Preparation and Characterization of Poly(melamine-urea-fbrmaldehyde) Tetradecanol Microcapsules Coated with Silver Particles

Abstract

A novel type of microencapsulated phase change materials (microPCMs) based on 1-tetradecanol (TD) core and silver-coated poly (melamine-urea-formaldehyde) (MUF) shell was successfully synthesized by in situ polymerization method followed by silver reduction. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM/EDS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to characterize the chemical structure, morphology and thermal properties of the as-prepared silver-coated microPCMs. FTIR analysis confirmed the successful encapsulation of TD with MUF wall materials. The SEM and EDS results indicated that the prepared silver-coated MUF microPCMs exhibited uniform spherical shape with a perfect silver outer layer. From XRD analysis, the Ag metal dispersed on the surface of microcapsules presented the form of elementary substance. The deposition weight of silver particles on the microcapsule surface increased with increasing the amount of silver nitrate, as indicated by EDS tests. The DSC results indicated that the melting temperature and the melting latent heat of microPCMs modified with 0.7 g of silver nitrate in 150 mL aqueous solution were 39.2 °C and 126.6 J·g⁻¹, respectively. Supercooling of the microPCMs coated with silver particles was effectively suppressed, compared with that of microPCMs without Ag. Thus, the encapsulation of TD with silver-coated MUF shell developed by this work can be an effective method to prepare the microPCMs with enhanced thermal transfer performance and phase change properties.

Keywords

phase change materials / microcapsule / 1-tetradecanol / silver / metal coating

References

[1] Pielichowska K, Pielichowski K. Phase Change Materials for Thermal Energy Storage[J]. Prog. Mater. Sci., 2014, 65(10): 67-123.

[2] Farid MM, Khudhair AM, Razack SAK, et al. A Review on Phase Change Energy Storage: Materials and Applications[J]. Energ. Convers. Manage., 2004, 45(9–10): 1 597-1 615.

[3] Karthikeyan M, Ramachandran T. Review of Thermal Energy Storage of Micro- and Nanoencapsulated Phase Change Materials[J]. Mater. Res. Innov., 2014, 18(7): 541-554.

[4] Yataganbaba A, Ozkahraman B, Kurtbas I. Worldwide Trends on Encapsulation of Phase Change Materials: A Bibliometric Analysis (1990–2015)[J]. Appl. Energ., 2017, 185: 720-731.

[5] Su W, Darkwa J, Kokogiannakis G. Development of Microencapsulated Phase Change Material for Solar Thermal Energy Storage[J]. Appl. Therm. Eng., 2017, 112: 1 205-1 212.

[6] Gao F, Wang X, Wu D. Design and Fabrication of Bifunctional Microcapsules for Solar Thermal Energy Storage and Solar Photocatalysis by Encapsulating Paraffin Phase Change Material into Cuprous Oxide[J]. Sol. Energy Mater. Sol. Cells, 2017, 168: 146-164.

[7] Döğüşcü DK, Altıntaş A, Sarı A, et al. Polystyrene Microcapsules with Palmitic-Capric Acid Eutectic Mixture as Building Thermal Energy Storage Materials[J]. Energ. Buildings, 2017, 150: 376-382.

[8] Giro-Paloma J, Al-Shannaq R, Fernández AI, et al. Preparation and Characterization of Microencapsulated Phase Change Materials for Use in Building Applications[J]. Materials, 2016, 9(1): 11

[9] Nomura T, Akiyama T. High-temperature Latent Heat Storage Technology to Utilize Exergy of Solar Heat and Industrial Exhaust Heat[J]. Int. J. Energ. Res., 2017, 41(2): 240-251.

[10] Alay A S, Alkan C, Tözüm MS, et al. Preparation and Textile Application of Poly (methyl methacrylate-co-methacrylic acid)/n-Octadecane and n-Eicosane Microcapsules[J]. J. Text. Inst., 2017, 108(1): 30-41.

[11] Li W, Zong J, Huang R, et al. Design, Controlled Fabrication and Characterization of Narrow-disperse Macrocapsules Containing Micro/NanoPCMs[J]. Mater. Design, 2016, 99: 225-234.

[12] Zhang S, Niu J. Experimental Investigation of Effects of Supercooling on Microencapsulated Phase-change Material (MPCM) Slurry Thermal Storage Capacities[J]. Sol. Energy Mater. Sol. Cells, 2010, 94(6): 1 038-1 048.

[13] Salunkhe PB, Shembekar PS. A Review on Effect of Phase Change Material Encapsulation on the Thermal Performance of a System[J]. Renew. Sust. Energ. Rev., 2012, 16(8): 5 603-5 616.

[14] Tang XF, Li W, Shi HF, et al. Fabrication, Characterization and Suppression of Supercooling in Microencapsulated n-Octadecane with Methyl Methacrylate-Octadecyl Methacrylate Copolymer as Shell[J]. Sci. Adv. Mater., 2014, 6(1): 119-126.

[15] Zhao CY, Zhang GH. Review on Microencapsulated Phase Change Materials (MEPCMs): Fabrication, Characterization and Applications[J]. Renew. Sust. Energ. Rev., 2011, 15(8): 3 813-3 832.

[16] Wu Q, Zhao D, Jiao X, et al. Preparation, Properties, and Supercooling Prevention of Phase Change Material n-Octadecane Microcapsules with Peppermint Fragrance Scent[J]. Ind. Eng. Chem. Res., 2015, 54(33): 8 130-8 136.

[17] Al-Shannaq R, Kurdi J, Al-Muhtaseb S, et al. Supercooling Elimination of Phase Change Materials (PCMs) Microcapsules[J]. Energy, 2015, 87: 654-662.

[18] Fan YF, Zhang XX, Wang XC, et al. Super-cooling Prevention of Microencapsulated Phase Change Material[J]. Thermochim. Acta, 2004, 413(1–2): 1-6.

[19] Cao F, Yang B. Supercooling Suppression of Microencapsulated Phase Change Materials by Optimizing Shell Composition and Structure[J]. Appl. Energy, 2014, 113(1): 1 512-1 518.

[20] Song QW, Li Y, Yuen M, et al. Supercooling of Silver Nano Composite PCM Microcapsules[J]. J. Fiber. Bioeng. Inf., 2008, 1(3): 239-248.

[21] Huang YT, Zhang H, Wan XJ, et al. Carbon Nanotube-enhanced Double-walled Phase-change Microcapsules for Thermal Energy Storage[J]. J. Mater. Chem. A, 2017, 5(16): 7 482-7 493.

[22] Al-Shannaq R, Kurdi J, Al-Muhtaseb S, et al. Innovative Method of Metal Coating of Microcapsules Containing Phase Change Materials[J]. Sol. Energy, 2016, 129: 54-64.

[23] Wang Z, Su H, Zhao S, et al. Influence of Phase Change Material on Mechanical and Thermal Properties of Clay Geopolymer Mortar[J]. Constr. Build. Mater., 2016, 120: 329-334.

[24] Song S, Dong L, Qu Z, et al. Microencapsulated Capric-Stearic Acid with Silica Shell as a Novel Phase Change Material for Thermal Energy Storage[J]. Appl. Therm. Eng., 2014, 70(1): 546-551.

[25] Karaman S, Karaipekli A, Sarı A, et al. Polyethylene Glycol(PEG)/diatomite Composite as a Novel Form-stable Phase Change Material for Thermal Energy Storage[J]. Sol. Energy Mater. Sol. Cells, 2011, 95(7): 1 647-1 653.

[26] Wang HP, Li MQ, Guo C, et al. Microencapsulation of Diglycidyl 1, 2-Cyclohexanedicarboxylate by In Situ Polymerization: Preparation and Characterization[J]. e-Polymers, 2015, 15(6): 377-383.

[27] Tang X, Li W, Shi H, et al. Fabrication, Characterization, and Supercooling Suppression of Nanoencapsulated n-Octadecane with Methyl Methacrylate-Octadecyl Methacrylate Copolymer Shell[J]. Colloid Polym. Sci., 2013, 291(7): 1 705-1 712.

[28] Zhang H, Wang X. Synthesis and Properties of Microencapsulated n-Octadecane with Polyurea Shells Containing Different Soft Segments for Heat Energy Storage and Thermal Regulation[J]. Sol. Energy Mater. Sol. Cells, 2009, 93(8): 1 366-1 376.

[29] Huang M, Luo Y, Zhong Y, et al. Preparation and Characterization of Microencapsulated Phase Change Materials with Binary Cores and Poly (allyl methacrylate) (PALMA) Shells Used for Thermo-regulated Fibers[J]. Thermochim. Acta, 2017, 655: 262-268.

[30] Xu C, Zhou R, Chen H, et al. Silver-coated Glass Fibers Prepared by a Simple Electroless Plating Technique[J]. J. Mater. Sci.: Mater. Electron., 2014, 25(10): 4 638-4 642.

[31] Li J, Wang S, Liu H, et al. Preparation and Application of Poly(melamine-urea-formaldehyde) Microcapsules Filled with Sulfur[J]. Polym. Plast. Technol. Eng., 2011, 50(7): 689-697.

[32] Salaün F, Vroman I. Influence of Core Materials on Thermal Properties of Melamine-formaldehyde Microcapsules[J]. Eur. Polym. J., 2008, 44(3): 849-860.

[33] Crispin X, Geskin V, Crispin A, et al. Characterization of the Interface Dipole at Organic/Metal Interfaces[J]. J. Am. Chem. Soc., 2002, 124(27): 8 131-8 141.

[34] Manoj L, Vishwakarma V, Samal SS, et al. Green Synthesis of Silver Nanoparticles Using Hypericin-rich Shoot Cultures of Hypericum Hookerianum and Evaluation of Anti-bacterial Activities[J]. J. Exp. Nanosci., 2015, 10(3): 181-188.

[35] Carreto L, Almeida AR, Fernandes AC, et al. Thermotropic Mesomorphism of a Model System for the Plant Epicuticular Wax Layer[J]. Biophys. J., 2002, 82(1): 530-540.

[36] Yin D, Ma L, Geng W, et al. Microencapsulation of n-Hexadecanol by In Situ Polymerization of Melamine-formaldehyde Resin in Emulsion Stabilized by Styrene-maleic Anhydride Copolymer[J]. Int. J. Energ. Res., 2015, 39(5): 661-667.

[37] Yang H, Liu F, Liu Z, et al. Fabrication and Characterization of Phase Change Microcapsules with Tetradecanol as Phase Change Material[J]. Chin. Plast. Ind., 2015, 43(4): 1-4. (Chinese)