Superporous Hydrogel Composites: A New Generation of Hydrogels with Fast Swelling Kinetics, High Swelling Ratio and High Mechanical Strength

Author(s):  
Kinam Park ◽  
Jun Chen ◽  
Haesun Park
2010 ◽  
Vol 95 ◽  
pp. 85-86 ◽  
Author(s):  
Eitan Zur

Few seconds setting time, superior flexibility along with high mechanical strength and moisture insensitivity are only a small portion of the characteristics of the unique technology named Polyurea. This technology is on the move around the globe and recently some intriguing projects were done also in Israel. This paper is a brief introduction of the Polyurea technology. Nearly two decades ago, a new technology was introduced to the world. It was not an innovative semi-flexible Epoxy, with a better UV stability. Nor was it a new kind of fast set Urethane, with improved chemical resistance. Rather, it was a new generation of polymers, which is free of some of the drawbacks of the old conventional coatings. It is well known, for example, that epoxies excels in chemical resistance, high mechanical strength and hardness. However, it is also known that in spite of the great advance of recent years, epoxies still tend to be brittle and crack due to thermal stress and other causes. Chalking and yellowing caused by UV exposure is another notorious characteristic of Epoxies. Urethanes on the other hand are very flexible and have excellent weatherabilty. But what about hydrolytic stability, moisture sensitivity during the application and chemical resistance issues? There is much room for improvement on this regard. Polyurea combines high mechanical strength, unusual elongation, excellent water resistance and good chemical resistance. UV stability of some Polyureas is nothing less than high quality aliphatic urethanes. Therefore, in recent years the Polyurea technology is on the move all over the world in diverse fields, such as the building, petrochemical and chemical industries, corrosion protection, flooring, water systems and wastewater treatment plants, bridges and tunnels, etc.


Author(s):  
Andrew Chang ◽  
Nasim Babhadiashar ◽  
Emma Barrett-Catton ◽  
Prashanth Asuri

Extensive experimental and theoretical research over the past several decades has culminated in the understanding of the mechanisms behind nanoparticle-mediated enhancements on the mechanical properties of hydrogels. This information is not only crucial to realizing applications that directly benefit from developing hydrogels with high mechanical strength, but also to guide the development of strategies to further enhance hydrogel properties by combining different approaches. In our study, we investigated the effect of combining two approaches – addition of nanoparticles and crosslinking two different polymers (to create double-network hydrogels) – on the mechanical properties of hydrogels. Our studies revealed that these approaches may be combined to synthesize hydrogel composites with enhanced properties; however, both polymers in the double-network hydrogel must strongly interact with the nanoparticles to fully benefit from the addition of nanoparticles. Moreover, the concentration of hydrogel monomers used for the preparation of the double-network hydrogels had a significant effect on the extent of nanoparticle-mediated enhancements; double-network hydrogel nanocomposites prepared using lower monomer concentrations showed higher enhancements in elastic moduli compared to those prepared using high monomer concentrations. Collectively, these results demonstrate that the hypotheses previously developed to understand the role of nanoparticles on the mechanical properties of hydrogel nanocomposites may be extended to double-network hydrogel systems and guide the development of next generation hydrogels with extraordinary mechanical properties through a combination of orthogonal approaches.


Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 470 ◽  
Author(s):  
Andrew Chang ◽  
Nasim Babhadiashar ◽  
Emma Barrett-Catton ◽  
Prashanth Asuri

Extensive experimental and theoretical research over the past several decades has pursued strategies to develop hydrogels with high mechanical strength. Our study investigated the effect of combining two approaches, addition of nanoparticles and crosslinking two different polymers (to create double-network hydrogels), on the mechanical properties of hydrogels. Our experimental analyses revealed that these orthogonal approaches may be combined to synthesize hydrogel composites with enhanced mechanical properties. However, the enhancement in double network hydrogel elastic modulus due to incorporation of nanoparticles is limited by the ability of the nanoparticles to strongly interact with the polymers in the network. Moreover, double-network hydrogel nanocomposites prepared using lower monomer concentrations showed higher enhancements in elastic moduli compared to those prepared using high monomer concentrations, thus indicating that the concentration of hydrogel monomers used for the preparation of the nanocomposites had a significant effect on the extent of nanoparticle-mediated enhancements. Collectively, these results demonstrate that the hypotheses previously developed to understand the role of nanoparticles on the mechanical properties of hydrogel nanocomposites may be extended to double-network hydrogel systems and guide the development of next-generation hydrogels with extraordinary mechanical properties through a combination of different approaches.


Author(s):  
Naozumi Teramoto ◽  
Keisuke Wakayama ◽  
Mitsuru Harima ◽  
Toshiaki Shimasaki ◽  
Mitsuhiro Shibata

Alloy Digest ◽  
2009 ◽  
Vol 58 (8) ◽  

Abstract DMV 59 is the material of choice for a wide variety of applications where significant corrosion resistance and high mechanical strength is necessary. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: Ni-672. Producer or source: Mannesmann DMV Stainless USA Inc.


Alloy Digest ◽  
1965 ◽  
Vol 14 (5) ◽  

Abstract BOFORS 2RM2 is a hardenable stainless cast steel having good weldability, high mechanical strength and improved corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low temperature performance and corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: SS-169. Producer or source: Aktiebolaget Bofors.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3574
Author(s):  
Pejman Heidarian ◽  
Hossein Yousefi ◽  
Akif Kaynak ◽  
Mariana Paulino ◽  
Saleh Gharaie ◽  
...  

Electroconductive hydrogels with stimuli-free self-healing and self-recovery (SELF) properties and high mechanical strength for wearable strain sensors is an area of intensive research activity at the moment. Most electroconductive hydrogels, however, consist of static bonds for mechanical strength and dynamic bonds for SELF performance, presenting a challenge to improve both properties into one single hydrogel. An alternative strategy to successfully incorporate both properties into one system is via the use of stiff or rigid, yet dynamic nano-materials. In this work, a nano-hybrid modifier derived from nano-chitin coated with ferric ions and tannic acid (TA/Fe@ChNFs) is blended into a starch/polyvinyl alcohol/polyacrylic acid (St/PVA/PAA) hydrogel. It is hypothesized that the TA/Fe@ChNFs nanohybrid imparts both mechanical strength and stimuli-free SELF properties to the hydrogel via dynamic catecholato-metal coordination bonds. Additionally, the catechol groups of TA provide mussel-inspired adhesion properties to the hydrogel. Due to its electroconductivity, toughness, stimuli-free SELF properties, and self-adhesiveness, a prototype soft wearable strain sensor is created using this hydrogel and subsequently tested.


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