Modified γ-cyclodextrin metal organic frameworks (γ-CD-MOFs) are a promising eco-friendly sorbent... more Modified γ-cyclodextrin metal organic frameworks (γ-CD-MOFs) are a promising eco-friendly sorbents for post-combustion CO2 capture. Polyethyleneimine (PEI) has been widely used for modifying MOFs to enhance their CO2 sorption capacity and selectivity through the introduction of CO2 selective amine groups. The main objective of this study was to determine the optimal PEI molecular weight and arrangement (linear or branched) to enhance γ-CD-MOF’s CO2 sorption capacity. γ-CD-MOFs were impregnated with linear as well as branched PEI with molecular weights of 600, 1200 or 10,000. The CO2 sorption capacity of the PEI-impregnated γ-CD-MOFs was determined using a quartz crystal microbalance assembly at CO2 partial pressures from 0.35–1.0 atm. Impregnation with 600 g/mole branched PEI achieved the highest CO2 sorption capacity of 0.9 mmole/g CO2 at 1 atm, followed by the linear PEI (0.12 mmol/g). Modification with the other branched PEI molecular weights did not achieve detectable CO2 sorpti...
Due to the inherent hydrophilic nature and porosity of the paper fibers, hydrophobic polymeric ma... more Due to the inherent hydrophilic nature and porosity of the paper fibers, hydrophobic polymeric materials, waxes, and inorganic fillers have been widely utilized as coatings and fillers, respectively, on a fiber-based substrate. Coatings also impart oxygen, aroma, and oil barrier properties desirable for food packaging applications. In addition, coatings improve the functional properties and characteristics of paper, including reduced water absorbance, enhanced surface finish, gloss finish, printability, readability, dimensional stability of the substrate, and antimicrobial performance. Such functional properties are highly desirable for consumer packaging applications. However, such coatings may limit the repulpability, recyclability, biodegradability, and compostability of paper and paperboard. In addition, the contamination of the substrate by-product also limits the recyclability of the fiber-based substrates, and the paper, paperboard, or corrugated material ends up in landfill ...
Poly(l-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt ext... more Poly(l-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt extrusion of PLLA with 5, 10 and 20% w/w of activated Cu3(BTC)2 MOF. The morphology and stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calorimetry (DSC), gel permeation chromatography, X-ray diffraction, and scanning electron microscopy (SEM). The composites showed improved toughness during the tensile tests as compared to the neat PLLA matrix. Toughness mechanism of the composites was studied using SEM and rheological studies. SEM images indicated that cavitation induced by debonding at the interface of PLLA and MOF particles during the uniaxial stress was primarily responsible for the improved toughness of the composites. The SEM images of the composites, the solid like plateau observed in the PLLA composites during the parallel plate rheology at low frequency, and the decrease in the cold crystallization enthalpy during the de...
Nanoporous, non-toxic, ɣ-cyclodextrin metal organic frameworks (ɣ-CDMOFs) have potential applicat... more Nanoporous, non-toxic, ɣ-cyclodextrin metal organic frameworks (ɣ-CDMOFs) have potential applications in fields such as drug delivery and organic compound storage. The properties of many methylxanthines (alkaloids such as caffeine and theophylline) could be improved through ɣ-CDMOF encapsulation, yet little research has been performed on the subject. In this study, ɣ-CDMOFs were synthesized in order to 1. Determine if the vapor diffusion synthesis method can produce ɣ-CDMOF crystals that replicate those in literature and 2. Determine if ɣ-CDMOFs are able to encapsulate methylxanthines. The ɣ-CDMOFs were synthesized through vapor diffusion of methanol in a solution of ɣ-cyclodextrin and potassium hydroxide (KOH). The synthesized crystals were activated at 25 °C and 45 °C to remove the residual methanol and water, freeing the nanopores of the crystals. The synthesized and activated crystals were characterized through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Caffeine and theophylline were encapsulated over 24 hours in the ɣ-CDMOFs, which were then analyzed using thermogravimetric analysis (TGA). Characterization results aligned with literature confirming a uniform cubic structure of the crystals with sizes primarily ranging from 1 to 10μm, with a median crystallite size of 2 μm. It was determined that 1. Vapor diffusion is a viable synthesis method for ɣ-CDMOFs and 2. ɣ-CDMOFs are able to encapsulate theophylline, however the data was not conclusive enough to confirm the encapsulation of caffeine.
Polymer-filler interactions significantly influence morphology, functionality and various desirab... more Polymer-filler interactions significantly influence morphology, functionality and various desirable properties of mixed matrix membranes (MMMs). In this study, chain mobility and crystallization of Poly(L-lactic acid) (PLLA) MMM films prepared by solvent casting PLLA with 1, 5, 10 and 20% wt./wt. of MIL-53(Al) metal organic framework (MOF) were evaluated. The fabricated MMMs were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). DSC studies indicated that the addition of MOF particles in the PLLA matrix reduces the polymeric chain mobility, which affects the crystallization process. The percent crystallinity of neat PLLA was found to decrease from 4% in neat PLLA to completely amorphous structures in PLLA-10% and PLLA-20% MMMs, as observed in the second heating cycle. FTIR data supports these observations. TGA results showed that PLLA-MOF films are thermally less stable than neat PLLA suggesting that MOF particles act as a depolymerization catalyst for PLLA. Partial agglomeration of MOF particles was observed in the samples using SEM studies. This study indicates strong PLLA-MIL-53(Al) MOF interactions. In addition, this study also provides insight into the effect of MOF particles on the segmental mobility and morphology of PLLA-MIL-53 (Al) composite films.
Gamma cyclodextrin (CD) metal organic frameworks (CDMOFs) were synthesized by coordinating γ-CDs ... more Gamma cyclodextrin (CD) metal organic frameworks (CDMOFs) were synthesized by coordinating γ-CDs with potassium hydroxide (KOH), referred hereafter as CDMOF-a, and potassium benzoate (C 7 H 5 KO 2), denoted as CDMOF-b. The obtained CDMOF structures were characterized using nitrogen sorption isotherm, thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). High surface areas were achieved by the γ-CD based MOF structures where the Langmuir specific surface areas (SSA) of CDMOF-a and CDMOF-b were determined as 1,376 m 2 .g-1 and 607 m 2 .g-1 ; respectively. The dehydrated CDMOF structures demonstrated good thermal stability up to 250 o C as observed by the TGA studies. XRD results for CDMOF-a and CDMOF-b reveal a body centered-cubic (BCC) and trigonal crystal system; respectively. Due to its accessible porous structure and high surface area, acetaldehyde was successfully encapsulated in CDMOF-b. During the release kinetic studies, we observed peak release of 53 μg of acetaldehyde per g of CDMOF-b, which was 100 times greater than previously reported encapsulation in β-CD. However, aldol condensation reaction occurred during encapsulation of acetaldehyde into CDMOF-a. This research work demonstrates the potential to encapsulate volatile organic compounds in CDMOFb, and their associated release for applications including food, pharmaceuticals and packaging.
Poly(llactic acid) (PLLA) 20% (w/w) and Cu3(BTC)(2) metal organic framework (MOF) based mixed mat... more Poly(llactic acid) (PLLA) 20% (w/w) and Cu3(BTC)(2) metal organic framework (MOF) based mixed matrix membranes (MMMs) were fabricated by a vertical corotating twin screw microcompounder followed by an injection molding process. Water vapor, CO2, O2, and selected aroma mass transfer properties of PLLA and PLLA MMMs were evaluated. The CO2/O2 permselectivity of PLLA ((CO2/O2)) MMMs increased from 7.6 to 10.3 with the incorporation of 20% Cu3(BTC)(2) MOF. Gravimetric permeability studies of trans2hexenal performed at 23 degrees C and 50% RH indicated that permeability coefficient of PLLA MMMs increased by around 60% as compared to regular PLLA film. However, no changes in mass transfer rates were observed for acetaldehyde. Furthermore, the thermal processing parameters as well as the presence of MOF did not show any significant effect on the molecular weight of the PLLA matrix nor on the crystalline structure of the Cu3(BTC)(2) MOF, which was confirmed by both gel permeation chromatography and Xray diffraction studies.
Poly(L-lactic acid) (PLLA) and metal-organic framework (MOF) mixed-matrix membranes were prepared... more Poly(L-lactic acid) (PLLA) and metal-organic framework (MOF) mixed-matrix membranes were prepared by melt extrusion of PLLAwith5%(w/w)of either activated or water-saturated Cu 3 (BTC) 2 (Cu 3 (C 9 H 3 O 6) 2 (H 2 O) 3-xH 2 O, HKUST-1).The morphology and the stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The presence of activated and saturated MOF crystals increased the cold crystallization onset temperature as compared to neat PLLA. This can be attributed to the MOF crystals incorporated in the PLLA matrix, which decreased the mobility of PLLA and thus impeded the crystallization process. According to the XRD results, the activated MOF crystals were successfully incorporated into the PLLA matrix without altering the crystal structure of the MOF. Moreover, the findings from permeability and tensile tests as well as SEM imaging indicated good interfacial interactions between PLLA and activated MOF. However, during melt extrusion of PLLA with saturated MOF, water molecules from the saturated MOF altered the MOF crystal structure and contributed to the degradation of the PLLA polymer by reducing its molecular weight by around 21%.
Poly(L-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt ext... more Poly(L-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt extrusion of PLLA with 5, 10 and 20% w/w of activated Cu 3 (BTC) 2 MOF. The morphology and stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calo rimetry (DSC), gel permeation chromatography, X-ray diffraction, and scanning electron microscopy (SEM). The composites showed improved toughness during the tensile tests as compared to the neat PLLA matrix. Toughness mechanism of the composites was studied using SEM and rheological studies. SEM images indicated that cavitation induced by debonding at the interface of PLLA and MOF particles during the uniaxial stress was primarily responsible for the improved toughness of the composites. The SEM images of the composites, the solid like plateau observed in the PLLA composites during the parallel plate rheology at low frequency, and the decrease in the cold crystallization enthalpy during the developed composites indicate potential for various applications, which include gas separation, energy and active packaging.
A mesoporous-cyclodextrin porous crystalline framework was synthesized using-cyclodextrin and pot... more A mesoporous-cyclodextrin porous crystalline framework was synthesized using-cyclodextrin and potassium benzoate (C 7 H 5 KO 2 as a source for K + ions. The synthesized crystals were characterized using N 2 sorption, thermal gravimetric analysis, diffraction and electron microscopy techniques. BET specific surface area, t-plots, pores size and pore size distribution were used to understand the micro-and mesoporosity of the synthesized structure. Highly crystalline, as revealed by X-ray diffraction and scanning electron microscopy analysis, a coordinated-cyclodextrin mesoporous structure with average BET SSA of 74 m 2 • g −1 was obtained. The water interaction of the porous framework structure was reduced due to the coordination of the K + ions with hydroxyl moieties reducing the availability of hydroxyl groups as observed in the water sorption isotherms. The dehydrated-cyclodextrin framework showed thermal stability up to 300 C. The obtained multifunctional bio-based novel structure can be potentially employed for various applications including food, pharmaceutical, packaging, and gas separation among others.
Maleic anhydride compatibilized peach waste as filler in polypropylene and high density polyethyl... more Maleic anhydride compatibilized peach waste as filler in polypropylene and high density polyethylene biocomposites Caralyn Bibi Araya Wong It is estimated that roughly 103, 515 tons of peach waste is produced annually in the US. The majority of the waste is disposed of in landfills, which contributes to climate change as they release 93 million metric tons of CO2 equivalent. Peach waste principally consists of remaining stone and seed after flesh removal. The agro-waste includes both cellulose and lignin, which can be utilized as a filler in plastic packaging to reduce carbon footprints and material cost. The objectives of this research are (1) to develop peach flour (PF)-filled biocomposites with a polyolefin matrix using maleic anhydride-g-high density polyethylene (MAH-g-HDPE) coupling agent resin and (2) to investigate the composites' physicomechanical, thermal, and water absorbance changes. First, preliminary experiments examined a range of PF concentrations (5-50%) and MAH concentrations (0-17%) were tested to narrow the variability of PF and MAH loading mixture in an HDPE matrix. Preliminary experiments suggested that a 2:1 ratio of PF:CR provides maximum tensile properties. Response surface methodology (RSM) was utilized to analyze and optimize the tensile strength of the PW composite. The RSM parameters were MAH loading (5-20%), PF loading (2.5-10%), and polyolefin matrix (HDPE or polypropylene). The properties of PF-HDPE biocomposites were analyzed using several instrumental analyses. Mechanical strength (including tensile strength, elongation, and Young's modulus) and thermal v properties (thermal degradation, melting point, and crystallinity), and water resistance with the addition of PF and MAH were investigated. Biocomposite mechanical properties generally resulted in a nonsignificant decrease compared to the controls. Water absorption significantly increased with PF loading (P<0.01, =0.05). PF-PP biocomposites demonstrated a shift in thermal stability with an average 9.6% increase in Td compared to its control, whereas PF-HDPE biocomposites displayed no change in Td compared to its control. PF-PP and PF-HDPE biocomposites experienced a 36.7% and 16.0% decrease, respectively, in crystallinity with PF addition. The results provided evidence that peach byproduct can be diverted from landfills and utilized a filler in a polyolefin matrix. Polyolefin biocomposites with 2.5% PF would possess comparable tensile strength to a commercially available control. PF-polyolefin biocomposites can be used for packaging, automotive, and nonweightbearing construction parts.
Food wastage is a major concern for sustainable health and agriculture. To reduce food waste, cla... more Food wastage is a major concern for sustainable health and agriculture. To reduce food waste, classical preservation techniques such as drying, pasteurization, freeze-drying, fermentation, and microwave are available. Nonetheless, these techniques display shortcomings such as alteration of food and taste. Such shortcomings may be solved by active food packaging, which involves the incorporation of active agents into the packaging material. Recently, metal-organic frameworks, a class of porous hybrid supramolecular materials, have been developed as an active agent to extend food shelf life and maintain safety. Here, we review metal-organic frameworks in active packaging as oxygen scavengers, antimicrobials, moisture absorbers, and ethylene scavengers. We present methods of incorporation of metal-organic frameworks into packaging materials and their applications.
Modified γ-cyclodextrin metal organic frameworks (γ-CD-MOFs) are a promising eco-friendly sorbent... more Modified γ-cyclodextrin metal organic frameworks (γ-CD-MOFs) are a promising eco-friendly sorbents for post-combustion CO2 capture. Polyethyleneimine (PEI) has been widely used for modifying MOFs to enhance their CO2 sorption capacity and selectivity through the introduction of CO2 selective amine groups. The main objective of this study was to determine the optimal PEI molecular weight and arrangement (linear or branched) to enhance γ-CD-MOF’s CO2 sorption capacity. γ-CD-MOFs were impregnated with linear as well as branched PEI with molecular weights of 600, 1200 or 10,000. The CO2 sorption capacity of the PEI-impregnated γ-CD-MOFs was determined using a quartz crystal microbalance assembly at CO2 partial pressures from 0.35–1.0 atm. Impregnation with 600 g/mole branched PEI achieved the highest CO2 sorption capacity of 0.9 mmole/g CO2 at 1 atm, followed by the linear PEI (0.12 mmol/g). Modification with the other branched PEI molecular weights did not achieve detectable CO2 sorpti...
Due to the inherent hydrophilic nature and porosity of the paper fibers, hydrophobic polymeric ma... more Due to the inherent hydrophilic nature and porosity of the paper fibers, hydrophobic polymeric materials, waxes, and inorganic fillers have been widely utilized as coatings and fillers, respectively, on a fiber-based substrate. Coatings also impart oxygen, aroma, and oil barrier properties desirable for food packaging applications. In addition, coatings improve the functional properties and characteristics of paper, including reduced water absorbance, enhanced surface finish, gloss finish, printability, readability, dimensional stability of the substrate, and antimicrobial performance. Such functional properties are highly desirable for consumer packaging applications. However, such coatings may limit the repulpability, recyclability, biodegradability, and compostability of paper and paperboard. In addition, the contamination of the substrate by-product also limits the recyclability of the fiber-based substrates, and the paper, paperboard, or corrugated material ends up in landfill ...
Poly(l-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt ext... more Poly(l-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt extrusion of PLLA with 5, 10 and 20% w/w of activated Cu3(BTC)2 MOF. The morphology and stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calorimetry (DSC), gel permeation chromatography, X-ray diffraction, and scanning electron microscopy (SEM). The composites showed improved toughness during the tensile tests as compared to the neat PLLA matrix. Toughness mechanism of the composites was studied using SEM and rheological studies. SEM images indicated that cavitation induced by debonding at the interface of PLLA and MOF particles during the uniaxial stress was primarily responsible for the improved toughness of the composites. The SEM images of the composites, the solid like plateau observed in the PLLA composites during the parallel plate rheology at low frequency, and the decrease in the cold crystallization enthalpy during the de...
Nanoporous, non-toxic, ɣ-cyclodextrin metal organic frameworks (ɣ-CDMOFs) have potential applicat... more Nanoporous, non-toxic, ɣ-cyclodextrin metal organic frameworks (ɣ-CDMOFs) have potential applications in fields such as drug delivery and organic compound storage. The properties of many methylxanthines (alkaloids such as caffeine and theophylline) could be improved through ɣ-CDMOF encapsulation, yet little research has been performed on the subject. In this study, ɣ-CDMOFs were synthesized in order to 1. Determine if the vapor diffusion synthesis method can produce ɣ-CDMOF crystals that replicate those in literature and 2. Determine if ɣ-CDMOFs are able to encapsulate methylxanthines. The ɣ-CDMOFs were synthesized through vapor diffusion of methanol in a solution of ɣ-cyclodextrin and potassium hydroxide (KOH). The synthesized crystals were activated at 25 °C and 45 °C to remove the residual methanol and water, freeing the nanopores of the crystals. The synthesized and activated crystals were characterized through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Caffeine and theophylline were encapsulated over 24 hours in the ɣ-CDMOFs, which were then analyzed using thermogravimetric analysis (TGA). Characterization results aligned with literature confirming a uniform cubic structure of the crystals with sizes primarily ranging from 1 to 10μm, with a median crystallite size of 2 μm. It was determined that 1. Vapor diffusion is a viable synthesis method for ɣ-CDMOFs and 2. ɣ-CDMOFs are able to encapsulate theophylline, however the data was not conclusive enough to confirm the encapsulation of caffeine.
Polymer-filler interactions significantly influence morphology, functionality and various desirab... more Polymer-filler interactions significantly influence morphology, functionality and various desirable properties of mixed matrix membranes (MMMs). In this study, chain mobility and crystallization of Poly(L-lactic acid) (PLLA) MMM films prepared by solvent casting PLLA with 1, 5, 10 and 20% wt./wt. of MIL-53(Al) metal organic framework (MOF) were evaluated. The fabricated MMMs were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). DSC studies indicated that the addition of MOF particles in the PLLA matrix reduces the polymeric chain mobility, which affects the crystallization process. The percent crystallinity of neat PLLA was found to decrease from 4% in neat PLLA to completely amorphous structures in PLLA-10% and PLLA-20% MMMs, as observed in the second heating cycle. FTIR data supports these observations. TGA results showed that PLLA-MOF films are thermally less stable than neat PLLA suggesting that MOF particles act as a depolymerization catalyst for PLLA. Partial agglomeration of MOF particles was observed in the samples using SEM studies. This study indicates strong PLLA-MIL-53(Al) MOF interactions. In addition, this study also provides insight into the effect of MOF particles on the segmental mobility and morphology of PLLA-MIL-53 (Al) composite films.
Gamma cyclodextrin (CD) metal organic frameworks (CDMOFs) were synthesized by coordinating γ-CDs ... more Gamma cyclodextrin (CD) metal organic frameworks (CDMOFs) were synthesized by coordinating γ-CDs with potassium hydroxide (KOH), referred hereafter as CDMOF-a, and potassium benzoate (C 7 H 5 KO 2), denoted as CDMOF-b. The obtained CDMOF structures were characterized using nitrogen sorption isotherm, thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). High surface areas were achieved by the γ-CD based MOF structures where the Langmuir specific surface areas (SSA) of CDMOF-a and CDMOF-b were determined as 1,376 m 2 .g-1 and 607 m 2 .g-1 ; respectively. The dehydrated CDMOF structures demonstrated good thermal stability up to 250 o C as observed by the TGA studies. XRD results for CDMOF-a and CDMOF-b reveal a body centered-cubic (BCC) and trigonal crystal system; respectively. Due to its accessible porous structure and high surface area, acetaldehyde was successfully encapsulated in CDMOF-b. During the release kinetic studies, we observed peak release of 53 μg of acetaldehyde per g of CDMOF-b, which was 100 times greater than previously reported encapsulation in β-CD. However, aldol condensation reaction occurred during encapsulation of acetaldehyde into CDMOF-a. This research work demonstrates the potential to encapsulate volatile organic compounds in CDMOFb, and their associated release for applications including food, pharmaceuticals and packaging.
Poly(llactic acid) (PLLA) 20% (w/w) and Cu3(BTC)(2) metal organic framework (MOF) based mixed mat... more Poly(llactic acid) (PLLA) 20% (w/w) and Cu3(BTC)(2) metal organic framework (MOF) based mixed matrix membranes (MMMs) were fabricated by a vertical corotating twin screw microcompounder followed by an injection molding process. Water vapor, CO2, O2, and selected aroma mass transfer properties of PLLA and PLLA MMMs were evaluated. The CO2/O2 permselectivity of PLLA ((CO2/O2)) MMMs increased from 7.6 to 10.3 with the incorporation of 20% Cu3(BTC)(2) MOF. Gravimetric permeability studies of trans2hexenal performed at 23 degrees C and 50% RH indicated that permeability coefficient of PLLA MMMs increased by around 60% as compared to regular PLLA film. However, no changes in mass transfer rates were observed for acetaldehyde. Furthermore, the thermal processing parameters as well as the presence of MOF did not show any significant effect on the molecular weight of the PLLA matrix nor on the crystalline structure of the Cu3(BTC)(2) MOF, which was confirmed by both gel permeation chromatography and Xray diffraction studies.
Poly(L-lactic acid) (PLLA) and metal-organic framework (MOF) mixed-matrix membranes were prepared... more Poly(L-lactic acid) (PLLA) and metal-organic framework (MOF) mixed-matrix membranes were prepared by melt extrusion of PLLAwith5%(w/w)of either activated or water-saturated Cu 3 (BTC) 2 (Cu 3 (C 9 H 3 O 6) 2 (H 2 O) 3-xH 2 O, HKUST-1).The morphology and the stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The presence of activated and saturated MOF crystals increased the cold crystallization onset temperature as compared to neat PLLA. This can be attributed to the MOF crystals incorporated in the PLLA matrix, which decreased the mobility of PLLA and thus impeded the crystallization process. According to the XRD results, the activated MOF crystals were successfully incorporated into the PLLA matrix without altering the crystal structure of the MOF. Moreover, the findings from permeability and tensile tests as well as SEM imaging indicated good interfacial interactions between PLLA and activated MOF. However, during melt extrusion of PLLA with saturated MOF, water molecules from the saturated MOF altered the MOF crystal structure and contributed to the degradation of the PLLA polymer by reducing its molecular weight by around 21%.
Poly(L-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt ext... more Poly(L-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt extrusion of PLLA with 5, 10 and 20% w/w of activated Cu 3 (BTC) 2 MOF. The morphology and stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calo rimetry (DSC), gel permeation chromatography, X-ray diffraction, and scanning electron microscopy (SEM). The composites showed improved toughness during the tensile tests as compared to the neat PLLA matrix. Toughness mechanism of the composites was studied using SEM and rheological studies. SEM images indicated that cavitation induced by debonding at the interface of PLLA and MOF particles during the uniaxial stress was primarily responsible for the improved toughness of the composites. The SEM images of the composites, the solid like plateau observed in the PLLA composites during the parallel plate rheology at low frequency, and the decrease in the cold crystallization enthalpy during the developed composites indicate potential for various applications, which include gas separation, energy and active packaging.
A mesoporous-cyclodextrin porous crystalline framework was synthesized using-cyclodextrin and pot... more A mesoporous-cyclodextrin porous crystalline framework was synthesized using-cyclodextrin and potassium benzoate (C 7 H 5 KO 2 as a source for K + ions. The synthesized crystals were characterized using N 2 sorption, thermal gravimetric analysis, diffraction and electron microscopy techniques. BET specific surface area, t-plots, pores size and pore size distribution were used to understand the micro-and mesoporosity of the synthesized structure. Highly crystalline, as revealed by X-ray diffraction and scanning electron microscopy analysis, a coordinated-cyclodextrin mesoporous structure with average BET SSA of 74 m 2 • g −1 was obtained. The water interaction of the porous framework structure was reduced due to the coordination of the K + ions with hydroxyl moieties reducing the availability of hydroxyl groups as observed in the water sorption isotherms. The dehydrated-cyclodextrin framework showed thermal stability up to 300 C. The obtained multifunctional bio-based novel structure can be potentially employed for various applications including food, pharmaceutical, packaging, and gas separation among others.
Maleic anhydride compatibilized peach waste as filler in polypropylene and high density polyethyl... more Maleic anhydride compatibilized peach waste as filler in polypropylene and high density polyethylene biocomposites Caralyn Bibi Araya Wong It is estimated that roughly 103, 515 tons of peach waste is produced annually in the US. The majority of the waste is disposed of in landfills, which contributes to climate change as they release 93 million metric tons of CO2 equivalent. Peach waste principally consists of remaining stone and seed after flesh removal. The agro-waste includes both cellulose and lignin, which can be utilized as a filler in plastic packaging to reduce carbon footprints and material cost. The objectives of this research are (1) to develop peach flour (PF)-filled biocomposites with a polyolefin matrix using maleic anhydride-g-high density polyethylene (MAH-g-HDPE) coupling agent resin and (2) to investigate the composites' physicomechanical, thermal, and water absorbance changes. First, preliminary experiments examined a range of PF concentrations (5-50%) and MAH concentrations (0-17%) were tested to narrow the variability of PF and MAH loading mixture in an HDPE matrix. Preliminary experiments suggested that a 2:1 ratio of PF:CR provides maximum tensile properties. Response surface methodology (RSM) was utilized to analyze and optimize the tensile strength of the PW composite. The RSM parameters were MAH loading (5-20%), PF loading (2.5-10%), and polyolefin matrix (HDPE or polypropylene). The properties of PF-HDPE biocomposites were analyzed using several instrumental analyses. Mechanical strength (including tensile strength, elongation, and Young's modulus) and thermal v properties (thermal degradation, melting point, and crystallinity), and water resistance with the addition of PF and MAH were investigated. Biocomposite mechanical properties generally resulted in a nonsignificant decrease compared to the controls. Water absorption significantly increased with PF loading (P<0.01, =0.05). PF-PP biocomposites demonstrated a shift in thermal stability with an average 9.6% increase in Td compared to its control, whereas PF-HDPE biocomposites displayed no change in Td compared to its control. PF-PP and PF-HDPE biocomposites experienced a 36.7% and 16.0% decrease, respectively, in crystallinity with PF addition. The results provided evidence that peach byproduct can be diverted from landfills and utilized a filler in a polyolefin matrix. Polyolefin biocomposites with 2.5% PF would possess comparable tensile strength to a commercially available control. PF-polyolefin biocomposites can be used for packaging, automotive, and nonweightbearing construction parts.
Food wastage is a major concern for sustainable health and agriculture. To reduce food waste, cla... more Food wastage is a major concern for sustainable health and agriculture. To reduce food waste, classical preservation techniques such as drying, pasteurization, freeze-drying, fermentation, and microwave are available. Nonetheless, these techniques display shortcomings such as alteration of food and taste. Such shortcomings may be solved by active food packaging, which involves the incorporation of active agents into the packaging material. Recently, metal-organic frameworks, a class of porous hybrid supramolecular materials, have been developed as an active agent to extend food shelf life and maintain safety. Here, we review metal-organic frameworks in active packaging as oxygen scavengers, antimicrobials, moisture absorbers, and ethylene scavengers. We present methods of incorporation of metal-organic frameworks into packaging materials and their applications.
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Papers by Ajay Kathuria