15072

13562

كارشناسي ارشد

پديده هاي انتقال

اصفهان : دانشگاه صنعتي اصفهان

1398

سيزده، 73ص. : مصور، جدول، نمودار

نسرين اعتصامي

محسن نصراصفهاني، افسانه ولي پوري

1398/06/31

كتابنامه

مهندسي شيمي

مهندسي شيمي

1398/06/31

2552682

Fabrication and Characterization of Lauric Acid Microencapsulation with and without Silica nanoparticles for Thermal Energy Storage Shila Rahnamaei shila rahnamaei@cc iut ac ir Date of Submission Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language PersianSupervisor Nasrin Etesami netesami@cc iut ac irAbstract Among various methods of thermal energy storage latent heat energy storage is more widelyused than sensible and chemical energy Phase change materials PCMs have been extensivelyused as latent heat storage materials in a variety of fields including solar energy utilization industrial heat loss recovery thermal insulation in construction textile industries and so on Fattyacids have superior advantages over other PCMs because of their properties such as high enthalpyof latent heat non toxicity non corrosiveness non flammability In the present work lauric acidmicrocapsules were fabricated with polystyrene shell and their thermal properties were comparedwith pure lauric acid Then the effect of silica hydrophobic nanoparticles on the thermal propertiesof microcapsules has been investigated In the first step the lauric acid microcapsule with apolystyrene shell was made without the presence of nanoparticles and its thermal properties wasanalysied In the next step silica nanoparticles at different weight percentages of 0 75 1 5 and3 were dispersed once in styrene as microcapsule shell and again in lauric acid as microcapsulecore using ultrasonic waves followed by encapsulation process through emulsion polymerizationmethod DSC FT IR SEM and XRD analysis weightless percentage at high temperature variations in thermal diffusivity of samples and thermal performance of the samples wereinvestigated and compared for all three types of products Results showed that lauric acidmicroencapsulated with a considerable encapsulation efficiency about 78 and the thermalstability of the resulting micro capsules was 36 more than that of pure lauric acid On the otherhand the presence of hydrophobic silica nanoparticles whether in lauric acid as a core or inpolystyrene as a shell made no chemical bond with the material however it disrupted the structureof the microcapsules according to SEM images and converts them into porous micron pores ofpolystyrene containing lauric acid and nanoparticles The encapsulation efficiency and thermalstability of the samples containing silica nanoparticles were much lower than the lauric acidmicrocapsules due to the decrease in the mass fraction of lauric acid limited in polystyrene

نسرين اعتصامي

محسن نصراصفهاني، افسانه ولي پوري