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1

Kontrowersje wokół natryskowych pianek PUR

Patoka K.

Materiały Budowlane

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2018

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nr 5

82--85

2

Piana PUR i polimocznik – innowacyjne izolacje natryskowe

Matusiak A., Szafran J.

Inżynier Budownictwa

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2018

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nr 4

45--50

PL

Nowoczesne budownictwo generuje nowe i nieprzeciętne wymagania względem stosowanych materiałów budowlanych. Dotyczy to również wyrobów wykorzystywanych do izolacji termicznej, hydroizolacji oraz izolacji przeciwwilgociowej. Tu rozwiązaniem mogą być nowoczesne izolacje natryskowe w postaci piany PUR i polimocznika. W artykule zaprezentowano podstawowe ich właściwości, również w kontekście konkurencyjności w stosunku do tradycyjnych ich odpowiedników.

EN

Modern construction generates new and demanding requirements regarding building materials. This also applies to products used for thermal insulation, waterproofing and damp proofing. The solution here might be modern spray insulation in the form of PUR foam and polyurea. The article presents their basic properties, while emphasising their competitive advantage over their traditional counterparts.

3

Wpływ kinetyki wulkanizacji z jednoczesnym spienianiem na rozwój morfologiczny pianek poliizoprenowych o zamkniętych komórkach

Vahidifar A., Esmizadeh E., Rodrigue D.

Elastomery

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2018

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T. 22, nr 1

3--18

PL

Pianki o zamkniętych komórkach oparte na kauczuku poliizoprenowym (IR) wytworzono przez formowanie tłoczne z zastosowaniem azodikarbonamidu (ADC), jako chemicznego poroforu. Zbadano wpływ temperatury przetwarzania na rozkład ADC oraz na wulkanizację IR z użyciem ADC i bez ADC, w celu określenia wpływu tego parametru na końcową morfologię pianki i właściwości mechaniczne. Badanie kinetyczne wykazało, że do interpretacji danych eksperymentalnych odpowiedni jest model autokatalityczny. Stwierdzono, że energia aktywacji rozkładu ADC (Ea = 181,8 kJ/mol) jest znacznie wyższa niż wulkanizacji IR bez ADC (Ea = 79,6 kJ/mol) lub z ADC (Ea = 72,3 kJ/mol) Wynika z tego, że wraz ze wzrostem temperatury, szybkość rozkładu ADC wzrasta bardziej niż szybkość wulkanizacji kauczuku, więc należy przeprowadzić optymalizację procesu. Zwiększenie temperatury ze 140 do 150°C zmniejszyło średni rozmiar komórek z 355 do 290 μm, zwiększając jednocześnie gęstość komórek z 73 do 118 komórek/mm3. Dalszy wzrost temperatury doprowadził jednak, ze względu na równowagę pomiędzy koalescencją komórek a sieciowaniem, do zwiększenia rozmiaru komórek oraz niższej gęstości komórek. Dla zoptymalizowanej temperatury (150°C) pianki miały najwyższy moduł sprężystości przy ściskaniu oraz twardość.

EN

Closed cell foams based on polyisoprene rubber (IR) were produced via compression molding using azodicarbonamide (ADC) as a chemical blowing agent. The effect of processing temperature on ADC decomposition, as well as IR curing with and without ADC were studied to determine the effect of this parameter on the final foam morphology and mechanical properties. The kinetic study showed that the autocatalytic model is appropriate to represent the experimental data. The activation energy for ADC decomposition (Ea = 181.8 kJ/mol) was found to be much higher than for IR curing without (Ea = 79.6 kJ/mol) or with (Ea = 72.3 kJ/mol) ADC. This indicates that with increasing temperature the rate of ADC decomposition accelerates faster than rubber vulcanization, so an optimization must be performed. For example, increasing the temperature from 140 to 150°C decreased the average cell size from 355 to 290 μm while increased the cell density from 73 to 118 cell/mm3. But further temperature increase led to larger cell size and lower cell density because of a balance between cell coalescence and crosslinking. For the optimized temperature (150°C), the foams had the highest modulus of elasticity and hardness.

4

Numerical study on closed cell foam structure damage mechanisms

Miedzińska D.

Journal of KONES

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2012

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Vol. 19, No. 2

321-327

EN

Metallic foams are currently being looked at as a new material for automobiles. The main goal of the use of metallic foams in vehicles is to increase sound dampening, reduce the weight of the automobile, and increase energy absorption in case of crashes, or in military applications, to combat the concussive force of IEDs. The metallic foams that are being looked at currently, are aluminum and its alloys due to their low density (0.4-0.9 g/cm3). In addition these foams have a high stiffness, are fire resistant, do not give off toxic fumes, are fully recyclable, have high energy absorbance, have low thermal conductivity, have low magnetic permeability, and are efficient at sound dampening, especially in comparison to light weight hollow parts. In addition, partial addition of metallic foams in hollow parts of the car will decrease weakness points usually associated with car crashes and noisy vibrations. These foams are cheap to cast by using powder metallurgy (as compared to casting of other hollow parts). The aim of the research was to describe and to assess the main mechanisms that appear in the foam structure during the compression. The development process of the finite element model of the closed cell foam microstructure is presented in the paper. The model geometry was based on the real structure research, which was carried out with the use of computed tomography. The model was built with the use of a unique computer code created to transform the scan point cloud into FE raster model based on solid 8-node elements. The experimental and numerical compression test results were compared and showed good compatibility. The stress distributions were studied to describe the main mechanisms in the structure.

5

Aluminium foam testing for impact energy absorption aims

Niezgoda T., Miedzińska D.

Journal of KONES

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2009

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Vol. 16, No. 3

283-289

EN

Aluminium foams are a new group of materials used for impact energy absorbing elements. They are light (typically 10-25% of the density of the metal they are made of) and stiff, and are frequently proposed as a light weight structural material. That is why they often are applied in automotive and transport industry solutions, for example as parts of bumpers. The methods of numerical modelling for open and closed cell aluminium foams are presented in the paper as well as closed and open cellfoam microstructure model. The numerical models of foam ideal microstructures created with shell finite elements are shown. The models were developed on the basis of Kefain tetrakaidecahedrons - structures consisting of six squares and eight hexagons. In the case of closed cell foams, the polyhedron with full walls was adopted. In the case of open cell foams the circle wholes were removed from polyhedron surfaces. Then the numerical analysis of a created models compressive test was carried out with the usage of LS Dyna computer code. The nonlinear procedures were applied. The results were analyzed in the scope of energy absorbing properties of aluminium foams.