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Papers by EMMA REBECA MACIAS BALLEZA

Bioresources, 2019

Natural lignocellulosic biomass is a valuable feedstock for soluble-grade cellulose (α-cellulose ... more Natural lignocellulosic biomass is a valuable feedstock for soluble-grade cellulose (α-cellulose > 90%) with advantageous features such as abundance, high strength, rigid structure, low weight, and it is biodegradable. The bagasse from Agave tequilana Weber var. azul is the main agroindustrial waste from the tequila industry and poses an environmental threat. However, due to its high cellulose content, Agave tequilana bagasse is an excellent candidate for the extraction and utilization of its components. In this study, alkaline cooking, followed by five stages of bleaching, was employed to obtain soluble-grade cellulose pulp. The obtained soda pulp material had a Kappa number (KN) of 23 ± 3, viscosity (μ) of 11.53 to 10.18 cp, degree of polymerization (DP) of 830 to 750, brightness of 87.5%, and percentage of alpha-cellulose (α) of 81 ± 3 at 94 ± 3%. The obtained material was characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron mic...

Carbohydrate polymers, 2018

A novel thermosensitive hydrogel consisting of phosphorylated β-cyclodextrin (βCD-PH), β-cyclodex... more A novel thermosensitive hydrogel consisting of phosphorylated β-cyclodextrin (βCD-PH), β-cyclodextrin (βCD) and chitosan was prepared by embedding βCD and βCD-PH, into the well-studied chitosan/αβ-glycerophosphate system (CS/αβGP). The relevance of this work is the use of βCD-PH to partially substitute αβGP as the gelling agent. The role of βCD and βCD-PH on the rheological properties of hydrogels, gelation time, and gelation temperature were investigated. The gelation time for all the samples (CS/αβGP, CS/αβGP/βCD, and CS/αβGP/βCD-PH) was less than a minute at 37 °C, which is suitable for biomedical applications. The gelation temperature for hydrogel CS/αβGP/βCD-PH increased linearly with the addition of βCD-PH within the interval 31.8-37.3 °C, at ratios CS:βCD-PH of 1:0.5, 1:1, 1:1.5 and 1:2 (w/w). The hydrogel thus obtained has potential applications in dual drug delivery (hydrophilic and hydrophobic).

Polymers

In this work, cellulose nanocrystals (CNCs), bleached cellulose nanofibers (bCNFs), and unbleache... more In this work, cellulose nanocrystals (CNCs), bleached cellulose nanofibers (bCNFs), and unbleached cellulose nanofibers (ubCNFs) isolated by acid hydrolysis from Agave tequilana Weber var. Azul bagasse, an agro-waste from the tequila industry, were used as reinforcements in a thermoplastic starch matrix to obtain environmentally friendly materials that can substitute contaminant polymers. A robust characterization of starting materials and biocomposites was carried out. Biocomposite mechanical, thermal, and antibacterial properties were evaluated, as well as color, crystallinity, morphology, rugosity, lateral texture, electrical conductivity, chemical identity, solubility, and water vapor permeability. Pulp fibers and nanocelluloses were analyzed via SEM, TEM, and AFM. The water vapor permeability (WVP) decreased by up to 20.69% with the presence of CNCs. The solubility decreases with the presence of CNFs and CNCs. The addition of CNCs and CNFs increased the tensile strength and You...

Nanocrystalline cellulose (NCC) was prepared from Agave tequilana Weber blue variety via acid hyd... more Nanocrystalline cellulose (NCC) was prepared from Agave tequilana Weber blue variety via acid hydrolysis. The NCC was used in forming acrylic acid/acrylamide hydrogels (AA/AM), (80/20 w/w), crosslinked with N-N-methylene bisacrylamide (MBA) at addition levels of 1, 2, 4, and 8 wt% of the monomeric phase. The NCC was dosed at 0.1, 0.5, and 1.0 wt%. Two synthesis routes were used. In the first route, polymerization was performed immediately after mixing the components. In the second route, the mixture of the components was kept at 2 °C ± 1 °C for 24 h before the polymerization (thermal treatment). All the hydrogels were characterized by nuclear magnetic resonance (NMR), water absorption tests, scanning electron microscope (SEM) analysis, and rheology tests. The NCC particles had a diameter of approximately 75 nm. The hydrogels that were subjected to the thermal treatment reached the equilibrium after approximately 72 h. The un-treated hydrogels reached the equilibrium after approximat...

Journal of Surfactants and Detergents

The temperature–composition phase diagram in the diluted region of the cationic surfactant cetyld... more The temperature–composition phase diagram in the diluted region of the cationic surfactant cetyldimethylbenzylammonium salicylate/water system was studied with a battery of techniques. The Krafft temperature (T k=33±1°C) was measured by differential scanning calorimetry, polarizing microscopy, conductimetry, viscosimetry, and rheometry. The critical vesicle concentration (cvc,~0.002wt%) and a vesicle–micellar transition (cvm,~0.005wt%) was detected at a temperature of 35°C. Below T k and concentrations ≤2wt%, a transparent solution is formed (I). Above 2–8.5wt%, a lamellar (L1) phase forms. At higher concentrations and up to 12wt%, a second lamellar phase (L2) is detected. From 12.4 to 15.5wt%, an emulsion phase (E) is formed. Rheological dynamic measurements for the I phase indicate that the system exhibits a predominantly viscous behavior (G′<G″) for concentrations lower than the overlap or entanglement concentration (C e,~0.75wt%). At higher concentrations, wormlike micelles f...

Bioresources, 2019

Natural lignocellulosic biomass is a valuable feedstock for soluble-grade cellulose (α-cellulose ... more Natural lignocellulosic biomass is a valuable feedstock for soluble-grade cellulose (α-cellulose > 90%) with advantageous features such as abundance, high strength, rigid structure, low weight, and it is biodegradable. The bagasse from Agave tequilana Weber var. azul is the main agroindustrial waste from the tequila industry and poses an environmental threat. However, due to its high cellulose content, Agave tequilana bagasse is an excellent candidate for the extraction and utilization of its components. In this study, alkaline cooking, followed by five stages of bleaching, was employed to obtain soluble-grade cellulose pulp. The obtained soda pulp material had a Kappa number (KN) of 23 ± 3, viscosity (μ) of 11.53 to 10.18 cp, degree of polymerization (DP) of 830 to 750, brightness of 87.5%, and percentage of alpha-cellulose (α) of 81 ± 3 at 94 ± 3%. The obtained material was characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron mic...

Carbohydrate polymers, 2018

A novel thermosensitive hydrogel consisting of phosphorylated β-cyclodextrin (βCD-PH), β-cyclodex... more A novel thermosensitive hydrogel consisting of phosphorylated β-cyclodextrin (βCD-PH), β-cyclodextrin (βCD) and chitosan was prepared by embedding βCD and βCD-PH, into the well-studied chitosan/αβ-glycerophosphate system (CS/αβGP). The relevance of this work is the use of βCD-PH to partially substitute αβGP as the gelling agent. The role of βCD and βCD-PH on the rheological properties of hydrogels, gelation time, and gelation temperature were investigated. The gelation time for all the samples (CS/αβGP, CS/αβGP/βCD, and CS/αβGP/βCD-PH) was less than a minute at 37 °C, which is suitable for biomedical applications. The gelation temperature for hydrogel CS/αβGP/βCD-PH increased linearly with the addition of βCD-PH within the interval 31.8-37.3 °C, at ratios CS:βCD-PH of 1:0.5, 1:1, 1:1.5 and 1:2 (w/w). The hydrogel thus obtained has potential applications in dual drug delivery (hydrophilic and hydrophobic).

Polymers

In this work, cellulose nanocrystals (CNCs), bleached cellulose nanofibers (bCNFs), and unbleache... more In this work, cellulose nanocrystals (CNCs), bleached cellulose nanofibers (bCNFs), and unbleached cellulose nanofibers (ubCNFs) isolated by acid hydrolysis from Agave tequilana Weber var. Azul bagasse, an agro-waste from the tequila industry, were used as reinforcements in a thermoplastic starch matrix to obtain environmentally friendly materials that can substitute contaminant polymers. A robust characterization of starting materials and biocomposites was carried out. Biocomposite mechanical, thermal, and antibacterial properties were evaluated, as well as color, crystallinity, morphology, rugosity, lateral texture, electrical conductivity, chemical identity, solubility, and water vapor permeability. Pulp fibers and nanocelluloses were analyzed via SEM, TEM, and AFM. The water vapor permeability (WVP) decreased by up to 20.69% with the presence of CNCs. The solubility decreases with the presence of CNFs and CNCs. The addition of CNCs and CNFs increased the tensile strength and You...

Nanocrystalline cellulose (NCC) was prepared from Agave tequilana Weber blue variety via acid hyd... more Nanocrystalline cellulose (NCC) was prepared from Agave tequilana Weber blue variety via acid hydrolysis. The NCC was used in forming acrylic acid/acrylamide hydrogels (AA/AM), (80/20 w/w), crosslinked with N-N-methylene bisacrylamide (MBA) at addition levels of 1, 2, 4, and 8 wt% of the monomeric phase. The NCC was dosed at 0.1, 0.5, and 1.0 wt%. Two synthesis routes were used. In the first route, polymerization was performed immediately after mixing the components. In the second route, the mixture of the components was kept at 2 °C ± 1 °C for 24 h before the polymerization (thermal treatment). All the hydrogels were characterized by nuclear magnetic resonance (NMR), water absorption tests, scanning electron microscope (SEM) analysis, and rheology tests. The NCC particles had a diameter of approximately 75 nm. The hydrogels that were subjected to the thermal treatment reached the equilibrium after approximately 72 h. The un-treated hydrogels reached the equilibrium after approximat...

Journal of Surfactants and Detergents

The temperature–composition phase diagram in the diluted region of the cationic surfactant cetyld... more The temperature–composition phase diagram in the diluted region of the cationic surfactant cetyldimethylbenzylammonium salicylate/water system was studied with a battery of techniques. The Krafft temperature (T k=33±1°C) was measured by differential scanning calorimetry, polarizing microscopy, conductimetry, viscosimetry, and rheometry. The critical vesicle concentration (cvc,~0.002wt%) and a vesicle–micellar transition (cvm,~0.005wt%) was detected at a temperature of 35°C. Below T k and concentrations ≤2wt%, a transparent solution is formed (I). Above 2–8.5wt%, a lamellar (L1) phase forms. At higher concentrations and up to 12wt%, a second lamellar phase (L2) is detected. From 12.4 to 15.5wt%, an emulsion phase (E) is formed. Rheological dynamic measurements for the I phase indicate that the system exhibits a predominantly viscous behavior (G′<G″) for concentrations lower than the overlap or entanglement concentration (C e,~0.75wt%). At higher concentrations, wormlike micelles f...