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Nanocellulose: Effect on Thermal, Structural, Molecular Mobility and Rheological Characteristics of Poly(Butylenes Adipate-Co-Butylene Terephthalate) Nanocomposites

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Materials Sciences and Applications 2022年第4期13卷 249-277页

作者： Gerson Alberto Valencia Albitres Francisco Pereira Araujo Junior Daniela França Silva Freitas Danielle Mattos Mariano Maria Ines Bruno Tavares Luis Claudio Mendes Universidade Federal do Rio de Janeiro Instituto de Macromoléculas Professora Eloisa Mano Rio de Janeiro Brazil

The concern with environmental preservation is a very current and relevant topic. Regarding polymers, the search for potentially ecofriendly matters has been the subject of scientific research. In this context, this work aimed to study the effect of adding nanocellulose (nCE) with 1, 3, and 5 wt.% on poly(butylene adipate-co-butylene terephthalate) (PBAT). Thermal, structural, relaxometric, and rheological assessments were carried out. Quantitative evaluation of PBAT copolymer by high field NMR revealed 56.4 and 43.6 m.% of the butylene adipate and butylene terephthalate segments, respectively. WAXD measurement on the deconvoluted diffraction patterns identified that nCE was a mixing of Cellulose I and Cellulose II polymorph structures. At any composition, nanocellulose interfered with the PBAT crystallisation process. Also, a series of new PBAT crystallographic planes appeared as a function of nanocellulose content. PBAT hydrogen molecular relaxation varied randomly with nanocellulose content and had a strong effect on the hydrogen relaxation. PBAT cold crystallisation and melting temperatures (Tcc and Tm) were almost unchangeable. Although Tcc did not change during polymer solidification from PBAT molten state, the sample’s degree of crystallinity varied with composition through the transcrystallization phenomenon. Nanocomposite thermal stability decreased possibly owing to the catalytic action of sulfonated amorphous cellulose chains. For the sample with 3 wt.% of nanocellulose, the highest values of complex viscosity and storage modulus were achieved.

关键词： Nanocellulose Poly(Butylene Adipate-Co-Butylene Terephthalate) Molecular Relaxation Nanocomposite

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Polymer Nanocomposites Used as Scaffolds for Bone Tissue Regeneration

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Materials Sciences and Applications 2018年第8期9卷 679-697页

作者： Raquel Couto de Azevedo Goncalves Mota Emerson Oliveira da Silva Lívia Rodrigues de Menezes instituto de macromoléculas professora eloisa Mano Universidade Federal do Rio de JaneiroRio de JaneiroBrazil

Scaffolds are three-dimensional biocompatible structures that can mimic the properties of the extracellular matrix (ECM) of a given tissue, like mechanical support and bioactivity, which provides a platform for cellular adherence, proliferation and differentiation. Consequently, scaffolds are frequently used in tissue engineering with the intention of assisting the regeneration of a damaged tissue, and a major application in bone regeneration. An ideal scaffold needs to be biodegradable, biocompatible, and needs to match the biomechanical properties of bone. Polymers are widely used in this field because they fulfil the first two requirements. However, no polymeric material can achieve mechanical properties similar to the bone. For that reason, polymeric nanocomposites, which consist of ceramic/metallic nanoparticles dispersed in a polymer matrix, are being considered for bone scaffold fabrication in order to overcome this problem, since nanoparticles are known to improve composite mechanical strength, and enhance other properties.

关键词： Scaffolds Polymer Nanocomposites Nanoparticles Bone Tissue Engineering

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Obtaining and Characterization of Biodegradable Composites Reinforced with Microcrystalline Cellulose Fillers

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Materials Sciences and Applications 2021年第12期12卷 561-577页

作者： Lucas Viana Costa Gisele C. Valle Iulianelli Paulo Sérgio Rangel C. da Silva Fernanda A. dos Santos instituto de macromoléculas professora eloisa Mano Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

In recent years, there has been a growing discussion about the problems related to the massive use of many synthetic plastic materials, which inevitably leads to an increase in environmental pollution caused by the inappropriate disposal of these materials. In this sense, biodegradable materials have been a subject of great interest, as they are a real alternative to replace these materials and tackle this issue. In this work, fully biodegradable composites were prepared by solution casting method. Microcrystalline cellulose (MCC) and treated microcrystalline cellulose (TMCC) were separately incorporated into biodegradable PLA and PHB matrices at ratios of 3, 5 and 7 wt% and the properties of the obtained biocomposites were evaluated by TGA, DSC, XRD and TD-NMR. From thermal analyses, it was seen that TMCC resulted in better thermal stability and 3 wt% of filler, in general, promoted a more pronounced thermal improvement. Furthermore Tg, Tc and Tm remained practically unchanged after MCC and TMCC addition. From XRD it was seen that the cellulose fillers influence in different ways the matrices, promoting increase or decrease in the degree of crystallinity. Finally, the results obtained by TD-NMR showed a decrease in the T1H values for all prepared biocomposites, indicating a good dispersion of the cellulose fillers in the matrices and pointed that the systems containing 3 wt% of cellulose fillers were the most homogeneous formulations.

关键词： PHB PLA Microcrystalline Cellulose Biocomposites TGA DSC XRD TD-NMR

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PVP/Clay/Vanadium Oxide Nanocomposites development and Characterization for Potential Use as Controlled Drug Release Matrix in Diabetes’ Treatment

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Materials Sciences and Applications 2019年第12期10卷 768-782页

作者： Dario Barreto Reino de Almeida Maria Inês Bruno Tavares instituto de macromoléculas professora eloisa Mano Universidade Federal do Rio de Janeiro Rio de Janeiro Brasil

Research in drug release field, nowadays, focuses on more efficient systems for better release of the drug and wider timespan of action, granting several benefits to the patient’s organism and to the industry. The present work aims on developing a matrix of polymer nanocomposite based on Polyvinylpyrrolidone (PVP), bentonite clay and two different vanadium oxides, via spray drying technique. The goal is to achieve a long and steady release of metformin hydrochloride in future formulations with this drug. Since either the nanocomposites or metformin hydrochloride is highly hydrophilic, it is most suited for a future formulation of tablets. For now, the nanocomposites obtained were characterized through Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). The SEM and XRD analysis portrayed a very amorphous and homogenized material. TGA and FTIR proved the insertion of the nanoparticles, thus granting to the new material a slightly higher thermal resistance. The NMR analysis, using T1H parameters, is key for determining the formulations would behave better for extending the resistance of the nanocomposite’s matrix with the drug in later dissolution of tablets.

关键词： Polyvinylpirrolidone Vanadium Pentoxide Vanadium (IV) Oxide Sulfate Hydrate Nanocomposite

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Effect of the Addiction of Metal Oxide Nanoparticles on the Physical, Chemical and Thermal Properties of PVA Based Nanocomposites

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Materials Sciences and Applications 2018年第5期9卷 473-488页

作者： Raquel Couto de Azevedo Gonç alves Mota Emerson Oliveira da Silva Lí via Rodrigues de Menezes instituto de macromolé culas professora eloisa Mano Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

In this study, poly(vinyl alcohol) (PVA)-based nanocomposites consisting of metallic oxide nanoparticles (TiO2, ZnO, ZrO2) were obtained from an aqueous solution of 7% PVA, in order to compare the microstructural, and physical properties of bionanocomposite films reinforced with various loading contents (0.1%, 0.2% and 0.3% w/w). They were evaluated regarding their molecular toughness through Nuclear Magnetic Resonance (NMR), regarding their chemical structural through Fourier Transform Infrared Spectroscopy (FTIR), regarding their crystallinity throught X-ray Diffraction (XRD), and regarding termal properties through Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The NMR results showed that the smallest concentrations of these oxides have a tendency to disperse better in the polymeric matrix, improving the structural toughness. Besides, changes in the termal resistance of the material were found with the use of TGA and DSC.

关键词： Poly(vinyl alcohol) Nanocomposites Metallic Oxides Titanium Oxide Zirconium Oxide Zinc Oxide

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Thermal and Crystallization Behavior of PLA/PLLA-Grafting Cellulose Nanocrystal

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Materials Sciences and Applications 2020年第1期11卷 44-57页

作者： Erika M. Inácio Diego H. S. Souza Marcos L. Dias instituto de macromoléculas professora eloisa Mano (IMA) Universidade Federal do Rio de Janeiro (UFRJ) Rio de Janeiro Brazil

PLLA-modified cellulose nanocrystals (CNC) were produced from commercial CNC by tin-catalyzed polymerization of lactide in presence of CNC. FTIR spectroscopy demonstrated that the result of the reaction produced the grafting of PLLA chains onto CNC surface (CNC-g-PLLA). Films of poly(lactic acid) (PLA) and PLA/CNC nanocomposites (with non-modified CNC and CNC-g-PLLA) containing 0.5% and 5% (w/w) of the nanofillers were prepared by casting in chloroform solution and the crystallization behavior and thermal properties investigated. All nano-composites had similar thermal stability when analyzed by TGA analyses under an inert nitrogen atmosphere. Addition of both types of CNC influenced crystallization, the higher crystallization rate being observed for 5% (w/w) CNC. Nanocomposites with 5% (w/w) CNC-g-PLLA had the strain resistance of PLA improved in the rubbery state. PLLA-modification of CNC surface increased the crystallization of PLA in PLA/CNC nanocomposites and improved the rigidity at temperatures above the glass transition, properties which are desirable for hot drinking application.

关键词： Nanocrystals Cellulose Poly(Lactic Acid) Grafting Crystallizations

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Morphological, Biological and Physicochemical Evaluation of ABS-Based Systems Containing Graphene Obtained by 3D Printing via Solution

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Materials Sciences and Applications 2022年第6期13卷 401-416页

作者： Antônio Carlos Santos Thiele Maria Inês Bruno Tavares instituto de macromoléculas professora eloisa Mano (IMA) Universidade Federal do Rio de Janeiro Rio de Janeiro RJ Brazil

3D printing is a valuable resource that allows flexibility in the production of objects based on a virtual file. When it is combined with nanotechnology, new features can be added to existing materials. Thus, form and function can be associated to achieve a specific goal, such as the development of support structures for cell growth applicable to systems aiding tissue regeneration. Based on this rationale, the present work proposes a system composed of ABS and graphene nanoparticles solubilized in acetone to be 3D impressed using solvent casting technique. Our main goal was to develop a biocompatible and non-degradable material that fully makes use of the design versatility of 3D printing, to enable new practical employments in the future, for example in the medical field. In this study, different characterization techniques were used—such as microscopy, TGA, DSC, and others—to understand the features and properties of the material obtained, as well as the viability of its use and diffusion. Moreover, the artifacts impressed proved to be non-cytotoxic and promoted cellular adhesion to the cellular lineage of fibroblasts L929. In sum, we believe that the technology described in this article has the potential to serve as a basis for the development of future biocompatible materials that take advantage of their three-dimensional design to perform their functions.

关键词： Acrylonitrile Butadiene Styrene Graphene Nanoplatelets 3D Printing Biocompatibility

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Spin-Spin Relaxation Time to Evaluate degradation of HIPS/Organoclaynano Composites by Aging

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Materials Sciences and Applications 2017年第5期8卷 342-350页

作者： Paulo Sergio Rangel Cruz da Silva Gisele Cristina Valle Iulianelli Maria Inês Bruno Tavares instituto de macromoléculas professora eloisa Mano-IMA Universidade Federal do Rio de Janeiro-UFRJ Rio de Janeiro-RJ Brasil

NMR relaxometry is one of the techniques that allow observing changes in the molecular mobility that come from materials’ morphology. T1H has been used to monitor food and polymer sciences. However, T2>H, although being a revealing as T1>H, is rarely used to analyze changes in thermoplastic systems it is more sensitive to the mobile region. High Impact Polystyrene nanomaterials were prepared through solution casting and were exposed for different times to UV light in the air. The samples, removed after each exposure interval, were characterized by T2>H, focusing on the changes in the relaxation data. The results for this parameter showed that the changes in the relaxation data come from the competition of chain scission and chain recombination processes, which occurs due to the UV light influence with increased time. The T2>H data indicated that the clay ratio can influence the chain degradation processes, acting to inhibit or accelerate the aging process [1] [2].

关键词： degradation High Impact Polystyrene Nanocomposites Relaxometry Spin-Spin

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Incorporation of Nano-Zinc Oxide in Lamellar Zirconium Phosphate: Synthesis and Characterization

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Materials Sciences and Applications 2023年第6期14卷 346-361页

作者： Danielle Mattos Mariano Daniela França Silva Freitas Gerson Alberto Valencia Albitres Luis Claudio Mendes Maria Ines Bruno Tavares instituto de macromoléculas professora eloisa Mano Centro de Tecnologia Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychloride octahydrate and phosphoric acid following its chemical modification with Jeffamine and nano-ZnO. Diffractometric, morphological, thermal, structural and relaxometric evaluations were conducted. Fourier transform infrared spectroscopy (FTIR) revealed increase of the area between 4000 - 3000 cm-1 due to the formation of ionic specie PO? +NH3-[C-(H)(CH3)-CH2-O-(C-(H)(CH3)-CH2-O)8-(CH2-CH2-O-CH3)] and nano-ZnO particles. Wide-angle X-ray diffraction indicated that intercalation of Jeffamine was successful. Thermogravimetry confirmed that nano-ZnO particle forced the expulsion of Jeffamine outside ZrP galleries. Scanning electron microscopy evidenced the Jeffamine intercalation and sample heterogeneity. Hydrogen molecular relaxation indicated the increase of molecular rigidity owing to the formation of ionic specie and the addition of nano-ZnO particles. It was postulated that a multifunctional and miscellaneous material constituted by as prepared ZrP, some delaminated ZrP platelets and nano-ZnO particles was achieved. The material has potential for usage as filler in polymeric composites.

关键词： Lamellar Zirconium Phosphate Jeffamine Nano-Zinc Oxide Intercalation

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Employment of Waste from the Textile Industry for the Production of Nanocomposites Aiming at the Generation of Thermal Shrinkable Films and the Non-Formation of Microplastics

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Materials Sciences and Applications 2023年第8期14卷 426-438页

作者： Dian Souza Garcia Bruno de Paula Amantes Maria Inês Bruno Tavares instituto de macromoléculas professora eloisa Mano Universidade Federal do Rio de Janeiro Centro de Tecnologia Rio de Janeiro Brasil

With the increase of incorrectly discarded materials in the environment, including clothes, the need for recycling and reusing them becomes one of the alternatives to work around this problem, following the law of the 3 Rs. However, these polymeric materials which are deposited in the marine environment and land generate microplastics, due to their degradation/fragmentation due to the action of the weather, in these regions, including being carried by the air and transported from various regions. With the aim of reducing the impact of this inappropriate disposal and obtaining a material that does not generate microplastics, this study used waste from the textile industry, which would be unusable, and a biodegradable polymer. The tissue residues were submitted to acid hydrolysis with sulfuric acid, in order to weaken the interactions between the cellulose fibrils and promote a better dispersion of the latter when processed with the polymer, during the extrusion process, generating biodegradable polymeric nanocomposites. The results showed that the samples submitted to acid hydrolysis presented a higher degree of crystallinity and a greater number of interactions and lower mobility of hydrogen atoms. In addition, the samples treated for a longer time showed a small release of fibrils, suggesting that this treatment can help in the production of nanocomposites during their extrusion.

关键词： Microplastic Nanotechnology Cellulose Textile Industry Biodegradable Polymer

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