Polyurethane composites with enhanced thermal conductivity containing boron nitrides/ Kompozyty poliuretanowe o zwiekszonym przewodnictwie cieplnym zawierajace azotek boru

Boron nitride (BN) is very promising particulate fillers for production of polyurethane (PUR) composites dedicated to thermally conductive materials in electronic devices. Composites containing polyurethane-based matrices filled with BN were prepared. The effect of the filler content on the mechanical (the compressive strength), physical (process parameters, the density) and thermal properties (thermal conductivity) of the final composite material were determined. Foams obtained were characterized in terms of their process parameters such as: cream time, gel time and tack-free time. The mechanical properties of the composites were improved (compressive strength increased about 40% reached at very low filler content 3 wt % of BN), and the relative increase of thermal conductivity, as compared to the matrix, was about 8%. It was concluded that BN can be used as a filler to obtain rigid PUR foams having the characteristics of thermal conductive material. Keywords: polyurethane foams, polymer composites, boron nitride, mechanical properties. B Streszczenie: O kreslono w plyw z awartosci c zastek a zotku b oru (BN) w k ompozytach p oliuretanowych (PUR) na ich wytrzymalosc na sciskanie, gestosc oraz wlasciwosci termiczne. Wyznaczono parametry procesowe uzyskanych pianek PUR, takie jak: czas kremowania, czas zelowania i czas suchego lica. Wlasciwosci mechaniczne kompozytow byly o ok. 40% lepsze niz osnowy PUR, przy bardzo malej zawartosci napelniacza-3% mas., a wzgledny wzrost przewodnosci cieplnej wynosil okolo 8%. Stwierdzono, ze czastki BN mozna stosowac jako napelniacz w celu uzyskania termoprzewodzacych sztywnych pianek PUR. Slowa kluczowe: pianki poliuretanowe, kompozyty polimerowe, azotek boru, wlasciwosci mechaniczne.