Experimental Study of the Thermal Properties of Microencapsulated Palmitic Acid Composites with CuCO₃ Shell as Thermal Energy Storage Materials

Abstract

A novel microencapsulated phase change material (PCM) with a Palmitic acid (PA) core and Copper (II) carbonate (CuCO 3 ) shell was successfully fabricated through a self-assembly method. Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to determine the chemical compositions, crystalloid phase, microstructure and morphology of PA@CuCO 3 microcapsules, respectively. The thermal properties and thermal stability of microcapsules were determined by differential scanning calorimetry (DSC) and a thermogravimetric analysis (TGA). The XRD and FT-IR results indicated the presence of all of the characteristic peaks of PA and CuCO 3 and proved that no chemical reaction had occurred between them. The SEM images showed a regular spherical morphology with rough surfaces for the PA@CuCO 3 microcapsule with average diameters ranged from 1.5 to 2 μm, and the TEM image confirmed the PA core to have been well encapsulated by CuCO 3 . In the DSC analysis results, the microcapsules indicated similar phase change behaviors as those of pristine PA, and the typical samples were melted at 66.9°C with a latent heat of 48.85 J/g and frozen at 55.7°C with a latent heat of 43.29 J/g for a microencapsulation ratio of 43.92%. TGA analyses indicated that the thermal stability of the PA was further improved due to the protection of the PA core encapsulated by the CuCO 3 shell.[a] Dr.step degradation behavior over a temperature range of 200-310°C, which is attributed to the decomposition of PA and CuCO 3 , respectively. It is clear from Figure 5 (parts b, c, and d) that the PA@CuCO 3 microcapsule samples all exhibited a maximum weight loss at higher temperatures in comparison with the pristine PA, which indicates that the CuCO 3 shells can improve the thermal stability of PA in the microcapsule.Using DSC, the phase change behaviors and latent heats of the pristine PA and PA@CuCO 3 microcapsules with different core/shell mass ratios were investigated. Figures 6 and 2 3 4 5 6 7 8

Synthesis of nano-fibers containing nano-curcumin in zein corn protein and its physicochemical and biological characteristics

“…However, there are still limitations to the solubility and stability of curcumin although many methods such as liposome 45 , polymeric nanoparticles 46 , solid lipid nanoparticles (SLNs) 47 , albumin nanoparticles 48 , microemulsions and nanoemulsions 49 , nanospheres, and microcapsules 50 have been devised in recent years to obtain a higher aqueous solubility, bioavailability, activity, and lower toxicity 28 , 51 . In this regard, the emulsion method has received much attention in recent decades due to containing a simple synthesizing process and high efficiency, as well as requiring low costs, and eco-friendly materials 52 – 56 . This method has been exerted to synthesize water-insoluble substances 57 , 58 , oils 59 , 60 , plant extracts 61 , 62 , proteins 63 , nucleic acids 64 , curcumin, and many other substances 49 for drug delivery intentions, while some of these materials have been evaluated even in nanofiber scaffolds 65 – 67 .…”