Effect of chain extender on microphase structure and performance of self‐healing polyurethane and poly(urethane‐urea)

2021 ◽  
pp. 51371
Author(s):  
Yulong Wang ◽  
Yaqiong Li ◽  
Maoyong He ◽  
Jingjing Bai ◽  
Bingxiao Liu ◽  
...  
Keyword(s):  
Chain Extender ◽  
Self Healing ◽  
And Performance

scholarly journals Self-Healing Many-Core Architecture: Analysis and Evaluation

VLSI Design ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Arezoo Kamran ◽  
Zainalabedin Navabi
Keyword(s):  
Normal Operation ◽  
External Control ◽  
Self Healing ◽  
Aging Effects ◽  
Analysis And Evaluation ◽  
Promising Solution ◽  
Self Test ◽  
And Performance ◽  
The Many ◽  
Many Core

More pronounced aging effects, more frequent early-life failures, and incomplete testing and verification processes due to time-to-market pressure in new fabrication technologies impose reliability challenges on forthcoming systems. A promising solution to these reliability challenges is self-test and self-reconfiguration with no or limited external control. In this work a scalable self-test mechanism for periodic online testing of many-core processor has been proposed. This test mechanism facilitates autonomous detection and omission of faulty cores and makes graceful degradation of the many-core architecture possible. Several test components are incorporated in the many-core architecture that distribute test stimuli, suspend normal operation of individual processing cores, apply test, and detect faulty cores. Test is performed concurrently with the system normal operation without any noticeable downtime at the application level. Experimental results show that the proposed test architecture is extensively scalable in terms of hardware overhead and performance overhead that makes it applicable to many-cores with more than a thousand processing cores.

scholarly journals Semantic-Aware Security Orchestration in SDN/NFV-Enabled IoT Systems

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3622 ◽  
Author(s):  
Alejandro Molina Zarca ◽  
Miloud Bagaa ◽  
Jorge Bernal Bernabe ◽  
Tarik Taleb ◽  
Antonio F. Skarmeta
Keyword(s):  
Optimal Allocation ◽  
Added Value ◽  
Virtual Network ◽  
Security Policies ◽  
Network Function Virtualization ◽  
Self Healing ◽  
Network Function ◽  
Semantic Conflict ◽  
And Performance ◽  
Self Protection

IoT systems can be leveraged by Network Function Virtualization (NFV) and Software-Defined Networking (SDN) technologies, thereby strengthening their overall flexibility, security and resilience. In this sense, adaptive and policy-based security frameworks for SDN/NFV-aware IoT systems can provide a remarkable added value for self-protection and self-healing, by orchestrating and enforcing dynamically security policies and associated Virtual Network Functions (VNF) or Virtual network Security Functions (VSF) according to the actual context. However, this security orchestration is subject to multiple possible inconsistencies between the policies to enforce, the already enforced management policies and the evolving status of the managed IoT system. In this regard, this paper presents a semantic-aware, zero-touch and policy-driven security orchestration framework for autonomic and conflict-less security orchestration in SDN/NFV-aware IoT scenarios while ensuring optimal allocation and Service Function Chaining (SFC) of VSF. The framework relies on Semantic technologies and considers the security policies and the evolving IoT system model to dynamically and formally detect any semantic conflict during the orchestration. In addition, our optimized SFC algorithm maximizes the QoS, security aspects and resources usage during VSF allocation. The orchestration security framework has been implemented and validated showing its feasibility and performance to detect the conflicts and optimally enforce the VSFs.

Self-Healing Polymeric Materials

2017 ◽  
Vol 727 ◽  
pp. 482-489 ◽  
Author(s):  
Cui Cui Su ◽  
Jian Sheng Chen
Keyword(s):  
Future Development ◽  
Smart Materials ◽  
Polymeric Materials ◽  
Development Trend ◽  
Self Healing ◽  
New Class ◽  
Advantages And Disadvantages ◽  
System Success ◽  
And Performance ◽  
External Intervention

During the last few years, synthetic self-healing materials have become a new class of emerging smart materials with the ability to repair damage and restore lost or degraded properties or performance using resources inherently available to the system. Success in the design of self-healing materials is important to material safety, product reliability and prolonged lifetime. This article covers fundamental material-independent principles and different self-healing approaches for polymeric materials. Among these approaches, some depend on specific external stimulus to achieve their goal while others regain the physical properties of the pristine material without such external intervention. Both the mechanisms and performance of different methods are discussed and evaluated, along with their advantages and disadvantages. In the end, both the potential application areas and the main challenges are also discussed in this article for a better understanding of future development trend of self-healing polymeric materials.

Polyurethane microcapsules for self-healing paint coatings

RSC Advances ◽  
2014 ◽  
Vol 4 (31) ◽  
pp. 16214-16223 ◽  
Author(s):  
Eunjoo Koh ◽  
Nam-Kyun Kim ◽  
Jihoon Shin ◽  
Young-Wun Kim
Keyword(s):  
Interfacial Polymerization ◽  
Chain Extender ◽  
Core Material ◽  
Self Healing ◽  
Paint Coatings ◽  
A Chain ◽  
Water Borne

Polyurethane microcapsules containing water-borne polyurethane (PU) paint as a core material for self-repairing protection coatings were successfully manufactured via interfacial polymerization of diol–diisocyanate prepolymer and 1,4-butanediol as a chain extender in an emulsion solution.

scholarly journals Development and Performance of Bacterial Self-healing Concrete - A Review

2018 ◽  
Vol 431 ◽  
pp. 062003 ◽  
Author(s):  
Muhd Afiq Hizami Abdullah ◽  
Nurul Ain Harmiza Abdullah ◽  
Mohamad Fahrurrazi Tompang
Keyword(s):  
Self Healing ◽  
And Performance

scholarly journals Introduction of Reversible Urethane Bonds Based on Vanillyl Alcohol for Efficient Self-Healing of Polyurethane Elastomers

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2201 ◽  
Author(s):  
Dae-Woo Lee ◽  
Han-Na Kim ◽  
Dai-Soo Lee
Keyword(s):  
Hydrogen Bonding ◽  
Microphase Separation ◽  
Chain Extender ◽  
The Self ◽  
Phenolic Hydroxyl ◽  
Vanillyl Alcohol ◽  
Self Healing ◽  
Alcohol Content ◽  
Urethane Group ◽  
Healing Efficiency

Urethane groups formed by reacting phenolic hydroxyl groups with isocyanates are known to be reversible at high temperatures. To investigate the intrinsic self-healing of polyurethane via a reversible urethane group, we synthesized vanillyl alcohol (VA)-based polyurethanes. The phenolic hydroxyl group of vanillyl alcohol allows the introduction of a reversible urethane group into the polyurethane backbone. Particularly, we investigated the effects of varying the concentration of reversible urethane groups on the self-healing of the polyurethane, and we proposed a method that improved the mobility of the molecules contributing to the self-healing process. The concentration of reversible urethane groups in the polyurethanes was controlled by varying the vanillyl alcohol content. Increasing the concentration of the reversible urethane group worsened the self-healing property by increasing hydrogen bonding and microphase separation, which consequently decreased the molecular mobility. On the other hand, after formulating a modified chain extender (m-CE), hydrogen bonding and microphase separation decreased, and the mobility (and hence the self-healing efficiency) of the molecules improved. In VA40-10 (40% VA; 10% m-CE) heated to 140 °C, the self-healing efficiency reached 96.5% after 30 min, a 139% improvement over the control polyurethane elastomer (PU). We conclude that the self-healing and mechanical properties of polyurethanes might be tailored for applications by adjusting the vanillyl alcohol content and modifying the chain extender.

scholarly journals Development and Performance Evaluation of Corrosion Resistance Self-Healing Coating

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Akshya Kumar Guin ◽  
Suryakanta Nayak ◽  
Manish Kumar Bhadu ◽  
Veena Singh ◽  
Tapan Kumar Rout
Keyword(s):  
Corrosion Resistance ◽  
Performance Evaluation ◽  
Urea Formaldehyde ◽  
Sol Gel ◽  
Core Material ◽  
Self Healing ◽  
Nacl Solution ◽  
The Core ◽  
Steel Protection ◽  
And Performance

Polymer based nanocapsule was developed using core-cell approach, where the core material was methyl diphenyl diisocyanate and the cell material was urea-formaldehyde. The synthesized capsules of 100 to 800 nm size were incorporated into sol-gel matrix to prepare a final coating for steel protection. This coating was found protecting the steel at the damage or crack locations in 3.5% NaCl solution. SEM micrographs confirmed healing of the coating at the damage or crack points.

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