scholarly journals The Impact of Clay Loading on the Relative Intercalation of Poly(Vinyl Alcohol)-Clay Composites

2016 ◽  
Vol 04 (10) ◽  
pp. 20-31 ◽  
Author(s):  
Moustafa M. Zagho ◽  
Mahmoud M. Khader
Keyword(s):  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Clay Loading ◽  
The Impact

Mechanical Properties and Structure of Melamine Formaldehyde/Poly(Vinyl Alcohol) Molecular Composites

1989 ◽  
Vol 171 ◽  
Author(s):  
Kecheng Gong ◽  
Xinghua Zhang
Keyword(s):  
Mechanical Properties ◽  
Composite Structure ◽  
Vinyl Alcohol ◽  
Impact Resistance ◽  
Poly Vinyl Alcohol ◽  
Melamine Formaldehyde ◽  
Two Component System ◽  
Transmission Electron ◽  
Molecular Composites ◽  
The Impact

ABSTRACTThe mechanical properties and structure of melamine formaldehyde (MF)/poly(vinyl alcohol) (PVA) composites were studied in this paper. When PVA content was less than a certain value(about 20 weight %), both flexible strength and impact resistance were improved obviously. While the impact resistance improvement remained the previous trend the flexible strength didn't increase so rapidly as before when the PVA content was more than 20%. The morphology and reactivity of the prepolymer powder and the morphology of the finished specimens were investigated by means of microscope, infrared spectrum and transmission electron microscope(TEM). The results indicated that molecular composite structure was formed in this two-component system. The well-distributed PVA in this system was beneficial to the formation of the molecular composite structure. That could explain the effects of PVA on the mechanical properties and showed that the molecular composite structure are favourable for making full use of the macromolecular potentiality.

Influence of adding poly(vinyl alcohol) fibres to poly(methyl methacrylate) matrix on the fracture behaviour of fibrereinforced composites

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Vladimir Pavelka ◽  
Josef Jancar ◽  
Eva Nezbedova
Keyword(s):  
Methyl Methacrylate ◽  
Vinyl Alcohol ◽  
Fibre Composite ◽  
Impact Resistance ◽  
Charpy Impact ◽  
Critical Stress Intensity Factor ◽  
Poly Vinyl Alcohol ◽  
Special Focus ◽  
Poly Methyl Methacrylate ◽  
The Impact

AbstractThis paper reports on the relationship between structure and mechanical properties of poly(methyl methacrylate) (PMMA) reinforced with randomly oriented short poly(vinyl alcohol) (PVA) fibres. Special focus was on the effect of fibre content on the impact resistance of PMMA/PVA composites. Instrumented Charpy impact tests were carried out to characterize the impact resistance of PMMA/PVA composites. Linear elastics fracture mechanics was used to determine the dynamic critical strain energy release rate (GId) and the critical stress intensity factor (KId). Fracture surfaces were observed using scanning electron microscopy (SEM). Dynamic mechanical analysis was carried out to describe the viscoelastic response of the material. Finally, the behaviour of PMMA/PVA composites was interpreted using current short-fibre composite models. It was shown that a small amount of added PVA fibres (0.42 - 1.68 vol.-%) led to an increase of elastic modulus and yield stress under impact conditions. GId was also slightly increased, but KId remained unchanged. Good agreement was found between SEM observations and fracture toughness measured under impact loading.

Solid Freeform Fabrication using Alumina-Poly(Vinyl Alcohol) Gel-Casting Suspensions

1998 ◽  
Vol 542 ◽  
Author(s):  
S. L. Morissette ◽  
J. A. Lewis ◽  
J. Cesarano ◽  
D. B. Dimos
Keyword(s):  
Vinyl Alcohol ◽  
Solid Freeform Fabrication ◽  
Poly Vinyl Alcohol ◽  
Mixing Rate ◽  
Freeform Fabrication ◽  
Gel Casting ◽  
On Line ◽  
Laser Profilometry ◽  
Cast Component ◽  
The Impact

AbstractSolid freeform fabrication of aqueous alumina (Al2O3)-poly(vinyl alcohol) (PVA) gelcasting suspensions was carried out using a computer-controlled extrusion apparatus fitted with a two-nozzle delivery system. The impact of casting parameters (e.g., tip diameter, mixing rate, etc.) and suspension composition on line resolution/uniformity, printability, and as-cast component properties was probed using laser profilometry and optical microscopy. Line uniformity depended on mixing rate (Rmix) and tip diameter (td) for the chamber and paddle geometry utilized. These data were used to establish processing maps that identify optimal print conditions for varying suspension composition.

scholarly journals The orthotropic viscoelastic characterisation of sub-zero 3D-printed poly(vinyl alcohol) cryogel

MRS Advances ◽  
2021 ◽  
Author(s):  
J. P. Crolla ◽  
M. M. Britton ◽  
D. M. Espino ◽  
L. E. J. Thomas-Seale
Keyword(s):  
Mechanical Properties ◽  
Vinyl Alcohol ◽  
Complex Geometry ◽  
Processing Parameters ◽  
Poly Vinyl Alcohol ◽  
Additive Manufacture ◽  
Storage And Loss Moduli ◽  
3D Printed ◽  
Orthotropic Properties ◽  
The Impact

Abstract Poly(vinyl alcohol) cryogel (PVA) is a versatile biomaterial used to replicate the biomechanics of tissues. Additive manufacture (AM) at sub-zero (°C) temperatures enables the manufacture of PVA with complex geometry; however, the effect of processing parameters on the mechanical properties of PVA has not been evaluated. The aim of this study is to understand the impact of print nozzle diameter and orientation on the viscoelastic mechanical properties of PVA. Samples of sub-zero AM PVA, with different filament thicknesses, were tested under tension relative to the print direction, to calculate the storage and loss moduli. As the nozzle size was decreased, AM PVA exhibited more pronounced orthotropic properties; the smallest size showed a 33% decrease in storage moduli when tested perpendicular to the print direction, as opposed to parallel. This study has demonstrated the ability of sub-zero AM to tailor the orthotropic properties of PVA. Graphic abstract

scholarly journals The Impact of Reactive Ionic Liquids Addition on the Physicochemical and Sorption Properties of Poly(Vinyl Alcohol)-Based Films

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1958
Author(s):  
Guoqiang Li ◽  
Edyta Rynkowska ◽  
Kateryna Fatyeyeva ◽  
Joanna Kujawa ◽  
Krzysztof Dzieszkowski ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Vinyl Alcohol ◽  
Water Sorption ◽  
Mechanical Stability ◽  
Tensile Tests ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Swelling Behavior ◽  
Poly Vinyl Alcohol ◽  
The Impact

A new type of hybrid polymeric-based film containing 1-(1,3-diethoxy-1,3-dioxopropan-2-ylo)-3-methylimidazolium bromide (RIL1_Br) and 1-(2-etoxy-2-oxoethyl)-3-methylimidazolium bromide (RIL2_Br) reactive ionic liquids was elaborated. Poly(vinyl alcohol) (PVA)-based films with 9–33 wt % of RILs were subsequently characterized using Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and TGA-FTIR. PVA-RIL films were also studied in tensile tests, contact angle and sorption measurements. RIL incorporation enhanced thermal and mechanical stability of PVA membranes due to the hydrogen bonds between RILs and polymer chains. Membrane swelling behavior in water (H2O), ethanol (EtOH), and propan-2-ol (IPA) and the kinetics of water sorption process revealed that PVA-RILs membranes possess the highest affinity towards water. It was pointed out that both the RIL type and the RIL amount in the polymer matrix have significant influence on the membrane swelling behavior and the water sorption kinetics.

scholarly journals The impact of the mulberry (Morus nigra L.) leaf extract on the physicochemical properties of poly(vinyl alcohol) blend films

2021 ◽  
Vol 1195 (1) ◽  
pp. 012016
Author(s):  
N S Rafflisman ◽  
S K Mah ◽  
S Y Lee ◽  
K S P Yee ◽  
S Chowdhury
Keyword(s):  
Vinyl Alcohol ◽  
Leaf Extract ◽  
Food Preservation ◽  
Poly Vinyl Alcohol ◽  
Blend Films ◽  
Mulberry Leaf ◽  
Morus Nigra ◽  
Mulberry Leaf Extract ◽  
Green Pigments ◽  
The Impact

Abstract In this work, mulberry (Morus nigra L.) leaf extract was added in poly(vinyl alcohol) (PVA)-based films and its impact on the film’s properties was evaluated. In addition, HCl and glycerol were studied for their use as additives to prepare PVA-based films. The results showed that HCl and glycerol have minimal impacts on the films’ appearance, while mulberry leaf extract imparted green colour to the films produced, mainly due to the presence of green pigments. Moreover, the results suggested that a significant interaction has occurred between the polymer matrix and leaf extract, contributing to a more compact and uniform film morphology. The tensile strengths of the films increased from 21.38 to 28.28 MPa after the addition of mulberry leaf extract. Additionally, the films were tested for their application as food wrapping films. Overall, the results showed that PVA-based films incorporated with mulberry leaf extract have higher capability to preserve the freshness of food when compared to commercial cling wraps from brands such as Diamond and Glad. Appropriate proportions of additives (mulberry leaf extract, HCl and glycerol) used in the formulation of P-GH-M20 films showed improvement in its mechanical properties and food preservation capability.

scholarly journals The Impact of Plasticizer and Degree of Hydrolysis on Free Volume of Poly(vinyl alcohol) Films

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1036 ◽  
Author(s):  
Rebecca Fong ◽  
Alexander Robertson ◽  
Peter Mallon ◽  
Richard Thompson
Keyword(s):  
Hydrogen Bonding ◽  
Free Volume ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Degree Of Hydrolysis ◽  
Atmospheric Conditions ◽  
Cavity Radius ◽  
Positron Annihilation Lifetime ◽  
Influence Of Water ◽  
The Impact

The effect of plasticizer species and the degree of hydrolysis (DH) on the free volume properties of poly(vinyl alcohol) (PVA) were studied using positron annihilation lifetime spectroscopy. Both glycerol and propylene glycol caused an increase in the free volume cavity radius, although exhibited distinct plasticization behavior, with glycerol capable of occupying existing free volume cavities in the PVA to some extent. The influence of water, normally present in PVA film under atmospheric conditions, was also isolated. Water added significantly to the measured free volume cavity radius in both plasticized and pure PVA matrices. Differences in plasticization behavior can be attributed to the functionality of each plasticizing additive and its hydrogen bonding capability. The increase in cavity radii upon plasticizer loading shows a qualitative link between the free volume of voids and the corresponding reduction in Tg and crystallinity. Cavity radius decreases with increasing DH, due to PVA network tightening in the absence of acetate groups. This corresponds well with the higher Tg observed in the resin with the higher DH. DH was also shown to impact the plasticization of PVA with glycerol, indicating that the larger cavities—created by the weaker hydrogen bonding acetate groups—are capable of accommodating glycerol molecules with negligible effect on the cavity dimensions.

scholarly journals The Effect of Glycerin Content in Sodium Alginate/Poly(vinyl alcohol)-Based Hydrogels for Wound Dressing Application

2021 ◽  
Vol 22 (21) ◽  
pp. 12022
Author(s):  
Katarzyna Bialik-Wąs ◽  
Klaudia Pluta ◽  
Dagmara Malina ◽  
Mateusz Barczewski ◽  
Katarzyna Malarz ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Vinyl Alcohol ◽  
Phosphate Buffer Solution ◽  
Dermal Fibroblasts ◽  
Poly Vinyl Alcohol ◽  
Buffer Solution ◽  
Adhesion Properties ◽  
Gel Fraction ◽  
Glycerin Content ◽  
The Impact

The impact of different amounts of glycerin, which was used in the system of sodium alginate/poly(vinyl alcohol) (SA/PVA) hydrogel materials on the properties, such as gel fraction, swelling ability, degradation in simulated body fluids, morphological analysis, and elongation tests were presented. The study shows a significant decrease in the gel fraction from 80.5 ± 2.1% to 45.0 ± 1.2% with the increase of glycerin content. The T5 values of the tested hydrogels were varied and range from 88.7 °C to 161.5 °C. The presence of glycerin in the matrices significantly decreased the thermal resistance, which was especially visible by T10 changes (273.9 to 163.5 °C). The degradation tests indicate that most of the tested materials do not degrade throughout the incubation period and maintain a constant ion level after 7-day incubation. The swelling abilities in distilled water and phosphate buffer solution are approximately 200–300%. However, we noticed that these values decrease with the increase in glycerin content. All tested matrices are characterized by the maximum elongation rate at break in a range of 37.6–69.5%. The FT-IR analysis exhibits glycerin changes in hydrogel structures, which is associated with the cross-linking reaction. Additionally, cytotoxicity results indicate good adhesion properties and no toxicity towards normal human dermal fibroblasts.

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