Evaluation of the thermal conductivity and mechanical properties of water blown polyurethane rigid foams reinforced with carbon nanofibers

Santiago‐Calvo, Mercedes; Tirado‐Mediavilla, Josías; Rauhe, Jens Chr. M.; Jensen, Lars Rosgaard; Ruiz‐Herrero, J.L.; Villafañe, Fernando; Rodríguez‐Pérez, Miguel Ángel

doi:10.1016/j.eurpolymj.2018.08.051

Cited by 39 publications

(38 citation statements)

References 41 publications

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“…For example, the modified foam is characterized by shorter tack free time with addition of nanosilica, indicating that fillers act as curing accelerator 13 . Third, dispersion of filler to matrix will increase dynamic strength and decrease thermal conductivity of the polymer 4,11,16 . Young's modulus and compressive stress appear to increase by 590% and 150% when reinforced foam by 4% of nanocellulose 3 .…”

Section: Introductionmentioning

confidence: 99%

Reinforcement of agricultural wastes liquefied polyols based polyurethane foams by agricultural wastes particles

Zhang

Hori

Takemura

2021

J of Applied Polymer Sci

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Four kinds of agricultural wastes particles (XS: oilseed rape straw [OS], rice straw [RS], wheat straw [WS], and corn stover [CS]) were used to reinforce agricultural wastes liquefied polyol (P‐XS) based polyurethane (PU) foam. Different XS loading dosages (0% ~ 15%) are investigated to confirm suitable filler concentrations for modifying foams. RS particles show great promoting ability, OS particles reveal complex influence, while WS and CS particles display mild effect on foaming process. With 1% of OS, 6% of RS, 3% of WS, or 1% of CS incorporating in matrix materials, the reinforced foam could keep applicable density, reach better physical and mechanical property, display more uniform cellular structure, and show higher thermal stability with more excellent water absorption ability. Using of agricultural wastes as polymer filler is economical, simple, environmental, and wide applicable for biomass utilization and biopolymer preparation.

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Section: Introductionmentioning

confidence: 99%

Reinforcement of agricultural wastes liquefied polyols based polyurethane foams by agricultural wastes particles

Zhang

Hori

Takemura

2021

J of Applied Polymer Sci

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“…[1] As a kind of polyurethane, rigid polyurethane foam (RPUF) with low thermal conductivity and lightweight has been widely used in construction and building. [2,3] However, the inflammability poses a threat to the residence and restricts its use in daily life, so it is necessary to improve the flame retardant property of RPUF. [4,5] At present, the method to improve the flame retardant property of RPUF is mainly the addition of the flame retardant.…”

Section: Introductionmentioning

confidence: 99%

Effects of ammonium polyphosphate microencapsulated on flame retardant and mechanical properties of the rigid polyurethane foam

Cheng

Niu

et al. 2020

J of Applied Polymer Sci

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In this article, a flame retardant microcapsule ammonium polyphosphate microencapsulated by polyurea (POAPP) was successfully synthesized by interfacial polymerization method using ammonium polyphosphate (APP) as core and polyurea as shell. The microencapsulation is observed by scanning electron microscopy and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and hydroscopicity test, which prove the success in synthesizing microencapsulation. When the POAPP is added into rigid polyurethane foam (RPUF), the flame retardant and mechanical properties are investigated using cone calorimeter, limited oxygen index test, and compressive strength test. The PHRR of RPUF‐POAPP20 decreased from 336.52 kW/m2 (Ref. RPUF) to 203.84 kW/m2 and the THR of RPUF‐POAPP20 was only 7.6 MJ/m2, which is 33.9% lower than that of Ref. RPUF. Furthermore, the limiting oxygen index of RPUF‐POAPP20 reaches 24.8%, which increased by 36.3% compared to Ref. RPUF. Whereas the maximum compressive strength of RPUF‐POAPP5 was 7.46 MPa, which is higher than that of RPUF‐APP5.

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“…Thus, the use of blowing agents with low thermal conductivities is one of the key strategies to improve the thermal properties of RPU foams. Moreover, the addition of fillers to the RPU matrix may also decrease the cell size and/or block infrared radiation, reducing the radiation contribution to the thermal conductivity …”

Section: Introductionmentioning

confidence: 99%

“…Thermal conductivity is the most important property for RPU foams used as insulating materials. The thermal conductivity is determined by the following heat transfer mechanisms: conduction along the solid phase ( λ s ), conduction through the gas phase ( λ g ), thermal radiation ( λ r ) and convection within the cells ( λ c ). The latter is negligible for foams with small cell sizes (less than 2 mm) .…”

Section: Introductionmentioning

confidence: 99%

Long‐term thermal conductivity of cyclopentane–water blown rigid polyurethane foams reinforced with different types of fillers

Santiago‐Calvo

Tirado‐Mediavilla

Ruiz‐Herrero

et al. 2019

Polymer International

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An understanding of the long‐term thermal conductivity of rigid polyurethane (RPU) foams presents great interest in the building field considering the conservation of energy efficiency. In this study, the effect of different types of particles (talc, diatomaceous earth and non‐porous silica) on the thermal conductivity of RPU foams blown with cyclopentane and water as blowing agents was investigated during 3 years of aging. The characterization of the cellular structure shows how the addition of particles causes a cell size reduction of the foams, and consequently an enhancement of the thermal properties just after production. However, this initial reduction is not maintained, because each foam shows a different thermal conductivity evolution with time. We have found, for the first time, a relationship between the slope of the thermal conductivity versus time at the first measurements and the internal temperature reached during the foaming process. The evolution of the RPU foams in which higher internal temperatures were reached is more pronounced than in those RPU foams where lower foaming temperatures were observed. This effect is related to the kinetics of the diffusion of the gas occluded inside the cells and imposes a new criterion for the selection of particles to reduce the thermal conductivity of RPU foams; these additives should ideally decrease the temperature reached during the foaming process. Moreover, the effect of aging on the thermal conductivity is explained by using theoretical models. © 2019 Society of Chemical Industry

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Evaluation of the thermal conductivity and mechanical properties of water blown polyurethane rigid foams reinforced with carbon nanofibers

Cited by 39 publications

References 41 publications

Reinforcement of agricultural wastes liquefied polyols based polyurethane foams by agricultural wastes particles

Reinforcement of agricultural wastes liquefied polyols based polyurethane foams by agricultural wastes particles

Effects of ammonium polyphosphate microencapsulated on flame retardant and mechanical properties of the rigid polyurethane foam

Long‐term thermal conductivity of cyclopentane–water blown rigid polyurethane foams reinforced with different types of fillers

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