Abstract

Phase change material (PCM) is one of the majorly growing techniques used for thermal heat storage in various fields including construction for insulation and packaging industry. PCMs are widely used to increase the shelf life of the produce and prevent from harsh climatic conditions during transportation. In this present investigation, a PCM system was developed in the form of microcapsules using lauric acid (LA) and capric acid (CA) emulsions in melamine formaldehyde (MF) solution and polyurethane foam (PUF) using polytetrahydrofuran, isoprene diisocyanate, and polyethylene glycol (PEG). Acetic acid and triethylamine were used to control the pH during microcapsule preparation. The developed PUF and microcapsules were subjected to various characterization techniques to obtain the thermal, morphological, chemical, and physical properties. Thermal properties like the melting temperature, and enthalpies, etc. were obtained using thermogravimetric analysis (TGA) and digital scanning calorimetry (DSC). The morphology of the developed microcapsule and PUF were determined using scanning electron microscopy (SEM) and optical microscope (OM), respectively. The chemical properties of the raw material, microcapsules, and PUF samples were determined by Fourier transform infrared (FTIR). The physical properties including the hydro activity of PUF were determined using the water absorption characterization technique. The characteristic carboxylic acid peaks at 2849.46 cm-1 and 1705 cm-1 LA and CA, respectively when subjected to FTIR characterization. The microcapsule displayed a series of characteristic peaks of the LA/CA fatty acid and MF prepolymer under FTIR spectroscopy. The peak around 1703 cm-1 and 1547 cm-1 corresponds to the carboxylic acid of the fatty acid and 1197 cm-1 corresponding to the N-H and C-H stretching of the secondary amides of the prepolymer. Further, the peak observed around 3330 cm-1 in the PUF samples. This peak confirms the urethane formation as this peak corresponds to the N-H functional group of the urethane linkages. The morphology of the microcapsules confirms the formation of the perfect spherical PCM with fatty acid core and MF shell. The initial degradation of the microcapsule was found to be 143.28 oC. The melting temperature (Tm) and recrystallization temperature (Trc) was found to be around 31 oC and 15 oC, respectively. The melting enthalpy (DHm) and the recrystallization enthalpy (DHrc) were found to be 15.32 J/g and 13.89 J/g, respectively. These temperatures were consistent after the end of tenth and twentieth cycle of the DSC analysis. The PUF with 4 g PEG (PUF3) was determined to be more suitable for PCM application in packaging industries. The onset degradation temperature was found to be 308.16 oC. The Tm of the first cycle (Tm1), of the second cycle (Tm2), and the Trc were found to be 23.32 oC, 23.67 oC, and 3.54 oC, respectively. The respective enthalpies (DH) were 21.09 J/g, 22.18 J/g, and 20.36 J/g. These results indicate the development of microcapsule and PUF foam that can be used as PCMs in low temperature packaging applications.

Library of Congress Subject Headings

Packaging--Materials--Technological innovations; Phase transformations (Statistical physics); Polyurethanes; Artificial cells

Publication Date

5-2024

Document Type

Thesis

Student Type

Graduate

Degree Name

Packaging Science(MS)

Department, Program, or Center

Packaging Science

College

College of Engineering Technology

Advisor

Changfeng Ge

Advisor/Committee Member

Christopher Lewis

Advisor/Committee Member

Kyle Dunno

Campus

RIT – Main Campus

Plan Codes

PACK-MS

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