Content Of nano-ZnO Research Articles

Development of polyethylene antifogging and antibacterial packaging films for lettuce preservation

The antifogging and antibacterial films were fabricated by employing low-density polyethylene (LDPE) with addition of nano-ZnO and surfactants (SF) via extrusion casting method. The SEM results showed that SF promoted the dispersion of nano-ZnO in the film. The LDPE films containing both nano-ZnO and SF exhibited excellent UV shielding, antifogging and antibacterial properties. The antifogging duration of films increased with the increase of nano-ZnO. The lettuces packed by the film containing SF could be clearly visible for its antifogging property. It showed the LDPE films added with nano-ZnO could delay quality deterioration of lettuces and the protective effect enhanced with increased nano-ZnO. Comparing the two films that contained same content of nano-ZnO, the film added with SF could maintain better quality for lettuces, which was also personified with better antibacterial activity against E. coli and S. aureus. This antifogging and antibacterial film was expected to be a candidate for the fruit and vegetable preservation.

A transparent kaolinite-loaded zinc oxide nanocomposite sunscreen with UV shielding rate over 99% based on bidirectional dispersion

Nano-sized TiO2 and ZnO are the most efficient and widely used inorganic sunscreen, but they still have some drawbacks including agglomeration, delamination, clogging pores and high cost. In this study, a kaolinite-loaded zinc oxide nanocomposite sunscreen was prepared and the key technical problems in application of inorganic nano-sized sunscreens was solved. The synthesized kaolinite-loaded zinc oxide nanocomposite was characterized by XRD, SEM, EDS, XRF and UV–vis spectrophotometry. The SEM image of the nanocomposite suggests that agglomeration of nano-ZnO is avoided by bidirectional dispersion of superfine kaolinite powder and nano-ZnO. Nano-effect and UV shielding rate are enhanced and the nanocomposite sunscreen possesses UV shielding efficiency of 1 + 1 > 2. The UV shielding rate of the nanocomposite sunscreen is greater than 99%, only 10% addition of it endows ordinary skin care products with excellent UV protective efficacy. Moreover, the content of nano-ZnO is reduced by half through introduction of kaolinite, the cost of the sunscreen is lowered, delamination and pore clogging are avoided. This work provides a technical approach for producing stronger, safer and more economical popularized anti-UV skincare products.

Synthesis of Nano-ZnO Composite Polystyrene Acrylic Emulsion and Its Application in Chinese Painting Pigments

With the continuous development of coating technology and environmental protection concepts, coating has become an indispensable item in the field of architecture and industry. Styrene acrylic emulsion as a new type of waterborne paint has attracted much attention since its emergence. Its functional modification is the focus of research, but the research results have not been ideal. To further improve the performance of styrene acrylic emulsion, nano-ZnO composite polystyrene emulsion was synthesized by emulsion polymerization, and its properties were analyzed. Aiming at the problem that nanopigments are prone to agglomeration, corresponding solutions are proposed, and the stability of nano-coatings is preliminarily studied. The inherent culture and essence of traditional culture and art is the wealth of realizing the unique nationalization and internationalization of design works. There is a lot of artistic quintessence in traditional Chinese painting art that can be used for reference to visual communication design. Through in-depth understanding and learning of Chinese painting theory and techniques, designers’ aesthetic abilities and innovation abilities can be qualitatively improved. First of all, the emulsion polymerization was carried out by semicontinuous method. The composite polystyrene emulsion containing different content of nano-ZnO was successfully prepared, which was recorded as N, Z, Z15, Z25, and Z35, respectively. The properties of the emulsion were determined, and the solid content, monomer conversion, viscosity, water absorption, and bacteriostatic effect of the emulsion were determined. The experimental results show that the solid content of emulsion Z15 (nano-ZnO content is 15%) reaches the highest value of 43.5%. The content of monomer in the emulsion affects the solid content, but the higher the monomer content, the better the solid content. The highest monomer conversion of Z15 was 86.4% at 80°C. The monomer conversion increased with the increase of polymerization temperature and tended to be stable after reaching the highest value. In the absence of nano-ZnO, the viscosity of the emulsion is the highest, and the viscosity of the emulsion decreases with the increase of the content of nano-ZnO monomer. Z35 (when the content of nano-ZnO is 35%) is the highest, which is 18.91%. The water absorption increases with the increase of nano-ZnO content. The content of nano-ZnO in the emulsion increased, the MIC value became smaller, and the bacteriostatic effect became better and better. This indicates that nano-ZnO composite polystyrene emulsion has good monomer conversion, super water resistance, and bacteriostatic effect, but its viscosity is relatively poor.

Facile in situ fabrication of ZnO-embedded cellulose nanocomposite films with antibacterial properties and enhanced mechanical strength via hydrogen bonding interactions

Nano-ZnO were in situ prepared and permanently embedded in regenerated cellulose (RC) films by chemical precipitation to endow antibacterial of films and simultaneously strengthen tensile strength. ZnCl2 was selected as a promoter of 1-allyl-3-methylimidazolium chloride for cellulose dissolution and as a precursor for nano-ZnO synthesis. Zn2+-absorbed cellulose solution was reacted with NaOH under ultrasonic to obtain nano-ZnO embedded RC films. The results indicated that RC films treated with the longest sonication time, highest regeneration solution basicity, and highest cellulose concentration were demonstrated to be the most effective against S. aureus, which agreed well with the dense and homogeneous distribution of high content of nano-ZnO on the film surface. The nanocomposite films achieved particularly high mechanical strength of 202.0 MPa with improved thermal stability. Strong H-bonding formed between nano-ZnO and cellulose, which contributed to high tensile strength and thermal stability of films. This work affords a simple approach to prepare cellulose nanocomposite with outstanding performance for potential application in packaging.

Preparation and Properties of Nano-ZnO/ Organic Fluorine Modified Polyacrylate Finishing Agent

A nano-ZnO/organic fluorine-modified polyacrylate leather finishing agent was prepared using a mixture of a Silyl-modified nano-ZnO, dodecafluoroheptyl methacrylate (DFMA), methyl methacrylate (MMA) and butyl acrylate (BA) as raw materials. A semi-continuous seeded emulsion polymerization followed. The overall research objective was to improve the bacteriostatic, hydrophobicity and anti-aging properties of leather articles. The structure of the composite emulsion and its film were characterized and analyzed by FT-IR, TEM and XPS. The results showed that the latex particles had an obvious core-shell structure, a smooth surface and were monodisperse. The particle size of the emulsion ranged between 30 and 50 nm. The average value of Zeta potential was -40.1 mV which signified a good emulsion stability. The composite emulsion and its film had good UV resistance and water resistance. When the content of organic fluorine in the film was a maximum 20 %, the contact angle of a water drop on the finished leather, tensile strength and tear strength were 133.48°, 620 N and 61 N, respectively. When the content of nano-ZnO in the film was 1.0%, the average width of antibacterial band of finished leather was 2.1 mm. The finished leather also demonstrated a good anti-aging property.

Effects of zinc oxide nanoparticles on early-age hydration and the mechanical properties of cement paste

Zinc oxide nanoparticles (nano-ZnO) were dispersed uniformly into cement paste by using ultrasonic treatment, and the effects of nano-ZnO on the setting time, strengths, hydration, and microstructure of the cement paste were investigated. The addition of nano-ZnO to cement paste showed a remarkable influence on the early hydration process of the cement paste, whose setting time increased drastically when the content of nano-ZnO was only 0.2 wt% (by weight of cement). The isothermal calorimetry and electrical resistance tests showed that the addition of nanoparticles can prolong the induction period of cement hydration and influence the hydration rate during the acceleration period. The mechanical test results indicated that long-age strengths of cement paste were improved with the increase of nano-ZnO concentrations. Furthermore, nano-ZnO refined the pore diameter distribution and formed a compact microstructure of the cement paste at 28 days.

Isotactic polypropylene toughened with poly(acrylonitrile-butadiene-styrene): compatibilizing role of nano-ZnO

ABSTRACTIn the present work, the toughening effect of poly(acrylonitrile-butadiene-styrene) (ABS) together with nano-ZnO on isotactic polypropylene (iPP) was investigated. Mechanical tests indicated that by introducing ABS and nano-ZnO simultaneously, iPP/ABS/ZnO blends showed not only great enhancement of toughness but also the reinforcement in rigidity. The phase morphology, dynamic rheological behavior and crystalline structure were examined to explain the probable toughening mechanism. The key to toughening of ABS and nano-ZnO on iPP is that the proper content of nano-ZnO selectively disperses at the phase interface between iPP and ABS. With the compatibilization of nano-ZnO, the dispersibility of ABS in iPP and interfacial adhesion between ABS and iPP were obviously improved. Moreover, both nano-ZnO and ABS have β nucleating activity, and ABS surrounded by nano-ZnO can be regarded as a kind of supported β-nucleating agent to significantly induce the formation of β-crystal in iPP matrix. Consequently, good impact toughness and rigidity could be obtained.

Fabrication of High Nano-ZnO Assembled Cotton Fabric with UV Blocking Property

In order to fabricate a novel ZnO/cotton composite, a high proportion of ZnO nanoparticles were assembled in cotton fibers, and the as-obtained cotton fabric can possess better UV blocking property compared with common ZnO/cotton composite. Firstly, the cotton fibers were pre-treated by hydrogen peroxide solution(H2O2) and sodium hydroxide(NaOH), urea(CON2H4). Secondly, the fabric was fabricated via in situ deposition. The effects of concentration of treatment liquid, ammonia-smoking time and curing temperature on the tensile property of the fabric, UV blocking property and water-washing durability test of as-obtained cotton fabrics were investigated. Thirdly, the as-obtained cotton sample was characterized by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM). It was shown that ZnO nanoparticles were assembled between cotton fibers, the surface and inside of the lumen and the mesopores of cotton fibers, while the content of nano-ZnO assembled in fabric can reach 15.63wt%. It is proved that the finished fabric can obtain a very excellent UV blocking property, under the condition of zinc ion in concentration of 15wt%, ammonia-smoking time for 10 min, curing temperature at 150 °C for 2 min.

Preparation of UV-protective starch/kefiran/ZnO nanocomposite as a packaging film: Characterization

Abstract In this study, UV-protective biodegradable nanocomposite films composed of starch/kefiran/ZnO were developed and characterized as a function of the content of nano ZnO (ZN) (1%, 3%, and 5% wt.). The packaging properties of the nanocomposite films i.e. WVP, moisture sensibility, mechanical properties, and UV-protection were measured. SEM and TGA/DSC analyses were used to investigate the microstructures and thermal properties of the films. Mechanical analysis demonstrated that by increasing ZN content up to 3%, the tensile strength and Young’s modulus of the specimens were increased. Elongation at break of the nanocomposites was decreased. The UV–vis spectrum confirmed the UV-protective property of the films. The thermal properties of the samples indicate that Tm increased by increasing ZN content. Also, decomposition temperature was enhanced by nanoparticle application. SEM micrographs confirmed that aggregation of the ZN particles increased with increasing ZN content.

Research on the Dielectric Properties of Nano-ZnO/Silicone Rubber Composites

The samples of 1%, 2%, 3% and 4% Zinc Oxide (ZnO) nano-composite silicone rubber were prepared by mechanical method. The dielectric properties of each sample were measured by dielectric spectroscopy. The experimental results showed that the dielectric constant of the silicone rubber composite increases with the increase of the content of nano-ZnO. The breakdown test results showed that with the increase of the content of nano-ZnO, the breakdown strength of silicone rubber composites increased first and then decreased. The breakdown test results indicate that the nano-ZnO can reduce the breakdown strength of silicone rubber. The hydrophobic test results showed that nano-ZnO will reduce the hydrophobic of silicone rubber.

Effect of nano-ZnO-supported 13X zeolite on photo-oxidation degradation and antimicrobial properties of polypropylene random copolymer

To improve the photo-oxidation degradation resistance and antimicrobial ability of ZnO-filled polypropylene random copolymer (PPR), 13X zeolite particles supported with nano-ZnO with different morphologies were prepared and used to manufacture filled PPR composites. The formation of ZnO with different morphologies on the surface of 13X zeolite was proved by atomic absorption spectroscopy, scanning electron microscope, UV–vis spectra, and fluorescence spectra. The results indicated that the photo-oxidation degradation resistance of nano-ZnO-supported 13X zeolite-filled PPR composites is higher than that of PPR composites filled by the same content of pure nano-ZnO. Antimicrobial experiment results show that nano-ZnO-supported 13X zeolite-filled PPR composites exhibit higher antimicrobial properties than ZnO-filled PPR composites prepared by directly adding nano-ZnO into PPR matrix for Staphylococcus aureus and Escherichia coli. The addition of nano-ZnO-supported 13X zeolite particles increases the crystallization temperature, but has no influence on the melting behavior of PPR composites.

Preparation, antimicrobial, crystallization and mechanical properties of nano-ZnO-supported zeolite filled polypropylene random copolymer composites

In order to increase the antimicrobial functionality of polypropylene random copolymer (PPR), nano-ZnO-supported on the surface of zeolite particles were prepared and used as functional fillers for PPR composites. The prepared nano-ZnO-supported zeolite particles were characterized by fluorescence and UV–Vis spectra, inductive coupled plasma and scanning electron microscopy. The crystallization behavior and crystalline morphology, antimicrobial ability and mechanical properties of zeolite, ZnO and nano-ZnO-supported zeolite filled PPR composites were investigated by differential scanning calorimeter, polarizing optical microscopy, antimicrobial and mechanical testing. The results indicated that the ZnO with flower-like morphology was formed on the surface of zeolite particles. The heterogeneous nucleation of zeolite and nano-ZnO-supported zeolite increase the crystallization temperature of PPR. The crystallization temperatures of nano-ZnO-supported zeolite filled PPR composites increase with increasing ZnO content in the nano-ZnO-supported zeolite. Incorporation of nano-ZnO-supported zeolite significantly decreases the size of spherulites of PPR. The nano-ZnO-supported zeolite filled PPR composites exhibit higher antimicrobial abilities than nano-ZnO filled PPR composite prepared by directly adding the same content of nano-ZnO into PPR matrix for the Staphylococcus aureus and Escherichia coli due to the flower-like morphology of ZnO in the nano-ZnO-supported zeolite. The nano-ZnO-supported zeolite content has little influence on the mechanical properties of PPR composites. nano-ZnO-supported zeolite as functional filler can be used to increase the antimicrobial ability of PPR.

Investigation of Nano-ZnO on Properties of Coatings Based on Fluorinated Polyurethane Emulsion

To develop environmentally friendly antifouling coatings, based on fluoro-modified polyurethane emulsion, eight coatings were prepared in which the content of nano-ZnO powder is respectively 0%, 0.2%,0.4%,0.6%,0.8%,1.0%,1.2% and 1.4 wt% in mass. Based on the measurement of mechanical and optical properties, surface roughness, morphological observation of coatings by Scanning Electron Microscopy (SEM), the influence of nano-ZnO was investigated on impact resistance, hardness, adhesive and flexibility, gloss, hydrophobicity, morphology and roughness of the coatings. The results showed that adding some nano-ZnO powder in paint did not affect the mechanical properties of the coatings, but it influenced obviously the surface topography and characteristics. The gloss reduces and the roughness increases with the content of nano-ZnO. The water contact angle is only 76.5° for the coating without nano-ZnO. The coating changed from hydrophilic to hydrophobic when nano-ZnO content increases up to 0.8 wt%, water contact angle excesses 90°, max water contact angle is up to 97.8° for coating with 1.4 wt % nano-ZnO powder.

Nano-ZnO incorporated titania composite coating for orthodontic applications

In the present study, a novel nano-ZnO incorporated nanotitania coating was developed for orthodontic applications with special reference to anticorrosive and antibacterial applications. High corrosion resistance and antibacterial activity of the titania coating were achieved due to the incorporation of nano-ZnO. Nano-ZnO was characterised using sophisticated techniques, including TEM, before the present study. The coating methodology adopted in the present work was distinct from other conventional high temperature processes. The content of nano-ZnO was optimised to be 30 wt-%, which caused high surface uniformity and homogeneity significantly even after dissolution in aggressive environments. The improvement in the layer-wise coating structure favoured other coating characteristics. In the present study, many of the tests and assessment were designed with special reference to electrochemical characterisation.

Effect of Nano-ZnO on Properties of Anti-Fouling Coatings Based on FEVE Coploymer

To develop anti-fouling coatings, the effect of nano-ZnO on properties of coatings based on FEVE copolymer was investigated in the paper. 8 coatings were prepared with controlling the content of nano- ZnO respectively 0%, 2%, 4%, 6%, 8%, 10%, 15% and 20 wt %. The mechanical properties and hydrophobicity of coatings were measured. Morphology of coatings were observed by SEM. Roughness was measured at the centre of along diagonal with rugosimeter Hommel T-6000. The results showed that nano-ZnO influences gloss, impact-resistance, and hydrophobicity of coatings. It does’t influence obviously the adhesive of the coatings to substract. The hydrophobicity and roughness of coatings increases with the augment of content of nano-ZnO in coatings. The impact-resistance decreases with the augment of content of nano-ZnO in coatings. When the content of nano-ZnO exceeds 15%, the surface roughness of coatings gets obviously bigger.