Aging of Rigid Polyurethane Foams: Thermal Conductivity of N2 and                 Cyclopentane Gas Mixtures

Marrucho, Isabel M.; Santos, Filipe M.; Oliveira, Nelson S.; Dohrn, Ralf

doi:10.1177/0021955x05053520

Cited by 14 publications

(9 citation statements)

References 14 publications

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“…Thermal conductivity of rigid foams is a fundamental parameter as an indicator of thermal insulation properties. This value of an RPUF depends on several parameters such as mean cell size, thermal conductivity of blowing agent in the cells, cell orientation, density and closed‐cell content of foam, and thermal conductivity of additives . The effect of increasing loading level of FRs on the thermal conductivity and mean cell size is illustrated in Figure .…”

Section: Resultsmentioning

confidence: 99%

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Akdoğan

Erdem

Üreyen

et al. 2019

J of Applied Polymer Sci

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Rigid polyurethane foam (RPUF) composites with triphenyl phosphate (TPhP), aluminum trihydrate (ATH), and zinc borate (ZnB) alone, as well as their binary blends, were prepared via a one-shot process. The amount of flame retardant (FR) or FR blend was varied from 10 to 50% by polyol weight percentage, and the weight fraction of the blends was also fixed at 40%. The effects of additives on thermal insulation, mechanical, and flame retardancy properties of the composites were investigated. Thermal conductivity of the neat foam (RPUF) decreased from 22.53 to 21.04-21.58 mW m −1 K −1 . The compressive strength of foams displayed an increase with increasing the amount of TPhP, ATH, and ZnB till 40% by weight. The limited oxygen index values of all foams increased and the flame spread rates of all foams significantly decreased. It was also observed that the flame was self-extinguished in some cases. The cone calorimeter test results indicated that the FR additives improved the flame retardancy of the RPUF. INDTRODUCTIONRigid polyurethane foams (RPUFs) are one of the most consumed polymeric materials to a great extent. They have wide range applications in insulation, transportation, building construction, domestic appliance, automobile industry, and many others because of their high closed-cell content, low thermal conductivity, high strength with low weight, good shock absorption, and so on. 1-3 Nowadays, humanity is under threat because of limited energy resources in the world. In that case, RPUFs possessing low thermal conductivity values come into prominence because RPUFs are one of the unique materials for thermal insulation. RPUFs predominantly contain closed-cell structures, and in the closed-cell structures of foams, a blowing agent constituting the gas is trapped during production. The thermal conductivity of an RPUF is strongly affected by this blowing agent. The lower thermal conductivity of the blowing agent causes the lower thermal conductivity of RPUF. 4,5 When RPUFs compare with the conventional thermal insulating materials such as brick, concrete, wood, glass fiber, and so on, the conventional materials need to be used at much higher thickness in an attempt to match the insulation performance of 50 mm RPUF, for instance, ranging from 1720 mm for brick, 200 mm for wood, and 80 mm for polystyrene. The excellent thermal insulation property of RPUFs is not the only parameter making RPUFs one of the most used engineering materials but also their high mechanical strength with low weight and their easy processability make it as an interesting material. 6,7 For example, RPUF is one of the most important structural element of the refrigerators' skeleton besides providing high insulation for home refrigerators.However, as in the case of a majority of polymeric materials, RPUF is also easily combustible. As a matter of fact that, it is more combustible than other materials because of its rigid cellular and organic structure, additionally, it contains flammable, explosive gases in its closed cells. During the burnin...

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Section: Resultsmentioning

confidence: 99%

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Akdoğan

Erdem

Üreyen

et al. 2019

J of Applied Polymer Sci

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“…This can be attributed to the plywood first taking in water due to the high humidity and then drying out once it is removed from the high humidity. It is clear from other studies that the blowing agent used has a significant effect on the performance of foam insulations, both on the gaseous thermal conductivity and in its rate of effusion from the foam cells [25], [26]. The overall decrease in thermal resistivity observed at both conditions is a result of both the loss of blowing agent and the infusion of higher thermal conductivity gases [27], such as air and water vapor.…”

Section: Foamsmentioning

confidence: 91%

Experimental study on the effects of humidity and temperature on aerogel composite and foam insulations

Alvey

Patel

Stephenson

2017

Energy and Buildings

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Building insulation materials have been subjected to various temperature and humidity conditions and their thermal performance during several weeks of controlled environmental exposure. Several commercially available insulation materials (three aerogel composite blankets, two extruded polystyrene foams (XPS) and one blown polyurethane foam (PUR)) were evaluated. The purpose is to compare performance of newer types (aerogel composites) with established types (foams). Thermal conductivity was measured with a heat flow metering apparatus at one week intervals for five weeks. Insulations were exposed to conditions of 65.6°C and 90% RH, 65.6°C and 60% RH, 65.6°C and 30% RH, and 32.2°C and 90% RH. Results indicate that humidity levels play a significant role in PUR performance, but not a significant role in XPS performance. The three aerogel composites have mixed results: one has little relationship between moisture content and thermal performance, one is strongly affected by moisture and the remaining is moderately affected by moisture. Fourier infrared spectrometry was performed on some of the materials to observe chemical stability. Results indicate that factors other than moisture content, such as hygroscopy and volume expansion, significantly contribute to thermal performance.

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“…Köpük malzemelerin ısı iletim katsayılarının zamana bağlı olarak artış gösterdiği bilinmektedir [37,38]. Üretilen köpük malzemelerde genel olarak yaklaşık 50 gün içerisinde belirli artışlar olur iken, 50'inci günden sonra artış oranı oldukça düşük seviyelere inmiştir.…”

Section: Tablo 1 Köpük Malzemelerin Kompozisyonları (Compositions Ofunclassified

Nanoki̇l Ve Kabaran Alev Geci̇kti̇ri̇ci̇ İlavesi̇ni̇n Ri̇ji̇t Poli̇üretan Köpük Malzemeleri̇n Isil Bozunma Ve Yanma Davranişlarina Etki̇leri̇ni̇n İncelenmesi̇

Aydoğan¹,

Usta²

2015

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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ÖZETRijit poliüretan köpük malzemelere, bu malzemelerin özeliklerini iyileştirmek ve maliyetleri düşürmek için farklı inorganik maddeler ilave edilmektedir. Bu inorganik maddeler içinde, kilin toplam kütlenin en fazla % 6 oranına kadar poliüretan köpük malzemeye ilave edildiği belirlenmiştir. Bu çalışmada ise, yazarların bilgisi dahilinde, ilk defa % 15'e varan oranda nanokil ve amonyum polifosfat/pentaeritritolden oluşan kabaran alev geciktiricinin ilavesi yapılmıştır. Nanokil ve kabaran alev geciktirici ilavesinin, köpük malzemelerin hücre boyutuna, ısı iletim katsayısına, ısıl bozunma ve yanmaya karşı direncine etkileri incelenmiştir. Bunlara ek olarak, köpük malzemelerin zamanla ısı iletim katsayılarındaki değişim ve dolgu/alev geciktiricilerin bu değişime etkileri üzerine literatürde yeterli bilgi bulunmadığı dikkate alınarak üretimden sonra iki aylık bir süre içerisinde, köpük malzemelerin ısı iletim katsayılarının değişimi de takip edilmiştir. Deneysel sonuçlar, nanokilin % 15 oranında ilavesi ile köpük malzemenin ısıl kararlılığının ve yanma direncinin iyileştirilebileceğini göstermektedir. Bununla birlikte, nanokil ve kabaran alev geciktiricinin birlikte ilavesinin köpük malzemenin ısıl bozunma ve yanmaya karşı direncini daha da iyileştirdiği belirlenmiştir. Aynı zamanda nanokil/kabaran alev geciktirici ilavesinin köpük malzemenin ısı iletim katsayısında az bir miktar artışa sebep olduğu da tespit edilmiştir.Anahtar Kelimeler: Rijit poliüretan köpük, nanokil, kabaran alev geciktirici, ısı iletim katsayısı, ısıl bozunma, yanma davranışı INVESTIGATION THE EFFECTS OF NANOCLAY AND INTUMESCENT FLAME RETARDANT ADDITIONS ON THERMAL AND FIRE BEHAVIOUR OF RIGID POLYURETHANE FOAMS ABSTRACTDifferent inorganic materials are added into rigid polyurethane foams for improving properties and reducing production costs. Among them, it was found that nanoclay was added up to 6 % in the total mass. In this study, with the best knowledge of the authors, nanoclay / intumescent flame retardant composed of ammonium polyphosphate and pentaerythritol were added up to 15 % in the total mass into the rigid polyurethane foams for the first time. The effects of nanoclay and intumescent flame retardant additions on the cell size, the coefficient of thermal conductivity, the thermal degradation and the fire resistance were investigated. Furthermore, there is a lack of information in the literature about changes of the thermal conductivity of the foams with respect to time and the effects of fillers and flame retardants on the changes. Therefore, the changes of thermal conductivity coefficients of the foams were examined during two months after the productions. Experimental results indicated that the fire resistance and the thermal stability of the foams could be enhanced with 15 % nanoclay addition. However, nanoclay and the intumescent flame retardant additions into rigid polyurethane foams caused better thermal stability and fire resistance. Meanwhile, it was found that the incorporation of nanoclay / the intumescent flame retardant...

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Aging of Rigid Polyurethane Foams: Thermal Conductivity of N2 and Cyclopentane Gas Mixtures

Cited by 14 publications

References 14 publications

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Rigid polyurethane foams with halogen‐free flame retardants: Thermal insulation, mechanical, and flame retardant properties

Experimental study on the effects of humidity and temperature on aerogel composite and foam insulations

Nanoki̇l Ve Kabaran Alev Geci̇kti̇ri̇ci̇ İlavesi̇ni̇n Ri̇ji̇t Poli̇üretan Köpük Malzemeleri̇n Isil Bozunma Ve Yanma Davranişlarina Etki̇leri̇ni̇n İncelenmesi̇

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