Francisco J. Rodríguez-Mercado

• Dr
• University of Santiago Chile

This study aimed to enhance the properties and compostability of active poly(lactic acid) (PLA) films by incorporating β-cyclodextrin (β-CD) inclusion complexes with allyl isothiocyanate (AITC). Films were prepared using melt extrusion and characterized based on their structural, chemical, morphological, thermal, and barrier properties. These inclu...

This study aimed to enhance the properties and compostability of active poly(lactic acid) (PLA) films by incorporating β-cyclodextrin (β-CD) inclusion complexes with allyl isothiocyanate (AITC). Films were prepared via melt extrusion and characterized by their structural, chemical, morphological, thermal and barrier properties. These inclusion comp...

Polymer‐based nanocomposites loaded with metal nanoparticles are an interesting alternative for the development of antimicrobial food packaging. However, affinity and dispersion of metal nanoparticles could be improved using nanoclays. Therefore, nanocomposite films based on poly(lactic acid) (PLA) and copper modified‐montmorillonite were developed...

Expanded polystyrene will account for 5.3% of total global plastic production in 2021 and is widely used for food packaging due to its excellent moisture resistance and thermal insulation. However, some of these packages are often used only once before being discarded, generating large amounts of environmentally harmful plastic waste. A very attrac...

It is known that ethylene plays an important role in the quality characteristics of fruits, especially in storage. To avoid the deterioration of fruits caused by ethylene, titanium dioxide (TiO2) has been used due to its photocatalytic capacity. The aim of this study was to develop films based on two types of biopolymers, Mater-Bi (MB) and poly-lac...

In this work, a colorimetric indicator based on gold nanoparticles (AuNP) and a biodegradable and eco-friendly polymer (sodium alginate, Alg.), has been developed, for the real-time detection of fish spoilage products. AuNP and colorimetric indicator were characterized by: UV-Vis, FTIR spectroscopies, TGA, DSC, XRD, TEM, and colorimetry. The UV-Vis...

Ethylene is a phytohormone that is responsible of fruit and vegetable ripening. TiO2 has been studied as a possible solution to slowing down unwanted ripening processes, due to its photocatalytic capacity which enables it to remove ethylene. Thus, the objective of this study was to develop nanocomposites based on two types of eco-friendly materials...

This work aims to evaluate the effect of the extrusion temperature of poly(lactic acid) (PLA) with different grape pomace (GP) content for the development of active biocomposite films. Two different GP concentrations (10 and 15 wt.%) were used to obtain GP/PLA composites through extrusion at three different temperature profiles. The biocomposites w...

β-cyclodextrin and allyl isothiocyanate inclusion complexes (β-CD:AITC) have been proposed for developing fresh fruit and vegetable packaging materials. Therefore, the aim of this research was to develop active materials based on poly(lactic acid) (PLA) loaded with β-CD:AITC and to assess changes in the material properties during the release of AIT...

Background: Allyl isothiocyanate is an excellent antimicrobial compound that has been applied in the development of active food packaging materials in the last years. However, the high volatility of this compound could prevent a lasting effect over time. In order to avoid this problem, cyclodextrin inclusion complexes have been proposed as an alter...

Abstract Eugenol (EUG) is the principal component of clove essential oil. It has demonstrated excellent antifungal properties against B. cinerea, one of the most important fungus in the fresh fruit decay. However, this substance is highly volatile, thermolabile and the direct contact with a food induce undesirable changes in the organoleptic proper...

This review was focused on describing the combination of electrospinning and cyclodextrin inclusion complexes as one of the newest alternatives for the development of food packaging materials with antimicrobial and/or antioxidant properties. The advantages of this technological combination, the routes to design the active materials, the characteriz...

Nanocomposite films based on PLA with 1.0% w/w silica nanoparticles (NP) and surface-functionalized silica nanoparticles with lactic acid (NP-LA), respectively, were obtained by extrusion process. Subsequently, cinnamaldehyde (ci) was incorporated through supercritical impregnation in the films at a pressure of 12 MPa, 40 °C temperature and 1.0 MPa...

En los últimos años, el desarrollo de nanocompósitos poliméricos se plantea como una interesante alternativa para el diseño de nuevos materiales para el envasado activo de alimentos. A pesar de esto, existe constante preocupación relacionada a la migración de los componentes activos incorporados en el material ya que, un material de envasado destin...

Inclusion complexes based on β-cyclodextrin (β-CD) and antimicrobial compounds, were prepared by co-precipitation method, and characterized by entrapment efficiency (EE), thermal analysis, X-ray diffraction, 1H NMR spectroscopy, and water sorption. In addition, experiments associated to evaluate the effect of relative humidity on the release of act...

The development of clay polymer nanocomposites has been presented as an interesting alternative for design of new active food packaging materials. In this work, low density polyethylene (LDPE) nanocomposites with ce-tylpyridinium bromide (CPB)-modified montmorillonite (Mt) were developed. In a first stage, Mt. was modified with different CPB propor...

Active films (AFs) using poly(lactic acid) (PLA) as a polymeric matrix containing various propolis concentrations (5, 8.5, and 13%) as the active agent (AA) were developed using a casting method. The purpose was to determine the effects of the incorporation of AA on the physical properties of the films and to evaluate the antioxidant and antimicrob...

The aim of the present study was oriented to evaluate the effect of a commercial organoclay and the technique of preparation on the physical and antimicrobial properties of active eco‐friendly nanocomposites films. To this antimicrobial nanocomposite films were fabricated from cellulose acetate (CA) powder, triethyl citrate (TEC) plasticizer, a com...

The aim of this investigation was obtain low density polyethylene with surfactant organoclay nanocomposites for food packaging applications.

The aim of this study was to develop, characterize and evaluate in vitro the efficacy of active films, based on an inclusion complex formed by β-cyclodextrin, 2-nonanone and two polymer matrices (polylactic acid and low density polyethylene). The different films were characterized by scanning electronic microscopy (SEM), differential scanning calor...

This study deals on the supercritical impregnation of thymol in polylactic acid (PLA) in order to obtain biodegradable antimicrobial films by means of a procedure, which is in agreement with the principles of green chemistry, reducing the environmental impact of products and of its preparation processes. The impregnation tests were carried out in a...

Systems including diphenylzinc, metallocene, and methylaluminoxane, at various combinations has been attempted, as initiating systems for homo- and copolymerization of styrene and various styrene related comonomers including : substituted styrenes, styrene derivatives, a-olefins, dienes and more recently cycohexenes including norbornene. The used m...

In the last decades, the petroleum-based plastic materials have become essential materials for many industries. This kind of materials has excellent physical properties with a wide range of applications, and moreover, they are low cost and easy processing materials. However, despite the advantages offered by these materials, a massive accumulation...

A new active packaging film based on murta leaf extract was elaborated. The extract was incorporated into a methylcellulose layer which was coated on a low-density polyethylene (LDPE) film. Its antioxidant effectivity, antimicrobial activity, and physicochemical properties were evaluated. The active film was able to keep its antimicrobial and antio...

An important issue in food technology is that antimicrobial compounds can be used for various applications, such as the development of antimicrobial active packaging materials. Yet most antimicrobial compounds are volatile and require protection. In the present study, the inclusion complexes of 2-nonanone (2-NN) with β-cyclodextrin (β-CD), were pre...

Polylactic acid (PLA) nanocomposites with two antimicrobial agents based on copper modified montmorillonite (MtCu(2+) and MtCu(o)) were developed in order to obtain a lower environmental impact material with antimicrobial activity for potential use in food packaging. Clay modification was permorfed by cation exchange between MtNa(+) and a copper sa...

An organoclay (MMT–CPB) based on montmorillonite (MMT) and cetylpyridinium bromide (CPB) was synthesized by a cationic interchange process. The presence of CPB into the clay structure was evidenced by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). This organoclay was then used to prepa...

Ethylene (C2H4) acts as a plant hormone, growth regulator that has a number of effects on the growth. Ethylene accelerates respiration, leading to maturity and also softening and ripening of many kinds of fruits. Although ethylene has some positive effects, it is often hazardous to the quality and shelf-life of fruits and vegetables. The removal of...

Nanocomposite films based on cellulose acetate butyrate, modified montmorillonite (Cloisite® 30B), plasticizer (triethyl citrate) and antimicrobial compounds (carvacrol and cinnamaldehyde) were prepared by extrusion. The effects of the Cloisite® 30B content and antimicrobial compound types on the morphology of the nanocomposite films were investiga...

Cellulose acetate (CA)/copper montmorillonite modified (MtCu2+) antimicrobial nanocomposites for food packaging containing 1, 3 and 5 wt.% nanoparticles were prepared by solution casting technique. X-ray diffraction (XRD) and transmission electron microscopy revealed the existence of intercalated and no intercalated clay form in the CA matrix. The...

Nanocomposites based on biopolymers have been recognized as potential materials for the development of new eco-friendly food packaging. In addition, if these materials incorporate active substances in their structure, the potential applications are much higher. So, this work was oriented to develop nanocomposites with antimicrobial activity based o...

The cellulose acetate butyrate/modified motmorillonite (Cloisite20A and Cloisite30B) nanocomposites were prepared by two different solvent casting methods. All antimicrobial nanofillers were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and antimicrobial components (carvacrol and cinnamaldehyde) include...

Nanocomposites based on cellulose acetate, a commercial organoclay (Cloisite30B), triethyl citrate and variable content of antimicrobial agents (thymol and cinnamaldehyde), were obtained using a solution casting technique. The properties of the nanocomposites were evaluated using X-ray diffraction, differential scanning calorimetry, thermogravimetr...

Nanocomposites based on cellulose acetate (CA), a commercial organoclay (Cloisite30B) and triethyl citrate (TEC) were obtained using a solution casting method. Different nanocomposites were prepared according to different organoclay contents (2.5, 5.0, 7.5 and 10.0 wt.%) and molecular weight of cellulose acetate (Mn 30,000 and 50,000). The properti...

Nowadays, consumers demand for fresh, high-quality seafood products continues to climb, especially in affluent, developed nations. At the same time, there is increasing attention regarding improved utilization of seafood for human consumption; Atlantic salmon is the main species in Chile aquaculture, and most of the salmon are exported as fresh fis...

The present work has been oriented on the development of cellulose acetate films with nanofillers of montmorillonite/alkylammonium (hexa- and tetra-decyltrimethylammonium) and montmorillonite/chitosan which have been synthesized using a cationic exchange process. All synthesized organoclays have been characterized using X-ray diffraction (XRD), the...

The antimicrobial efficiency of novel MtCu2+/LDPE nanocomposites against Escherichia coli 0157:H7 n/t was tested in the present work. Montmorillonite modified with copper (MtCu2+) was obtained using cation exchange in solution and nanocomposite films were prepared by melt mixing in an extruder at 200 °C with different compositions. Characterization...

Binary metallocene-MAO and ternary diphenylzinc-metallocene-MAO initiator systems have been tested as initiators in the homopolymerization of styrene and also in its copolymerization with several diverse comonomers including substituted styrenes, styrene derivatives, α-olefins and dienes. Various titanocenes and zirconocenes and some exploratory ex...

It has been observed in the production of polypropylene nanocomposites containing silicate materials that the molecular weight of the polymer used can have a significant effect on the final quality of the composites. The availability of polypropylene over a range of molecular weights with similar material properties (e.g. melting temperature and ta...

BACKGROUND: The present work is part of a general study regarding the homo- and copolymerization of styrene using diphenylzinc–additive initiator systems, with the aim of improving the properties of commercial atactic polystyrene. The study is focused on syndiotactic polystyrene and/or copolymers of styrene (S) with substituted styrene, styrene der...

Poly(styrene-co-p-tert-butyldimethylsilyloxystyrene) copolymers, P(S/p-TBDMSOS), with contents in the substituted comonomer within the 0–50% range were prepared using combined Ph2Zn–CpTiCl3–MAO initiator systems and some of them were used as precursors of poly(styrene-co-p-hydroxystyrene), P(S/p-HOS), copolymers. p-tert-Butyldimethylsilyloxystyrene...

Homopolymerization of disubstituted styrenes (2,4- and 2,5-dimethylstyrene) and trisubstituted styrene (2,4,6-trimethylstyrene) and their copolymerization with styrene were carried out using diphenylzinc–metallocene–methylaluminoxane initiator systems for metallocene (n-BuCp)2TiCl2 and for half-metallocene CpTiCl3. The studied comonomers were found...

Initiator systems resulting from the combination of cyclopentadienyltitanium trichloride (CpTiCl3), ethylaluminium dichloride (EtAlCl2) with and without methylaluminoxane (MAO), were used to initiate styrene (S) homopolymerization and S/1-alkene copolymerization. The CpTiCl3-EtAlCl2 system turned out to be an effective initiator of styrene homopoly...

A combination of diphenylzinc, a metallocene and methylaluminoxane (Ph2Zn‐metallocene‐MAO) is a suitable initiator system for the polymerization of styrene and for its copolymerization with para‐alkyl substituted styrenes. This paper reports new experimental results which reinforce our previous findings indicating that polymerization processes are...

Diphenylzinc-metallocene-MAO initiator systems have proven to be effective initiator systems for styrene and for substituted styrenes as well as for their styrene/(styrene-derivative) copolymerization. Titanocene produced almost pure syndiotactic polymers while zirconocenes gave atactic polystyrene together with a low content, less than 20%, of syn...

Combined systems including diphenylzinc, Ph2Zn, a metallocene, and methylaluminoxane, MAO, have been employed to initiate styrene polymerization and the copolymerization of styrene with p-alkylsubstituted styrenes and -olefins. Both polymerization and copolymerization processes depend on the nature of the metallocene included in the initiator syste...

Combined systems including diphenylzinc (Ph2Zn), a metallocene, and methylaluminoxane (MAO), have been employed to initiate the copolymerization of styrene (S) with p-alkylsubstituted styrenes and with α-olefins. The copolymerization processes depend largely on the comonomer, the nature of the metallocene included in the initiator system, the prese...

Combined systems including diphenylzinc, Ph2Zn, a metallocene, and methylaluminoxane, MAO, have been employed to initiate styrene polymerization. These initiator systems have been also used to initiate the copolymerization of styrene with p-alkylsubstituted styrenes and with α-olefins. Both polymerization and copolymerization processes depend on th...

The copolymerization of styrene with 1-alkene (1-hexene, 1-decene and 1-hexadecene) has been tested using combined diphenylzinc-additive initiator systems, including diphenylzinc (Ph2Zn), a metallocene and methylaluminoxane (MAO). The metallocene were biscyclopentadienyltitanium dichloride, bis(n-butylcyclopentadienyl)titanium dichloride, cyclopent...

Linear polydimethylsiloxanes (PDMS) and 3- and 4-arm star-shaped PDMS of narrow molecular weight distribution (MWD) have been synthesized by anionic polymerization. The MWD was obtained by Size Exclusion Chromatography (SEC). Some of the anionically synthesized PDMS showed a relative broad MWD, especially when they were terminated after 3 or more d...

Combination of diphenylzinc, Ph2Zn, cyclopentadienyl titanium trichloride, CpTiCl3, and methylaluminoxane, MAO, were used to initiate styrene, S, polymerization and its copolymerization with 1-hexadecene, 1-C16H32, and with p-tert-butylstyrene, p-(BuS)-S-t. For homopolymerization an almost pure syndiotatic polystyrene, s-PS, was obtained when using...