الفهرس 
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Abstract
The generation of heat without rapid, continues and controlled release causes over-heating of the electronic components which in turn affects the efficiency, working life, and the reliability of the electronic devices. The non-uniform heat distribution in GaN transistors and microprocessors, results in degradation of their performance and poorreliability. The heat generated by LEDs causes efficiency reduction,change in the light color, and reduction of their life time. Accordingly, the need for efficient and novel heat dissipating materials has beenemerged as a pressing issue. To reduce this heating, the preparation of polyvinyl-formaldehyde (PVF)/multi walled carbon nanotubes (MWCNTs) foams as efficientheat sink nano composites was presented here, (MWCNTs) has been prepared with laser ablation. The PVF foam was loaded with 1 wt%, 2 wt%, and 4 wt% of MWCNTs. Thermal conductivity of the PVF/MWCNTs foams are investigated within the temperature range 25–200 oC. The structure of the pre-pared foams were characterized by Fourier transform infrared (FTIR), Raman spectroscopy, and differential scanning calorimetry (DSC). The results show that the MWCNTs are homogeneously distributed inside the PVF foam and attached to the PVF matrix via van der Waals forces. The addition of the MWCNTs increased the thermal stability of the PVF foam through connecting and filling the pores of the PVF foam. The maximum thermal conductivity value was found to be ≈5 W/mK for 4 wt٪ of PVF/MWCNTs foam atroom temperature. This value is 166 times higher than the thermal conductivity of neat PVF foam. In addition, this value is higher than that of the previously published values for many carbon nanomaterials(CNMs)/polymer nano composites heat sinks. The thermal conductivity of the 4 wt% of PVF/MWCNTs reached 65 W/mK at 200 oC. The 4 wt٪ PVF/MWCNTs foam lowered the temperature of a hot surface from ≈ 40 to 30oC, leading to cooling efficiency of 40٪. Based on the experimental results, the PVF/MWCNTs foams show an improved capability for heat dissipation through easily and scalable preparation method.