scholarly journals Effect of UV Radiation on Optical Properties and Hardness of Transparent Wood

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2067
Author(s):  
Igor Wachter ◽  
Tomáš Štefko ◽  
Peter Rantuch ◽  
Jozef Martinka ◽  
Alica Pastierová

Optically transparent wood is a type of composite material, combining wood as a renewable resource with the optical and mechanical properties of synthetic polymers. During this study, the effect of monochromatic UV-C (λ—250 nm) radiation on transparent wood was evaluated. Samples of basswood were treated using a lignin modification method, to preserve most of the lignin, and subsequently impregnated with refractive-index-matched types of acrylic polymers (methyl methacrylate, 2-hydroxyethyl methacrylate). Optical (transmittance, colour) and mechanical (shore D hardness) properties were measured to describe the degradation process over 35 days. The transmittance of the samples was significantly decreased during the first seven days (12% EMA, 15% MMA). The average lightness of both materials decreased by 10% (EMA) and 17% (MMA), and the colour shifted towards a red and yellow area of CIE L*a*b* space coordinates. The influence of UV-C radiation on the hardness of the samples was statistically insignificant (W+MMA 84.98 ± 2.05; W+EMA 84.89 ± 2.46), therefore the hardness mainly depends on the hardness of used acrylic polymer. The obtained results can be used to assess the effect of disinfection of transparent wood surfaces with UV-C radiation (e.g., due to inactivation of SARS-CoV-2 virus) on the change of its aesthetic and mechanical properties.

2019 ◽  
Vol 12 (24) ◽  
pp. 52-59
Author(s):  
Alaa A. Abdul-Hamead

In this paper a thin films of selenium was prepare on substrates of n-Si by evaporation in a vacuum technique with thickness about 0.5μm. And then an annealing process was done on samples at two temperature (100 and 200) C ° in a vacuum furnace (10-3 torr).Some structural, optical and mechanical properties of prepared thin films were measured. Results showed that the prepared film was the crystallization, optical transmittance and micro hardness of the prepared thin films increased significantly after annealing.


Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 433
Author(s):  
Tianshi Feng ◽  
Jiankun Qin ◽  
Yali Shao ◽  
Lili Jia ◽  
Qi Li ◽  
...  

Transparent jute fiber (TJF) was prepared from delignified jute fiber (DJF) and was subjected to various surface knitting densities (190 and 340 g/m2) before epoxy resin (ER) impregnation under vacuum. The preparation process and properties of TJF were evaluated. The mechanical properties and surface morphology of the jute fiber samples were also studied. The mechanical properties were compared with transparent coir fiber (TCF) and transparent balsa wood (TBW). Optical properties, such as surface color, optical transmittance, and visual haze, of natural jute fiber (JF) and TJF were measured to better understand the influence of delignification. The experimental results showed transparency of 51% even for dense jute fiber cloth, and the maximum transmittance was as high as 60% with a low surface density. TJF had similar tensile strength as TBW but was higher than TCF, indicating a maximum tensile strength of 43.25 MPa with a surface density of 340 g/m2. These results suggest that TJF has the potential to meet the particular optical and mechanical properties of transparent wood. Transparent jute fiber can replace transparent wood for industrial production because of the simple preparation process and lower price.


2021 ◽  
Vol 56 (12) ◽  
pp. 7451-7463
Author(s):  
Yusheng Wang ◽  
Xiaowei Wu ◽  
Nahong Song ◽  
Xiaohui Yang ◽  
Yafeng Zheng ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahib Hasan ◽  
Khagendra Baral ◽  
Neng Li ◽  
Wai-Yim Ching

AbstractChalcogenide semiconductors and glasses have many applications in the civil and military fields, especially in relation to their electronic, optical and mechanical properties for energy conversion and in enviormental materials. However, they are much less systemically studied and their fundamental physical properties for a large class chalcogenide semiconductors are rather scattered and incomplete. Here, we present a detailed study using well defined first-principles calculations on the electronic structure, interatomic bonding, optical, and mechanical properties for 99 bulk chalcogenides including thirteen of these crytals which have never been calculated. Due to their unique composition and structures, these 99 bulk chalcogenides are divided into two main groups. The first group contains 54 quaternary crystals with the structure composition (A2BCQ4) (A = Ag, Cu; B = Zn, Cd, Hg, Mg, Sr, Ba; C = Si, Ge, Sn; Q = S, Se, Te), while the second group contains scattered ternary and quaternary chalcogenide crystals with a more diverse composition (AxByCzQn) (A = Ag, Cu, Ba, Cs, Li, Tl, K, Lu, Sr; B = Zn, Cd, Hg, Al, Ga, In, P, As, La, Lu, Pb, Cu, Ag; C = Si, Ge, Sn, As, Sb, Bi, Zr, Hf, Ga, In; Q = S, Se, Te; $$\hbox {x} = 1$$ x = 1 , 2, 3; $$\hbox {y} = 0$$ y = 0 , 1, 2, 5; $$\hbox {z} = 0$$ z = 0 , 1, 2 and $$\hbox {n} = 3$$ n = 3 , 4, 5, 6, 9). Moreover, the total bond order density (TBOD) is used as a single quantum mechanical metric to characterize the internal cohesion of these crystals enabling us to correlate them with the calculated properties, especially their mechanical properties. This work provides a very large database for bulk chalcogenides crucial for the future theoretical and experimental studies, opening opportunities for study the properties and potential application of a wide variety of chalcogenides.


2019 ◽  
Vol 1184 ◽  
pp. 443-451 ◽  
Author(s):  
Amanda M.L. Estolano ◽  
Nathan B. Lima ◽  
Rogerio V.A. Junior ◽  
Marcia K.D.L. Belarmino ◽  
Anderson I.S. Silva ◽  
...  

2013 ◽  
Vol 341 ◽  
pp. 169-180 ◽  
Author(s):  
A.M. Abdul-Kader ◽  
Y.A. El-Gendy ◽  
Awad A. Al-Rashdi ◽  
A.M. Salem

The effect of ion beam bombardment on the optical and mechanical properties of ultra-high molecular weight polyethylene (UHMWPE) was investigated. UHMWPE polymer samples were bombarded with 150 keV N2ions under vacuum at room temperature to high fluences ranging from 1x1016to 2x1017ions cm-2. The untreated as well as treated samples were investigated by ultraviolet-visible (UV-Vis) spectrophotometer and Vickers micro-hardness techniques. The direct and indirect optical band gap decreased from 2.9 and 1.65 eV for pristine sample to 1.7 and 1 eV for those bombarded with N2ion beam at the highest fluence, respectively. With increasing ion fluence, an increase in the number of carbon atoms per conjugation length, N and number of carbon atoms per cluster, M in a formed cluster were observed. A significant improvement in surface hardness was obtained by increasing the ion fluence.


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