Jorge R. Robledo-Ortíz

Jorge R. Robledo-Ortíz
University of Guadalajara | UDG · Departamento de Madera, Celulosa y Papel

Professor

About

81
Publications
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Introduction
Jorge R. Robledo-Ortíz currently works at the Department of Wood, Cellulose and Paper, University of Guadalajara. Jorge does research in Chemical Engineering, Materials Engineering and Environmental Engineering.

Publications

Publications (81)
Article
Over the last decades, adsorption has emerged as a potential separation process for the removal of heavy metals that are extensively released in effluents from different industries. Among heavy metals, Cr(VI) is relevant due to its high toxicity, and its required concentration limit between 50 and 100 µg/L in water for human consumption. Several ad...
Article
Currently, poly(lactic acid) (PLA) and its natural fiber biocomposites have a growing interest as a sustainable and biodegradable alternative to conventional polymers. Their intrinsic susceptibility to weathering degradation limits their applications. This review discusses the accelerated weathering of PLA and how fillers, reinforcements, and addit...
Article
In this work, biocomposites made of polyhydroxyalkanoates (PHA) with natural fibers were produced via compression molding. In particular, polyhydroxybutyrate (PHB) and polyhydroxybutyrate‐co‐hydroxyvalerate (PHBV) were reinforced with 20 wt% of agave fibers. Different compatibilization strategies were investigated to improve the fiber‐matrix intera...
Article
Cellulose beads loaded with graphene nanoplatelets (GNP) were prepared by a physical gelation method, which was feasible under mild conditions. The phases spontaneously separate when the cellulosic solution is dropped into an acid solution, maintaining semi-spherical shapes with diameter between 3.4 and 3.9 mm, which is desirable for continuous-flo...
Article
The linearization of adsorption equations is controversial. The estimation of fitting parameters strongly depends on the linearization method, magnitude of experimental error, and data range. Although many studies contrast linear versions of these equations with their non-linear counterparts, linearization is preferred due to its simplicity since a...
Article
Combining polylactic acid (PLA) with waste fibers to produce reinforced biocomposites is of top interest to replace conventional polymers for environmentally friendlier materials. Natural fibers have a remarkable effect on the mechanical and thermal properties of the biocomposites. This reinforcing effect strongly depends on the chemical compositio...
Article
Nowadays, there is a growing interest in lignocellulosic nanoscale materials produced from alternative recycled sources because of their attractive physical, chemical, and mechanical properties, as well as their ecological contribution. In this work, MFC preparation through mechanical fibrillation using lignocellulosic fibers from OCC cardboard was...
Article
Full-text available
Sugarcane straw (SCS) is a common agro-industrial waste that is usually incinerated or discarded in fields after harvesting, increasing the importance of developing added-value applications for this residue. In this study, sustainable biocomposites were produced, and the effect of sugarcane straw as a filler/reinforcement of commercial biopolymers...
Article
Chitosan was supported on a porous composite using 3-aminopropyltriethoxysilane (APTES) as silanizing agent through a simple and green method to enhance Cr(VI) uptake performance under batch and continuous-flow systems. Chemical modification was corroborated through ATR-FTIR and SEM/EDX analyses, showing a silane loading of 6.2% onto the surface of...
Article
In this work, PLA biocomposites were prepared by two different processing methods to evaluate two coupling agents: maleic anhydride grafted PLA (MA-g-PLA) and glycidyl methacrylate grafted PLA (GMA-g-PLA). Coupling agents were directly incorporated during extrusion before injection molding and through fiber surface treatment before dry-blending (DB...
Article
Full-text available
In order to provide a second economic life to agave fibers, an important waste material from the production of tequila, filaments based on polylactic acid (PLA) were filled with agave fibers (0, 3, 5, 10 wt%), and further utilized to produce biocomposites by fused deposition modeling (FDM)-based 3D printing at two raster angles (−45°/45° and 0/90°)...
Article
This work aimed to develop zwitterionic cellulose with a versatile potential for removing anionic and cationic dyes. A grafting degree of 22% in a 3:2 ratio of the anionic and cationic groups was determined by elemental analysis. Spectroscopic characterization by carbon 13 Nuclear Magnetic Resonance (¹³C NMR) confirmed the zwitterionic functionaliz...
Article
Full-text available
Abstract The Thomas model is the most common equation to describe the dynamics of fixed-bed adsorption columns. However, its parameters validity strongly depend on the breakthrough curve region considered for the data fitting. This work aimed to provide a rigorous analysis of the linear and non-linear forms of the Thomas model based on diferent err...
Article
This study focused on the effect of the processing method on the thermal, mechanical, and biodegradation properties of polylactic acid/polyhydroxybutyrate (PLA/PHB) blends and their wood biocomposites. The blending techniques were dry‐blending or twin‐screw extrusion, both followed by compression molding. PLA/PHB blends were prepared using 15 and 2...
Article
Full-text available
The biodegradable nature of polyhydroxyalkanoates (PHAs) is an outstanding feature for the replacement of petroleum-based polymers. The most studied PHAs are polyhydroxybutyrate and its copolymer with hydroxyvalerate. However, PHAs have a considerably higher cost than conventional polymers, which is one of the main obstacles to their growth in the...
Article
Full-text available
In this study, the accelerated weathering of PLA and its biocomposites produced with agro-industrial waste agave fibers was evaluated to better understand the lifetime of these materials. The effects of the fiber content, the fiber treatment with glycidyl methacrylate grafted PLA, and the fiber/matrix adhesion on the degradation of the materials we...
Article
Polylactic acid is one of the most used biopolymers due to its overall properties and biodegradability. Nevertheless, polylactic acid has important drawbacks such as brittleness, low thermal stability, and higher cost than most commodity polymers. In order to overcome those disadvantages without compromising biodegradability, the addition of wood p...
Article
Full-text available
The effects of zinc borate (ZB) on physical and mechanical properties of wood plastic composites (WPCs) were assessed. WPCs were elaborated with 0, 1, 3, y 5 % ZB concentrations, wood flour, mesh 60 and polypropylene in 50/48, 50/47, 50/45 y 50/43 proportions as a function of ZB concentration. 2 % of maleic anhydride of polypropylene (MAPP) was inc...
Article
In this work, novel polysaccharide-based sorbents modified with plasma technologies are discussed. Plasma selectively modifies the surface properties by generating specific moieties, enhancing adsorption performance, and the physical-chemical properties of the material without modifying its bulk properties. Among plasma technologies, cold plasma is...
Article
In this study, the main processing and formulation factors that affect the performance of panels manufactured with post-consumer TetraPak® and high-density polyethylene compounds were analyzed. The water uptake of the materials during immersion was also studied to identify the limitations on the application of this compound. Before obtaining the bo...
Article
The growing interest in research and development of eco-friendlier materials makes attractive the use of bio-based and biodegradable polymers such as polylactic acid (PLA). However, the higher cost of PLA compared to conventional polymers limits its applications. Moreover, raw materials for rotational molding must be in a powder form, which further...
Article
Los biopolímeros son una alternativa prometedora para mitigar la contaminación ambiental debido a que son generalmente de naturaleza renovable y/o biodegradables. Algunos ejemplos importantes son el ácido poliláctico (PLA), los polihidroxialcanoatos (PHAs), la policaprolactona (PCL), el polibutileno succinato (PBS) o incluso el polietileno “verde”...
Article
A highly porous composite was developed as a support for chitosan to provide dimensional stability for the continuous-flow adsorption of Cr(VI) in a fixed-bed column. The high-porosity adsorbent was prepared by incorporating polystyrene into a low-density polyethylene/agave blend to enhance the pore formation using azodicarbonamide as a blowing age...
Article
Full-text available
In this work, sustainable rotomolded composites based on green polyethylene (Green-PE) and natural fibers (coir and agave) were studied. Fibers’ surface was treated with maleated polyethylene to improve the fiber-matrix compatibility. Samples were characterized by morphology, mechanical properties (impact, tension, and flexion) and water absorption...
Article
Full-text available
Con el objetivo de identificar las propiedades químicas y los antioxidantes de interés en la industria de los biopolímeros se realizó la caracterización química del jugo de cuatro variantes de cladodios de Opuntia megacantha; las variantes presentan dos grados de madurez (tiernos y maduros) y dos manejos diferentes durante su desarrollo (silvestres...
Article
Two bacterial strains able to produce polyhydroxyalkanoates (PHAs) from a wide variety of pure carbon sources (dextrose, xylose, sucrose, lactose, and glycerol) were isolated from forest soils and identified as Achromobacter mucicolens and Stenotrophomonas rhizophila. A. mucicolens also produced poly(3‐hydroxybutyrate) (PHB) from different wastes (...
Article
This work aimed at developing a highly porous polymeric lignin composite and to evaluate its adsorptive properties in batch and continuous experiments. Lignin has a strong dye-binding capacity due to its abundant phenolic and carboxyl groups, presenting a removal efficiency of 77% and an adsorption capacity of 8.1 mg/g. The novelty of this work was...
Article
Full-text available
Two zwitterionic celluloses were prepared by grafting amphoteric precursors AS (APTES with 1,4 butane sultone) and TAS (Trimethoxysilylpropyldiethylenetriamine with 1,4 butane sultone) onto activated cellulose with NH4OH in a heterogeneous system. Information about the zwitterionic modification in celluloses was achieved by FT-IR and ¹³C/²⁹Si NMR C...
Article
In this study, two different surface treatments were evaluated to improve the compatibility of coir fibers with poly(lactic acid). The chemical modifications were achieved by fiber surface treatment with a maleic anhydride grafted to poly(lactic acid) (MAPLA) solution or a poly(methyl vinyl ether‐alt‐maleic anhydride) (MA‐c‐PMVE) aqueous solution....
Article
Full-text available
In this work, hexavalent chromium adsorption onto LDPE and agave fiber composites coated with chitosan or cellulose was studied in batch experiments. Chemical modifications consisting in cross-linked chitosan, cross-linked chitosan xanthate, and cellulose xanthate were applied to the polysaccharide-coated sorbents in order to increase their stabili...
Article
In this work, three different nanoclays (1.44P, 1.34MN, and Cloisite 15A) were used to reinforce an injection grade poly(lactic acid) (PLA). The nanocomposites (NCs) were prepared using three different nanoclay concentration levels (1, 3, and 5 wt%) in a twin-screw extruder. To evaluate their mechanical performance (static and dynamic tests) and th...
Article
Full-text available
In this work, agave fibers were surface treated using maleated PLA (MAPLA) in order to increase the fiber content (from 10 up to 40% wt.) in polylactic acid (PLA) biocomposites produced by rotational molding and to study the effect of the agave fiber and its treatment on the physical, mechanical and thermal properties of the biocomposites. This che...
Article
Low power conversion efficiency represents the main drawback of organic solar cells (OSC) compared to inorganic devices. Therefore, a novel bulk electron transport layer of silver nanostructures (AgNs) inside poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] is proposed to be used in OSC. Different concentrati...
Article
Due to its renewability and biodegradability, biopolymers have developed interest in order to substitute oil-derived plastics. In particular, polylactic acid (PLA) is a promising biopolymer in terms of mechanical and biodegradable properties that is used for different applications. Nevertheless, PLA has some disadvantages like brittleness and proce...
Article
In this work, the possibility to produce polylactic acid (PLA) and agave fiber biocomposites by dry-blending and rotational molding was studied. The samples were also produced by compression molding to compare the effect of processing conditions on the biocomposites properties. In particular, the effect of fiber content (0–40 wt.%) on morphology, d...
Article
The biosynthesis of silver nanoparticles (AgNPs) using an aqueous extract of an agroindustrial residue of the tequila industry [i.e. leaves of Agave tequilana Weber var. azul (AT)], and silver nitrate or silver acetate as precursor salts is reported. The presence of AgNPs was confirmed by color change, scanning electron microscopy, ultraviolet visi...
Article
In this study, the internal air temperature (IAT) profile was measured to analyze the thermal behavior of a polymer for a complete rotational molding cycle. Foamed and unfoamed linear low density polyethylene parts were produced by biaxial rotational molding using a chemical blowing agent based on azodicarbonamide at different concentrations (0, 0....
Article
In this study, the effect of chitosan alkali treatment supported onto agave fiber-high density polyethylene composites over their Pb(II) adsorption properties was evaluated. The chitosan was placed in a beaker with a solution of NaOH bubbling air for 24 hours and controlling the pH around 10. Afterwards the chitosan was washed, filtered and dried....
Chapter
Polylactic acid (PLA) is a well-known and commercially available biopolymer that can be produced from different sources. Although PLA has several advantages like good rigidity and strength, it also has some drawbacks like brittleness and low thermal stability. To improve the use of PLA, several avenues have been investigated but the addition of nat...
Conference Paper
In this work, biocomposites of agave fibers (Agave tequilana Weber var. Azul) and polylactic acid (PLA) were produced by rotational molding. In particular, a simple dry-blending technique was used to disperse the agave fibers in the biodegradable polymer matrix. The effect of fiber content was studied (0, 10, 20, 30, and 40 wt.%) and the samples we...
Article
In this study, agave fibers which are an important waste product of the Tequila industry are evaluated for the production of green biocomposites prepared with two biopolymers: polyhydroxybutyrate (PHB) and its copolymer with hydroxyvalerate P(HB-HV). The biocomposites were produced by compression molding with two main objectives: (1) to reduce the...
Article
In this study, high-density polyethylene/agave-coir composites with two fiber contents (20 and 30 wt%) and different coir-agave fiber ratios (1–0, 0.8–0.2, 0.6–0.4, 0.4–0.6, 0.2–0.8, and 0–1) were produced in a two step process using twin-screw extrusion followed by injection molding. The effect of mixing two different natural fibers and the additi...
Article
Tissue engineering scaffolding is the external media or structure in which cell growth, migration and reproduction is enabled in order to stimulate tissue regeneration. In order to promote tissue regeneration, scaffolding materials are required to have certain properties such as biocompatibility, adequate mechanical properties and surface topograph...
Article
Overall, autologous bone grafting continues to be the gold standard for the restoration of bone defects while other practices include metallic meshes and plates. These practices are not always suitable particularly when performing reconstructive surgery in the maxillofacial region as the defects tend to be complex in terms of size and shape. These...
Conference Paper
In this study, Agave fibers (Agave tequilana Weber var. Azul) were surface treated with maleated polyethylene (MAPE) to increase the polymer-fiber compatibility with two main objectives: 1) to improve the mechanical properties of composites produced by rotational molding, and 2) to increase the fiber content in the composite. The rotomolded composi...
Conference Paper
In this study, temperature profiles for the air inside the mold was measured to analyze the thermal behavior of a polymer for a complete rotational molding cycle. Foamed and unfoamed linear medium density polyethylene (LMDPE) parts were produced by biaxial rotational molding. A chemical blowing agent (azodicarbonamide, ACA) was used at different co...
Article
Full-text available
In this study, natural fibers (agave, coir, and pine) were surface treated with maleated polyethylene (MAPE) with two main objectives: (1) to improve the mechanical properties of natural fiber composites produced by rotational molding and (2) to increase the fiber content in the composite. The rotomolded composites were produced at 0, 10, 20, 30, a...
Article
In this work, a comparison between different agave fiber surface treatments has been presented to improve the mechanical properties of rotomolded natural fiber composites (NFC). The fiber treatments were carried out with sodium hydroxide, 2-chlorobenzaldehyde, maleic anhydride grafted polyethylene, acrylic acid, methyl methacrylate, and triethoxy v...
Article
Polylactic acid (PLA) biocomposites were produced by a combination of extrusion and injection molding with three cellulosic reinforcements (agave, coir, and pine) and contents (10, 20, and 30%). In particular, some samples were subjected to thermal annealing (105 degrees C for 1 h) to modify the crystallinity of the materials. In all cases, morphol...
Article
In this work, the effect of natural fiber surface treatment with maleated polyethylene (MAPE) is presented to improve the mechanical properties of natural fiber composites (NFC). In particular, a simple dry blending technique was used to disperse natural fibers (agave) in a polymer matrix (linear low density polyethylene) and produce samples via co...
Article
In this paper partial or total replacement of natural aggregates by recycled polymeric foams was used to lighten cement mortars. The influence of foamed material in mortar compressive strength was studied. Siliceous sand was substituted by different amounts of foamed high-density polyethylene (HDPE) nanocomposites (18-100%). Foamed materials were o...
Article
Full-text available
This paper presents a study of the performance of wood flour-polypropylene composites formulated with 60 and 100 mesh and fine pine wood particles, with wood/polypropylene proportions of 6-730, 57-40 and 47-50, with 2 % of coupling agent (maleic anhydride polypropylene) and 1 % of calcium stearate. These composites were exposed to natural weatherin...
Article
Full-text available
This paper presents a study of the performance of wood flour-polypropylene composites formulated with 60 and 100 mesh and fine pine wood particles, with wood/polypropylene proportions of 6-730, 57-40 and 47-50, with 2 % of coupling agent (maleic anhydride polypropylene) and 1 % of calcium stearate. These composites were exposed to natural weatherin...
Article
Full-text available
This work investigates the combination of different fiber sizes (self-hybridization) on the mechanical properties of composite materials. High density polyethylene composites based on agave and pine fibers were prepared using different ratios of long and short fibers. Furthermore, the effect of coupling agent (maleated polyethylene) versus self-hyb...
Article
Full-text available
Foamed linear medium density polyethylene parts were prepared by rotational molding in biaxial mode, using different amounts of chemical-blowing agent (azodicarbonamide). Morphological and mechanical properties are presented and discussed in terms of foam density, cell density, average cell diameter, and open cell content. Internal air temperature...
Article
This work reports on the properties of high density polyethylene based hybrid composites made with two natural fibers: agave and pine. The composites were produced by a combination of extrusion and injection molding. The effect of hybridization was analyzed via morphological, mechanical and water immersion tests for two total fiber contents, 20 and...
Article
This research shows the elaboration of nanocomposites using polylactid acid (PLA) as polimeric matrix and cellulose nanocrystals (CNC) as reinforcement element. The concentrations were of 0.5, 1.0 and 2.0% (w/w). Because the poor affinity between PLA and CNC, a solvent exchange was applied to CNC employing ethanol and acetone for then mixed with PL...
Article
Self-hybrid thermoplastic composites (combination of two fiber sizes) were obtained by injection molding using pine or agave fibers with polypropylene (PP). The effect of self-hybridization was determined through mechanical properties and water absorption for different total fiber contents between 10 and 30% wt. The results showed that impact stren...
Chapter
The chapter on wood and natural fiber-based composites (NFCs) first briefly discusses the historical development of NFCs. Then, the chapter outlines the types of natural fibers as well as the factors that promote their increasing use in commercial products. The types of polymers and additives used are also described in this section. Next, the proce...
Chapter
This chapter covers various aspects of polymer materials and/or their applications in specific end-products. The chapter includes, first, a general description of blown film and ribbon extrusion, including the most important parameters that need to be controlled. Then, the chapter presents the equations used to calculate the final dimensions of fil...
Article
Full-text available
Corn cob was characterized chemically and hydrothermally treated under subcriti-cal conditions to modify their recalcitrance and render a solid fraction of cellulose and lignin and a soluble fraction rich in xylose. The chemical characterization of carbohydrates was carried out by HPLC, while lignin and xylan were characterized by means of FTIR-ATR...
Article
Full-text available
Corn cob was characterized chemically and hydrothermally treated under subcritical conditions to modify their recalcitrance and render a solid fraction of cellulose and lignin and a soluble fraction rich in xylose. The chemical characterization of carbohydrates was carried out by HPLC, while lignin and xylan were characterized by means of FTIR-ATR...
Article
In this work, the processing and properties of blown films prepared from thermoplastic corn starch (TPS) and polycaprolactone (PCL) were studied, in particular at high TPS content. The influence of processing parameters and material moisture content on the tensile properties was also studied. The results show that final film properties are mainly c...