was as high as 50% in nitrogen at 800°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
2.
As an additive manufacturing technology, ultraviolet (UV)‐curing three‐dimensional printing, which requires the use of a photocurable resin, is increasingly being used to produce customized end‐user parts of many complex shapes. In this study, to improve the strength and ductility of printing materials, nano‐SiO 2‐reinforced photocurable resins were prepared by a planetary ball mill; then, the morphology, photochemistry, thermal property, and mechanical properties of the nanocomposites were investigated and characterized. Transmission electron microscopy analysis indicated that the modified nano‐SiO 2 was well dispersed in the photocurable resin. The glass‐transition temperature increased from 67.2°C for the unfilled resin to 71.7 and 80.1°C for nanocomposites with nano‐SiO 2 contents of 0.3 and 0.7 wt %, respectively. The tensile strength and impact strength were increased by 46.7 and 165.3% for nanocomposites with 0.3 wt % nano‐SiO 2. The flexural modulus of the nanocomposites increased from 1.7 to 8.0 GPa when 0.7 wt % nano‐SiO 2 was added to the photocurable resin; this appeared to originate from the relatively high level of dispersion and the intimate combination of the nano‐SiO 2 with the matrix. The investigation of the physical and chemical properties of such UV‐curing materials showed that the low filler concentration (<1 wt %) of nano‐SiO 2 did not affect the processability of the nanocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42307. 相似文献
3.
Crosslinked alginate‐based nanocomposites at different SiO 2 contents were prepared successfully by blending the nano‐SiO 2 solution into low concentration alginate solution (0.5 wt %), with the alginate concentration increased step by step to the resulted concentration, in this course glycerol was used as plasticizer and 5 wt % CaCl 2 as crosslinker. The combined effect of SiO 2 content (1.5–8 wt %) on the microstructural, physical, mechanical, and optical properties of the nanocomposite films were investigated. The results showed that tensile strength and elongation was improved by about 40.33% and 89%, respectively, upon increasing the SiO 2 content to 4.5 wt %. In addition, water vapor permeability and swelling degree decreased by 19% and 16% with increasing SiO 2 content up to 8 and 4.5 wt %, respectively with respect to pure crosslinked alginate film. Thermogravimetric analysis also revealed that nano‐SiO 2 can improve the thermal stability of sodium alginate films produced by this method. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45286. 相似文献
4.
The purpose of this article is to investigate the effects of nano‐tianium dioxide (nano‐TiO 2) on the high‐amylose starch/polyvingl alcohol (PVA) blend films prepared by a solution casting method. The results show that at the concentration of 0.6% of nano‐TiO 2, the film demonstrated the best tensile strength at 9.53 MPa, and the elongation at break was noted as 49.50%. The optical transmittance of the film was decreased and the water resistance was improved with further increase of the concentration of nano‐TiO 2. Using the techniques of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and field‐emission scanning electron microscopy (SEM), the molecular and the crystal structures of the films were characterized. The results indicate that the miscibility and compatibility between high‐amylose starch and PVA were increased with the addition of nano‐TiO 2 into the films due to the formation of hydrogen and C? O? Ti bonds. The antimicrobial activities of the blend films were also explored. The results show that there were inhibitory zones around the circular film disc, which is attributable to the addition of nano‐TiO 2. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42339. 相似文献
5.
The purpose of this work was to improve the properties of the starch/poly(vinyl alcohol) (PVA) films with nano silicon dioxide (nano SiO 2). Starch/PVA/nano‐SiO 2 biodegradable blend films were prepared by a solution casting method. The characteristics of the films were assessed by Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS). The results obtained in this study indicated that the nano‐SiO 2 particles were dispersed evenly within the starch/PVA coating and an intermolecular hydrogen bond and a strong chemical bond C? O? Si were formed in the nano‐SiO 2 and starch/PVA. That the blending of starch, PVA and nano‐SiO 2 particles led to uniform starch/PVA/nano‐SiO 2 blend films with better mechanical properties. In addition, the nano‐SiO 2 particles can improve the water resistance and light transmission of the blend films. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
6.
Dielectric and conduction properties of polyimide/silica nano‐hybrid films were investigated with the silica content and the testing frequency, using a small electrode system. The hybrid films were prepared through sol‐gel process and thermal imidization, by using pyromellitic dianhydride and 4,4′‐oxydianiline as polyimide precursors, and tetraethoxysilane and methyltriethoxysilane as silica precursors. The dielectric coefficient of PI/SiO 2 films was monotonically increased with increasing silica content, and decreased with increasing testing frequency. The dielectric loss of PI/SiO 2 films had no obvious changes with increasing silica content, but monotonically increased with increasing testing frequency. These can be contributed to the different quantity and migration chunnels of current carriers, which were mainly influenced by a few of complicated factors. There were remarkable differences between conduction property of PI/TEOS‐SiO 2 films and PI/MTEOS‐SiO 2 films because of the different size and dispersion status of silica particles in the polyimide matrix. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers 相似文献
7.
The nano‐ZnO and nano‐TiO 2 were added into chitosan (CS) anion layer to prepare polyvinyl alcohol (PVA) ‐ sodium alginate (SA)/ TiO 2‐ZnO‐CS (here, PVA:polyvinyl alcohol; SA:sodium alginate) bipolar membrane (BPM), which was characterized using scanning electron microscopy, atomic force microscopy (AFM), thermogravimetric analysis (TG), electric universal testing machine, contact angle measurer, and so on. Experimental results showed that nano‐TiO 2‐ZnO exhibited better photocatalytic property for water splitting at the interlayer of BPM than nano‐TiO 2 or nano‐ZnO. The membrane impedance and voltage drop (IR drop) of the BPM were obviously decreased under the irradiation of high‐pressure mercury lamps. At a current density of 60 mA/cm 2, the cell voltage of PVA‐SA/TiO 2‐ZnO‐CS BPM‐equipped cell decreased by 1.0 V. And the cell voltages of PVA‐SA/TiO 2‐CS BPM‐equipped cell and PVA‐SA/ZnO‐CS BPM‐equipped cell were only reduced by 0.7 and 0.6 V, respectively. Furthermore, the hydrophilicity, thermal stability, and mechanical properties of the modified BPM were increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
8.
A novel low‐cost SiO 2/Polyvinylchloride (PVC) membrane with different nano‐SiO 2 particles loading (0–4 wt %) was prepared by the phase‐inversion process. The optimum nano‐SiO 2 dosage was determined as 1.5 wt % based on the casting solution compositions, the membranes' mechanical properties and hydrophilicities, the pure water fluxes, microstructures, and absorption of protein. Compared with the bare membrane, the membrane with 1.5 wt % nano‐SiO 2 addition presented better capabilities against the protein absorption and bacterial attachment, better antifouling performance, and higher flux recovery ratio in filtration of the supernatant liquor which collected from a secondary sedimentation tank in a municipal wastewater plant. The SiO 2/PVC membranes have applicable potential in the municipal wastewater treatment for their low price, good antifouling performance and high removal efficiencies of SS (over 97.2%), COD (up to 82.9%) and total bacteria (more than 93.6%). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41267. 相似文献
9.
An in situ deposition approach was used for the synthesis of nano‐CaSO 4 and nano‐Ca 3(PO 4) 2. The nanosize particles were confirmed with an X‐ray diffraction technique. Composites of polypropylene (PP) with 0.1–0.5 wt % nano‐ or commercial CaSO 4 or nano‐Ca 3(PO 4) 2 were prepared. The transition from the α phase to the β phase was observed for 0.1–0.3 wt % nano‐CaSO 4/PP and nano‐Ca 3(PO 4) 2/PP composites. This was confirmed by Fourier transform infrared. A differential scanning calorimetry analysis was carried out to determine the thermal behavior of the nanocomposites with increasing amounts of the nano‐CaSO 4 and nano‐Ca 3(PO 4) 2 fillers. Increases in the tensile strength and Young's modulus were observed up to certain loading and were followed by a decrease in the tensile strength. A continuous decrease in the elongation at break (%) was also observed for commercial CaSO 4 and larger nano‐Ca 3(PO 4) 2. A decrease in the mechanical properties after a certain loading might have been due to the agglomeration and phase transition of PP in the composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 670–680, 2007 相似文献
10.
Nano‐SiO 2 was introduced into in‐situ composites of polycarbonate (PC) and a thermotropic liquid crystalline polymer (TLCP) using a twin‐screw extruder. The rheology of these composites was characterized with capillary rheometry, and the morphology of the dispersed TLCP observed with scanning electron microscopy. The rheological data revealed that the viscosity decrease of PC melts by only the addition up to 20 wt% TLCP remained smaller than 30%, while it became ~48% upon further addition of only about 1 wt% nano‐SiO 2 and larger than 60% upon ~9 wt% nano‐SiO 2 filling, in contrast to a 50% viscosity increase of PC melts with increase in nanosilica loading up to ~9 wt%. These silica‐filled composites exhibited markedly low viscosity, especially at relatively high shear rates. The morphology of TLCP extracted from unfilled and silica‐filled composites indicated that the largest viscosity reduction was correlated well with the fibrillation of TLCP droplets enhanced by nano‐SiO 2. The TLCP/SiO 2/PC composites exhibited rheological hybrid effect with fillers at nanometer scale. POLYM. ENG. SCI., 47:757–764, 2007. © 2007 Society of Plastics Engineers 相似文献
11.
A nanosize CaCO 3 filler was synthesized by an in situ deposition technique, and its size was confirmed by X‐ray diffraction. CaCO 3 was prepared in three different sizes (21, 15, and 9 nm). Styrene–butadiene rubber (SBR) was filled with 2–10 wt % nano‐CaCO 3 with 2% linseed oil as an extender. Nano‐CaCO 3–SBR rubber composites were compounded on a two‐roll mill and molded on a compression‐molding machine. Properties such as the specific gravity, swelling index, hardness, tensile strength, abrasion resistance, modulus at 300% elongation, flame retardancy, and elongation at break were measured. Because of the reduction in the nanosize of CaCO 3, drastic improvements in the mechanical properties were found. The size of 9 nm showed the highest increase in the tensile strength (3.89 MPa) in comparison with commercial CaCO 3 and the two other sizes of nano‐CaCO 3 up to an 8 wt % loading in SBR. The elongation at break also increased up to 824% for the 9‐nm size in comparison with commercial CaCO 3 and the two other sizes of nano‐CaCO 3. Also, these results were compared with nano‐CaCO 3‐filled SBR without linseed oil as an extender. The modulus at 300% elongation, hardness, specific gravity, and flame‐retarding properties increased with a reduction in the nanosize with linseed oil as an extender, which helped with the uniform dispersion of nano‐CaCO 3 in the rubber matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2563–2571, 2005 相似文献
12.
A new method of surface chemical modification of nano‐SiO 2 was proposed in the paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano‐SiO 2 reacted with AB 2‐type monomer ( N, N‐dihydroxyethyl‐3‐amino methyl propionate) by one‐step polycondensation. And the product's Fourier transform infrared graphs and transmission electron microscopy (TEM) images proved that hyperbranched poly(amine‐ester) (HPAE) was grafted from nano‐SiO 2 surface successfully. Moreover, polyvinyl chloride (PVC)/modified nano‐SiO 2 composites were made by melt‐blending. The composites' structures and mechanical properties were characterized by TEM, scanning electron microscopy, and electronic universal testing machine. The results showed that nano‐SiO 2 grafted by HPAE increased obviously in dispersion in PVC matrix, and mechanical properties of PVC were effectively improved. Additionally, it was found that mechanical properties of PVC/nano‐SiO 2 composites reached the best when weight percent of nano‐SiO 2 in PVC matrix was 1%. Compared with crude PVC, the tensile strength of HPAE grafted nano‐SiO 2/PVC composite increased by 24.68% and its break elongation, flexural strength, and impact strength increased by 15.73, 4.07, and 184.84%, respectively. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers 相似文献
13.
In this study, various polypropylene (PP) nanocomposites were prepared by melt blending method. The effects of different spherical nanofillers, such as 50 nm CaCO 3 and 20 nm SiO 2, on the linear viscoelastic property, crystallization behavior, morphology and mechanical property of the resulting PP nanocomposites were examined. Rheological study indicated that coincorporation of nano‐SiO 2 and nano‐CaCO 3 favored the uniform dispersion of nanoparticles in the PP matrix. Differential scanning calorimeter (DSC) and polarizing optical microscopy (POM) studies revealed that the coincorporation of SiO 2 and CaCO 3 nanoparticles could effectively improve PP crystallizability, which gave rise to a lower supercooling temperature (Δ T), a shorter crystallization half‐life ( t1/2) and a smaller spherulite size in comparison with those nanocomposites incorporating only one type of CaCO 3 or SiO 2 nanoparticles. The mechanical analysis results also showed that addition of two types of nanoparticles into PP matrix gave rise to enhanced performance than the nanocomposites containing CaCO 3 or SiO 2 individually. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
14.
High‐performance nanosilica composites based on epoxy‐modified polybenzoxazine matrices are developed. Chemorheological study of benzoxazine–epoxy resin mixtures reveals that processing window of the benzoxazine resin (BA‐a) is substantially broadened with an addition of the liquid epoxy. Glass transition temperature ( T g) of the BA‐a copolymerized with epoxy resin shows a synergistic behavior with a maximum T g value (174°C) at the benzoxazine–epoxy mass ratio of 80:20. The copolymer at this composition is also used as a matrix for nano‐SiO 2 composites. A very low melt viscosity of the benzoxazine–epoxy mixtures promotes good processability with the maximum attainable nano‐SiO 2 loading up to 35 wt%. From scanning electron microscopy investigation, fracture surface of the 35 wt% nano‐SiO 2‐filled benzoxazine–epoxy composite reveals relatively homogeneous distribution of the nano‐SiO 2 in the copolymer with good particle wet‐out. In addition, very high reinforcing effect was also observed in such high content of the nano‐SiO 2, i.e., about 2.5 times in modulus improvement. This improvement is attributed to the strong bonding between the copolymer matrix and the nano‐SiO 2 through ether linkage as confirmed by Fourier‐transform infrared investigation. POLYM. COMPOS., 38:2261–2271, 2017. © 2015 Society of Plastics Engineers 相似文献
15.
Biodegradable films are used in a variety of applications, including packaging. However, their use is limited due to their high moisture and water sensitivity. In this work, cassava starch (CS) was blended with poly(vinyl alcohol) (PVA). Silica particles (SiO2) were incorporated to increase the hydrophobicity of the blend by intermolecular interaction through hydrogen bonding between the three components. Instead of a plasticizer or crosslinker, a small amount of triethylamine was added to eliminate residual acetate groups in PVA. The miscibility of CS and PVA phases was confirmed by smooth fracture surfaces and a single glass transition temperature. When SiO2 content was below 5% (wt), the particles were well dispersed in a continuous phase of polymer matrix. At this loading of SiO2, the increase in tensile strength was as high as 170% and in elongation-at-break, 250%. All loadings of SiO2 increased thermal stability of the blend films because silanol groups on the surface of SiO2 particles formed effective interfacial interactions with hydroxyl groups of the polymers. These interactions also prevented the ingress of water molecules, significantly increasing the hydrophobicity of the films. The water contact angle increased as high as 113° and moisture absorbency and water solubility were low. These highly hydrophobic, photodegradable, biodegradable CS/PVA/SiO2 films show great potential as a low-cost, eco-friendly material. 相似文献
16.
Poly(vinyl chloride‐ co‐vinyl acetate) (PVVA)/nano‐SiO 2 composite resin was prepared by radical suspension polymerization of the monomers in the presence of fumed nano‐SiO 2 particles premodified with γ‐methylacryloxypropyl trimethoxysilane. The cool dioctyl phthalate absorption percentage, granule porosity, and specific surface area of the composite resin were enhanced through incorporation of nano‐SiO 2 into the PVVA. Scanning electron microscope pictures showed the resin had higher porosity. PVVA/nano‐SiO 2 composite resin was mixed with pure PVC resin to form a mixture sample (polymer‐composite blend [PCB]) and the mixture was fused in the torque rheometer. The rheological test results indicated that, at a certain nano‐SiO 2 content, the fusion speed of PCB was accelerated and the fusion temperature of PCB was decreased, owing to nano‐SiO 2 dispersed evenly in the polymer matrix. When excessive nano‐SiO 2 was loaded, the fusion torque, the fusion time, and the fusion temperature of PCB were all increased. These properties are correlative to the dispersive density of nano‐SiO 2 in the polymer matrix. This study also demonstrated that the introduction of small amounts of nano‐SiO 2 into the resin increased the impact strength and tensile strength of PCB simultaneously. J. VINYL ADDIT. TECHNOL., 20:230–236, 2014. © 2014 Society of Plastics Engineers 相似文献
17.
This study is focused on the development of high‐performance composite materials based on nano silicon dioxide (nano‐SiO 2) modified by polydopamine (PDA). A facile one‐step method was developed to synthesize core–shell structured SiO 2@polydopamine (PDA) nanospheres. During the synthesis, a PDA shell was simultaneously coated on the SiO 2 nanospheres to form the core–shell nanostructure which was blended with polypropylene (PP) and β nucleating agent (β‐NA) to enhance both mechanical and hydrophilic properties. Nano‐SiO 2 particles modified by PDA (SiO 2@polydopamine) influence the crystallization of PP seriously. The results indicated that when 1%wt SiO 2@polydopamine was added, the impact strength of composite reached the maximum value 12.60k J/m 2 increasing 137% compared with PP, the bending strength and bending modulus decreased slightly reaching 41.85 MPa, and 2192 MPa, respectively, the composite possessed hydrophilic performance with the water contact angle of 88.32°. β nucleating agent was used in all formulations, the synergistic effect toward mechanical properties with SiO 2@polydopamine was studied. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45004. 相似文献
18.
Poly(vinyl alcohol) (PVA) nanocomposite and modified CaCO 3 nanoparticles (NPs) were fabricated by ultrasound agitation method with particle content altering from 3, 5, and 8 wt %. The CaCO 3 surface was successfully treated by 10 wt % of bioactive dicarboxylic acid (DA). The influences of loading modified NPs on the thermal, mechanical, adsorption, contact angle, and physical properties of the poly(vinyl alcohol) nanocomposite films were thoroughly studied. The results showed that incorporation of modified CaCO 3 into the PVA matrix had better performance than the pure PVA. Meanwhile, tensile strength, Young's modulus, and thermal stability are enhanced from 33.36 MPa, 1.26 GPs, and 242.918C (neat PVA) to 81.7 MPa, 4.81 GPa, and 312.95 °C (PVA/CaCO 3‐DA NC 5 wt %), respectively. Also, the adsorption capacity of the PVA/CaCO 3‐DA NCs 5 and 8 wt % revealed that the NC films could act as an appropriate absorbent for the removal of Cd(II) ions with maximum adsorption capacity of about 20.70 and 25.19 mg g ?1 for Cd(II), respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45414. 相似文献
19.
Comprehensive high‐performance epoxy nanocomposites were successfully prepared by co‐incorporating organo‐montmorillonite (o‐MMT) and nano‐SiO 2 into epoxy matrix. Because of the strong interaction between nanoscale particles, the MMT layers were highly exfoliated, and the exfoliated nanoscale MMT monoplatelets took an interlacing arrangement with the nano‐SiO 2 particles in the epoxy matrix, as evidenced by X‐ray diffraction measurement and transmission electron microscopy inspection. Mechanical tests and thermal analyses showed that the resulting epoxy/o‐MMT/nano‐SiO 2 nanocomposites improved substantially over pure epoxy and epoxy/o‐MMT nanocomposites in tensile modulus, tensile strength, flexural modulus, flexural strength, notch impact strength, glass transition temperature, and thermal decomposition temperature. This study suggests that co‐incorporating two properly selected nanoscale particles into polymer is one pathway to success in preparing comprehensive high‐performance polymer nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
20.
A single‐step deposition of cobalt‐doped zinc oxide (Co‐ZnO) thin film nano‐composites on three different crystalline substrates, viz., Al 2O 3 (c‐sapphire), silicon (100) (Si), and SiO 2 (quartz) is reported, using pulsed electron beam ablation (PEBA). The results indicate that the type of substrate has no effect on Co‐ZnO films stoichiometry, morphology, microstructure, and film thickness. The findings show the presence of hexagonal close‐packed metallic Co whose content increases in the films deposited on Al 2O 3 and Si substrates relatively to SiO 2 substrate. The potential of the films as model nano‐catalysts has been evaluated in the context of the Fischer‐Tropsch (FT) process. Fuel fractions, which have been observed in FT liquid products, are rich in diesel and waxes. Specifically, Co‐ZnO/Al 2O 3 nano‐catalyst shows a selectivity of ~4%, 31%, and 65% towards gasoline, diesel, and waxes, respectively, while Co‐ZnO/SiO 2 nano‐catalyst shows a selectivity of ~12%, 51%, and 37%, for gasoline, diesel, and waxes, respectively. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3332–3340, 2018 相似文献
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