Researches On The Thermal Conductivity Of Filler Contacts In Filled Composites

Polymer heat exchangers are one of the effective methods to solve the corrosion and scaling problems of metal heat exchangers.However,the thermal conductivity of the polymer is poor,which limits its promotion and application.Adding high thermal conductive fillers to base materials has been recognized as an efficient way to increase the thermal conductivity of composites material.However,the thermal conductivity of the composite is not high when the filler content is low;the thermal conductivity of filled composite is improved significantly with filler contents,but mechanical strength of the composite is drastically reduced.The heat conductive network is formed by filler content,it has a significant impact on the improvement of the thermal conductivity of filled composite.However,the current experimental and theoretical studies on the thermal network neglect the quantitative study of the filler contact,resulting in a low heat transfer efficiency of the thermal network,and the prediction results of the theoretical model are not accurate.This paper focuses on the effect of filler contact on the thermal conductivity of composites.The research results can guide the preparation of high-performance thermal composites.The results show that the effect on the thermal conductivity of filled composite is very small for sphere filler contacts.For the cubic filler,cylindrical filler and wafer-shaped filler,when filler contacts and the volume content is more than 10%,the thermal conductivity increases sharply,that's mean the filler contact has a significant effect on the thermal conductivity of filled composite.What's more,the heat conductive network has been formed by fillers,which is much lower than previously reported.When filler non contacts,the thermal conductivity of filled composite increases linearly with the rise of the filler's volume content,indicating that the thermal conductivity of filler non-contact composites is only related to the volume content of fillers.The comparison of the four different shaped fillers shows that,the thermal conductivity of wafer fillers > cylinder fillers > cube fillers > sphere fillers.Comparing the results of the numerical simulation with the experimental results,it is found that the thermal conductivity of the experiment is higher than the cube filler non-contact composite,which is lower than the composite with cube filler contacts,and the thermal conductivity increases sharply when the filler's volume content reaches about 10%.The growth trend of the thermal conductivity is similar to the composite with cube filler contacts,the results indicate that the thermal conductivity of filled composite materials can be accurately predicted by numerical simulation.