Yazar "Tamrakar, Sandeep" seçeneğine göre listele

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    Flexible polyurethane foams reinforced with graphene and boron nitride nanofillers
    (Wiley, 2023) Li, Owen; Tamrakar, Sandeep; Iyigundogdu, Zeynep; Mielewski, Debbie; Wyss, Kevin; Tour, James M.; Kiziltas, Alper
    The effect of three types of nanofillers on the physical, mechanical, and thermal properties of flexible polyurethane foams (FPUF) was studied. FPUF with nanofillers are of interest to the automotive industry due to their potential for enhancing compression properties and enabling sustainable foams. Holey and wrinkled flash graphene, and untreated and silane coated boron nitride were tested as fillers up to 0.1 wt% loading level. Flash graphene filled FPUF showed significant improvement in compressive properties, especially at the 0.025 wt% loading level, showing a 22% increase in compressive force deflection at 25% strain and a 17% increase at 50% strain compared to the unfilled control foam sample. Boron nitride nanoparticles, treated and untreated, were shown to be an effective means of reducing wet compression set properties, addressing a key area of concern for sustainable polyols. Wet compression set was reduced by 20%-30% for most boron nitride foams compared to their unfilled control samples. Boron nitride may enable implementation of more sustainable polyols in automotive FPUF. Nanofillers did not significantly improve thermal stability of FPUF.
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    Öğe
    Long-term durability of thermoplastic elastomer containing antiviral additives for mobility applications
    (Wiley, 2024) Iyigundogdu, Zeynep; Couvreur, Rachel; Tamrakar, Sandeep; Yoon, Jaewon; Basar, Basak; Ersoy, Osman G.; Sahin, Fikrettin
    In the mobility market, there is a demand from customers for antimicrobial protection. As a result, the market has grown considerably to provide antiviral and antimicrobial polymers and coatings. This study examines how the efficacy of a non-commercial antimicrobial thermoplastic elastomer will change over the life of the application. Using an example application of an electric scooter handlebar grip, durability requirements were identified, and antiviral efficacy (exceeding a log value of 3 or >99.9 microbial growth reduction) was compared before and after testing. A scooter handlebar grip was selected as the ideal example application as it was a high-touch surface, with several different riders. During the start of this study, scooter companies were encouraging their riders to disinfect scooter handlebars before riding, use hand sanitizer, and wear gloves. If the handlebar grip could be antimicrobial, then they could eliminate these steps and provide a safe ride for the users. In order to simulate long-term durability, UV exposure, temperature, humidity, artificial sweat, sunscreen, insect repellent, and abrasion tests were performed and evaluated in terms of antiviral activity. Accelerated weathering reduced the virucidal activity of the sample versus unexposed antiviral thermoplastic elastomer (TPE). However, the efficacy increased with contact time from 90% to 96.83% at 30 and 120 min, respectively. Abrasion resistance of antiviral TPE showed a volume loss of 66 mm3 compared to control samples of 83 mm3. The antiviral TPE sample exhibited slightly lower efficacy compared to the control after exposure to the artificial sweat (99.43% vs. 99.95%). Additionally, a skin tolerance test conducted on rabbits showed that antiviral TPE was not an irritant and showed no dermal toxicity. The outcome of this study will lead to the development of long-term durable antimicrobial material for the transportation industry.
  • [ X ]
    Öğe
    Long-term durability of thermoplastic elastomer containing antiviral additives for mobility applications
    (Wiley, 2024) Iyigundogdu, Zeynep; Couvreur, Rachel; Tamrakar, Sandeep; Yoon, Jaewon; Basar, Basak; Ersoy, Osman G.; Sahin, Fikrettin
    In the mobility market, there is a demand from customers for antimicrobial protection. As a result, the market has grown considerably to provide antiviral and antimicrobial polymers and coatings. This study examines how the efficacy of a non-commercial antimicrobial thermoplastic elastomer will change over the life of the application. Using an example application of an electric scooter handlebar grip, durability requirements were identified, and antiviral efficacy (exceeding a log value of 3 or >99.9 microbial growth reduction) was compared before and after testing. A scooter handlebar grip was selected as the ideal example application as it was a high-touch surface, with several different riders. During the start of this study, scooter companies were encouraging their riders to disinfect scooter handlebars before riding, use hand sanitizer, and wear gloves. If the handlebar grip could be antimicrobial, then they could eliminate these steps and provide a safe ride for the users. In order to simulate long-term durability, UV exposure, temperature, humidity, artificial sweat, sunscreen, insect repellent, and abrasion tests were performed and evaluated in terms of antiviral activity. Accelerated weathering reduced the virucidal activity of the sample versus unexposed antiviral thermoplastic elastomer (TPE). However, the efficacy increased with contact time from 90% to 96.83% at 30 and 120 min, respectively. Abrasion resistance of antiviral TPE showed a volume loss of 66 mm3 compared to control samples of 83 mm3. The antiviral TPE sample exhibited slightly lower efficacy compared to the control after exposure to the artificial sweat (99.43% vs. 99.95%). Additionally, a skin tolerance test conducted on rabbits showed that antiviral TPE was not an irritant and showed no dermal toxicity. The outcome of this study will lead to the development of long-term durable antimicrobial material for the transportation industry.
  • [ X ]
    Öğe
    Thermoplastic elastomers containing antimicrobial and antiviral additives for mobility applications
    (Elsevier Sci Ltd, 2022) Iyigundogdu, Zeynep; Basar, Basak; Couvreur, Rachel; Tamrakar, Sandeep; Yoon, Jaewon; Ersoy, Osman G.; Sahin, Fikrettin
    The transmission of the SARS-CoV-2 coronavirus has been shown through droplets generated by infected people when coughing, sneezing, or talking in close contact. These droplets either reach the next person directly or land on nearby surfaces. The objective of this study is to develop a novel, durable, and effective disinfecting antimicrobial (antiviral, antibacterial, and antifungal) styrene-ethylene/butylene-styrene (SEBS) based thermoplastic elastomers (TPE). TPE incorporated with six different formulations was investigated for mechanical and antiviral performance. The formulations consist of a combination of zinc pyrithione (ZnPT), sodium pentaborate pentahydrate (NaB), disodium octaborate tetrahydrate (DOT), and chlorhexidine (CHX). ZnPT and DOT incorporated TPE showed a reduction of microbes such as bacteria by up to 99.99%, deactivated Adenovirus, Poliovirus, Norovirus, and reduced a strain of the coronavirus family by 99.95% in 60 min on TPE samples. Control samples had higher tensile strengths among all formulations and tensile strength decreased by around 14%, 21% and 27% for ZnPT and DOT combinations compared to control samples. The elongation at break decreased by around 7%, 9% and 12% with ZnPT and DOT combinations, where it reached minimum values of 720%, 702% and 684%, respectively. The 100% Modulus and 300% Modulus slightly increased with ZnPT and NaB combination (reaching values from 1.6 to 1.9 MPa and 2.6-2.9 MPa respectively) in comparison with control samples. The MFI also decreased with antimicrobial and antiviral additives (decreasing values from 64.8 to 43.3 g/10 min). ZnPT and NaB combination showed the lowest MFI (43.3 g/10 min) and reduced the MFI of control sample by around 33%. TPE samples containing ZnPT and DOT combination showed biocidal activity against the microorganisms tested and can be used to develop antimicrobial products for multiple touchpoints within a vehicle and micro-mobility.