Composites of recyclate rigid pur-pir foams
Kazimierz Piszczek, Jolanta Tomaszewska Akademia Techinczno-Rolnicza, Wydział Technologii i Inżynierii Chemicznej, ul. Seminaryjna 3, 85-326 Bydgosz
Annals 2 No. 4, 2002 pages 208-211
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abstract The morphology and properties of composites prepared by a low and high pressure compression moulding, from PUR-PIR foam and reactive polyurethan systems, were investigated. The reactive polyurethane system was a liquid polybutadiene rubber with isocyanate groups Krasol NN22 and oligoetherole Rokopol TG500 mixed in proportion 10:3. The recyclates were prepared by grinding of foams with density of 171 (type A), 113 (type B) and 94 kg/m3 (type C) characterized by various morphology (Fig. 1a, 1c). The composites of the reactive polyurethane with 50, 70 and 90 wt.% of PUR-PIR recyclates were formed by compression molding, using a high (50 MPa) and low (0.05 MPa) pressure procedure. As it may be seen on Figure 1b the recyclates based on foam type A has an irregular form, in which a certain number of primary cells were preserved. On the contrary, the recyclate of foam with lower density present predominantly elongated form (Fig. 1d). It was ascertained that the morphology and the properties of the composites depend as well on the density and morphology of primary PUR-PIR foam as on the compostion and processing conditions of the recycled systems. In composites, formed by a low pressure procedure, relative large and irregular cells may be observed (Fig. 2), on the contrary as a result of high pressure compression moulding composites with lower porosity are noted (Fig. 3). As higher the recyclate content and forming pressure as higher the density and compression strength of the products (Figs 4 and 5). It was found also that the density and the mechanical properties of the composites are directly related to the density of the primary foams where the increase of the composites density leads to higher values of the compressive strength (Fig. 6). A satisfactory uniform morphology and properties of the composites were observed for composites produced by the high pressure moulding. It was also found that the thermal diffusivity D increases with the composite density where the ratio between the relative values of D for primary foams, low pressure composites and high pressure composites may be presented as 1:4:20.