Pseudoelasticity and Nonideal Mullins Effect of Nanocomposite Hydrogels

2016 ◽  
Vol 83 (11) ◽  
Author(s):  
Jingda Tang ◽  
Xing Chen ◽  
Yongmao Pei ◽  
Daining Fang
Keyword(s):  
Polymer Network ◽  
Residual Deformation ◽  
Polymer Chains ◽  
Residual Fraction ◽  
Mullins Effect ◽  
Nanocomposite Hydrogels ◽  
High Toughness ◽  
Physically Crosslinked ◽  
Two Parameters ◽  
The Ideal

The polymer network of a nanocomposite (NC) hydrogel is physically crosslinked by nanoclay. Recently reported high toughness of nanocomposite (NC) hydrogels highlights the importance of their dissipative properties. The desorption of polymer chains from clay surface may contribute mostly to the hysteresis of NC hydrogels. Here, we proposed a mechanistically motivated pseudoelastic model capable of characterizing the hysteresis of NC hydrogels. The two parameters in the proposed damage variable can be determined by the experiments. We applied the model to the uniaxial tension and reproduced the ideal Mullins effect of NC hydrogels. Furthermore, we considered two nonideal effects: residual deformation and nonideal reloading in multicycle test, using newly proposed damage parameters. A power law with the order of 1/3 is established between the residual fraction of the stretch and the re-adsorption ratio of polymer chains. Finally, we demonstrated the dissipative properties of various NC hydrogels with the model.

The energy dissipation and Mullins effect of tough polymer/graphene oxide hybrid nanocomposite hydrogels

2017 ◽  
Vol 8 (32) ◽  
pp. 4659-4672 ◽  
Author(s):  
Ziqing Tang ◽  
Feng Chen ◽  
Qiang Chen ◽  
Lin Zhu ◽  
Xiaoqiang Yan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Energy Dissipation ◽  
High Strength ◽  
Mullins Effect ◽  
Hybrid Nanocomposite ◽  
Nanocomposite Hydrogels ◽  
High Toughness

Polyacrylamide/graphene oxide hybrid NC gels exhibited high strength, high toughness and rapid self-recovery properties.

Kinetics of methylene blue dye adsorptive removal using halloysite nanocomposite hydrogels

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sadia Ata ◽  
Sadaf Amin ◽  
Ismat Bibi ◽  
Ijaz-ul- Mohsin ◽  
Atif Islam ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Polymer Chains ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Nanocomposite Hydrogels ◽  
Antimicrobial Efficiency ◽  
Nano Clay ◽  
Swelling Capacity ◽  
Solution Casting Method ◽  
Adsorption Desorption

Abstract In the present work, halloysite nano-clay (HNTs) based hydrogel was fabricated and their efficiency for the removal of methylene blue dye was studied. The hydrogel films were prepared with varying amount of halloysite nano-clay via facile solution casting method. Effect of halloysite clay on adsorption performance of composite was investigated. The hydrophobic thermoplastic synthetic polymer, polylactic acid (PLA) was blended with hydrophilic polymer polyvinyl alcohol (PVA) and HNTs to synthesize hydrogels. Swelling behavior and antimicrobial efficiency was also evaluated. The halloysite incorporating films showed excellent antibacterial activity. Swelling capacity of hydrogel with increased halloysite content was reduced due to increased crosslinking among polymer chains. Halloysite incorporated hydrogel exhibited higher adsorption ability as compared to film comprising of only PVA and PLA and dye removal followed pseudo first order kinetics. Film with 0.03 g HNTs rapidly attained adsorption-desorption equilibria and removed the dye completely within 30 min. Results confirmed that synthesized film could be potentially used for the removal of cationic dye and fabricated hydrogel film have promising potential for wastewater treatment since a higher adsorption capacity was observed for halloysite nano-clay incorporated hydrogel.

scholarly journals Printable Alginate Hydrogels with Embedded Network of Halloysite Nanotubes: Effect of Polymer Cross-Linking on Rheological Properties and Microstructure

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4130
Author(s):  
Svetlana A. Glukhova ◽  
Vyacheslav S. Molchanov ◽  
Boris V. Lokshin ◽  
Andrei V. Rogachev ◽  
Alexey A. Tsarenko ◽  
...  
Keyword(s):  
3D Printing ◽  
Rheological Properties ◽  
Shear Thinning ◽  
Halloysite Nanotubes ◽  
Polymer Chains ◽  
Cross Linking ◽  
Saxs Data ◽  
Nanocomposite Hydrogels ◽  
Embedded Network ◽  
The Cross

Rapidly growing 3D printing of hydrogels requires network materials which combine enhanced mechanical properties and printability. One of the most promising approaches to strengthen the hydrogels consists of the incorporation of inorganic fillers. In this paper, the rheological properties important for 3D printability were studied for nanocomposite hydrogels based on a rigid network of percolating halloysite nanotubes embedded in a soft alginate network cross-linked by calcium ions. Particular attention was paid to the effect of polymer cross-linking on these properties. It was revealed that the system possessed a pronounced shear-thinning behavior accompanied by a viscosity drop of 4–5 orders of magnitude. The polymer cross-links enhanced the shear-thinning properties and accelerated the viscosity recovery at rest so that the system could regain 96% of viscosity in only 18 s. Increasing the cross-linking of the soft network also enhanced the storage modulus of the nanocomposite system by up to 2 kPa. Through SAXS data, it was shown that at cross-linking, the junction zones consisting of fragments of two laterally aligned polymer chains were formed, which should have provided additional strength to the hydrogel. At the same time, the cross-linking of the soft network only slightly affected the yield stress, which seemed to be mainly determined by the rigid percolation network of nanotubes and reached 327 Pa. These properties make the alginate/halloysite hydrogels very promising for 3D printing, in particular, for biomedical purposes taking into account the natural origin, low toxicity, and good biocompatibility of both components.

scholarly journals Polymer gel with a flexible and highly ordered three-dimensional network synthesized via bond percolation

2019 ◽  
Vol 5 (12) ◽  
pp. eaax8647 ◽  
Author(s):  
X. Li ◽  
S. Nakagawa ◽  
Y. Tsuji ◽  
N. Watanabe ◽  
M. Shibayama
Keyword(s):  
Network Formation ◽  
General Scheme ◽  
Polymer Network ◽  
Three Dimensional ◽  
Geometric Constraints ◽  
Polymer Chains ◽  
Bond Percolation ◽  
Polymer Gel ◽  
Temporal Correlations ◽  
Before And After

Gels are a soft elastic material consisting of a three-dimensional polymer network with nanometer-sized pores and are used in a variety of applications. However, gel networks typically have a substantial level of defects because the network formation reaction proceeds stochastically. In this study, we present a general scheme to fabricate gels with extremely low levels of defects by applying geometric constraints into pregel solution based on the “bond percolation” concept. In the formed gel, stationary laser speckles, which are an indicator of spatial defects, were not observed at all. In addition, we found that the concentration fluctuations of the polymer chains were ergodic across the whole gel network. In such a homogeneous gel, both the spatial and temporal correlations of polymer chains are the same before and after gelation.

Wear resistance of arc ion-plated chromium nitride coatings

1993 ◽  
Vol 8 (5) ◽  
pp. 1109-1115 ◽  
Author(s):  
Yuji Chiba ◽  
Toshio Omura ◽  
Hiroshi Ichimura
Keyword(s):  
Phase Diagram ◽  
Wear Resistance ◽  
Surface Morphology ◽  
Bias Voltage ◽  
Gas Pressure ◽  
Chromium Nitride ◽  
Nitrogen Gas ◽  
High Toughness ◽  
Nitride Coatings ◽  
Two Parameters

Wear resistance of arc ion-plated chromium nitride films has been studied. It has been found that texture and phases composing the films depend much on bias voltage and nitrogen gas pressure at the deposition. A phase diagram was constructed as a function of these two parameters, which indicated that three categories exist: CrN single, CrN and Cr2N dual, and CrN and Cr dual phased regions, respectively. Results of Falex No. 2 test showed that the wear resistance of CrN single phased films is superior to others, especially when (220) preferred orientation is developed. Since hardness and surface morphology do not differ much between these films, a high toughness of CrN single phased film is considered to make a difference by suppressing abrasion wear.

Molecular insight into the Mullins effect: irreversible disentanglement of polymer chains revealed by molecular dynamics simulations

2017 ◽  
Vol 19 (29) ◽  
pp. 19468-19477 ◽  
Author(s):  
Chi Ma ◽  
Tuo Ji ◽  
Christopher G. Robertson ◽  
R. Rajeshbabu ◽  
Jiahua Zhu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Molecular Model ◽  
Polymer Chains ◽  
Mullins Effect ◽  
Key Characteristics ◽  
Dynamics Simulations ◽  
First Time ◽  
Insight Into

For the first time, the key characteristics associated with the Mullins effect are captured by a molecular model.

The Study on Mechanical Properties of POSS Hybrid PVA Hydrogels

2014 ◽  
Vol 1022 ◽  
pp. 30-33
Author(s):  
Yi Chen ◽  
Jun Hong Yang ◽  
Wen Yong Liu ◽  
Guang Sheng Zeng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compression Strength ◽  
Water Soluble ◽  
Polymer Chains ◽  
Hybrid Nanocomposite ◽  
Nanocomposite Hydrogels

A novel POSS hybrid nanocomposite hydrogels were synthesized by introducing water-soluble Oa-POSS into the PVA hydrogels. The mechanical properties are obviously dependent on the composition of gels. With the increase of Oa-POSS, the tensile strength and modulus increases significantly while the elongation break decreases. The gels exhibit higher compression strength than pure PVA hydrogels. This phenomenon is attributed to the effective entanglement of polymer chains around nanoparticles and enhanced interaction between PVA chains.

Conformation of Free Linear Polymer Chains in a Polymer Network

1997 ◽  
Vol 30 (16) ◽  
pp. 4704-4712 ◽  
Author(s):  
Xiaodu Liu ◽  
Barry J. Bauer ◽  
Robert M. Briber
Keyword(s):  
Polymer Network ◽  
Polymer Chains ◽  
Linear Polymer

scholarly journals Rheological and thermal stability of interpenetrating polymer network hydrogel based on polyacrylamide/hydroxypropyl guar reinforced with graphene oxide for application in oil recovery

2021 ◽  
Vol 41 (9) ◽  
pp. 788-798
Author(s):  
Amir Narimani ◽  
Farid Kordnejad ◽  
Prabhjyot Kaur ◽  
Saeed Bazgir ◽  
Mahmood Hemmati ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Oil Recovery ◽  
Polymer Network ◽  
High Viscosity ◽  
Interpenetrating Polymer Network ◽  
Flow Activation Energy ◽  
Nanocomposite Hydrogels ◽  
Hydroxypropyl Guar ◽  
Hydrogel Matrix

Abstract The purpose of the present work is to enhance the thermal stability and rheological properties of semi-interpenetrating polymer network (IPN) hydrogel based on partially hydrolyzed polyacrylamide/hydroxypropyl guar (HPAM/HPG) nanocomposite reinforced with graphene oxide (GO), at temperatures (200 and 240 °F) for use in oil recovery applications. FTIR spectra of the IPN nanocomposite hydrogels revealed interactions of GO with HPAM/HPG chains. An increase in the viscosity is also observed from the rheological study. Moreover, IPN and its nanocomposite hydrogels exhibited non-Newtonian behavior. The decline of viscosity of IPN nanocomposite hydrogels was observed with an increase in the temperature from 200 to 240 °F but was still higher than IPN hydrogel without GO. Dispersion of GO through the HPAM/HPG hydrogel matrix was evaluated by SEM morphology and electrical conductivity. The IPN nanocomposite hydrogels showed high viscosity stability, thermal stability, and flow activation energy as compared to IPN hydrogel without GO. Therefore, the addition of 0.1 wt.% of GO to the HPAM/HPG matrix is suitable to create a cross-linked polymer solution with improved properties which may be beneficial for use in oil recovery applications.

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