Changes Induced by PVA in the Cement Microstructure Surrounding Aggregate

1994 ◽  
Vol 370 ◽  
Author(s):  
Un-Jen Chu ◽  
Jae-Ho Kim ◽  
Cheol Park ◽  
Richard E. Robertson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Cement Paste ◽  
Vinyl Alcohol ◽  
Secondary Electron ◽  
Poly Vinyl Alcohol ◽  
Backscattered Electron ◽  
And Behavior ◽  
Scanning Electron

AbstractThe presence of poly(vinyl alcohol) (PVA) in portland cement during its hydration was found to induce changes in the microstructure and behavior of the paste that forms around aggregate. The microstructure was studied with scanning electron microscopy in secondary electron, backscattered electron, and EDX mapping modes and with Fourier-transform infraredspectroscopy. The adhesion between cement paste and aggregate was examined with planar aggregate surfaces. With concentrations of the order of 1% by weight of PVA based onthe weight of the cement, the deposition of calcium hydroxide on the aggregate surface was found to be diminished and the porous layer that usually surrounds the aggregate to be reduced in thickness. Also, the bond between the aggregate and cement paste was increasedenough for the bond to approach the strength of the cement.

Radiation – induced preparation of polyaniline/poly vinyl alcohol nanocomposites and their properties

2019 ◽  
Vol 107 (8) ◽  
pp. 725-735
Author(s):  
Hoda H. Saleh ◽  
Rehab Sokary ◽  
Zakaria I. Ali
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Vinyl Alcohol ◽  
Oxidative Polymerization ◽  
Nanocomposite Films ◽  
Poly Vinyl Alcohol ◽  
Transmission Electron ◽  
Scanning Electron

Abstract Polyaniline (PANI) nanoparticles and PANI/poly vinyl alcohol (PVA) nanocomposite films were synthesized by the oxidative polymerization of aniline and ammonium peroxodisulfate (APS), as an oxidizing agent in aqueous medium. The PANI/PVA nanocomposite films were exposed to γ-irradiation after oxidative polymerization. Synthesized polyaniline (PANI) nanoparticles and PANI/PVA nanocomposite films were characterized by attenuated total reflectance infrared spectroscopy (FTIR-ATR), X-ray diffraction, high resolution scanning electron microscopy, (HRSEM) high resolution transmission electron microscopy, (HRTEM) and UV-VIS absorption spectroscopy. Energy band gap of PANI nanofibers was determined from Tauc’s plots which equal 4.2 eV. Scanning electron microscopy images show that chemically synthesized of polyaniline has nanofibers structure and irradiated PANI/PVA nanocomposite have a mixture of nanorod and nanosphere structures. The transmission electron microscopy show that chemically synthesized of polyaniline has average length in the range 34 ± 10 nm with less wide distribution, where as the irradiated PANI/PVA nanocomposite has coreshell structure.

Characterization of Glue Sizing Layers in Portuguese Wood Paintings from the 15th and 16th Centuries by SEM Secondary Electron Images and μ-FTIR

2013 ◽  
Vol 20 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Vanessa Antunes ◽  
Maria J.Oliveira ◽  
Helena Vargas ◽  
António Candeias ◽  
Ana Seruya ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Secondary Electron ◽  
16Th Century ◽  
Animal Glue ◽  
Precise Characterization ◽  
The Stability ◽  
Scanning Electron

AbstractAccording to treatises on 15th and 16th century paintings, artists dedicated particular attention to the sizing layer—consisting mainly of animal glue applied onto the wood support before further application of the ground layer. The stability of a painting mainly depends on the presence of a very cohesive sizing layer. However, the study of these layers has not received special attention from researchers. In this article we present a methodology for characterization of the sizing layer both chemically, by IR spectroscopy (Fourier transform infrared spectroscopy), and morphologically, by scanning electron microscopy (SEM). Secondary electron images obtained by SEM allow precise characterization of such layers. Painting reconstructions were used as references in development of the method to study the sizing layer in real painting samples. Presented herein are examples of this study on 15th and 16th century Portuguese paintings, particularly on the Triptych of S. Simão, from the Aveiro Museum, and S. Pedro, belonging to the Mercy of Tavira.

Modification and characterization of polysulfone films by ionizing radiation (gamma-rays) with enhanced hydrophilicity

MRS Advances ◽  
2018 ◽  
Vol 3 (63) ◽  
pp. 3833-3837
Author(s):  
Israel Fredy Sánchez-Salinas ◽  
Javier Illescas ◽  
Claudia Rosario Muro-Urista ◽  
Guillermina Burillo ◽  
María del Carmen Díaz Nava
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Reaction Time ◽  
Gamma Rays ◽  
Poly Vinyl Alcohol ◽  
Scanning Electron

AbstractPolysulfone (Pfu) films were modified by grafting poly(vinyl alcohol) (PVA) by the oxidative pre-irradiation technique. To achieve this modification, some parameters were modified such as the radiation dose, the concentration of PVA, the temperature and the reaction time. It was found that the grafted films with 12% presented a greater grafting percentage (0.86%). The modified films were characterized by means of the contact angle, Fourier transform infrared spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM) techniques.

Effect of Poly(vinyl alcohol)/Chitosan Ratio on Electrospun-Nanofiber Morphologies

2012 ◽  
Vol 463-464 ◽  
pp. 734-738 ◽  
Author(s):  
Tongsai Jamnongkan ◽  
Amnuay Wattanakornsiri ◽  
P. Pungboon Pansila ◽  
Claudio Migliaresi ◽  
Supranee Kaewpirom
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Vinyl Alcohol ◽  
Weight Ratio ◽  
Electrospun Nanofibers ◽  
Poly Vinyl Alcohol ◽  
Electrospun Nanofiber ◽  
Electrospinning Method ◽  
Chitosan Content ◽  
Scanning Electron

Series of poly (vinyl alcohol)/chitosan (PVA/CS) electrospun nanofibers with different weight ratio of PVA and CS were fabricated by electrospinning method. The surface morphology, diameter, and structure of electrospun nanofibers were investigated by scanning electron microscopy (SEM). As a result of PVA and CS composition measurements, the electrospun nanofibers morphologies were mainly affected by weight ratio of the polymer solution. When increasing the chitosan content in the blend solution, the electrospun nanofibers could hardly form. This result indicates that the electrospun nanofiber formation is enhanced by chitosan content.

Effect of Ultrasonic Vibration on Electrospun Poly(vinyl Alcohol) (PVA) Nanofibers

2013 ◽  
Vol 843 ◽  
pp. 1-8 ◽  
Author(s):  
Na Si ◽  
Lan Xu ◽  
Mei Zhen Wang ◽  
Fu Juan Liu
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Ultrasonic Vibration ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
The Novel ◽  
Novel Strategy ◽  
Radiation Time ◽  
Scanning Electron

Poly (vinyl alcohol) (PVA), a classical biodegradable polymer, is successfully fabricated into nanofibers via the vibration-electrospinning, and the obtained nanofibers are characterized by the scanning electron microscopy (SEM). The viscosity and electrical conductivity of PVA solution vary dramatically with the ultrasonic radiation time and intensity. The novel strategy can produce finer nanofibers than those obtained without ultrasonic vibration.

Removed at authors request.

2014 ◽  
Vol 575 ◽  
pp. 191-194
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Energy Dispersive Spectroscopy ◽  
Vinyl Alcohol ◽  
Mixed Matrix Membranes ◽  
Poly Vinyl Alcohol ◽  
Separation Performance ◽  
Mixed Matrix ◽  
Scanning Electron

In the present study, single-walled nanotubes-poly (vinyl alcohol) (SWNT-PVA) mixed-matrix-membranes (MMMs) are prepared and carefully characterized via various solid-state techniques, including scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). We investigate how the separation performance of SWNT-PVA MMM in an ethanol-water pervaporation system is improved with the loading of SWNTs in the membranes.

scholarly journals STUDI SCANNING ELECTRON MICROSCOPY (SEM) UNTUK KARAKTERISASI PROSES OXIDASI PADUAN ZIRKONIUM

2017 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Agus Sujatno ◽  
Rohmad Salam ◽  
Bandriyana Bandriyana ◽  
Arbi Dimyati
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Secondary Electron ◽  
Energy Dispersive ◽  
X Ray ◽  
Backscattered Electron ◽  
Scanning Electron

STUDI SCANNING ELEKTRON MICROSCOPY (SEM) UNTUK KARAKTERISASI PROSES OXIDASI PADUAN ZIRKONIUM. Studi analisis Scanning Electron Microscopy (SEM) telah dilakukan untuk mengkarakterisasi struktur mikro dan lapisan oksida paduan zirkonium, bahan yang prospektif digunakan sebagai material kelongsong bahan bakar reaktor nuklir generasi ke IV dan struktur reaktor fusi modern. Tujuan penelitian adalah guna mendapatkan informasi yang detil dan akurat yang diperlukan untuk mendukung analisis ketahanan korosi paduan zirkonium yang disebabkan oleh proses oksidasi suhu tinggi dengan menggunakan berbagai metode analisis pada SEM. Sampel uji yang digunakan adalah ingot paduan zirkonium ZrNbMoGe setelah tes oksidasi dalam Mass Suspension Balance (MSB) pada temperatur 500 dan 700 oC masing-masing selama 5 jam. Komposisi unsur dalam sampel paduan adalah 96,9 %Zr, 2,5 %Nb, 0,5 %Mo dan 0,1 %Ge. Pengujian SEM dilakukan dengan JEOL JSM-6510LA yang dilengkapi dengan perangkat Energy Dispersive X-Ray Spectroscopy (EDS) untuk analisis komposisi kimia. Metode Secondary Electron (SE) dan Backscattered Electron (BSE) dengan opsi Low-Vacuum dilakukan untuk mendapatkan kontras yang optimal. Hasil analisa menunjukan bahwa pada kedua sampel telah tumbuh lapisan oksida berupa ZrO2 dengan ketebalan maksimal 2.4 dan 3.5 mm untuk masing-masing temperatur 500 dan 700 oC. Gambar BSE telah menunjukan batas lapisan dengan jelas, tidak memberikan ruang untuk interpretasi ganda.

Sign in / Sign up

Export Citation Format

Share Document