scholarly journals Preparation of Cellulose-Based Fluorescent Materials as Coating Pigment by Use of DMSO/DBU/CO2 System

Author(s):  
Qinghua Cao ◽  
Jinyue Dai ◽  
Xin Bao ◽  
Zhenyu Zhang ◽  
Fei Liu ◽  
...  

Abstract A series of cellulose-based fluorescent materials are prepared under relative mild conditions by use of the DMSO/DBU/CO2 system to utilize as coating pigments. Through the observation under 365nm UV light, the cellulose-based fluorescent materials exhibit good fluorescence response and bright color. Furthermore, due to the limitation of the molecular skeleton of cellulose, the intrinsic aggregation caused quenching phenomenon commonly existed in conventional organic fluorescent pigments can be effectively inhibited, which is very helpful to retain good fluorescence response in epoxy-based coating material and its coating films. Moreover, the addition of cellulose-based fluorescent materials also increases the mechanical properties of the coating film. The increase of tensile strength and tensile modulus respectively reaches ~39% and ~66%. Solvent resistance and thermal property of the coating films generally remain unchanged. The fabrication of cellulose-based fluorescent materials in DMSO/DBU/CO2 system provides a feasible way to develop the functional application of cellulose.

2021 ◽  
Author(s):  
Qinghua Cao ◽  
Jinyue Dai ◽  
Xin Bao ◽  
Zhenyu Zhang ◽  
Fei Liu ◽  
...  

Abstract A series of cellulose-based fluorescent materials are prepared under relative mild conditions by use of the reversible DMSO/DBU/CO2 system to utilize as coating pigments. Through the observation under 365nm UV light, the cellulose-based fluorescent materials exhibit good fluorescence response and bright color. Furthermore, due to the limitation of the molecular skeleton of cellulose, the intrinsic aggregation caused quenching phenomenon commonly existed in conventional organic fluorescent pigments can be effectively inhibited, which is very helpful to retain good fluorescence response in epoxy-based coating material and its coating films. Moreover, the addition of cellulose-based fluorescent materials also increases the mechanical properties of the coating film. The increase of tensile strength and tensile modulus respectively reaches ~ 39% and ~ 66%. Solvent resistance and thermal property of the coating films generally remain unchanged. The fabrication of cellulose-based fluorescent materials in DMSO/DBU/CO2 system provides a feasible way to develop the functional application of cellulose.


2021 ◽  
Author(s):  
Qinghua Cao ◽  
Jinyue Dai ◽  
Xin Bao ◽  
Zhenyu Zhang ◽  
Fei Liu ◽  
...  

Abstract A series of cellulose-based fluorescent materials are prepared under relative mild condition by use of the particular reversible DMSO/DBU/CO2 system to utilize as coating pigments. Through the observation under 365nm UV light, the cellulose-based fluorescent materials exhibit good fluorescence response and bright color. Furthermore, due to the limitation of the molecular skeleton of cellulose, the intrinsic aggregation caused quenching phenomenon commonly existed in conventional organic fluorescent pigments can be effectively inhibited, which is very helpful to retain good fluorescence response in epoxy-based coating material and its coating films. Moreover, the addition of cellulose-based fluorescent materials also increases the mechanical properties of the coating film. The increase of tensile strength and tensile modulus respectively reaches ~ 39% and ~ 66%. Solvent resistance and thermal property of the coating films generally remain unchanged. The fabrication of cellulose-based fluorescent materials in DMSO/DBU/CO2 system provides a feasible way to develop the functional application of cellulose.


2021 ◽  
Vol 10 (1) ◽  
pp. 403-411
Author(s):  
Youliang Cheng ◽  
Mingjie Wang ◽  
Changqing Fang ◽  
Ying Wei ◽  
Jing Chen ◽  
...  

Abstract To change the optical properties and improve the antibacterial performances of carbon quantum dots (CQDs) and Ag NPs, mesoporous SiO2 spheres were combined with them to form the composites. In this paper, CQDs with a uniform size of about 3.74 nm were synthesized using glucose as carbon source. Then, CQDs/mesoporous SiO2/Ag NPs composites were obtained in situ under UV light irradiating by using mesoporous SiO2 and Ag NO3 as the carrier and silver resource, respectively. The diameter of CQDs/mesoporous SiO2/Ag NPs particles was in the range of 200–250 nm. With the increase in irradiating time, the red-shift in the UV-Vis spectrum for as-prepared CQDs/mesoporous SiO2/Ag NPs composites was found, and the adsorption peak was widened. In addition, the composites showed a high antibacterial activity against Staphylococcus aureus and Escherichia coli via disc diffusion method. These results indicated that inhibition circles for Ag NPs/mesoporous SiO2/CQDs and mesoporous SiO2/Ag NPs were similar in diameter. Furthermore, the two composites had a better bactericidal performance compared with other particles. Therefore, as-prepared CQDs/mesoporous SiO2/Ag NPs composites in this paper have great potential applications for fluorescent materials and antibacterial materials.


2018 ◽  
Vol 8 (11) ◽  
pp. 2285
Author(s):  
Sejin Jung ◽  
Jung Kim ◽  
Jang Ko ◽  
Wonseok Choi

In this study, functional coating film was fabricated on glass for photovoltaic (PV) modules to improve the anti-pollution characteristics of PV modules. The functional coating film applied to a glass substrate through the spray coating method was annealed at 300 °C for 10 min in H2, N2, Ar, O2, and vacuum ambient. The contact angle of the coated surface was measured and it was confirmed that the anti-pollution characteristics were improved as the contact angle decreased. The light transmittance was measured and it exhibited the most excellent characteristics in vacuum. The hardness and adhesion were measured as the mechanical characteristics and they were all excellent regardless of the annealing ambient. Based on the analyzed characteristics, the process conditions of functional coating films were optimized to improve the anti-pollution and mechanical characteristics. If the coating process optimized in this study is applied to PV modules based on these results, improvement in the anti-pollution characteristics can be expected.


2017 ◽  
Vol 263 ◽  
pp. 85-89
Author(s):  
Tadahiro Wada ◽  
Hiroyuki Hanyu

In turning hardened steel, polycrystalline cubic boron nitride (cBN) compacts are widely used, due to their high hardness and high thermal conductivity. However, in milling hardened steel, fracture of cBN cutting tools readily occurs because they have poor fracture toughness. Therefore, coated cemented carbide tools, which have good fracture toughness and wear resistance, are generally and widely used. In this study, hardened steel (ASTM D2, JIS SKD11, 60HRC) was milled with three physical vapor deposition coated cemented carbide end mill cutters in order to determine effective tool materials for milling hardened steel. The coating films used were two types of aluminum/chromium/tungsten/silicon-based-coating films and (Ti,Al)N-coating film. The two types of aluminum/chromium/tungsten/silicon-based-coating films are a new type of coating film, and the Type I and Type II coating film was a two-layered and multi-layered structure, respectively. The following results were obtained: (1) In milling hardened steel at a cutting speed of 2.5 m/s, Type II coating film was the best coating material among the three types of coated film. Type I coating film was superior to (Ti,Al)N-coating film. (2) The critical scratch load of both Type I and Type II of over 130 N became larger than that of the (Ti,Al)N-coating film of 65 N. (3) The multi-layered structure is expected to improve the tool life.


1998 ◽  
Vol 517 ◽  
Author(s):  
T. Hirano ◽  
K. Yoshida ◽  
Y. Yamazaki ◽  
T. Namikawa ◽  
M. Kishi

AbstractNano-size R2BiAlxFe5-xO12(R: Dy, Gd, Th) particles were prepared with a coprecipitation and annealing method. The coating films of the particles were prepared with a coating technique. The magnetic and magneto-optical properties of the particles and films were investigated. The coercive forceHcof the particles and films was increased and saturation magnetizationMs. dropped with the Al contentx. TheHcof the coating films was about 200 Oe at the compositions of dispersed particles for which theMswas almost zero. These results suggest that the increase was made with magnetic compensation. The BiTb2A10.6Fe4.4O12coating film shows Faraday rotation spectra. The figure of merit of the film is about 0.5 at 520 nm. The coating BiTb2A10.6Fe4.4O12film is one of the candidate materials for a new economical magneto-optical storage medium.


2007 ◽  
Vol 544-545 ◽  
pp. 813-816
Author(s):  
Moon Kyong Na ◽  
Myeong Sang Ahn ◽  
Hoy Yul Park

Two kinds of colloidal silica(CS)/silane sol solutions were prepared. Two sol solutions are involved with the kinds of silane such as methyltrimethoxysilane(MTMS) and -Glycidoxypropyl trimethoxysilane(ETMS) using LS CS. MTMS was added to two sol solutions. Whether ETMS was added or not, two kinds of sol solutions were synthesized. Using two kinds of sol solutions, sol-gel coating films were formed on glass substrates via dip-coating process. Here, seasoning effect of for enhancing properties of sol-gel coating layer on glass was investigated while such sol-gel solutions were left for 7days. Also, their properties such as surface free energy, roughness, thermal property, potential hardness and elastic portion were characterized in order to understand the effect of addition of ETMS. In this case of LS/MTMS sol, the coating film had low surface free energy and more enhanced flat surface than that of the case of LS/MTMS/ETMS sol. ETMS forms hydrophilic hydroxyl group in sol solution, then surface free energy of LS/MTMS/ETMS coating film increased. In the beginning of reaction sol solution seemed to be unstable, but 4days later their coating film properties such as surface free energy and roughness enhanced. The elastic portion of coating films obtained from LS/MTMS/ETMS sol increased with addition of ETMS, but thermal stability decreased.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nurlatifah ◽  
Haruhiko Nakata

AbstractPlastic debris has gained attention as anthropogenic waste in the environment, but less concerned given to metal waste despite its high abundance in aquatic environment. Metal packaging, such as can, utilizes polymeric coating films as barrier between metals and products which leads to be potential source of microplastic pollution. In this study, 27 beer cans from 16 countries for both body and lid parts as well as inside and outside layers were investigated. Despite the country’s origin, epoxy resin was the major polymeric coating used in all beer cans for lid (inside and outside) and body (inside). Whereas poly(1,2-butanediol isophthalate) was frequently used for outside layer of can body. DEHP and BHT were detected in almost all samples with the highest concentration of 5300 ng/g and 520 ng/g. Despite its lower detection frequency, DOA was detected as high as 9600 ng/g in Belgian beer can. There was no apparent relationship present between the home countries of beer cans and amount of additives used. Despite of being broken down, additives concentration in one environmental sample was found to be one to two orders of magnitude higher compared to the new can. This result proved that adsorption of chemical additives took place in the environment and degraded metal debris may become source of microplastic with higher risk of additives pollution in the environment.


2019 ◽  
Vol 5 (2) ◽  
pp. 12 ◽  
Author(s):  
Mishbak H. H ◽  
Glen Cooper ◽  
Paulo Jorge Da Silva Bartolo

Alginate is a biocompatible material suitable for biomedical applications, which can be processed under mild conditions upon irradiation.  This paper investigates the preparation and the rheological behaviour of different pre-polymerised and polymerised alginate-methacrylate systems for 3D photopolymerisation bioprinting. The effect of the functionalization time on the mechanical, morphological, swelling and degradation characteristics of crosslinked alginate hydrogel is also discussed.  Alginate was chemically-modified with methacrylate groups and different reaction times considered. Photocurable alginate systems were prepared  by dissolving functionalized alginate with 0.5-1.5% photoinitiator solution and crosslinked by ultraviolet (UV) light (8 mW/cm2).


Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1076
Author(s):  
Ayako Yano ◽  
Kyoichi Hamada ◽  
Kenji Amagai

In this paper, we invented a novel observation method of the coating film formation process using the fluorescence method. With this method, the temporal change in the coating film thickness can be evaluated quantitatively. In addition, since the thickness and flow of the coating film can be measured simultaneously, the detailed coating film formation process was clarified. In the experiment, the adhesion behavior of the spray-paint droplets when applied to a wall was investigated. The characteristics of coating films formed by the spray droplets, particularly the influence of injection pressure on the coating film formation, were determined using the fluorescence method. At the initial stage of the coating process, the coating area increased linearly. When the ratio of the coating area to the measurement range reached about 80%, the rate at which the coating area increased slowed down, and an overlap began. The amount of paint that adhered to the coating film formation could be estimated by calculating the overlap ratio. Moreover, the thickness and smoothness of the coating film were evaluated using the histogram data of the fluorescence intensity. The leveling process was discussed in relation to the standard deviation of the histogram data. In addition, the flow of the paint during the coating film formation was investigated using tracer particles, and the effect of the spray gun injection pressure on the leveling process was investigated. Changes in the film thickness and flow during the coating film formation process could be evaluated through fluorescence observation.


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