Author
Ana Rita Morales
Other affiliations: University of Connecticut
Bio: Ana Rita Morales is an academic researcher from State University of Campinas. The author has contributed to research in topics: Montmorillonite & Differential scanning calorimetry. The author has an hindex of 19, co-authored 56 publications receiving 1892 citations. Previous affiliations of Ana Rita Morales include University of Connecticut.
Papers published on a yearly basis
Papers
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TL;DR: In this article, the authors give an overview of properties, synthesis and applications of bentonite and polymer nanocomposites and describe the research performed until the present moment, including different synthesis techniques, modifications with several chemical compounds as quaternary alkylammonium salts and also biomolecules as enzymes that provide applicability in a variety of fields.
911 citations
TL;DR: In this article, the effects of cellulose nanocrystals modified with octadecyl isocyanate on rheological, mechanical and degradation properties of nanocomposites based on poly (butylene adipate-co-terephthalate) (PBAT) were reported.
144 citations
TL;DR: In this paper, the authors presented a life cycle assessment (LCA) comparing three forms of poly(lactic acid) (PLA) disposal: mechanical recycling, chemical recycling and composting.
Abstract: This paper presents a life cycle assessment (LCA) comparing three forms of poly(lactic acid) (PLA) disposal: mechanical recycling, chemical recycling and composting. The LCA data was taken from lab scale experiments for composting and hydrolysis steps. Polymerization data in chemical recycling was obtained from computer simulation. Mechanical recycling data from lab scale were combined with the data from a plastics commercial mechanical recycling plant. The analysis considered two different product systems based on the input of the recycled PLA in the product system. Considering the categories: climate change, human toxicity and fossil depletion, the LCA showed that mechanical recycling presented the lowest environmental impact, followed by chemical recycling and composting. Among the forms of recycling, the most important input was the electricity consumption.
141 citations
Abstract: This paper presents a study of biodegradation, in soil, of samples of poly(butylene adipate-co-terephthalate)(PBAT), poly(lactic acid) (PLA) and blends of these materials prepared in torque rheometer with the addition of a chain extender. Film samples of these materials were buried in soil under controlled laboratory conditions. The degraded samples were regularly taken from soil and analyzed by visual inspection, size exclusion chromatography, differential scanning calorimetry and infrared spectroscopy. Respirometry biodegradation tests were conducted to assess samples mineralization degree. Blends showed higher degree of crystallinity compared to pure polymers. Crystallinity degree enhanced during the biodegradation process in all samples, being able to causing the samples to degrade slowly. The study showed the great complexity of the biodegradation process of PLA and PBAT blends when compatibilized with a chain extender. The biodegradation rate showed different results depending on the characteristic applied to evaluate it: visual, molecular weight or mineralization. The chain extender had strong influence in PBAT and blends degradation, slowing the process as observed by the variation of molecular weight and carbonyl index. Blends showed an intermediate behavior compared to the original polymers.
118 citations
TL;DR: This paper present a revisao bibliografica sobre argilas organofilicas, especialmente as obtidas a partir de bentonitas e de sais quaternarios de amonio.
Abstract: As argilas sao materiais muito usados e que atualmente apresentam inumeras aplicacoes devido as interessantes propriedades que apresentam. A modificacao superficial de argilas e uma area que tem recebido bastante atencao dos pesquisadores porque por meio dos diversos tipos de modificacao e possivel a preparacao de novos materiais e novas aplicacoes. Este trabalho tem como objetivo apresentar uma revisao bibliografica sobre argilas organofilicas, especialmente as obtidas a partir de bentonitas e de sais quaternarios de amonio. Diversos estudos vem sendo realizados baseados em diferentes tecnicas e parâmetros de sintese desses materiais, incluindo argilas de diferentes regioes e diferentes agentes de modificacao, bem como as diferentes aplicacoes que sao propostas.
97 citations
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31 Oct 2001
TL;DR: The American Society for Testing and Materials (ASTM) as mentioned in this paper is an independent organization devoted to the development of standards for testing and materials, and is a member of IEEE 802.11.
Abstract: The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.
3,792 citations
01 Jan 1987
TL;DR: Eisma et al. as mentioned in this paper showed that the CEC can vary over 2 orders of magnitude for various types of, minerals and can vary one order of magnitude within one soil type.
Abstract: Positive ions that are available in soils absorb on grain surfaces. The total sum of cations that can be absorbed bij a soil/sediment at a certain PH is defined by the cation-exchange capacity (CEC, in meq g-1: mol equivalents per gram). The uptake of cations is an important parameter in agriculture and the larger the CEC, the more cations can be absorbed to the soil. The CEC depends highly on the pH of soil and sediments, where the CEC decreases with decreasing PH (increasing acidity). The exchange of ions on sediments occurs commonly fast on geological time scales, but the kinetics of adsorption in natural environments is still poorly understood. The strength of the bonding between the cations and the sediments varies from weak Van der Waals bondings (physical adsorption) to strong chemical bonds. The CEC is widely used for agricultural assessment because it is a measure of general soil fertility as well as an indicator of structural stability because CED is capabel of enhancing development of shrinkage cracks. The list below shows the CEC for different types of minerals. The data indicate that the CEC can vary over 2 orders of magnitude for various types of , minerals and can vary one order of magnitude within one soil type. Cation exchange capacity for different types of sediment (Eisma, 1992; Locher and de Bakker, 1990):
1,169 citations
TL;DR: Nanoparticles have proportionally larger surface area than their microscale counterparts, which favors the filler-matrix interactions and the performance of the resulting material as mentioned in this paper, and they can have other functions when added to a polymer, such as antimicrobial activity, enzyme immobilization, biosensing, etc.
1,058 citations
TL;DR: A review of the current status of PLA mass production, processing techniques and current applications is presented, and the methods to tailor PLA properties, the main PLA degradation reactions, PLA products' end-of-life scenarios and the environmental footprint are covered.
800 citations
TL;DR: It is shown that biodegradation tests carried out in artificial environments lack transferability to real conditions and, therefore, the necessity of environmentally authentic and relevant field-testing conditions is highlighted.
Abstract: In recent years the littering of plastics and the problems related to their persistence in the environment have become a major focus in both research and the news. Biodegradable polymers like poly(lactic acid) are seen as a suitable alternative to commodity plastics. However, poly(lactic acid) is basically non-degradable in seawater. Similarly, the degradation rate of other biodegradable polymers also crucially depends on the environments they end up in, such as soil or marine water, or when used in biomedical devices. In this Minireview, we show that biodegradation tests carried out in artificial environments lack transferability to real conditions and, therefore, highlight the necessity of environmentally authentic and relevant field-testing conditions. In addition, we focus on ecotoxicological implications of biodegradable polymers. We also consider the social aspects and ask how biodegradable polymers influence consumer behavior and municipal waste management. Taken together, this study is intended as a contribution towards evaluating the potential of biodegradable polymers as alternative materials to commodity plastics.
753 citations