Thermal expansion of crosslinked closed-cell polyethylene foams

Rodríguez‐Pérez, Miguel Ángel; Alonso, O.; Duijsens, A.; Saja, J.A. de

doi:10.1002/(sici)1099-0488(199810)36:14<2587::aid-polb11>3.0.co;2-7

Cited by 36 publications

(18 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These trends have been explained qualitatively8, 9 in terms of the gas and polymer contributions to the total thermal expansion coefficient. However, the goal has been to develop a model predicting the thermal expansion coefficient from the polyhedral cell structure and the material properties.…”

Section: Introductionmentioning

confidence: 91%

“…Two types of measurements were made: The temperature was raised from 20 to 130 °C at 5 °C/min to characterize the overall thermal expansion response. To measure the linear thermal expansion coefficient, away from any thermal transitions of the polymer,8 the foam was cooled from room temperature to 5 °C, at which it was kept for 15 min. It was then heated from 5 to 25 °C at 1 °C/min and kept at 25 °C for 15 min.…”

Section: Ldpe Foam Characterizationmentioning

confidence: 99%

“…The thermal conductivity5–7 varies almost linearly with R for R > 0.15. In previous articles,8–10 the thermal expansion coefficient of PE foams has been reported To increase slightly between 0 and 40 °C. To be approximately equal to the PE value for foam densities greater than 80 kg/m 3 but to increase at lower densities. To decrease if Young's modulus ( E ) of PE increases. To be anisotropic, with lower values in the direction in which cells are elongated. …”

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

Thermal expansion coefficient and bulk modulus of polyethylene closed‐cell foams

Almanza

Masso-Moreu

Mills

et al. 2004

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

A regular Kelvin foam model was used to predict the linear thermal expansion coefficient and bulk modulus of crosslinked, closed‐cell, low‐density polyethylene (LDPE) foams from the polymer and gas properties. The materials used for the experimental measurements were crosslinked, had a uniform cell size, and were nearly isotropic. Young's modulus of biaxially oriented polyethylene was used for modeling the cell faces. The model underestimated the foam linear thermal expansion coefficient because it assumed that the cell faces were flat. However, scanning electron microscopy showed that some cell faces were crumpled as a result of foam processing. The measured bulk modulus, which was considerably smaller than the theoretical value, was used to estimate the linear thermal expansion coefficient of the LDPE foams. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3741–3749, 2004

show abstract

Section: Introductionmentioning

confidence: 91%

Section: Ldpe Foam Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Thermal expansion coefficient and bulk modulus of polyethylene closed‐cell foams

Almanza

Masso-Moreu

Mills

et al. 2004

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

show abstract

“…Low‐magnification micrographs (20×) were analyzed using an ImageJ macro specifically developed for this purpose 21. The following cellular structure parameters were determined:22 cell size distribution; average cell size; the normalized standard deviation, as an index of the cell size homogeneity; cell density, (i.e. the number of cells per cm 3 ) and the anisotropy ratio (i.e.…”

Section: Methodsmentioning

confidence: 99%

Foaming behavior, cellular structure and physical properties of polybenzoxazine foams

Raso

Rodríguez‐Pérez

Saja

et al. 2011

Polymers for Advanced Techs

View full text Add to dashboard Cite

In this paper, polymer foams based on a benzoxazine resin have been successfully prepared using azodicarbonamide (ADC) as a chemical blowing agent and have been characterized regarding their foaming behavior, cellular structure, and physical properties. The effect of the ADC on the curing process of the resin was analyzed using differential scanning calorimetry and blowing agent decomposition was followed by thermogravitmetric analysis (TGA). The characterization of the cellular structure of the foamed samples was done using scanning electron microscopy. The mechanical properties of the foams were determined using compression tests and the thermal conductivity was assessed using the transient plane source method. The results indicated that the curing process and gas release took place in a similar time interval. The foams showed an isotropic cellular structure with relative densities in the range 0.35–0.60, and showed compressive strengths and compressive moduli in the range of 10–70 MPa and 400–1100 MPa, respectively. Thermal conductivities were in the range of 0.06–0.12 W m−1K−1. The findings in this paper demonstrate the possibility of producing polybenzoxazine foams using a simple process in which curing and foaming take place simultaneously. In addition, the mechanical characterization of these materials indicates that they are suitable for structural applications.Peer ReviewedPostprint (published version

show abstract

“…Low-magnification micrographs were analyzed using the intercept counting method, 32 measuring the distance between pairs of cell walls along 10 reference lines, in order to obtain the average cell size ( ) and cell density. The average cell size, being the most used cell structure parameter, [33][34] was determined using the procedure presented in Ref. [35].…”

Section: Testing Proceduresmentioning

confidence: 99%

Characterization of Carbon Nanofibre-Reinforced Polypropylene Foams

Antunes¹,

Velasco²,

Realinho³

et al. 2010

J. Nanosci. Nanotech.

View full text Add to dashboard Cite

In this paper, carbon-nanofibre-reinforced polypropylene foams were prepared and characterized regarding their foaming behaviour, cellular structure and both thermo-mechanical as well as electrical properties. Polypropylene (PP) nanocomposites containing 5, 10 and 20 wt% of carbon nanofibres (CNF) and a chemical blowing agent were prepared by melt-mixing inside a twin-screw extruder and subsequently water-cooled and pelletized. The extruded nanocomposites were later foamed using a one-step compression-moulding process. The thermo-mechanical properties of the CNF-reinforced PP foams were studied, analyzing the influence of the carbon nanofibres on the cellular structure and subsequent thermo-mechanical behaviour of the foams. Carbon nanofibres not only seemed to act as nucleating agents, reducing the average cell size of the foams and increasing their cell density for similar expansion ratios, but also helped produce mechanically-improved foams, even reaching for the 20 wt% CNF-reinforced ones a specific modulus around 1.2 GPa x cm3/g for densities as low as 300 kg/m3. An increasingly higher electrical conductivity was assessed for both the solids as well as the foams with increasing the amount of carbon nanofibres.

show abstract

Thermal expansion of crosslinked closed-cell polyethylene foams

Cited by 36 publications

References 9 publications

Thermal expansion coefficient and bulk modulus of polyethylene closed‐cell foams

Thermal expansion coefficient and bulk modulus of polyethylene closed‐cell foams

Foaming behavior, cellular structure and physical properties of polybenzoxazine foams

Characterization of Carbon Nanofibre-Reinforced Polypropylene Foams

Contact Info

Product

Resources

About