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María Sánchez-García

Bio: María Sánchez-García is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: Biochar & Compost. The author has an hindex of 15, co-authored 23 publications receiving 1377 citations.

Papers
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TL;DR: In this article, cellulose nanowhiskers (CNW) were used as a reinforcing element to reduce the gas and vapour permeability of the biopolyester matrix.
Abstract: Polylactic acid (PLA) nanocomposites were prepared using cellulose nanowhiskers (CNW) as a reinforcing element in order to asses the value of this filler to reduce the gas and vapour permeability of the biopolyester matrix. The nanocomposites were prepared by incorporating 1, 2, 3 and 5 wt% of the CNW into the PLA matrix by a chloroform solution casting method. The morphology, thermal and mechanical behaviour and permeability of the films were investigated. The CNW prepared by acid hydrolysis of highly purified alpha cellulose microfibers, resulted in nanofibers of 60–160 nm in length and of 10–20 nm in thickness. The results indicated that the nanofiller was well dispersed in the PLA matrix, did not impair the thermal stability of this but induced the formation of some crystallinity, most likely transcrystallinity. CNW prepared by freeze drying exhibited in the nanocomposites better morphology and properties than their solvent exchanged counterparts. Interestingly, the water permeability of nanocomposites of PLA decreased with the addition of CNW prepared by freeze drying by up to 82% and the oxygen permeability by up to 90%. Optimum barrier enhancement was found for composites containing loadings of CNW below 3 wt%. Typical modelling of barrier and mechanical properties failed to describe the behaviour of the composites and appropriate discussion regarding this aspect was also carried out. From the results, CNW exhibit novel significant potential in coatings, membranes and food agrobased packaging applications.

317 citations

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TL;DR: The results suggest that biochar, as composting additive, improved the physical properties of the mixture by preventing the formation of clumps larger than 70 mm, and favoured microbiological activity without a relevant impact on N losses and gaseous emissions.

273 citations

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TL;DR: The incorporation of nanoclays, micro and nanofibers of cellulose and carbon nanofibrers and nanotubes into bioplastics is attracting a great deal of research interest regarding improvement of general physical properties in plastics and bioplastic materials as mentioned in this paper.
Abstract: The incorporation of nanoclays, micro and nanofibers of cellulose and carbon nanofibers and nanotubes into bioplastics is attracting a great deal of research interest regarding improvement of general physical properties in plastics and bioplastics. The present overview shows, beyond the reviewed state of the art, nanobiocomposites specifically developed for food packaging applications, in which mainly cellulose biofibers, their highly crystalline building nanoblocks and food contact complying non-MMT (non-montmorillonite) nanoclays have been used in melt blending and solution casting processing routes to improve the barrier properties to gases and vapours and to impart additional functionalities to biopackaging plastics. Bar rier properties are known to be very strong limiting factors for the current widespread application of, mainly, biopolyesters in self-life extension of biopackaged foods. The paper specifically exemplifies on novel functionalities by showing novel nanobiocomposite films of biopolyesters with enhanced gas, vapour and UV barrier and simultaneously exhibiting controlled release capacity of an antimicrobial and antioxidant natural plant extract of interest in active antimicrobial food biopackaging applications.

161 citations

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TL;DR: In this paper, the authors showed that the effectiveness of using biochar for reducing N2O emissions from a particular soil is linked to its dominant N 2O formation pathway, which was probably the cause of increased N 2 O emissions.
Abstract: In spite of the numerous studies reporting a decrease in soil nitrous oxide (N2O) emissions after biochar amendment, there is still a lack of understanding of the processes involved. Hence the subject remains controversial, with a number of studies showing no changes or even an increase in N2O emissions after biochar soil application. Unraveling the exact causes of these changes, and in which circumstances biochar decreases or increases emissions, is vital to developing and applying successful mitigation strategies. With this objective, we studied two soils (Haplic Phaeozem (HP) and Haplic Calcisol (HC)), which showed opposed responses to biochar amendment. Under the same experimental conditions, the addition of biochar to soil HP decreased N2O emissions by 76%; whereas it increased emissions by 54% in soil HC. We combined microcosm experiments adding different nitrogen fertilizers, stable isotope techniques and the use of a nitrification inhibitor (dicyciandiamide) with the aim of improving our understanding of the mechanisms involved in the formation of N2O in these two soils. Evidence suggests that denitrification is the main pathway leading to N2O emissions in soil HP, and ammonia oxidation and nitrifier-denitrification being the major processes generating N2O in soil HC. Biochar systematically stimulated nitrification in soil HC, which was probably the cause of the increased N2O emissions. Here we demonstrate that the effectiveness of using biochar for reducing N2O emissions from a particular soil is linked to its dominant N2O formation pathway.

132 citations

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TL;DR: In this paper, the authors studied the morphological, thermal, and barrier properties of novel melt-mixed nanobiocomposites of PHB, poly(e-caprolactones) (PCL), and layered phyllosilicates based on commercial organomodified kaolinite and montmorillonite clay additives.
Abstract: Polyhydroxybutyrate (PHB) is generally considered to be a very uneasy biopolymer to handle because of significant instability during melt processing and some excessive brittleness. This work studied the morphological, thermal, and barrier properties of novel melt-mixed nanobiocomposites of PHB, poly(e-caprolactones) (PCL), and layered phyllosilicates based on commercial organomodified kaolinite and montmorillonite clay additives. The addition of PCL component to the blend was seen to reduce oxygen permeability but it was also found to lead to a finer dispersion of the clay. The addition of highly intergallery swollen organomodified montmorillonite clays to the PHB blend led to a highly dispersed morphology of the filler, but this simultaneously increased to a significant extend the melt instability of the biopolymer. Nevertheless, the organomodified kaolinite clay, despite the fact that it was found to both lead to less dispersed and irregular morphology, particularly for higher clay loadings, it led to enhanced barrier properties to oxygen, D-limonene, and water. D-limonene and specially water molecules were, however, found to sorb in both hydrophobic and hydrophilic sites of the filler, respectively, hence diminishing the positive barrier effect of an enlarged tortuosity factor in the permeability. Mass transport properties were found to depend on the type of penetrant and modeling of the permeability data to most commonly applied formalisms was not found to be satisfactory because of factors such as morphological alterations, heterogeneity in the clay dispersion, and penetrant solubility in the filler. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

112 citations


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Journal ArticleDOI
01 Nov 2011
TL;DR: Several applications of nanomaterials in food packaging and food safety are reviewed, including polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomMaterial-based assays for the detection of food-relevant analytes.
Abstract: In this article, several applications of nanomaterials in food packaging and food safety are reviewed, including: polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomaterial-based assays for the detection of food-relevant analytes (gasses, small organic molecules and food-borne pathogens). In addition to covering the technical aspects of these topics, the current commercial status and understanding of health implications of these technologies are also discussed. These applications were chosen because they do not involve direct addition of nanoparticles to consumed foods, and thus are more likely to be marketed to the public in the short term.

1,568 citations

Journal ArticleDOI
TL;DR: A recent review as mentioned in this paper highlights the main researches and developments in polylactide-based nanocomposites during this last decade, highlighting the main applications of PLA in automotive and electronics.

962 citations

Journal ArticleDOI
TL;DR: A broad review on the recent advances in the research and development of biobased plastics and bionanocomposites that are used in various applications such as packaging, durable goods, electronics and biomedical uses is presented in this paper.

863 citations

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TL;DR: In this article, the authors investigated the effects of corn-straw biochar under the application of urea in layered soil columns in order to assess the change of bacterial diversity and community structure utilizing the Illumina technology.

728 citations

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TL;DR: A review of cellulose chemically extracted nanocrystals can be found in this article, where the authors provide an overview about several aspects that involve this material, including sources, properties, challenges, and perspectives.
Abstract: Cellulosic nanoparticles with high Young's modu- lus, crystallinity, specific surface area, and aspect ratio can be found in the natural structure of plant fibers. Indeed, lignocel- lulosic fibers consist of semicrystalline cellulose nanofibrils embedded in an amorphous matrix mainly composed of lignin and hemicelluloses. These nanostructures give the mechanical strength to higher plant cells, and are biodegradable, renew- able, resistant, and widely available to produce nanocompo- sites with low density, and improved and controlled mechanical, optical, and barrier properties. Nanoparticles can be extracted from cellulose using a top-down mechanically or chemically assisted deconstructing strategy, and owing to their highly reactive surface ensuing nanomaterials can be chemi- cally modified to tailor their properties for a wide range of applications. This review is limited to cellulose chemically extracted nanocrystals and aims to provide an overview about several aspects that involve this material, including sources, properties, challenges, and perspectives. V C 2014 Wiley Periodi- cals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 00, 000-000

670 citations