Optimization of testing parameters for tensile property evaluation of poly(vinyl alcohol) nanofibers webs

J of Applied Polymer Sci

Kendall

et al. 2020

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A tensile properties testing study was conducted to understand the influence of thickness, cross-head speed (speed of testing), gauge length (GL; specimen test length), and sample shape on important tensile properties of polyvinyl alcohol (PVA) nanofiber webs. The effects of each testing parameter on load at break, extension at break, Young's modulus, and tensile stress-strain curve of PVA nanofiber webs are analyzed. The Welch two sample t-tests show the significant difference among tested data. Using interaction plots, two-way analysis of variance, and margin mean plots, the interaction effects among testing parameters have been analyzed. Of all the factors, cross-head speed, the interaction among GL, and sample thickness (GL: Thickness) and the interaction among GL, testing speed and sample thickness (GL: Speed: Thickness) have significant influence on the tensile properties of PVA nanofiber webs. Moreover, the hypothesized model of mechanism of tensile strain-stress curve of PVA nanofiber webs has been proposed. Based on the model, the tensile strain-stress curve can be split into three stages: linear elastic, partial break up, and complete breakage. This study will provide a better understanding of tensile testing parameters' effects and their interaction effects on the tensile properties of nanowebs.

Section: Introductionmentioning

confidence: 99%

Tensile testing and fracture mechanism analysis of polyvinyl alcohol nanofibrous webs

J of Applied Polymer Sci

Kendall

et al. 2020

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“…Mechanical Property Evaluation : Tensile properties of the PVDF/TiO 2 nanofiber webs were measured using the Instron tensile tester (Model Instron 5569, Instron Corporation, Massachusetts) at a crosshead speed of 5 mm min −1 . A modified standard test method with a 2.5 Newton load cell (ASTM D638‐10) developed in our laboratory was used to carry out the mechanical property measurements at a temperature of 21 ± 1 °C and RH of 65% ± 2%. The average width, length, thickness, and gauge length of the nanowebs were 25.4, 76.2, 0.02, and 5 mm, respectively.…”

Section: Methodsmentioning

confidence: 99%

Visible Light Photocatalytic Functional TiO₂/PVDF Nanofibers for Dye Pollutant Degradation

Part & Part Syst Charact

Wang

Lee

et al. 2019

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contaminated water becomes an environmental hazard.Functional photocatalytic nanofiber webs [6,7] are promising environmentally friendly candidates for the photodegradation of organic pollutants, such as dyes and pigments. Nanofibers have high specific morphology, [8] small diameter [9] and small pore size, [10] and customizable physicochemical characteristics, [11] which make them excellent candidates in wastewater treatment, [12] biomedical applications, [13][14][15] protein purification, [16] and air filtration. [17] Poly(vinylidene fluoride) (PVDF) [18] is a commonly used hydrophobic polymer for wastewater treatment, due to its excellent thermal stability, mechanical stability, chemical resistance, and selective permeability. However, interception effect (meaning large particles would be intercepted by small pore size nanofiber webs), the major ultrafiltration mechanism for unfunctionalized PVDF nanofiber webs, [19] limits their applications because of their low filtration efficiency and poor functionality. The addition of nanoparticles could improve the photocatalytic properties, [20] mechanical properties, [21] hydrophobicity, [22,23] and other functional performances of nanofiber webs. [19][20][21][22][23] Moreover, physical modification methods (addition of functional nanoparticles) have proved to be simpler and more effective than chemical modification methods. [24] Commonly used nanoparticles include titanium dioxide (anatase TiO 2 ), [25] zinc oxide (ZnO), [26] aluminum oxide (Al 2 O 3 ), [27] magnetite (Fe 3 O 4 ), [28] graphite oxide (GO), [29] multiwalled carbon nanotubes (MWCNTs), [30] and polymeric nanoparticles. [31] Polymeric nanoparticles, including nanospheres and nanocapsules, are formed by a polymeric matrix and mainly used for drug delivery, where the molecules are absorbed in or on the matrix, for example, encapsulation of insulin in poly(lactic-co-glycolic acid) nanoparticles. [32] Among these nanoparticles, anatase titanium dioxide is the most widely used catalyst for water treatment because of low cost, stability in water, and high photocatalytic property. [19][20][21] The addition of TiO 2 in nanofiber webs can greatly improve the degradation rate of organic pigments/dyes pollutants, [19] antibacterial properties, [20] and other performances (antifouling property, wettability). [20,21,23] Electrospinning is a popular and simple method to produce functional nanofiber webs among all existing nanofiber webs technologies, such as melt spinning, solution spinning, andThe photodegradation of poly(vinylidene fluoride) (PVDF)/titanium oxide (TiO 2 ) nanofibers under visible light is described, something that has not been previously reported in the literature. Visible light photocatalytic electrospun PVDF/TiO 2 nanofiber webs with anatase TiO 2 concentration varying from 0% to 20% (0%, 1%, 3%, 5%, 10%, and 20%) are produced, and their ability to degrade a toxic pollutant, Rhodamine B (RhB), is studied. Photodegradation study using UV-vis spectroscopy on PVDF/TiO 2 nanofiber webs (with TiO 2 con...

“…This section outlines the test method used to measure the mechanical properties of PVA/VB2/TiO 2 nanofiber webs. A modified standard test method (ASTM D638–10) developed in our laboratory , was used to evaluate the tensile characteristics of nanowebs. The Instron tensile tester (Instron 5569, Instron Corp.) was used at a crosshead speed of 5 mm·min –1 and a 2.5 N load cell.…”

Section: Methodsmentioning

confidence: 99%

Functional PVA/VB2/TiO₂ Nanofiber Webs for Controlled Drug Delivery

Subbiah

Smith

et al. 2019

ACS Appl. Bio Mater.

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Drug (vitamin B2, riboflavin, VB2)/nanoparticle (TiO 2 , coated on drug surface) loaded poly(vinyl alcohol) (PVA) nanofiber webs were successfully produced by the electrospinning process. The characteristics of nanofiber structure, chemical composition, mechanical properties, and drug-release properties were investigated. The morphology and diameter of nanofibers were analyzed by atomic force microscopy and scanning electron microscopy. The chemical composition and mechanical properties of nanofiber webs were examined by Fourier transform infrared spectroscopy and Instron tensile tester. The drug-release properties of nanofiber webs were studied by liquid chromatography−mass spectrometry (LC-MS/MS). The influences of TiO 2 :VB2 ratios (0, 18:1, 9:1, 4.5:1, 2.25:1, and 1:1) and releasing time on release behavior of PVA/VB2/TiO 2 nanofiber webs were also investigated, with the corresponding virgin PVA nanofibers and LC-MS grade water as control. Among all of the tested samples, PVA/VB2/TiO 2 nanofiber webs with TiO 2 :VB2 ratios of 18:1 and 9:1 exhibited a steady release rate with 60% of VB2 released around 168 h and all VB2 released around 10 days. In addition, by coating VB2 with TiO 2 , the burst release was effectively prevented due to three mechanisms: surface modification, polymer morphology, and coated surface. The results in this study indicate drug-loaded and nanoparticle-coated hydrophilic nanofiber webs are useful candidates for steady drug release in the drug delivery application field.