Characterization Study Of Paraffin Based Composite Phase Change Materials With Infrared Radiation Energy

Infrared stealth technology can protect vehicles from infrared detection availably by reducing infrared radiation intensity and changing infrared radiation property. From Stern-Boltzmann Law: M=εσT~4, there are two methods which can reduce infrared radiation intensity effectively: reduce surface emissivity and control surface temperature.The purpose for this study is to prepare paraffin-based composite which has low infrared emissivity and temperature control capability. The phase-change composite which has the properties of temperature control and low-emissivity was prepared by paraffin as phase change material and special morphology of Al as the filler. Meanwhile, the process parameters were optimized. After that the paraffin-based composite was characterized, the properties of emissivity, thermal behavior and temperature control effect were tested. the papers also did further studies on low emissivity and temperature control effect of composite, the result demonstrated the feasibility of the use of phase transition temperature control composite in infrared radiation in theory. To solve the problem that the melted paraffin will be running, the shape-stabilized paraffin of uniformity and stability was prepared.The main findings and conclusions are as follows:1 Prepared paraffin-based composite with low emissivity and phase transition temperature control property successfully, and optimized the preparing progress parameters of the composite. when the filler content was 40%,the coatings had the lowest infrared emissivity near to 0.2, and the influence factor of emissivity was analysed such as filler content, roughness and coating thickness.2 The temperature controlled effect of modified paraffin was tested using plank method and analysed temperature controlled effect of paraffin-based composite with different quality of paraffin and different emissivity and two layers composite with same emissivity respectively. The results indicate that the greater the amount of paraffin and the higher emissivity, the better the phase change temperature controlled effect. When the emissivity is constant the paraffin-based composite phase change temperature controlled effect is better than that of PU composite, the temperature controlled effect of single layer composite is better than the two layers composite. 3 Combining infrared emissivity and phase change temperature controlled results with stern- Boltzmann Law, the use of paraffin-based phase change temperature controlled composite in infrared stealth field is feasible. The results shows that paraffin-based composite with Al powder content of 40% has 87% reduction of infrared radiation in theory.4 The shape-stabilized paraffin of uniformity and stability was prepared by melt blending. The phase temperature of the shape-stabilized paraffin is that of paraffin, with increasing of paraffin content latent heat increases, and measured value are equivalent with calculated value of latent heat corresponding to paraffin content. The shape-stabilized paraffin with paraffin content of 80% doesn't change. The loss of the shape-stabilized paraffin increases with the content of paraffin, and the loss rate increase to 4.3800% at the paraffin content of 75%.