scholarly journals Thermal, Mechanical and Chemical Analysis of Poly(vinyl alcohol) Multifilament and Braided Yarns

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3644
Author(s):  
Tania F. Freire ◽  
Tiago Quinaz ◽  
Aureliano Fertuzinhos ◽  
Nguyễn T. Quyền ◽  
Marcelo F. S. M. de de Moura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Static Loading ◽  
Vinyl Alcohol ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Poly Vinyl Alcohol ◽  
Creep Tests ◽  
Storage And Loss Moduli ◽  
Thermomechanical Behaviour ◽  
Scanning Electron

Poly(vinyl alcohol) (PVA) in multifilament and braided yarns (BY) forms presents great potential for the design of numerous applications. However, such solutions fail to accomplish their requirements if the chemical and thermomechanical behaviour is not sufficiently known. Hence, a comprehensive characterisation of PVA multifilament and three BY architectures (6, 8, and 10 yarns) was performed involving the application of several techniques to evaluate the morphological, chemical, thermal, and mechanical features of those structures. Scanning electron microscopy (SEM) was used to reveal structural and morphological information. Differential thermal analysis (DTA) pointed out the glass transition temperature of PVA at 76 °C and the corresponding crystalline melting point at 210 °C. PVA BY exhibited higher tensile strength under monotonic quasi-static loading in comparison to their multifilament forms. Creep tests demonstrated that 6BY structures present the most deformable behaviour, while 8BY structures are the least deformable. Relaxation tests showed that 8BY architecture presents a more expressive variation of tensile stress, while 10BY offered the least. Dynamic mechanical analysis (DMA) revealed storage and loss moduli curves with similar transition peaks for the tested structures, except for the 10BY. Storage modulus is always four to six times higher than the loss modulus.

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.

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.

Electrospun Antibacterial Chitosan/Poly (Vinyl Alcohol) Nanofibers Containing Silver Nanoparticles

2010 ◽  
Vol 152-153 ◽  
pp. 1333-1336 ◽  
Author(s):  
Xu Pin Zhuang ◽  
Zheng Li ◽  
Wei Min Kang ◽  
Bo Wen Cheng
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Electrospun Fibers ◽  
X Ray ◽  
High Antibacterial Activity ◽  
Transmission Electron ◽  
Scanning Electron

New chitosan/poly (vinyl alcohol) (PVA) nanofibers functionalized with silver nanoparticles were electrospun using solutions of PVA blended with silver nanoparticles-chitosan composites. The structure of the electrospun fibers were studied with the aid of scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results indicated that the electrospun fibers smoothly with 220 to 650 nm diameter, and the silver nanoparticles were successfully embed into the fibers which show high antibacterial activity against E.coli.

Synthesis, Preparation and Characterization of Amine-Induced Bacterial Cellulose-Poly(Vinyl Alcohol) Semi-Interpenetrating Network Hydrogel

2020 ◽  
Vol 841 ◽  
pp. 238-242
Author(s):  
Joachim Emeka Arikibe ◽  
Roselyn Lata ◽  
David Rohindra
Keyword(s):  
Electron Microscopy ◽  
Bacterial Cellulose ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Gluconacetobacter Xylinus ◽  
Interpenetrating Network ◽  
Equilibrium Water Content ◽  
Network Chain ◽  
Scanning Electron

Bacterial cellulose (BC) was synthesized using Gluconacetobacter xylinus (BCRC 14182). Synthesized BC was powdered and dissolved in Bis(ethylenediamine) copper (II) hydroxide (Cuen) solution to introduce the amine (NH2) group onto the BC network to yield modified BC (mBC) which was then blended with poly (vinyl alcohol) (PVA) and subsequently crosslinked with genipin (Gp). Pristine, modified and crosslinked hydrogels were studied using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and swelling behavior in water. FTIR revealed a distortion on the BC network chain via a reduction in the absorption of OH peak of mBC and the emergence of peaks at 1587 and 1560 cm-1 attributed to N-H stretching of the induced NH2 group. SEM confirmed the 3-D fibril and porous structure of BC which became distorted after modification and crosslinking. The hydrogels showed equilibrium water content of 86.5%, 67.5%, 66.7% and 33.0 % for BC, PVA, mBC-PVA and mBC-PVA-Gp, respectively. The decreased swelling in mBC-PVA-Gp indicated that genipin was able to crosslink the modified BC.

Study on Biomineralization of Poly (Vinyl Alcohol) Film via a Biomimetic Process

2009 ◽  
Vol 610-613 ◽  
pp. 1090-1095
Author(s):  
Yue Wen Guo ◽  
Ling Li Li ◽  
Guang Li ◽  
Jian Ming Jiang
Keyword(s):  
Electron Microscopy ◽  
Tissue Regeneration ◽  
Vinyl Alcohol ◽  
Bone Substitute ◽  
Bone Tissue Regeneration ◽  
Organic Polymer ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Organic polymer–hydroxyapatite (HA) hybrid was expected as a promising bone substitute. In this work, poly(vinyl alcohol) (PVA) was used as a polymer substrate and the PVA-HA hybrid was prepared by a biomimetic process. The resultant PVA-HA composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. It was found that HA could deposite on PVA surface when PVA soaked in water for a little swelling and then was carried out CaP treatment previously. The formed HA showed bone-like structure and had a good interaction with PVA substrate. The resultant hybrid might exhibit good osteoconductivity and biocompatibility, and could be expected as a useful scaffold for bone tissue regeneration.

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.

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.

Poly(vinyl Alcohol)/Cellulose Nanocomposite Pervaporation Membranes for Ethanol Dehydration

2011 ◽  
Vol 675-677 ◽  
pp. 383-386 ◽  
Author(s):  
Lu Bai ◽  
Ping Qu ◽  
Shuai Li ◽  
Yuan Gao ◽  
Li Ping Zhang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Cellulose Nanocrystals ◽  
Vinyl Alcohol ◽  
Model System ◽  
Poly Vinyl Alcohol ◽  
Permeation Flux ◽  
Water Mixture ◽  
Ethanol Dehydration ◽  
Scanning Electron

In this study, pervaporation membranes were prepared from poly( vinyl alcohol) (PVA) with different amounts of cellulose nanocrystals as filler, and characterized by scanning electron microscopy (SEM). The characterization results demonstrated that cellulose nanocrystal particles dispersed homogeneously within the PVA matrix. Moreover, the pervaporation performance of these membranes was investigated using the separation of ethanol-water mixture as model system. Among all the prepared membranes, PVA/cellulose nanocomposite membrane containing 1 wt% cellulose nanocrystals exhibited the best pervaporation performance, whose averaged permeation flux reduced slightly but separation factor was increased from 83 to 163 for 80% aqueous solution of ethanol at 80 °C respectively.

Development of Poly(Vinyl Alcohol)-Collagen-Hydroxyapatite Nanohybrids for Tissue Grafting

2007 ◽  
Vol 330-332 ◽  
pp. 329-332 ◽  
Author(s):  
Xiao Min Wang ◽  
Xu Dong Li ◽  
Gui Qiu Zheng ◽  
Xiao Liang Wang ◽  
Xing Dong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vinyl Alcohol ◽  
In Situ Synthesis ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infra Red ◽  
Physical Crosslinking ◽  
Scanning Electron

Poly(vinyl alcohol) (PVA) was introduced during in situ synthesis of hydroxyapatite (HA) in neutral collagen (COL) solution and final PVA-COL-HA nanohybrids were achieved via sequential steps including gelation by fibrillogenesis, freezing-thawing physical crosslinking, removal of unreacted residues and dehydration. This method is expected to endow the pure PVA with good bioactivity and meanwhile the presence of elastic PVA would improve the properties of COL-HA composites. The phase, microstructure and possible molecular interactions of the achieved PVA-COL-HA nanohybrids were analyzed by using X-ray diffraction, Fourier transform infra-red spectroscopy and scanning electron microscopy. The results indicate that the inorganic phase is poorly crystallized apatite with a nanometer size due to the confinement of organic macromolecules which forms a network structure.

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