Is density of an object proportional to its conductivity?

Yes, the density of an object is proportional to its conductivity.

Explanation:

The "Thermal conductivity" of an object is dependent on three things: temperature, density and moisture content. This means that an object becomes more conductive if it has a higher temperature, higher density and more moisture in its content. This makes them directly proportional to each other.

The denser an object is, the more likely it will conduct heat because its atoms are tightly packed compared to less denser ones like air. Such position of atoms hastens the transfer of energy.