Paraffin Wax Testing

Kenisarin, Murat, et al. Solar Energy Materials and Solar Cells 200 (2019): 110026.

Phase change materials (PCMs) based on paraffin wax (PW) have attracted significant attention for thermal energy storage applications due to their high latent heat capacity. However, their low thermal conductivity limits performance. This study investigated the thermal and structural properties of paraffin wax/expanded graphite (PW/EG) composite PCMs with varying EG mass fractions (2%, 4%, and 6%). FireCarb TEG-315 and FireCarb TEG-160 were used as A-type and B-type EG, respectively.

Structural analysis using polarizing optical microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy (FTIR) revealed a distinct intermolecular interaction between B-type EG and PW, which enhanced the thermo-physical properties of the composite. While pure PW and PW/A-type EG composites exhibited both solid-solid and solid-liquid phase transitions, PW/B-type EG composites only showed the solid-liquid phase change, indicating stronger interaction with B-type EG.

Thermal conductivity analysis demonstrated significant improvements. Pure PW had a thermal conductivity of 0.258 W/m°C, while PW composites with 6% EG exhibited enhanced values of 0.977 W/m°C for A-type EG and 1.263 W/m°C for B-type EG, corresponding to enhancement ratios of 3.79 and 4.9, respectively. Despite ultrasonic treatment, the composite structure remained inhomogeneous, suggesting further improvements could increase thermal performance.

FTIR analysis supported the presence of unique intermolecular interactions in PW/B-type EG composites, as indicated by distinct spectral differences. These findings underscore the potential of PW/EG composites for improved thermal energy storage, with B-type EG showing greater enhancement potential.

Sobolciak, Patrik, et al. Renewable Energy 88 (2016): 372-382.

Paraffin wax (PW)-based phase change materials (PCMs) are widely used for thermal energy storage due to their high latent heat capacity. However, their low thermal conductivity limits efficiency. This study explores the thermal properties of composite PCMs consisting of linear low-density polyethylene (LLDPE), paraffin wax (W), and expanded graphite (EG) using the transient guarded hot plane method (TGHPT).

PCMs with 40 wt.% paraffin wax exhibited a latent heat of 36 J/g, while those with 50 wt.% paraffin wax demonstrated a higher latent heat of 49 J/g within the phase change temperature range of 20–50 °C. Sensible heat (Qsens) in the 25–35 °C range decreased from 31 to 24 J/g with increasing EG concentration. The addition of EG significantly improved the thermal conductivity of PCMs, increasing from 0.252 W/m°C in pure PW to 1.329 W/m°C in composites containing 15 wt.% EG. This enhancement reduced the melting and solidification time of the PCMs, improving thermal energy storage and release efficiency.

The study highlights that the increased EG content enhances the thermal conductivity of paraffin wax-based PCMs, optimizing their performance in thermal management applications. The findings underscore the potential of PW/EG composites for improving heat storage capacity and thermal response, making them ideal for advanced energy storage systems.

Kim, Soojong, Heejang Moon, and Jinkon Kim. Thermochimica acta 613 (2015): 9-16.

Paraffin wax (PW)-based fuels have gained attention for hybrid rocket applications due to their high regression rates and combustion efficiency. This study investigates the thermal properties and combustion performance of paraffin wax/low-density polyethylene (LDPE) blends with LDPE concentrations of 5% (SF-5) and 10% (SF-10).

Scanning electron microscopy (SEM) confirmed that the PW/LDPE blends exhibited uniform mixtures despite the immiscibility of components, as evidenced by two degradation steps in thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) showed that increasing PW content reduced the melting temperature of LDPE, aligning with the additive rule for specific melting enthalpy. Thermomechanical analysis (TMA) revealed that the linear coefficient of thermal expansion (LCTE) decreased with increasing LDPE loading, but the effect was minimal at low LDPE concentrations.

The improved regression rates and combustion efficiency of the blends over pure PW highlight their potential as novel rocket fuels. Unlike phase change material (PCM) applications, where high LDPE content is preferred for structural stability, rocket fuel applications benefit from low LDPE content to maximize combustion performance. These findings suggest that PW/LDPE blends could enhance the efficiency and performance of hybrid rocket systems, making them promising candidates for advanced aerospace applications.