scholarly journals Changing Compliance of Poly(Vinyl Alcohol) Tubular Scaffold for Vascular Graft Applications Through Modifying Interlayer Adhesion and Crosslinking Density

2021 ◽  
Vol 7 ◽  
Author(s):  
YeJin Jeong ◽  
Yuan Yao ◽  
Tizazu H. Mekonnen ◽  
Evelyn K. F. Yim
Keyword(s):  
Mechanical Properties ◽  
Wall Thickness ◽  
Vinyl Alcohol ◽  
Vascular Graft ◽  
Small Diameter ◽  
Crosslinking Density ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Water Soluble Polymer ◽  
Physical Crosslinking

Poly(vinyl alcohol) (PVA) is a water-soluble polymer and forms a hydrogel that has been studied as a potential small-diameter (<6 mm) vascular graft implant. The PVA hydrogel crosslinked using sodium trimetaphosphate (STMP) has been shown to have many beneficial properties such as bioinert, low-thrombogenicity, and easy surface modification. Compared to conventional synthetic vascular graft materials, PVA has also shown to possess better mechanical properties; however, the compliance and other mechanical properties of PVA grafts are yet to be optimized to be comparable with native blood vessels. Mechanical compliance has been an important parameter to be studied for small-diameter vascular grafts, as compliance has been proposed to play an important role in intimal hyperplasia formation. PVA grafts are made using dip-casting a cylindrical mold into crosslinking solution. The number of dipping can be used to control the wall thickness of the resulting PVA grafts. In this study, we hypothesized that the number of dip layers, chemical and physical crosslinking, and interlayer adhesion strength could be important parameters in the fabrication process that would affect compliance. This work provides the relationship between the wall thickness, burst pressure, and compliance of PVA. Furthermore, our data showed that interlayer adhesion as well as chemical and physical crosslinking density can increase the compliance of PVA grafts.

scholarly journals Reconstruction of Fibroin Nanofibers (FNFs) via Electrospinning: Fabrication of Poly(vinyl alcohol)/FNFs Composite Nanofibers from Aqueous Solution

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 43
Author(s):  
Shohei Fujita ◽  
Huaizhong Xu ◽  
Yubing Dong ◽  
Yoko Okahisa
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Thermal Properties ◽  
Fiber Orientation ◽  
Vinyl Alcohol ◽  
Composite Nanofibers ◽  
Water Soluble ◽  
Phase Image ◽  
Poly Vinyl Alcohol ◽  
Water Soluble Polymer

Fibroin nanofibers (FNFs) achieved from physical treated silk can keep its original crystal structure, showing excellent mechanical properties, however, processing the FNFs into fibers is still a challenge. Herein, a brand-new environmentally friendly approach is proposed to manufacture FNFs-based composite nanofibers. The water-soluble polymer, poly(vinyl alcohol) PVA, was applied to increase the viscoelasticity of the spinning dope, and the content of FNFs can reach up to 20 wt%. The established phase image of spinning suggested that the concentrations ranging from 6 wt% to 8 wt% are premium to achieving relatively homogenous FNFs/PVA nanofibers. Random fibers were deposited on a fixed collector, while the fiber orientation intensity increased with the rotational speed of drum and started decreasing after 12 m/s. The mechanical properties of the composite nanofibers showed the similar tendency of variation of fiber orientation. In addition, chemical changes, crystallinity, and thermal properties of the composite nanofibers were further clarified by means of FTIR, DSC, and TG. As a result, high FNFs contained nanofibers with excellent thermal properties were created from an aqueous solution. This study is the first original work to realize the spinnability of FNFs, which provides a new insight of the FNFs.

scholarly journals Self-Healing Polymer-Clay Hybrids by Facile Complexation of a Waterborne Polymer with a Clay

2021 ◽  
Author(s):  
Aranee Pleng Teepakakorn ◽  
Makoto Ogawa
Keyword(s):  
Vinyl Alcohol ◽  
Aqueous Media ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Self Healing ◽  
Soluble Polymer ◽  
Water Soluble Polymer ◽  
Smectite Clay

Water-induced self-healing materials were prepared by the hybridization of a water-soluble polymer, poly(vinyl alcohol), with a smectite clay by mixing in an aqueous media and subsequent casting. Without using chemical...

Rheological properties of pectin, poly(vinyl alcohol) and their blends in aqueous solutions

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Katarzyna Lewandowska ◽  
Aldona Dąbrowska ◽  
Halina Kaczmarek
Keyword(s):  
Aqueous Solutions ◽  
Rheological Properties ◽  
Vinyl Alcohol ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Concentric Cylinder ◽  
Water Soluble Polymer ◽  
Flow Measurements ◽  
Result Show ◽  
Different Temperatures

AbstractThe new blends composed of natural polysaccharide - pectin and synthetic water soluble polymer - poly(vinyl alcohol) (PVA) are attractive materials due to their biocompatibility, non-toxicity and biodegradability. In this work the rheological properties of aqueous solutions of pectin (PEC), poly(vinyl alcohol) and their mixtures at various weight ratios (70/30, 50/50, 30/70) have been investigated. Flow measurements were carried out using a rotary viscometer with concentric cylinder at different temperatures (20-70 ºC) and shear rates (24- 1234 s-1). The flow parameters and energy of activation have been calculated from the flow curves and Arrhenius plots, respectively. It was found that studied polymer solutions exhibited non-Newtonian behavior, moreover, the flow properties were dependent on the blend composition. The result show that practically there was no thixotropy in studied system but some interactions between PVA and pectin in water occurred.

Effect of banana fibers and plasticizer on melt processing of poly(vinyl alcohol)

2017 ◽  
Vol 37 (4) ◽  
pp. 335-343 ◽  
Author(s):  
Yottha Srithep ◽  
Dutchanee Pholharn ◽  
Onpreeya Veang-in ◽  
Suphan Yangyuen
Keyword(s):  
Mechanical Properties ◽  
Crystallization Temperature ◽  
Vinyl Alcohol ◽  
Tensile Modulus ◽  
Melt Processing ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Mechanical And Thermal Properties ◽  
Melt Blending ◽  
Banana Fibers

Abstract Poly(vinyl alcohol) (PVOH) resin is one of the most widely used water-soluble biodegradable polymer. Because of thermal degradation, PVOH exhibits limited melt processing and lacks moldability. The effects of adding glycerol as plasticizer and banana fibers (BF) to PVOH on its moldability and mechanical property were investigated. Melt blending of PVOH with glycerol and/or BF was performed in an internal mixer. The blended materials were then compression molded to produce tensile specimens. Various characterization techniques were employed to study the mechanical properties, compatibility, and crystallization behavior of the PVOH blends. By melt blending with glycerol, PVOH could be processed but decreased the tensile modulus, tensile strength, and crystallization temperature. Furthermore, the addition of BF enhanced the mechanical and thermal properties and crystallization temperature of plasticized PVOH due to compatibility between the two components. Apart from enhancing the mechanical properties and thermal stability, the incorporation of BF can reduce the production cost.

Poly(Vinyl Alcohol) (Core)-Polyurethane (Shell) Nanofibers Produced by Coaxial Electrospinning

2016 ◽  
Vol 705 ◽  
pp. 68-71 ◽  
Author(s):  
Ga Young Park ◽  
So Young Lee ◽  
Woo Jin Kim ◽  
Jin Hyun Choi
Keyword(s):  
Vinyl Alcohol ◽  
Water Soluble ◽  
Polymer Mixture ◽  
Poly Vinyl Alcohol ◽  
Coaxial Electrospinning ◽  
Resonance Spectroscopy ◽  
Bioactive Substances ◽  
Water Contact ◽  
Water Soluble Polymer ◽  
Small Pore

Nanoweb fabricated by electrospinning has a large specific area and a small pore size which can be controlled through a spinning process to enable a strong adsorption and selective permeability. It is required to produce nanofiber of different polymer mixture with a limited miscibility for improvement of physical, chemical, or biological properties. In this study, poly (vinyl alcohol) (PVA)/polyurethane (PU) nanofibers were produced by coaxial electrospinning. PVA (core)/PU (shell) nanofibers were defect-free and had a uniform thickness. The pseudo core/shell structure of PVA/PU nanofibers was confirmed by transmission electron microscopy. The presence of PVA and PU in the nanofibers was identified by 13C solid state nuclear magnetic resonance spectroscopy, fourier transform infrared spectroscopy, and X-ray diffraction analysis. Water contact angle was reduced by incorporation of PVA in a core of PU nanofiber. For variety of biomedical applications, bioactive substances such as antibiotics and proteins can be incorporated in a core of hydrophobic PU nanofiber by coaxial electrospinning of water-soluble polymer/bioactive substance mixture.

Highly percolated poly(vinyl alcohol) and bacterial nanocellulose synthesized in situ by physical-crosslinking: exploiting polymer synergies for biomedical nanocomposites

RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 90742-90749 ◽  
Author(s):  
C. Castro ◽  
R. Zuluaga ◽  
O. J. Rojas ◽  
I. Filpponen ◽  
H. Orelma ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Vinyl Alcohol ◽  
Culture Medium ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Bacterial Nanocellulose ◽  
Physical Crosslinking ◽  
Soluble Poly

Bacterial cellulose (BC) grown from a culture medium in the presence of water-soluble poly(vinyl alcohol) (PVA) produced an assemblage that was used as precursor for the synthesis of biocompatible nanocomposites.

scholarly journals Thickness-dependent humidity sensing by poly(vinyl alcohol) stabilized Au–Ag and Ag–Au core–shell bimetallic nanomorph resistors

2018 ◽  
Vol 5 (6) ◽  
pp. 171986 ◽  
Author(s):  
Parag Adhyapak ◽  
Rohini Aiyer ◽  
Sreekantha Reddy Dugasani ◽  
Hyeong-U Kim ◽  
Chung Kil Song ◽  
...  
Keyword(s):  
Metal Ions ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Nanocomposite Materials ◽  
Water Soluble ◽  
Shell Structures ◽  
Poly Vinyl Alcohol ◽  
Core Shell ◽  
Water Soluble Polymer ◽  
Bimetallic Nanostructures

We herein report a simple chemical route to prepare Au–Ag and Ag–Au core–shell bimetallic nanostructures by reduction of two kinds of noble metal ions in the presence of a water-soluble polymer such as poly(vinyl alcohol) (PVA). PVA was intentionally chosen as it can play a dual role of a supporting matrix as well as stabilizer. The simultaneous reduction of metal ions leads to an alloy type of structure. Ag(c)–Au(s) core–shell structures display tendency to form prismatic nanostructures in conjunction with nanocubes while Au(c)–Ag(s) core–shell structures show formation of merely nanocubes. Although UV–visible spectroscopy and X-ray photoelectron spectroscopy analyses of the samples typically suggest the formation of both Ag(c)–Au(s) and Au(c)–Ag(s) bimetallic nanostructures, the definitive evidence comes from high-resolution transmission electron microscopy–high-angle annular dark field elemental mapping in the case of Au(c)–Ag(s) nanomorphs only. The resultant nanocomposite materials are used to fabricate resistors on ceramic rods having two electrodes by drop casting technique. These resistors are examined for their relative humidity (RH) response in the range (2–93% RH) and both the bimetallic nanocomposite materials offer optimized sensitivity of about 20 Kohm/% RH and 300 ohm/% RH at low and higher humidity conditions, respectively, which is better than that of individual nanoparticles.

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