Search

Your search keyword '"Hydrophobic"' showing total 5 results
Start Over Descriptor "Hydrophobic" Language portuguese
5 results on '"Hydrophobic"'

1. COMPÓSITOS DE PEAD/SÍLICA - PARTE I: PREPARAÇÃO E CARACTERIZAÇÃO DE SÍLICAS ORGANOFUNCIONALIZADAS COM GRUPOS METILSILANO E OCTILSILANO.

Author

Babinski RAMOS, Vanessa Machado, Gammertt RÖHNELT, Maurício, and BRAMBILLA, Rodrigo

Subjects
*HYDROPHOBIC surfaces, *SILANE, *SILICA gel, *SCANNING electron microscopy, *THERMAL stability, *PARTICLES, *SILICA
Abstract

This paper reports the main results concerning the synthesis and characterization of methylsilane and octylsilane-modified silicas. The modification of the silicas with these groups aims to make the silica surface hydrophobic and thus compatible with high-density polyethylene (HDPE) in HDPE/silica composites. In the present work, two types of silica were organofunctionalized: a pyrogenic silica and a silica gel. The silicas were characterized by a series of complementary techniques with the objective of investigating the nature of the surface species and their textural and morphological characteristics. The SEM images showed that the modification of the silicas with organosilanes has been not resulted in changes on the morphology and on the size of silica particles. In relation to the texture properties, determined by N2 adsorption-desorption porosimetry, the silica modification resulted in a decrease of the specific area (SBET) and the mean pore volume, a behavior attributed to the partial coverage of the adsorption sites by the organosilane molecules. The TGA analysis showed that both the methylsilane groups and the octylsilane groups on the surface of silica and silica gel are thermally stable up to 200 ° C, which enables the organofunctionalized silicas in terms of thermal stability, for the process of preparing the composites by extrusion. The results of applying these organofunctionalized silicas in the development of HDPE/silica composites will be presented in a subsequent article, part II of this research. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

2. Studies on Anionic Surfactant Structure in the Aggregation with (Hydroxypropyl)cellulose

Author

Ricardo M. de Martins, Carolina A. Silva, Cristiane Becker, Dimitrios Samios, Clara I. D. Bica, and Marcelo Christoff

Subjects
Aggregate, bile salt, hydrophobic, (hydroxypropyl) cellulose, fluorescence, light scattering, viscosity, Chemical technology, TP1-1185
Abstract

Fluorescence probing, viscosity and light scattering measurements have been combined to study the aggregation of different anionic surfactants mainly in dilute solutions (0.5% w/v) of (hydroxypropyl)cellulose (HPC MW 173,000), in moderate ionic strength (NaCl 0.1 mol.L-1). The set of surfactants includes natural cholesterol derivatives, sodium cholate (CS) and sodium deoxycholate (DC), and the alkylsulphate, sodium dodecylsulphate (SDS). At 298 K the critical surfactant concentration related to aggregate/HPC formation (C1) decreases for SDS and DC whereas it increases slightly for CS. At 312 K the C1 values for CS and DC are slightly shifted toward higher values whereas it is not changed for SDS. All surfactant/HPC systems increase C1 values as the HPC concentration increases to 1.2%. Above C1 the viscosity increases for all surfactant/HPC systems but it is sharper in the increasing order CS, DC and SDS. The hydrodynamic behavior indicates that CS induces higher diffusion to HPC than SDS and DC. The aggregation in the surfactant/HPC systems is analyzed through the feature of surfactant/aggregate structure (size, charge density, etc).

Published
2002
Full Text
View/download PDF

3. Plasma treatments for surface modification of conventional polymers and plasma-deposited polymers

Author

Amorim, Milena Kowalczuk Manosso, Universidade Estadual Paulista (Unesp), and Durrant, Steven Frederick [UNESP]

Subjects
Polímeros, Hidrofóbica, Polymers, Filmes finos, Thin films, Plasma treatment, Tratamento a plasma, Hydrophobic
Abstract

Submitted by Milena Kowalczuk Manosso Amorim (milenamanosso@gmail.com) on 2018-09-10T23:00:08Z No. of bitstreams: 1 versão repositorio 10-09.pdf: 2679208 bytes, checksum: 1f7039ea349763e1a7142ce20ee9a3de (MD5) Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2018-09-11T16:47:09Z (GMT) No. of bitstreams: 1 amorim_mkm_me_bauru.pdf: 2679208 bytes, checksum: 1f7039ea349763e1a7142ce20ee9a3de (MD5) Made available in DSpace on 2018-09-11T16:47:09Z (GMT). No. of bitstreams: 1 amorim_mkm_me_bauru.pdf: 2679208 bytes, checksum: 1f7039ea349763e1a7142ce20ee9a3de (MD5) Previous issue date: 2018-07-27 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Este trabalho investiga os efeitos de tratamento a plasma frio em polímeros convencionais, polipropileno e poliestireno, e em filme amorfo do tipo a-C-H, produzido através de Deposição Química de Vapor Assistida por Plasma (PECVD). Após etapas preliminares de escolha de gás e tempo a serem utilizados, as amostras foram tratadas em plasma de hexafluoreto de enxofre (SF6) em cinco diferentes potências e cinco diferentes pressões, totalizando 25 condições para cada substrato. As superfícies foram caracterizadas por goniometria, perfilometria, Espectroscopia de Infravermelho com Transformada de Fourier (FTIR), Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Raios-X por Energia Dispersiva (EDS) e Espectroscopia de Fotoelétrons Excitados por Raios-X (XPS). Assim, foram examinados ângulo de contato, rugosidade, estrutura química, morfologia, composição química e composição química da superfície, respectivamente. O tratamento com SF6 aumenta a característica hidrofóbica dos três materiais, possivelmente devido à incorporação de flúor nas superfícies. A combinação de potência e pressão que promoveu aumento mais significativo em ϴ variou para cada material: 80 W e 80 mTorr para o filme amorfo, aumentando de 60,6° para 111,1° nestas condições, 20 W e 40 mTorr para o polipropileno, aumentando de 81,8° para 119° e 100 W e 60 mTorr para o poliestireno, aumentando de 74° para 95°. As análises por XPS indicaram a presença de flúor após os tratamentos com plasmas de SF6, mostrando um aumento da razão F/C de 0 para todas as amostras não tratadas para 0,03 para o filme amorfo tratado, 0,14 para o polipropileno tratado, e 0,60 para o poliestireno tratado. The present work investigates the effects of plasma treatment on conventional polymers, polypropylene and polystyrene, and on amorphous hydrogenated carbon, a-C-H, obtained by Plasma Enhanced Chemical Vapour Deposition, (PECVD). After preliminary studies to establish the plasma gas and treatment times, samples were treated in sulphur hexafluoride (SF6) plasmas at five different powers and five different pressures. Surfaces were characterized by goniometry, profilometry, Fourier Transform Infrared Spectrometry, Scanning Electron Microscopy (SEM), EnergyDispersive X-ray Spectroscopy (EDS) and X-Ray Photoelectron Spectroscopy (XPS). Thus, contact angle, roughness, chemical structure, morphology, chemical composition and surface chemical composition were examined. Results show that SF6 treatments increase the hydrophobicity of the three substrates, possibly due to the surface incorporation of fluorine. The power and pressure combinations that caused the greatest improvements in ϴ were as follows: 80 W and 80 mTorr for the amorphous film, resulting in an increase from 60.6° to 111.11°; 20 W and 40 mTorr for polypropylene, resulting in an increase from 81,8° to 119°; 100 W and 60 mTorr for polystyrene, resulting in an increase from 74° to 95°. The presence of fluorine following the SF6 plasma treatments was confirmed by the XPS analyses, which showed that F/C increased from 0 for all the untreated samples to 0,03 on treated amorphous films, to 0,14 on treated polypropylene, and to 0,60 on treated polystyrene.

Published
2018

4. A eficácia de produtos hidrofóbicos aplicados em tecidos 90% poliéster 10% elastano estampados

Author

Luis Fernando Folle and Vanessa Lorscheiter

Subjects
010302 applied physics, Tecnologia Aplicada ao Design, Textile, General Physics and Astronomy, 02 engineering and technology, General Chemistry, Thermal comfort, 021001 nanoscience & nanotechnology, Hydrophobic, 01 natural sciences, Conforto Térmico, Hidrofóbico, Applied Technology to Design, 0103 physical sciences, Têxtil, Design Research, General Materials Science, 0210 nano-technology, Pesquisa em Design
Abstract

RESUMO Os avanços industriais para o setor de vestuário, ligam os desejos e as necessidades dos usuários a soluções relacionadas a aspectos da moda, da tecnologia e do conforto dos tecidos. Com o objetivo de contribuir para o desenvolvimento de processos de inovação por meio do design, o presente estudo analisa a eficácia de dois produtos hidrofóbicos de empresas do Rio Grande do Sul, o produto 1495 da Claritex e o produto 1003 da Corium. Estes produtos foram aplicados nos tecidos Dress e Sublime, ambos com 90% poliéster 10% elastano e estampados por sublimação, da empresa têxtil Santaconstancia, São Paulo. Busca-se avaliar se os tecidos perdem as propriedades hidrofóbicas após várias lavagens e se mantêm sua permeabilidade ao vapor de água, a qual contribui ao conforto térmico. Foram analisados, o processo de lavagem doméstica, os ensaios de permeabilidade ao vapor de água e o ângulo de contato da gota. Os resultados mostraram que os dois produtos hidrofóbicos analisados são eficazes, mas o produto 1003 obteve a maior média do ângulo de contato da gota após 20 lavagens. Outro resultado obtido foi que os tecidos analisados não sofreram mudanças significativas nos valores de permeabilidade ao vapor de água quando comparados aos tecidos crus, sem aplicação de estampa e sem o produto hidrofóbico. ABSTRACT Industrial breakthroughs for the clothing sector connect the consumers' desires and needs to solutions related to fashion and technology aspects, and the comfort of the fabrics. In order to contribute to the development of innovation processes through design, this study examines the effectiveness of two hydrophobic products from Rio Grande do Sul companies: the product 1495, from Claritex, and the product 1003 from Corium. These products were applied to the fabrics Dress and Sublime, both with 90% polyester, and 10% elastane, and printed by sublimation, from the textile company Santaconstancia. The objective is to evaluate if the fabrics lose their hydrophobic properties after multiple washings, and if they maintain their permeability to water steam, which contributes to thermal comfort. It was analyzed assays with resistance to domestic laundering, the water steam permeability and the contact angle from the drop of water. The results showed that both hydrophobic products analyzed are effective, but the product 1003 had the highest average of contact angle from the drop of water after 20 washes. Another result is that the fabrics analyzed haven't suffered significant changes in the permeability to the water steam values when they compared to fabrics without application of print and the hydrophobic product.

Published
2017

5. Otimização da Hidrofugação do Couro Wetwhite

Author

Carvalho, Mayerlys Maria Ascanio Moncada, Pinto, Gilberto António, Ribeiro, António Alfredo Crispim, and Silva, Vânia da

Subjects
Leather, Hidrofugação, Waterproofing, Re-tanning, Otimização Energética na Indústria Química, Whet-white, Hydrophobic, Hidrofóbico, Couro, Recurtume
Abstract

Submitted by Ana Rebelo (amsr@isep.ipp.pt) on 2016-02-04T14:47:00Z No. of bitstreams: 1 DM_MayerlysCarvalho_2013_MEQ.pdf: 4321980 bytes, checksum: 26893fdd9ecb1fbf575d00e1f152e6db (MD5) Approved for entry into archive by Ana Rebelo (amsr@isep.ipp.pt) on 2016-02-04T14:48:07Z (GMT) No. of bitstreams: 1 DM_MayerlysCarvalho_2013_MEQ.pdf: 4321980 bytes, checksum: 26893fdd9ecb1fbf575d00e1f152e6db (MD5) Made available in DSpace on 2016-02-04T14:48:07Z (GMT). No. of bitstreams: 1 DM_MayerlysCarvalho_2013_MEQ.pdf: 4321980 bytes, checksum: 26893fdd9ecb1fbf575d00e1f152e6db (MD5) Previous issue date: 2013

Published
2013

Catalog

Books, media, physical & digital resources
See catalog results