Physical Properties of Polyvinyl Alcohol Prepared from Freeze-Thaw Cycled Gel

2016 ◽  
Vol 72 (8) ◽  
pp. P-387-P-392
Author(s):  
TAKAHIKO NAKAOKI
Keyword(s):  
Polyvinyl Alcohol ◽  
Physical Properties ◽  
Freeze Thaw

Physical Properties of Building Blocks from Hemp Shives Aggregate and Cementitious Binder, Manufactured in the Expanded Clay (Vibro Pressing) Production Line

2017 ◽  
Vol 908 ◽  
pp. 118-122 ◽  
Author(s):  
Giedrius Balčiūnas ◽  
Viktor Kizinievič ◽  
Justinas Gargasas
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Physical Properties ◽  
Production Line ◽  
Scientific Literature ◽  
Building Blocks ◽  
Freeze Thaw ◽  
Cementitious Binder ◽  
Pressing Technology

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.

scholarly journals Impact of Structural Variations on Pre-Hollow/Micro-Porous Yarn's Tensile and Physical Properties

2012 ◽  
Vol 7 (1) ◽  
pp. 155892501200700 ◽  
Author(s):  
Arunangshu Mukhopadhyay ◽  
Saiyed Muzffar Ishtiaque ◽  
Devanand Uttam
Keyword(s):  
Polyvinyl Alcohol ◽  
Physical Properties ◽  
Product Quality ◽  
Tensile Behavior ◽  
Structural Variations ◽  
Yarn Strength ◽  
The Core

In the present study impact of structural variations on pre-hollow/micro-porous yarn's tensile and physical properties were investigated in view of their processing and ultimate product quality. The results show that: the core pre-hollow yarns and doubled pre-hollow yarns possessing continuous polyvinyl alcohol (PVA) filaments are better in tensile behavior than blended pre-hollow yarns which contain discrete PVA staple fibers. The doubled pre-hollow yarns were found to have the lowest unevenness, thick places, thin places and total imperfections followed by blended pre-hollow and core pre-hollow yarns, while blended pre-hollow yarns showed lowest number of neps. The core pre-hollow yarns exhibit lowest hairiness followed by blended pre-hollow yarns and doubled pre-hollow yarns. Use of double roving during spinning is beneficial for improving yarn strength, unevenness imperfections and hairiness in all the pre-hollow yarns.

Performance of silty sand reinforced with aqueous solution of polyvinyl alcohol subjected to freeze-thaw cycles

2020 ◽  
Vol 174 ◽  
pp. 103054
Author(s):  
Artem Krainiukov ◽  
Jiankun Liu ◽  
Ekaterina Kravchenko ◽  
Dan Chang
Keyword(s):  
Aqueous Solution ◽  
Polyvinyl Alcohol ◽  
Silty Sand ◽  
Freeze Thaw

scholarly journals Electroactive Hydrogels Made with Polyvinyl Alcohol/Cellulose Nanocrystals

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1615 ◽  
Author(s):  
Tippabattini Jayaramudu ◽  
Hyun-U Ko ◽  
Hyun Kim ◽  
Jung Kim ◽  
Ruth Muthoka ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Active Drug ◽  
X Ray Diffraction ◽  
Uptake Capacity ◽  
X Ray ◽  
Freeze Thaw ◽  
Actuation Mechanism ◽  
Water Uptake Capacity ◽  
Electrostatic Effect ◽  
Scanning Electron

This paper reports a nontoxic, soft and electroactive hydrogel made with polyvinyl alcohol (PVA) and cellulose nanocrystal (CNC). The CNC incorporating PVA-CNC hydrogels were prepared using a freeze–thaw technique with different CNC concentrations. Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy results proved the good miscibility of CNCs with PVA. The optical transparency, water uptake capacity and mechanical properties of the prepared hydrogels were investigated in this study. The CNC incorporating PVA-CNC hydrogels showed improved displacement output in the presence of an electric field and the displacement increased with an increase in the CNC concentration. The possible actuation mechanism was an electrostatic effect and the displacement improvement of the hydrogel associated with its enhanced dielectric properties and softness. Since the prepared PVA-CNC hydrogel is nontoxic and electroactive, it can be used for biomimetic soft robots, actively reconfigurable lenses and active drug-release applications.

scholarly journals PREPARATION OF CARBOXYMETHYL CELLULOSE AND POLYVINYL ALCOHOL (CMC/PVA) HYDROGELS USING FREEZE−THAW PROCESSES FOR ADSORPTION OF Zn2+ AND Cu2+

2021 ◽  
Vol 55 (3-4) ◽  
pp. 375-383
Author(s):  
NEDA PAVANDI ◽  
ELHAM TAGHAVI ◽  
NAVIDEH ANARJAN
Keyword(s):  
Polyvinyl Alcohol ◽  
Carboxymethyl Cellulose ◽  
Numerical Optimization ◽  
Polynomial Equations ◽  
Swelling Ratio ◽  
Process Variables ◽  
Freeze Thaw ◽  
Gel Fraction ◽  
Zero Order Kinetics ◽  
Order Polynomial

"The preparation of carboxymethyl cellulose and polyvinyl alcohol (CMC/PVA) composites is proposed in the present work. The CMC/PVA hydrogels were prepared using freeze−thaw processes. The effects of freezing time and of the number of freeze−thaw cycles on the swelling ratio and gel fraction of achieved hydrogels were evaluated using response surface methodology. The multiple regression analysis suggested second order polynomial equations as models for predicting changes of the studied hydrogel characteristics by selected process variables, with relatively high coefficients of determination (R2 > 0.82). The numerical optimization suggested that freezing the polymer solutions for 5 h and repeating the freeze−thaw process for 5 times would give the most desirable hydrogels with highest either swelling ratio or gel fraction. Remarkably, the ion adsorption studies showed that the adsorption of Cu2+ and Zn2+ ions by the hydrogels obeys zero order kinetics and the high capability of the produced optimum hydrogels to adsorb selected ions from synthetic waste was confirmed."

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