There are two approaches to improving the thermal conductivity of thermally conductive plastics:

First, synthesizing structural polymers with a high thermal conductivity, such as polyacetylene, polyaniline, and polypyrrole, which have good thermal conductivity and conduct heat mainly through an electronic conduction mechanism, or polymers with complete crystallinity that conduct heat via electrons.

Second, filling the polymer with highly thermally conductive inorganic materials to prepare polymer/inorganic thermally conductive composites. Because organic polymers with good thermal conductivity are expensive, filling is currently the most widely adopted method for preparing thermally conductive polymers. The metals and inorganic fillers that can be used as thermally conductive particles are broadly the following:

(1) Metal powder fillers: copper powder, aluminum powder, gold powder, silver powder; (2) Metal oxides: aluminum oxide, bismuth oxide, beryllium oxide, magnesium oxide, zinc oxide; (3) Metal nitrides: aluminum nitride, boron nitride; (4) Inorganic non-metals: graphite, silicon carbide, etc.

When inorganic non-metallic materials are used as thermally conductive fillers to fill a polymer matrix, how good the filling effect is depends mainly on the following factors:

(1) the type and characteristics of the polymer matrix; (2) the shape, particle size, and size distribution of the filler; (3) the interfacial bonding characteristics between the filler and the matrix, and the interaction between the two phases. Methods commonly used in the past include: using particles or whiskers with a certain aspect ratio to form a continuous thermally conductive network chain; selecting a combination of fillers with different particle sizes to achieve higher packing density; using coupling agents to improve the filler–matrix interface so as to reduce the thermal resistance at the interface; and filling plastics with nanomaterials to increase thermal conductivity, which has been a research hotspot in recent years.

It is believed that, with the advancement of technology, thermally conductive plastics with better performance will be developed, and they will be applied not only to LED lighting fixtures but also more widely to other products such as electronic and electrical appliances.