  Micro/nano porous polymeric material is considered a unique industrial
material due to its extremely low thermal conductivity, low density, and high
surface area. Therefore, it is necessary to establish an accurate thermal
conductivity prediction model suiting their applicable conditions and provide a
theoretical basis for expanding of their applications. In this work, the
development of the calculation model of equivalent thermal conductivity of
micro/nano porous polymeric materials in recent years was summarized. Firstly,
it reviews the process of establishing the overall equivalent thermal
conductivity calculation model for micro/nano porous polymers. Then, the
predicted calculation models of thermal conductivity are introduced according
to the conductive thermal conductivity models and the radiative thermal
conductivity models separately. In addition, the thermal conduction part is
divided into the gaseous thermal conductivity model, solid thermal conductivity
model and gas-solid coupling model. Finally, it is concluded that, compared
with other porous materials, there are few studies on heat transfer of
micro/nano porous polymers, especially on the special heat transfer mechanisms
such as scale effects at the micro/nanoscale. In particular, the following
aspects of porous polymers still need to be further studied: micro scaled
thermal radiation, heat transfer characteristics of special morphologies at the
nanoscale, heat transfer mechanism and impact factors of micro/nano porous
polymers. Such studies would provide a more accurate prediction of thermal
conductivity and a wider application in energy conversion and storage systems.
