Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
1.
J Nanosci Nanotechnol ; 17(2): 968-76, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29671484

RESUMO

Silver nanoparticles contribute a giant share to the realm of modern nanobiotechnology. Their utility as antimicrobial agents is also well documented. Green synthesis of nanoparticle has several advantages over its chemical synthesis. In the present study, Thuja occidentalis leaf extract mediated silver nanoparticles were prepared without using a stabilizing agent and tested for their anticancer and anti-microbial activity. Thuja occidentalis leaf extract mediated silver nanoparticles were prepared under ambient conditions which showed a narrow size distribution within the range of 10­15 nm, with average particle size of 12.7 nm. Interestingly, these nanoparticles exhibited anti-cancer activity against human breast (MCF 7, MDA MB 231) and cervical cancer (HeLa) as well as mouth epidermoid carcinoma (KB) cell lines at a concentration range of 6.25­50 µg/mL. Contrarily, they are compatible with human peripheral blood mononuclear cells and rat hepatocytes. Moreover, their efficient inhibitory effect was witnessed against Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and Pseudomonas aeruginosa with inhibitory concentration at 5­10 µg/mL. The prepared nanoparticles were highly biocompatible and have strong potential in the development of non-toxic chemotherapy with antibacterial attributes.


Assuntos
Antineoplásicos , Nanopartículas Metálicas , Prata , Antibacterianos/química , Antibacterianos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Neoplasias da Mama , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Neoplasias Bucais , Tamanho da Partícula , Prata/química , Prata/farmacologia , Neoplasias do Colo do Útero
2.
J Nanosci Nanotechnol ; 14(7): 5435-42, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24758045

RESUMO

Here, bio-based shape memory polymers have generated immense interest in recent times. Here, Bio-based hyperbranched polyurethane/triethanolamine functionalized multi-walled carbon nanotube (TEA-f-MWCNT) nanocomposites were prepared by in-situ pre-polymerization technique. The Fourier transform infrared spectroscopy and the transmission electron microscopic studies showed the strong interfacial adhesion and the homogeneous distribution of TEA-f-MWCNT in the polyurethane matrix. The prepared epoxy cured thermosetting nanocomposites exhibited enhanced tensile strength (6.5-34.5 MPa), scratch hardness (3.0-7.5 kg) and thermal stability (241-288 degrees C). The nanocomposites showed excellent shape fixity and shape recovery. The shape recovery time decreases (24-10 s) with the increase of TEA-f-MWCNT content in the nanocomposites. Thus the studied nanocomposites have potential to be used as advanced shape memory materials.

3.
J Nanosci Nanotechnol ; 14(6): 4455-61, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24738412

RESUMO

The present study reports the use of water soluble sodium sulfate (Na2SO4) nanorods as a versatile template for generation of tubular copper sulfide (CuS) nanostructures. The Na2SO4 nanorods were synthesized from ammonium sulfate (NH4)2SO4 and sodium hydroxide (NaOH), under refluxing condition. The shape and morphology control of the Na2SO4 nanorods were studied with respect to nature of surfactant used and reactant mole ratio. While, PVP mole ratio was important to obtain homogeneous nanorods. Uniform and stable nanotubes of CuS were than obtained by the dissolution of the nanorods in water. The use of simple chemicals for synthesis of such nanotube templates opens the prospect for wide scale downstream applications.


Assuntos
Cobre/química , Cristalização/métodos , Impressão Molecular/métodos , Nanotubos/química , Nanotubos/ultraestrutura , Sulfatos/química , Água/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Solubilidade , Propriedades de Superfície
4.
Int J Biol Macromol ; 256(Pt 1): 128253, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37989430

RESUMO

In recent years, hydrogels as drug carriers have been receiving great interest due to their ability to change their behavior in response to one or more external stimuli. However, their initial burst release profile limits their practical applications. Therefore, we prepared a bio-based hydrogel nanocomposite (HNC) using starch, itaconic acid, acrylic acid and gelatin in the presence of CNF/ZnO-based nanohybrid (ZONH) and used it to evaluate the pH-sensitive drug release properties in different pH solutions. The prepared HNCs were analyzed using various spectroscopic and microscopic techniques. The BET analysis and swelling test of the HNC indicated improved porosity and swelling capacity due to the addition of ZONH. From the drug release study, sustained drug release rate was observed at pH 4 than those at pH 7.4 and 9, indicating controlled release as well as pH responsive behavior of the HNC. Moreover, the drug released HNC was reused as a photocatalyst for dye degradation and achieved good degradation (%). The antibacterial activity of ZONH and HNC was observed against EC and SA bacterial strains from the antibacterial test. In summary, the prepared HNC can be considered as a potential sustainable DDS for biomedical applications as well as a photocatalyst for dye contaminated water treatment.


Assuntos
Nanocompostos , Nanofibras , Succinatos , Óxido de Zinco , Hidrogéis/química , Óxido de Zinco/química , Gelatina , Amido , Antibacterianos/farmacologia , Antibacterianos/química , Nanocompostos/química , Concentração de Íons de Hidrogênio , Liberação Controlada de Fármacos
5.
ACS Appl Bio Mater ; 7(3): 1910-1924, 2024 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-38391158

RESUMO

Creating polymers that combine various functions within a single system expands the potential applications of such polymeric materials. However, achieving polymer materials that possess simultaneously elevated strength, toughness, and self-healing capabilities, along with special properties, remains a significant challenge. The present study demonstrates the preparation of S and Mo codoped graphitic carbon nitride (g-C3N4) (Mo@S-CN) nanohybrid and the fabrication of self-healing waterborne polyurethane (SHWPU)/Mo@S-CN (SHWPU/NS) nanocomposites for advanced applications. Mo@S-CN is an intriguing combination of g-C3N4 nanosheets and molybdenum oxide (MoOx) nanorods, forming a complex lamellar structure. This unique arrangement significantly improves the inborn properties of SHWPU to an impressive degree, especially mechanical strength (28.37-34.11 MPa), fracture toughness (73.65-140.98 MJ m-2), and thermal stability (340.17-348.01 °C), and introduces fluorescence activity into the matrix. Interestingly, a representative SHWPU/NS0.5 film is so tough that a dumbbell of 15 kg, which is 53,003 times heavier than the weight of the film, can be successfully lifted without any significant crack. Remarkably, fluorescence activity is developed because of electronic excitations occurring within the repeating polymeric tris-triazine units of the Mo@S-CN nanohybrid. This fascinating feature was effectively harnessed by assessing the usability of aqueous dispersions of the Mo@S-CN nanohybrid and photoluminescent SHWPU/NS nanocomposites as sustainable stains for bioimaging of human dermal fibroblast cells and anticounterfeiting materials, respectively. The in vitro fluorescence tagging test showed blue emission from 365 nm excitation, green emission from 470 nm excitation, and red emission from 545 nm excitation. Most importantly, in vitro hemocompatibility assessment, in vitro cytocompatibility, cell proliferation assessment, and cellular morphology assessment supported the biocompatibility nature of the Mo@S-CN nanohybrid and SHWPU/NS nanocomposites. Thus, these materials can be used for advanced applications including bioimaging.


Assuntos
Grafite , Nanocompostos , Compostos de Nitrogênio , Poliuretanos , Humanos , Proliferação de Células , Eletrônica , Nanocompostos/toxicidade , Polímeros
6.
Int J Biol Macromol ; 253(Pt 1): 126555, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37659498

RESUMO

In this work, wastepaper powder was used as a modifying agent for a biodegradable hydrogel composite of starch, itaconic acid, and acrylic acid. After the addition of an optimum amount of the modifying agent, the swelling ability of the hydrogel was enhanced from 503 g/g to 647 g/g. Further, the hydrogel was also used for sustained release of NPK fertilizer and subsequent effect of the fertilizer loaded hydrogel in okra seed germination was also studied. The NPK loaded-hydrogel showed good sustained-release behavior and 98 % of N, 81 % of P and 95 % of K release were observed after 20th day of incubation. Moreover, the release study was explained by using different kinetic models. In seed germination study, a higher and faster germination rate for okra seeds was observed in case of NPK loaded hydrogel compared to the control system, which was attributed to the synergistic effect of essential macronutrients (N, P, and K) and water that were inside the hydrogel. Most importantly, the hydrogel was found to be biodegradable by using soil burial method and further confirmed by FTIR and SEM analyses. Thus, this work provides an efficient way for utilization of wastepaper in the production of a biodegradable hydrogel for agricultural applications.


Assuntos
Fertilizantes , Hidrogéis , Fertilizantes/análise , Amido
7.
Int J Biol Macromol ; 242(Pt 2): 125020, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37217054

RESUMO

The current scenario of environmental pollution caused by non-biodegradable plastic and depleting non-renewable resources has called upon the need for biodegradable bioplastic production from renewable resources. Starch bioplastics production from underutilized sources is a viable option for packaging materials that are non-toxic, environmentally benign, and easily biodegradable under disposed conditions. Pristine bioplastic production results in some undesirable qualities and hence requires further modification in order to elevate its potential applicability in real-world scenarios. In this work, yam starch was extracted from a local variety of yams through an eco-friendly and energy-efficient process which was further utilized for bioplastic production. The produced virgin bioplastic was subjected to physical modification through the introduction of plasticizers such as glycerol, while citric acid (CA) was employed as modifier in order to produce the desired starch bioplastic film. The different compositions of starch bioplastics were analyzed for their mechanical properties and maximum tensile strength of 24.60 MPa was observed as the best possible experimental result. The biodegradability feature was further highlighted through soil burial test. Apart from their general function of preservation and protection, the produced bioplastic can be employed for pH-sensitive food spoilage detection through the minute introduction of plant-derived anthocyanin extract into it. The produced pH-sensitive bioplastic film showed distinct changes in color upon an extreme change in the pH value and hence has potential to be used as a smart food packaging material.


Assuntos
Dioscorea , Amido , Animais , Amido/química , Antocianinas , Ácido Cítrico/química , Plastificantes
8.
ACS Appl Bio Mater ; 6(7): 2771-2784, 2023 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-37414749

RESUMO

The synthesis of eco-friendly and biocompatible waterborne polyurethanes (WPUs) through judicious molecular engineering with supreme mechanical strength, good shape recoverability, and high self-healing efficiency is still a formidable challenge because of some mutually exclusive conflicts among these properties. Herein, we report a facile method to develop a transparent (80.57-91.48%), self-healable (efficiency 67-76%) WPU elastomer (strain 3297-6356%) with the highest reported mechanical toughness (436.1 MJ m-3), ultrahigh fracture energy (126.54 kJ m-2), and good shape recovery (95% within 40 s at 70 °C in water). These results were accomplished by introducing high-density hindered urea-based hydrogen bonds, an asymmetric alicyclic architecture (isophorone diisocyanate-isophorone diamine), and the glycerol ester of citric acid (a bio-based internal emulsifier) into the hard domains of the WPU. Most importantly, platelet adhesion activity, lactate dehydrogenase activity, and erythrocyte or red blood corpuscle lysis demonstrated the hemocompatibility of the developed elastomer. Simultaneously, the cellular viability (live/dead) assay and the cell proliferation (Alamar blue) assay of human dermal fibroblasts corroborated the biocompatibility under in vitro conditions. Furthermore, the synthesized WPUs showed melt re-processability with retention of mechanical strength (86.94%) and microbe-assisted biodegradation. The overall results, therefore, indicate that the developed WPU elastomer might be used as a potential smart biomaterial and coating for biomedical devices.


Assuntos
Elastômeros , Poliuretanos , Humanos , Poliuretanos/química , Materiais Biocompatíveis/química , Água/química
9.
J Mater Chem B ; 11(13): 2927-2936, 2023 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-36912351

RESUMO

In recent years, polysaccharide-based hydrogels have received increased attention due to their inherent biodegradability, biocompatibility, and non-toxicity. The feasibility of using polysaccharides for the synthesis of hydrogels is dependent on their noteworthy mechanical strength and cell compatibility, which are required for practical applications, especially for biomedical uses. In this study, we demonstrate a facile synthetic route for the construction of a mechanically tough, biocompatible, and biodegradable hydrogel using polysaccharides such as starch and agar. A synthetic monomer-free hydrogel was synthesized using epichlorohydrin as a cross-linker, and a mechanical strength of 9.49 ± 1.29-6.16 ± 0.37 MPa was achieved. The introduction of agar into the hydrogel resulted in agar dose-dependent swelling-induced mechanical strength. Moreover, along with incredible mechanical strength, the hydrogel also exhibited prominent cell viability against human embryonic kidney cells. In addition, the hydrogel showed good encapsulation efficiency for antibacterial drugs like ciprofloxacin hydrochloride hydrate, with controlled releasing ability over a sustained period. The antibacterial activity of the encapsulated drug was observed against Staphylococcus aureus and Bacillus subtilis bacterial strains. Thus, the studied hydrogel with loaded drug exhibited all the required qualities to be utilized as a promising candidate in wound dressing applications.


Assuntos
Hidrogéis , Amido , Humanos , Hidrogéis/farmacologia , Ágar , Antibacterianos/farmacologia , Polissacarídeos , Bandagens
10.
RSC Adv ; 13(6): 3910-3941, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36756545

RESUMO

Sustainable development is a critical concern in this fast-paced technological world. Therefore, it is essential to employ renewable resources to move towards sustainable development goals (SDGs). The polyols attained from renewable resources, including lignin, chitosan, vegetable oils, cellulose, etc. and the polymers derived from them have attracted the attention of the majority of researchers, both in academia and industry. The development of bio-based polymers from vegetable oils start emerging with different properties to generate a value-added system. This review will give an impression to readers about how coatings generated from vegetable oils can find a way towards better protective properties against corrosion either by using fillers or by using molecular structure modifications in the system, thus covering a range of vegetable oil-based self-healing polymers and their application in anti-corrosion coatings.

11.
Int J Biol Macromol ; 237: 124206, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36990413

RESUMO

A facile one-pot approach was adopted to prepare a polysaccharide-based hydrogel of oxidized starch (OS)-chitosan. The synthetic monomer-free, eco-friendly hydrogel was prepared in an aqueous solution and employed for controlled drug release application. The starch was first oxidized under mild conditions to prepare its bialdehydic derivative. Subsequently, the amino group-containing a modified polysaccharide, "chitosan" was introduced on the backbone of OS via a dynamic Schiff-base reaction. The bio-based hydrogel was obtained via a one-pot in-situ reaction, where functionalized starch acts as a macro-cross-linker that contributes structural stability and integrity to the hydrogel. The introduction of chitosan contributes to stimuli-responsive properties and thus pH-sensitive swelling behavior was obtained. The hydrogel showed its potential as a pH-dependent controlled drug release system and a maximum of 29 h sustained release period was observed for ampicillin sodium salt drug. In vitro studies confirmed that the prepared drug-loaded hydrogels showed excellent antibacterial ability. Most importantly, the hydrogel could find potential use in the biomedical field due to its facile reaction conditions, biocompatibility along with controlled releasing ability of the encapsulated drug.


Assuntos
Quitosana , Amido , Quitosana/química , Preparações de Ação Retardada/química , Hidrogéis/química , Polissacarídeos/química , Liberação Controlada de Fármacos , Excipientes , Concentração de Íons de Hidrogênio
12.
Carbohydr Polym ; 289: 119428, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483842

RESUMO

Mechanically tough self-healing hydrogels have attracted tremendous attraction in recent years owing to their flexibility and excellent deformation-resistance. Herein, we synthesized a bio-based self-healing hydrogel by incorporating starch onto a hydrophobically associated (HA) domain. The inclusion of physically cross-linked starch onto the HA-poly(acrylamide) (PAM) chain enhanced the mechanical strength of the hydrogel and this enhancement depends on dose level of starch. The ductile and tough HA-PAM network could bear stress and recombine the damage zones within a short time, and hence exhibit noteworthy self-healing ability. Moreover, the introduction of the reversible and physically cross-linked starch network was unable to eliminate self-healing attribute of the HA-PAM network completely. Most importantly, synthesized hydrogel was dimensionally stable after swelling and exhibited noteworthy mechanical strength under such conditions. Thus, this work provides a novel starch incorporated mechanically tough, self-healing hydrogel that can hopefully enrich the current hydrogel research and expand its practical application spectrum.


Assuntos
Hidrogéis , Amido , Resinas Acrílicas , Resistência à Tração
13.
Appl Microbiol Biotechnol ; 87(6): 1983-92, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20490787

RESUMO

The present work reports the integration of polymer matrix-supported nanomaterial and enzyme biotechnology for development of industrially feasible biocatalysts. Aqueous leaf extract of Mesua ferrea L. was used to prepare silver nanoparticles distributed within a narrow size range (1-12 nm). In situ oxidative technique was used to obtain poly(ethylene glycol)-supported iron oxide nanoparticles (3-5 nm). Sonication-mediated mixing of above nanoparticles generated the immobilization system comprising of polymer-supported silver-iron oxide nanoparticles (20-30 nm). A commercially important enzyme, Aspergillus niger amyloglucosidase was coupled onto the immobilization system through sonication. The immobilization enzyme registered a multi-fold increment in the specific activity (807 U/mg) over the free counterpart (69 U/mg). Considerable initial activity of the immobilized enzyme was retained even after storing the system at room temperature as well as post-repeated magnetic recycling. Evaluation of the commendable starch saccharification rate, washing performance synergy with a panel of commercial detergents, and antibacterial potency strongly forwards the immobilized enzyme as a multi-functional industrially feasible system.


Assuntos
Aspergillus niger/enzimologia , Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Glucana 1,4-alfa-Glucosidase/química , Química Verde/métodos , Nanopartículas Metálicas/química , Polímeros/farmacologia , Aspergillus niger/química , Bactérias/efeitos dos fármacos , Biocatálise , Química Verde/instrumentação , Cinética , Magnetismo , Nanopartículas Metálicas/microbiologia , Polímeros/química
14.
Carbohydr Polym ; 242: 116320, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32564829

RESUMO

A double-network hydrophobic-hydrogel was successfully synthesized. Here epichlorohydrin (ECH) and N, N-methylene bis-acrylamide act as the crosslinkers for starch and poly(acrylic acid), respectively. The synthesized hydrogel having both positive and negative charge exhibited amphoteric properties and employed for the exclusion of anionic and cationic dyes from waste aqueous solution. The formation of positive charge occurs via reaction of triethylamine with the open up epoxy ring of ECH while carboxylate ion of poly(acrylic acid) gives the negative charge in the hydrogel. The formation of double cross-linking and the presence of quaternized alkyl chains lead towards hydrophobicity with much lower swelling ability. As an adsorbent, the hydrogel was able to remove both cationic dye (methylene blue) and anionic dye (congo red) with adsorption maxima of 133.65 mg/g and 64.73 mg/g, respectively. This study showed that the synthesized hydrogel offers enormous potential as the toxic dye adsorbent for effluent treatment of industrial wastewater.


Assuntos
Corantes/química , Hidrogéis/química , Amido/química , Adsorção , Ânions/química , Cátions/química , Corantes/isolamento & purificação , Hidrogéis/síntese química , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície , Eliminação de Resíduos Líquidos , Águas Residuárias/química
15.
Nanotechnology ; 20(22): 225107, 2009 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-19433867

RESUMO

Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 degrees C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG(6000) and 0.062:1 molar ratio of PEG to FeCl2 x 4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.


Assuntos
Enzimas Imobilizadas/química , Compostos Férricos/química , Nanopartículas/química , Peptídeo Hidrolases/química , Polietilenoglicóis/química , Animais , Bacillus subtilis/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Campos Eletromagnéticos , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Reutilização de Equipamento , Cabras , Cabelo/metabolismo , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Transmissão , Peptídeo Hidrolases/metabolismo , Análise de Regressão , Espectrofotometria Ultravioleta , Temperatura , Difração de Raios X
16.
ACS Omega ; 4(5): 9219-9227, 2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31460011

RESUMO

Anticounterfeiting materials are neo-advanced materials with utility in covert and security strategies. In this context, a photoluminescent, mechanically robust, and thermally stable hyperbranched polyurethane (PU) nanocomposite was fabricated with oxygeneous-graphitic carbon nitride nanodots. The nanocomposite was characterized using infrared, ultraviolet-visible, and photoluminescence spectroscopy, X-ray diffractometry, transmission electron microscopy, and thermogravimetric analysis. The processed nanocomposite demonstrated improved physico-mechanical stability as well as enhanced thermal stability than the pristine PU. The nanocomposite displayed remarkable photoluminescence under long ultraviolet light (365 nm), courtesy of dispersion of oxygeneous-carbon nitride nanodots in the polymer matrix, without any solid-state quenching. The nanocomposite was consequently employed as an ultraviolet light-detectable anticounterfeiting ink material having reinforcing ability.

17.
RSC Adv ; 9(36): 20829-20840, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35515558

RESUMO

Bio-resources have carved a unique niche for the ever-increasing thrust of the global scientific community to impart green credentials to various research outputs along with the demands for advanced materials. In this milieu, the authors wish to fabricate a fully bio-based waterborne polyester nanocomposite as an advanced material using different bio-based reactants and cellulose nanofibers as the nanomaterial. Three different compositions of the nanocomposite were prepared at different loadings of cellulose nanofibers (0.25, 0.5 and 1 weight%) which were isolated from waste brewed green tea leaves. The structural attributes of the nanocomposites were evaluated by Fourier transform infrared spectroscopic, X-ray diffraction, scanning electron microscopic and transmission electron microscopic studies. The nanocomposites were further cured with glycerol based epoxy and fatty acid based poly(amido amine) as the hardener to obtain the respective thermosets. The significant improvements in mechanical properties including tensile strength (13.71-22.33 MPa), elongation at break (128-290%), toughness (15.65-45.18 MJ m-3) and scratch hardness (8 to >10 kg) were observed for the thermosetting nanocomposites and the thermogravimetric analysis supports their high thermostability (234-265 °C). Further, the thermosetting nanocomposites were found to be highly biodegradable by Bacillus subtilis and Pseudomonas aeruginosa bacterial strains, hemocompatible with the erythrocytes present in RBCs and showed antioxidant properties. Thus, this nanocomposite could be used as a promising eco-friendly material for different related applications.

18.
J Colloid Interface Sci ; 540: 247-257, 2019 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30641402

RESUMO

HYPOTHESIS: Fabrication of polymeric nanocomposites with suitable nanomaterial via an in-situ polymerization approach results in multifunctional advanced materials. EXPERIMENTS: The present work demonstrates the fabrication of interpenetrating polymer network (IPN)-based smart nanocomposites of polyurethane and polystyrene (PS) with different weight percentages of multi-walled carbon nanotubes (MWCNT). The MWCNT was grafted with pre-polymer of PS. The grafted-MWCNT and the nanocomposites were analyzed by Fourier transform infrared and Raman spectroscopic, X-ray diffraction, transmission electron microscopic studies. Further, different properties of the nanocomposites were evaluated. FINDINGS: The fabricated nanocomposites showed excellent enhancement in mechanical (tensile strength: 175.9%; elongation at break: 161.9%; and toughness: 279.8%) and thermal (initial degradation temperature: 107.8%) properties compared to the pristine IPN. The improved properties are because of strong interfacial matrix-nanomaterial interactions. In addition, the nanocomposites demonstrated high water repellence (static contact angle varied from 127.9° to 143.6°), outstanding self-cleaning and anti-icing (freezing delay time of 1850-2700 s) behaviors. Most interestingly, the fabricated nanocomposites exhibited excellent self-healing ability under the exposure of microwave (within 46-22 s at 300 W power input) and sunlight (within 318-257 s, light intensity: 0.9-1.1 × 105 lux). Therefore, the studied nanocomposites hold significant potential to be used in the domains of advanced smart materials.

19.
Mater Sci Eng C Mater Biol Appl ; 105: 110055, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546416

RESUMO

Designing of mechanically tough elastomeric materials encompassed with intrinsic surface hydrophobicity, antistatic and antimicrobial attributes is in skyrocketing demands, especially to protect the instruments which are submerged in water. Herein, the authors depicted the fabrication of interpenetrating polymer network-based nanocomposites containing different doses of octadecylamine capped Cu/RGO nanohybrid. The structures and morphologies of the synthesized nanohybrid and the fabricated nanocomposites were characterized by using FTIR, XRD, XPS, TGA, FESEM and TEM analyses. Most interestingly the nanocomposites showed good hydrophobicity (static contact angle: 119.2°-129.3°), low surface resistivity (~107 Ω m) and strong antimicrobial activity towards Gram negative (Pseudomonas aeruginosa and Yersinia pestis) and Gram positive (Bacillus cereus) bacterial strains. The fabricated nanocomposites also exhibited antifungal (Candida albicans) activity. In addition, the fabricated nanocomposites showed excellent mechanical properties including high tensile strength (14.03-20.9 MPa), outstanding flexibility (1887-2470%), excellent toughness (249.89-510.1 MJ.m-3), high scratch resistance (>10 kg) and high thermostability (281-288 °C). Therefore, the fabricated nanocomposites can be used as an effective thin film for many advanced applications.


Assuntos
Aminas , Anti-Infecciosos , Substâncias Antieletricidade Estática , Bactérias/crescimento & desenvolvimento , Candida albicans/crescimento & desenvolvimento , Cobre , Grafite , Nanocompostos , Aminas/química , Aminas/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Substâncias Antieletricidade Estática/química , Substâncias Antieletricidade Estática/farmacologia , Cobre/química , Cobre/farmacologia , Grafite/química , Grafite/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Nanocompostos/química , Nanocompostos/uso terapêutico , Oxirredução
20.
ACS Omega ; 3(2): 1757-1769, 2018 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-31458492

RESUMO

Herein, we wish to report fabrication of multifaceted environmentally friendly benign renewable resource-based waterborne hyperbranched polyester nanocomposites using three different doses of carbon dot@TiO2 nanohybrid through a facile in situ polymerization technique in the absence of solvent or additional catalyst. Carbon dot@TiO2 nanohybrid was prepared through a greener one-pot hydrothermal process from bio-based raw materials. The nanocomposites were characterized by different instrumental techniques. The thermosets of these nanocomposites are obtained by curing them with glycerol-based hyperbranched epoxy and fatty acid-based poly(amido amine). Enhancements of 6.67 folds tensile strength, 3.8 folds toughness, 1.7 folds Young's modulus, >2.5 units gloss, and 46 °C thermal stability were observed for the thermosets by the formation of nanocomposites. The nanocomposites also showed antifogging and anti-icing properties. More interestingly, they can also be used for efficient separation of crude oil and water from their mixture. Thus, these environmentally benign polymeric materials could find applications in different fields.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA