Thermal Resistance Properties of Polyurethanes and Its Composites

Amado, Javier Carlos Quagliano

doi:10.5772/intechopen.87039

Cited by 6 publications

(4 citation statements)

References 61 publications

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“…Thermal degradation is mainly initiated within the hard segments of the microstructure, which normally has a faster degradation stage. 19 Statistical analysis confirmed the lack of significant differences in the results of air permeability for all mask layers tested before and after gas and plasma sterilization, Table 7. Significant differences were found for all three masks layers tested before and after steam sterilization.…”

Section: Air Permeabilitymentioning

confidence: 56%

Assessment of the possibility of surgical masks re-use after a sterilization process in the pandemic condition of COVID-19

Zimniewska

Witmanowski

Kicińska-Jakubowska

et al. 2021

Textile Research Journal

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The aim of this study was to explore the possibility to re-use disposable masks in order to prevent excessive waste generation during the pandemic period. The COVID-19 pandemic has caused rapidly increasing waste production resulting from the necessity of common usage of disposable personal protective equipment. This research covers the evaluation of the structure of surgical masks subjected to a threefold steam, gas or plasma sterilization process in order to verify the possibility of their re-use. The results of the study showed that gas sterilization even after three cycles did not cause significant changes in mask structure or air permeability. Hydrogen peroxide plasma sterilization caused significant changes in the structure of layer A after the third cycle of sterilization; nonetheless, it did not influence the air permeability of the mask. A significant reduction in the cover ratio of layers composing surgical masks causes an increase of air permeability in the case of steam sterilization, leading to a reduction of the mechanical ability to prevent the penetration of microorganisms. The reduction in cover ratio limits the filtration efficiency. Surgical masks subjected to threefold gas sterilization can be recommended for re-use. This allows one to use the mask thrice, ensuring safety for users and limiting the mask-waste production to one-third of the volume compared with when the mask is used once. The volume of mask-waste can be reduced with the application of the sterilization process for used masks during the pandemic period. Currently, it is not possible to sterilize all one-use masks, but implementation of this method in hospitals and medical centers is a step in the pro-environmental direction.

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Section: Air Permeabilitymentioning

confidence: 56%

Assessment of the possibility of surgical masks re-use after a sterilization process in the pandemic condition of COVID-19

Zimniewska

Witmanowski

Kicińska-Jakubowska

et al. 2021

Textile Research Journal

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show abstract

“…As mentioned in the description of the TGA tests, OP accelerates the initial stage of degradation, but stabilizes the final decomposition of the material. Time to ignition (TTI) for the reference PU was the longest and amounted to 24 s. Phosphorus flame retardants have low thermal stabilities, decompose earlier, but protect the underlying PU matrix [57]. Time to flameout (TTF) was about three times longer for REF compared to OP-containing materials and was equal to 591 s with 0.0% residue (R) after testing.…”

Section: Cone Calorimeter (Cc)mentioning

confidence: 99%

Novel Cast Polyurethanes Obtained by Using Reactive Phosphorus-Containing Polyol: Synthesis, Thermal Analysis and Combustion Behaviors

2021

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Phosphorus-containing polyol applications in polyurethane synthesis can prevent volatilization of flame retardants and their migration on the surface of a material. In this work, novel cast polyurethanes were prepared by a one-step method with the use of different amounts of phosphorus-containing polyol, 4,4′–diphenylmethane diisocyanate and 1,4-butanediol. The chemical structure, thermal, physicochemical and mechanical properties and flame resistance of the prepared materials were investigated. The results obtained for cast flame-retarded polyurethanes were compared with cast polyurethane synthesized with commonly known polyether polyol. It has been shown that with an increasing amount of phosphorus content to polyurethane’s chemical structure, an increased flame resistance and char yield were found during combustion tests. Phosphorus polyol worked in both the condensed (reduced heat and mass exchange) and gas phase (inhibition of flame propagation during burning). The obtained materials contained phosphorus polyol, indicating higher thermal stability in an oxidative environment than an inert atmosphere.

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“…Higher long-term operating temperatures (above 90 °C) acting on polyurethanes have a significant negative effect on the material properties and primary mechanical properties, and pyrolysis can occur at temperatures above 200 °C. It can therefore be argued that thermal stability is a limiting factor for the application of these materials [ 4 , 5 , 6 ]. Focusing on the positive properties mentioned above, these are mainly due to the two-phase microstructure composed of hard and soft segments [ 5 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

“…It can therefore be argued that thermal stability is a limiting factor for the application of these materials [ 4 , 5 , 6 ]. Focusing on the positive properties mentioned above, these are mainly due to the two-phase microstructure composed of hard and soft segments [ 5 , 7 ]. It can thus be argued that a PUR is a block copolymer with alternating soft and hard segment components along the macromolecular chain [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive Study of Polyurethane Potting Compounds Doped with Magnesium Oxide Nanoparticles

et al. 2023

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Recently, polyurethanes (PURs) have become a very promising group of materials with considerable utilization and innovation potential. This work presents a comprehensive analysis of the changes in material properties important for PUR applications in the electrical industry due to the incorporation of magnesium oxide (MgO) nanoparticles at different weight ratios. From the results of the investigations carried out, it is evident that the incorporation of MgO improves the volume (by up to +0.5 order of magnitude) and surface (+1 order of magnitude) resistivities, reduces the dielectric losses at higher temperatures (−62%), improves the thermal stability of the material, and slows the decomposition reaction of polyurethane at specific temperatures (+30 °C). In contrast, the incorporation of MgO results in a slight decrease in the dielectric strength (−15%) and a significant decrease in the mechanical strength (−37%).

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Thermal Resistance Properties of Polyurethanes and Its Composites

Cited by 6 publications

References 61 publications

Assessment of the possibility of surgical masks re-use after a sterilization process in the pandemic condition of COVID-19

Assessment of the possibility of surgical masks re-use after a sterilization process in the pandemic condition of COVID-19

Novel Cast Polyurethanes Obtained by Using Reactive Phosphorus-Containing Polyol: Synthesis, Thermal Analysis and Combustion Behaviors

A Comprehensive Study of Polyurethane Potting Compounds Doped with Magnesium Oxide Nanoparticles

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