Chemical Modification
Mostrando 25-36 de 712 artigos, teses e dissertações.
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25. Hybrids membranes with potential for fuel cells – Part 3: extruded films of nanocomposites based on sepiolite and PC/sulfonated PC blends
Abstract Fuel Cells based in polymers are an alternative for the conventional energetic matrices. However, materials currently available still present disadvantages to overcome. Membranes of polycarbonate (PC)/sulfonated polycarbonate (PCs) blend/sepiolite nanocomposites have previously been studied by the authors, resulting in good mechanical properties an
Polímeros. Publicado em: 21/05/2018
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26. Development of a Novel Mixed Titanium, Silver Oxide Polyacrylonitrile Nanofiber as a Superior Adsorbent and its Application for MB Removal in Wastewater Treatment
In this study, a novel electrospun nanofibrous composite was synthesized from polyacrylonitrile (PAN) and well-dispersed oxide nanoparticles containing Ti and Ag (PAN-TA). The nanoparticles incorporated into the nanofibers can endow the composite with photocatalytic and antimicrobial ability. The morphologies and structure of the nanofibers were characterize
J. Braz. Chem. Soc.. Publicado em: 2018-03
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27. Modification of palm oil crystallization by phytosterol addition as a tool for structuring a low saturated lipid blend
Abstract Fat structural modifications promoted by phytosterol addition ( a hypocholesterolemic component ( to palm oil and a mixture of palm oil and canola oilwere evaluated in order to develop fats with reduced saturated fatty acids. Palm oil added with free or esterified phytosterols was investigated in terms of triacylglycerol composition, microstructure,
Braz. J. Chem. Eng.. Publicado em: 2018-01
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28. Modification of thermal and rheological behavior of asphalt binder by the addition of an ethylene-methyl acrylate-glycidyl methacrylate terpolymer and polyphosphoric acid
Abstract This study evaluated the modification effects of adding ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMGMA) in the presence of polyphosphoric acid (PPA) to an asphalt binder graded as 50/70 (0.1mm) in the Brazilian penetration grade specification (AC 50/70). The EMGMA terpolymer has been presented as a new alternative to modify asphalt
Polímeros. Publicado em: 2017-12
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29. Cholesterol improves the transfection efficiency of polyallylamine as a non-viral gene delivery vector
ABSTRACT Cationic polymers such as polyallylamine (PAA) having primary amino groups are poor transfection agents and possess a high cytotoxicity index when used without any chemical modification. In this study, PAA was modified with cholesterol in order to improve transfection efficiency and to reduce cytotoxicity. PAA polymers with molecular weights of 15 a
Braz. J. Pharm. Sci.. Publicado em: 26/10/2017
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30. Epoxidized natural rubber and hydrotalcite compounds: rheological and thermal characterization
Abstract Epoxidized natural rubber (ENR) and synthetic non-modified hydrotalcite (HT) compounds were prepared and evaluated. Natural rubber (NR) was epoxidized with 20.6% of epoxy groups from a chemical modification of the latex. A sulfur-based curing system formulation with accelerators was used. The amounts of HT in the ENR-HT compositions was varied betwe
Polímeros. Publicado em: 21/09/2017
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31. Terpene Esters from Natural Products: Synthesis and Evaluation of Cytotoxic Activity
ABSTRACT Natural steroids and triterpenes such as b-sitosterol, stigmasterol, lupeol, ursolic and betulinic acids were transformed into its hexanoic and oleic esters, to evaluate the influence of chemical modification towards the cytotoxic activities against tumor cells. The derivatives were evaluated against five tumor cell lines [OVCAR-8 (ovarian carcinoma
An. Acad. Bras. Ciênc.. Publicado em: 14/08/2017
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32. Application of polyester derived from biomass in petroleum asphalt cement
Abstract This study evaluated the effects of the incorporation of a new additive to asphalt cement oil (CAP). A polyol product was obtained through the oxypropylation reaction of sugarcane bagasse. This polyol was polymerised with pyromellitic anhydride in order to obtain a polyester (BCP) to test its suitability in terms of the material properties to be app
Polímeros. Publicado em: 29/06/2017
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33. Effect of the modification by titanium dioxide nanotubes with different structures on the fatigue response of Ti grade 2
Nanotechnology is seeing as having potential to raise benefits to several research and application areas. Recently materials with nanostructured surfaces of nanopores, nanotubes and nanowires have become an important investigation field, since their chemical and physical properties may be substantially different from those of the corresponding substrate. In
Mat. Res.. Publicado em: 18/05/2017
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34. Evaluation of disposable medical device packaging materials under ozone sterilization
Abstract Introduction Ozonization is an alternative sterilization process for heat-sensitive medical devices. However, the side effects of this process on packaging materials should be verified. Methods Four types of commercial disposable packaging for medical devices were evaluated after undergoing ozone sterilization: crepe paper sheet, non-woven fabric
Res. Biomed. Eng.. Publicado em: 2017-03
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35. Utilization of banana stalk fiber as reinforcement in low density polyethylene composite
ABSTRACT Natural fibers could serve as viable and abundant alternatives to the expensive and non - renewable synthetic fibers as reinforcement in thermoplastic composites. The potentiality of banana stalk fiber at reinforcing a low density polyethylene matrix was examined in this study. Fibers were extracted from the stalk of banana plant and characterized f
Matéria (Rio J.). Publicado em: 2016-12
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36. Manufacture of nanosized apatite coatings on titanium with different surface treatments using a supersaturated calcification solution
The biomimetic method is used for the deposition of calcium phosphate coatings (Ca - P) on the surface of different biomaterials. However, the application of this method requires long exposure times in order to obtain a suitable layer thickness for its use in medical devices. In this paper, we present a fast approach to obtain apatite coatings on titanium, u
Quím. Nova. Publicado em: 2016-12