scholarly journals Declining Performance of Silicone-Based Magnetorheological Elastomers after Accelerated Weathering

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6389
Author(s):  
Wibowo Wibowo ◽  
Bhre Wangsa Lenggana ◽  
Ubaidillah Ubaidillah ◽  
Dody Ariawan ◽  
Fitrian Imaduddin ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Storage Modulus ◽  
Uv Light ◽  
Light Exposure ◽  
Test Chamber ◽  
Magnetic Flux Density ◽  
Accelerated Weathering ◽  
Test Results ◽  
Magnetorheological Elastomers ◽  
Rheometer Test

Magnetorheological elastomers (MRE)-based products are usually located in an area directly exposed to sunlight and rain. However, there is no specific research on the behavior of MRE after accelerated weathering. Therefore, in this study, the changes to the chemical and rheological properties of both isotropic and anisotropic MRE after accelerated weathering were examined. Treated and untreated specimens were compared. MRE specimens with 40% by weight CIP were prepared with no current excitation and another sample was prepared with 1.5 T of magnetic flux density. Each specimen was treated in an accelerated weathering machine, Q-Sun Xe-1 Xenon Test Chamber, under a UV light exposure cycle and water spray. A material characterization was carried out using FTIR and a rheometer to determine the changes to the chemical and rheological properties. The morphological analysis results showed that after the weather treatment, the surface was rough and more cavities occurred. The rheometer test results showed a significant decrease in the storage modulus of each treated MRE specimen, unlike the untreated MRE specimens. The decrease in the storage modulus value with currents of 0, 1, 2, and 3 Amperes was 66.67%, 78.9%, 85.2%, and 80.5%, respectively. Meanwhile, FTIR testing showed a change in the wave peak between the untreated and treated MRE specimens. Thermogravimetric analysis (TGA) also showed a decrease in MRE weight for each specimen. However, for both treated and untreated MRE specimens, the decrease in TGA was not significantly different. In all the tests carried out on the MRE samples, weather acceleration treatment caused significant changes. This is an important consideration for developers who choose silicone as the MRE matrix.

scholarly journals Performance Degradation of Silicon Based Magnetorheological Elastomer Under Accelerated Weathering Treatment

2020 ◽  
Author(s):  
W. Wibowo ◽  
Bhre Wangsa Lenggana ◽  
U. Ubaidillah ◽  
Dody Ariawan ◽  
Fitrian Imaduddin ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Negative Impact ◽  
Uv Light ◽  
Light Exposure ◽  
Test Chamber ◽  
Magnetic Flux Density ◽  
Accelerated Weathering ◽  
Magnetorheological Elastomer ◽  
Rubber Composite ◽  
Significant Negative Impact

Silicone RTV-based engineering rubber composite products have been widely used for several applications in various fields as a major component such as structure, automotive, and medical. In its application, the rubber composite product is placed in an open area that is directly exposed to sunlight and rain. It has a significant negative impact on changes in chemical and rheological properties, making the product life of rubber composite products shorter. Therefore, in this study, changes in the chemical and rheological properties of both isotropic and anisotropic magnetorheological elastomer (MRE) treated with accelerated weathering were studied compared to untreated specimens with specimens that had been treated. MRE specimens with 40% by weight CIP were prepared with no current excitation and another sample were made under 1.5 T of magnetic flux density. Each specimen was treated in an accelerated weathering machine Q-Sun Xe-1 Xenon Test Chamber with a UV light exposure cycle for 102 minutes and 18 minutes of UV light combined with water spray for 24 hours followed by a condensation cycle of 4 hours in a dark period. Material characterization was carried out using FTIR and Rheometer to determine the changes in chemical and rheological properties. The morphological analysis results showed that the surface was rough and more cavities occurred after being given weather treatment. Rheometer test results showed a decrease in storage modulus in each MRE specimen that had been treated compared to untreated MRE specimens. Meanwhile, FTIR testing showed a change in wave peak between untreated and treated MRE specimens.

scholarly journals Photostabilization of rubberwood using cerium oxide nanoparticles. Part 1: Characterization and colour changes

Les/Wood ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 57-70
Author(s):  
Kavyashree Srinivasa ◽  
Krishna Kumar Pandey ◽  
Marko Petrič
Keyword(s):  
Cerium Oxide ◽  
Uv Light ◽  
Light Exposure ◽  
Visible Region ◽  
Accelerated Weathering ◽  
Uva Light ◽  
Nanoparticles Concentration ◽  
Colour Changes ◽  
Good Transparency ◽  
Harmful Radiation

Light induced darkening and deterioration of wood used outdoors is undesirable. Photoprotection of wood could be achieved by using additives that reflect or absorb harmful radiation responsible for degradation. Nano metal oxides have strong absorption in the UV range of solar radiation and good transparency in the visible region. They offer unique benefits in protecting coatings and coated substrates from being degraded by UV radiation. However, to exploit the properties of nanoparticles, homogenous dispersion without agglomeration is necessary. In the present work, the photostabilization of rubberwood surfaces coated with cerium oxide (CeO2) was studied. The nanoparticles were surface functionalized with an organic alkoxy silane (3-glycidyloxypropyltrimethoxy silane) to improve the homogenous distribution in coatings, and the modified nanoparticles were dispersed in isopropanol and polyurethane (PU) coating. Rubberwood surfaces coated with dispersed nanoparticles (concentration 0.5 % to 6 % w/v) were exposed to a fluorescent UVA light source (λ=340 nm) at 60 °C in an accelerated weathering tester for 500 h and 1000 h. Colour changes due to UV light exposure were monitored using a spectrocolourimeter. Dispersion of CeO2 nanoparticles in PU coatings (concentration >2 %) restricted the photoyellowing of wood polymers.

Effects of Sasobit on Rheological Properties of Asphalt Binders

2012 ◽  
Vol 509 ◽  
pp. 136-141
Author(s):  
Zhi Fei Liu ◽  
Jia Ping Liu ◽  
Jin Xiang Hong ◽  
Chong Huang
Keyword(s):  
Melting Point ◽  
Rheological Properties ◽  
Warm Mix Asphalt ◽  
Asphalt Binders ◽  
Test Results ◽  
Dynamic Shear ◽  
Dynamic Shear Rheometer ◽  
Rutting Resistance ◽  
Modified Binders ◽  
Rheometer Test

Research in the laboratory was carried out to determine if addition of warm mix asphalt additive (Sasobit) has potential to reduce the temperature comparison with control mix. To fulfill this purpose five types of asphalt binders have been produced with a Sasobit additive in concentration range from 0 to 10% by weight of the asphalt. Viscosity test and dynamic shear rheometer test are conducted for the investigation of effects of Sasobit on rheological properties characteristics of binders. Viscosity tests on binders indicated that the Sasobit binders had significantly lower viscosities compared to control binders at the temperature above 100°C, indicating that Sasobit can reduce the mixing and compaction temperatures above the melting point of Sasobit. Sasobit modified binders are more sensitive cracking and had more excellent rutting resistance properties at service temperatures compared with original bitumen. Based on the test results, the suggest content of Sasobit addition is 3% by weight.

Nano titanium dioxide/PAoQ-coated polybenzoxazol fibers for enhancing anti-ultraviolet performance

2017 ◽  
Vol 88 (19) ◽  
pp. 2267-2275 ◽  
Author(s):  
Jie Jiang ◽  
Shixia Wang ◽  
Sihang Zhang ◽  
Qingbi Li ◽  
Yingchun Gu ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Uv Light ◽  
Light Exposure ◽  
Morphological Structure ◽  
Layer By Layer ◽  
Test Results ◽  
Self Assembling ◽  
Aging Test ◽  
Pbo Fiber ◽  
Nano Titanium Dioxide

Inspired by the composition of adhesive in mussels, polydopamine has been widely used for surface modification of various materials. In accord with the formation mechanism of polydopamine coating, the catechol containing two o-phenol groups and triethylenetetramine (TETA) containing two primary amine groups were used to copolymerize and deposit a polyamine-o-benzoquinone polymers (PAoQ) film on the polybenzoxazol (PBO) fibers. In order to enhance the anti-ultraviolet performance of PBO fibers, rutile nano titanium dioxide particles (TiO2) were also decorated on the PBO fibers by the layer-by-layer self-assembling technique. The optimum modification conditions were obtained by orthogonal method. Morphological structure and chemical composition of the modified fibers were studied using scanning electron microscopy with energy dispersive X-ray, and Fourier transform infrared spectroscopy. The UV-aging test results showed that under 144 h UV-light exposure at 340 nm, the modified PBO fibers’ strength retention was promoted to 80.8%, 34.4% higher than that of the original PBO fiber. The thermal stability of the modified fibers had no obvious change after modification with TiO2/PAoQ, while their carbon residue rate increased slightly.

Photostabilizers performance on the surface analysis of green composites

2020 ◽  
Vol 29 (1) ◽  
pp. 57-64
Author(s):  
Hasret Ece Sönmez ◽  
Mehmet Safa Bodur ◽  
Alper Adrian Baysan ◽  
Mustafa Bakkal ◽  
Ersin Serhatli
Keyword(s):  
Surface Analysis ◽  
Color Change ◽  
Uv Light ◽  
Light Exposure ◽  
Accelerated Weathering ◽  
Reinforced Composites ◽  
Color Changes ◽  
Photodegradation Mechanism ◽  
Ldpe Composites

In this work, various stabilizers have been introduced to prevent or delay degradation due to ultraviolet (UV) light exposure to prolong the service life of cotton fiber-reinforced composites. The effect of various additives like hindered amine light stabilizer, UV absorber (UVA), and antioxidant as photostabilizers of CF/low-density polyethylene (CF/LDPE) composites was compared. We showed how they influence to delay or eliminate the photodegradation of CF/LDPE subjected accelerated weathering. Surface analysis was performed by Fourier transform infrared spectroscopy and color measurements. The results showed us the insight of the photodegradation mechanism of weathered CF/LDPE composites undergoing photooxidative reactions which causes a loss surface quality such as micro-cracking and color change. Among the stabilizers, UVA was found to be the most effective to delay some color changes in long term.

scholarly journals Laboratory Testing of Self-Healing Polymer Modified Asphalt Mixtures Containing Recycled Asphalt Materials (RAP/RAS)

2019 ◽  
Vol 271 ◽  
pp. 03003
Author(s):  
Sharareh Shirzad ◽  
Marwa M. Hassan ◽  
Max A. Aguirre ◽  
Samuel Cooper ◽  
Louay N. Mohammad ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Asphalt Mixtures ◽  
Self Healing ◽  
Test Results ◽  
Recycled Asphalt ◽  
Cracking Performance ◽  
Specimen Test ◽  
Low Temperature Cracking ◽  
Healing Temperature

The objective of this study was to evaluate the efficiency of an innovative light-induced self-healing polymers in enhancing the durability of asphalt mixtures and improving its self-healing properties. Mixtures were prepared using two different binders, with and without recycled materials, and self-healing polymer. Results showed that the addition of recycled asphalt material to mixtures prepared with an unmodified binder negatively affected the healing recovery at room temperature. Furthermore, Self-healing properties of the mixtures were improved by increasing the healing temperature. The addition of 5% self-healing polymer to the control mixture, followed by UV light exposure resulted in an increase in self-healing properties of the mixtures prepared with PG 67-22 binder. Semi-Circular Bending (SCB) test results showed that the incorporation of self-healing polymer and 48 h of UV light exposure improved the cracking resistance. Loaded-Wheel Test (LWT) results showed that the self-healing polymer caused an increase in the rut depth of the samples prepared with an unmodified binder. However, the final rut depth was less than the acceptable rutting performance. Thermal-Stress Restrained Specimen Test (TSRST) test results showed that self-healing polymer improved the low temperature cracking performance of the mixtures.

Photocatalytic Discolouration of Solutions of Reactive Dyes in the Presence of H2O2

1995 ◽  
Vol 30 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Deng Nansheng ◽  
Tian Shizhong ◽  
Xia Mei
Keyword(s):  
Photochemical Reaction ◽  
Uv Light ◽  
Reactive Dyes ◽  
Solar Light ◽  
Rate Equations ◽  
Oh Radical ◽  
Test Results ◽  
Dye Molecules ◽  
First Order ◽  
Dye Solutions

Abstract Tests for the photocatalytic degradation of solutions of three reactive dyes, Red M-5B, Procion Blue MX-R and Procion Black H-N, in the presence of H2O2 were carried out. When the solutions of the three reactive dyes were irradiated by UV or solar light, the colour of the solutions disappeared gradually. A statistical analysis of the test results indicated a linear relation between the concentration of dyes and the time of irradiation. The discolouration reaction of the solutions was of the first order. Rate equations for the discolouration reactions of dye solutions were developed. The dark reactions or the dye solutions containing H2O2 were very slow, illustrating that the photochemical reaction played a very important role. It was demonstrated that UV light and solar light (300 to 380 nm) photolyzes the HO and that the resulting OH radical reacts with the dye molecules and destroys the chromophore.

scholarly journals Stability and ocular biodistribution of topically administered PLGA nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sean Swetledge ◽  
Renee Carter ◽  
Rhett Stout ◽  
Carlos E. Astete ◽  
Jangwook P. Jung ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Polymeric Nanoparticles ◽  
Plga Nanoparticles ◽  
Eye Disease ◽  
Control Group ◽  
Eye Tissues ◽  
Nanoparticle Morphology ◽  
The Stability

AbstractPolymeric nanoparticles have been investigated as potential delivery systems for therapeutic compounds to address many ailments including eye disease. The stability and spatiotemporal distribution of polymeric nanoparticles in the eye are important regarding the practical applicability and efficacy of the delivery system in treating eye disease. We selected poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with lutein, a carotenoid antioxidant associated with eye health, as our model ophthalmic nanodelivery system and evaluated its stability when suspended in various conditions involving temperature and light exposure. We also assessed the ocular biodistribution of the fluorescently labeled nanoparticle vehicle when administered topically. Lutein-loaded nanoparticles were stable in suspension when stored at 4 °C with only 26% lutein release and no significant lutein decay or changes in nanoparticle morphology. When stored at 25 °C and 37 °C, these NPs showed signs of bulk degradation, had significant lutein decay compared to 4 °C, and released over 40% lutein after 5 weeks in suspension. Lutein-loaded nanoparticles were also more resistant to photodegradation compared to free lutein when exposed to ultraviolet (UV) light, decaying approximately 5 times slower. When applied topically in vivo, Cy5-labled nanoparticles showed high uptake in exterior eye tissues including the cornea, episcleral tissue, and sclera. The choroid was the only inner eye tissue that was significantly higher than the control group. Decreased fluorescence in all exterior eye tissues and the choroid at 1 h compared to 30 min indicated rapid elimination of nanoparticles from the eye.

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