scholarly journals Self-Healable Biocomposites Crosslinked with a Combination of Silica and Quercetin

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4028
Author(s):  
Olga Olejnik ◽  
Anna Masek ◽  
Małgorzata Iwona Szynkowska-Jóźwik
Keyword(s):  
Natural Rubber ◽  
Healing Process ◽  
Crosslinking Density ◽  
Mechanical Tests ◽  
Epoxidized Natural Rubber ◽  
Self Healing ◽  
Human Beings ◽  
Healing Efficiency ◽  
Before And After ◽  
The Impact

In this publication, novel bio-based composites made of epoxidized natural rubber with 50 mol% of epoxidation (ENR-50) are presented. The obtained materials, partially cured with a totally environmentally friendly crosslinking system consisting of natural ingredients, including quercetin and silica, exhibit a self-healing ability resulting from the self-adhesion of ENR-50 and reversible physical forces between the curing agent and the matrix. The impact of natural components on the crosslinking effect in uncured ENR-50 matrix was analyzed based on rheometric measurements, mechanical tests and crosslinking density. The partially crosslinked samples were next cut into two separate pieces, which were instantly contacted together under a small manual press, left at room temperature for a few days for the healing process to occur and finally retested. The healing efficiency was estimated by measuring mechanical properties before and after the healing process and was also confirmed by photos taken using optical and scanning electron microscope (SEM). According to the results, a combination of silica and quercetin is a totally safe, natural and effective crosslinking system dedicated to epoxidized natural rubber. The novel composites containing ingredients safe for human beings exhibit promising self-healing properties with a healing efficiency of up to 45% without any external stimuli and stand a chance of becoming innovative biomedical materials.

scholarly journals Aging Resistance of Biocomposites Crosslinked with Silica and Quercetin

2021 ◽  
Vol 22 (19) ◽  
pp. 10894
Author(s):  
Anna Masek ◽  
Olga Olejnik
Keyword(s):  
Natural Rubber ◽  
Crosslinking Agent ◽  
Mechanical Tests ◽  
Epoxidized Natural Rubber ◽  
Hydroxyl Groups ◽  
Self Healing ◽  
Aging Resistance ◽  
Before And After ◽  
Free Hydroxyl ◽  
The Impact

This research focuses on revealing the double role of quercetin accompanied by silica in epoxidized natural rubber. A crosslinking ability with antioxidative properties exists and reveals the dependence of these functions on quercetin content. Here, the aging resistance of self-healable biocomposites was analyzed. The self-healing properties were presented in our previous work. The stabilizing effect of quercetin applied as a crosslinking agent has been studied in epoxidized natural rubber with a 50 mol% of epoxidation (ENR-50). Some of five -OH moiety groups existing in the quercetin structure are able to react with epoxy rings of ENR-50 and cure this elastomer, whereas other free hydroxyl groups can donate the hydrogen molecule to a radical molecule, stabilizing it. The aging resistance of prepared composites was estimated by mechanical tests conducted before and after different types of aging, as well as by differences in color and surface energy between aged and un-aged samples. Changes within the oxygen function, which occurred as a result of the aging process, were observed using FT-IR absorbance spectroscopy. Furthermore, the impact of quercetin content on composites’ thermal stability was investigated by thermogravimetry (TGA). According to the results, a proper dose of quercetin can act as a crosslinker and antioxidant in ENR-50 at the same time.

scholarly journals The Role of Non-Rubber Components on Molecular Network of Natural Rubber during Accelerated Storage

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2880
Author(s):  
Huifeng Zhang ◽  
Lu Zhang ◽  
Xu Chen ◽  
Yueqiong Wang ◽  
Fuchun Zhao ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Network Formation ◽  
Crosslinking Density ◽  
Factors Affecting ◽  
Hardening Mechanism ◽  
Accelerated Storage ◽  
Before And After ◽  
The Impact ◽  
Vital Factor

Though the non-rubber components have long been recognized to be a vital factor affecting the network of natural rubber (NR), the authentic role of non-rubber components on the network during accelerated storage has not been fully illuminated. This work attempts to clarify the impact of non-rubber components on the network for NR during accelerated storage. A natural network model for NR was proposed based on the gel content, crosslinking density, and the non-rubber components distribution for NR before and after centrifugation. Furthermore, the effect of non-rubber components on the network was investigated during accelerated storage. The results show that terminal crosslinking induced by non-rubber components and entanglements are primary factors affecting the network formation during accelerated storage. By applying the tube model to analyze the stress-strain curves of NR, we found that the contribution of the entanglements to the network formation is larger than that of terminal crosslinking during accelerated storage. The work highlights the role of non-rubber components on the network during accelerated storage, which is essential for understanding the storage hardening mechanism of NR.

scholarly journals Self-Healing UV-Curable Acrylate Coatings for Wood Finishing System, Part 2: Impact of Monomer Structure and Self-Healing Parameters on Self-Healing Efficiency

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1328
Author(s):  
Chloé Paquet ◽  
Stephen Brown ◽  
Jolanta E. Klemberg-Sapieha ◽  
Jean-François Morin ◽  
Véronic Landry
Keyword(s):  
Crosslinking Density ◽  
Wood Products ◽  
The Self ◽  
Mechanical Resistance ◽  
Self Healing ◽  
Uv Curable ◽  
Monomer Structure ◽  
Healing Efficiency ◽  
Wood Flooring ◽  
The Impact

Wood is increasingly used in construction for the benefits it brings to occupants and for its ecological aspect. Indoor wood products are frequently subject to mechanical aggressions, their abrasion and scratch resistance thus need to be improved. The coating system ensures the wood surface protection, which is, for wood flooring, a multilayer acrylate UV-curable 100% solid system. To increase the service life of wood flooring, a new property is studied: self-healing. The objective of this study is to observe the impact of monomer structure on self-healing efficiency and the effect of self-healing parameters. A previous formulation was developed using hydrogen bond technology to generate the self-healing property. In this paper, the assessment of the formulation and the self-healing parameters’ impact on self-healing efficiency as well as the physicochemical properties are presented. The composition of the monomer part in the formulations was varied, and the effect on the conversion yield (measured by FT-IR), on the Tg and crosslinking density (measured by DMA) and on mechanical resistance (evaluated via hardness pendulum, indentation, and reverse impact) was analyzed. The self-healing efficiency of the coatings was determined by gloss and scratch depth measurements (under constant and progressive load). It was proven that monomers with three acrylate functions bring too much crosslinking, which inhibits the chain mobility necessary to observe self-healing. The presence of the AHPMA monomer in the formulation permits considerably increasing the crosslinking density (CLD) while keeping good self-healing efficiency. It was also observed that the self-healing behavior of the coatings is different according to the damage caused. Indeed, the self-healing results after abrasion and after scratch (under constant or progressive load) are different. In conclusion, it is possible to increase CLD while keeping self-healing behavior until a certain limit and with a linear monomer structure to avoid steric hindrance. Moreover, the selection of the best coatings (the one with the highest self-healing) depends on the damage.

scholarly journals Numerical Studies of the Effects of Water Capsules on Self-Healing Efficiency and Mechanical Properties in Cementitious Materials

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Haoliang Huang ◽  
Guang Ye
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Cementitious Materials ◽  
Self Healing ◽  
Negative Effects ◽  
Numerical Studies ◽  
Healing Efficiency ◽  
The Impact ◽  
Positive Effect

In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was determined numerically. By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement was quantified. In addition, the impact of capsules on mechanical properties was investigated numerically. The amount of released water increases with the dosage of capsules at different slops as the size of capsules varies. Concerning the best efficiency of self-healing, the optimizing size of capsules is 6.5 mm for capsule dosages of 3%, 5%, and 7%, respectively. Both elastic modulus and tensile strength of cementitious materials decrease with the increase of capsule. The decreasing tendency of tensile strength is larger than that of elastic modulus. However, it was found that the increase of positive effect (the capacity of inducing self-healing) of capsules is larger than that of negative effects (decreasing mechanical properties) when the dosage of capsules increases.

scholarly journals Lamb-Wave-Based Method in the Evaluation of Self-Healing Efficiency

2020 ◽  
Vol 10 (7) ◽  
pp. 2585
Author(s):  
Maciej Radzieński ◽  
Paweł Kudela ◽  
Wiesław Ostachowicz ◽  
Patryk Bolimowski ◽  
Rafał Kozera ◽  
...  
Keyword(s):  
Lamb Wave ◽  
Composite Laminates ◽  
Impact Damage ◽  
Healing Process ◽  
Nondestructive Method ◽  
Laser Vibrometer ◽  
Self Healing ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Healing Efficiency

The aim of this research is a feasibility study of self-healing process monitoring in composite laminates. A novel nondestructive method based on the full wavefield of Lamb wave processing is proposed. Experimental verification is presented for glass-fiber-reinforced polymer plate with embedded self-healing function in the form of a dry microcapsule powder. After impacting the specimen to create barely visible impact damage, a series of laser vibrometer full wavefield measurements were carried out and processed to assess self-healing efficiency.

Self-Healing Behavior of Blends Based on Ionomers with Ethylene/Vinyl Alcohol Copolymer or Epoxidized Natural Rubber

2011 ◽  
Vol 296 (12) ◽  
pp. 1119-1127 ◽  
Author(s):  
Md. Arifur Rhaman ◽  
Maurizio Penco ◽  
Gloria Spagnoli ◽  
Antonio Mattia Grande ◽  
Luca Di Landro
Keyword(s):  
Natural Rubber ◽  
Vinyl Alcohol ◽  
Epoxidized Natural Rubber ◽  
Self Healing ◽  
Ethylene Vinyl Alcohol ◽  
Ethylene Vinyl Alcohol Copolymer

The effects of textile reinforcements on the protective properties of self-healing polymers intended for safety gloves

2020 ◽  
Vol 90 (17-18) ◽  
pp. 1974-1986
Author(s):  
Emilia Irzmańska ◽  
Anna Bacciarelli-Ulacha ◽  
Agnieszka Adamus-Włodarczyk ◽  
Anna Strąkowska
Keyword(s):  
Healing Process ◽  
Polymeric Composite ◽  
Polymeric Materials ◽  
Economic Loss ◽  
The Self ◽  
Raw Material ◽  
Protective Equipment ◽  
Self Healing ◽  
Hybrid Molecules ◽  
The Impact

In the environment where glove material is exposed to harmful chemicals, hazards related to faster penetration of dangerous substances into the glove interior may cause microdamage. One of the solutions to overcome this problem is to use the self-healing polymeric materials that can minimize economic loss and accidents in the workplace. The current work aims to present the impact of different types of textile reinforcement on the effectiveness and efficiency of the self-healing process of methyl vinyl silicone rubber containing hybrid molecules with an inorganic silsesquioxane intended for use on all-rubber gloves. Three knitted fabrics with a similar structure and differentiated raw material composition were selected: polyamide, cotton–polyamide, and cotton. Evaluation of the self-healing process of the elastomeric composite to personal protective equipment was performed. For this purpose the assessment of the surface morphology of materials has been performed before and after the self-healing process. The implementation of knitted fabric into the polymeric composite in the tested samples allowed us to obtain the best results in all tests. The studied composite samples exhibited an increased resistance to three types of damage: penetration, abrasion and puncture. The samples also underwent the self-healing processes and regeneration after a proper conditioning period. Thus, the obtained results confirmed the possibility of using tested elastomeric composites in the construction of protective gloves and showed an effectivity of the self-healing process for the long-term usage of that protective equipment.

scholarly journals Self-Healable Supramolecular Vanadium Pentoxide Reinforced Polydimethylsiloxane-Graft-Polyurethane Composites

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Ali Berkem ◽  
Ahmet Capoglu ◽  
Turgut Nugay ◽  
Erol Sancaktar ◽  
Ilke Anac
Keyword(s):  
Tensile Strength ◽  
Vanadium Pentoxide ◽  
Coupling Reaction ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Healing Time ◽  
The Self ◽  
Supramolecular Polymer ◽  
Self Healing ◽  
Healing Efficiency

The self-healing ability can be imparted to the polymers by different mechanisms. In this study, self-healing polydimethylsiloxane-graft-polyurethane (PDMS-g-PUR)/Vanadium pentoxide (V2O5) nanofiber supramolecular polymer composites based on a reversible hydrogen bonding mechanism are prepared. V2O5 nanofibers are synthesized via colloidal route and characterized by XRD, SEM, EDX, and TEM techniques. In order to prepare PDMS-g-PUR, linear aliphatic PUR having one –COOH functional group (PUR-COOH) is synthesized and grafted onto aminopropyl functionalized PDMS by EDC/HCl coupling reaction. PUR-COOH and PDMS-g-PUR are characterized by 1H NMR, FTIR. PDMS-g-PUR/V2O5 nanofiber composites are prepared and characterized by DSC/TGA, FTIR, and tensile tests. The self-healing ability of PDMS-graft-PUR and composites are determined by mechanical tests and optical microscope. Tensile strength data obtained from mechanical tests show that healing efficiencies of PDMS-g-PUR increase with healing time and reach 85.4 ± 1.2 % after waiting 120 min at 50 °C. The addition of V2O5 nanofibers enhances the mechanical properties and healing efficiency of the PDMS-g-PUR. An increase of healing efficiency and max tensile strength from 85.4 ± 1.2% to 95.3 ± 0.4% and 113.08 ± 5.24 kPa to 1443.40 ± 8.96 kPa is observed after the addition of 10 wt % V2O5 nanofiber into the polymer.

Autonomic Self-Healing in Epoxidized Natural Rubber

2013 ◽  
Vol 5 (4) ◽  
pp. 1494-1502 ◽  
Author(s):  
Md Arifur Rahman ◽  
Luciana Sartore ◽  
Fabio Bignotti ◽  
Luca Di Landro
Keyword(s):  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Self Healing

The Placebo Phenomenon and Well-Being: Notes on the Healing Process as an Evolutionary Adaptive Trait

2012 ◽  
Vol 19 (3-4) ◽  
pp. 181-203 ◽  
Author(s):  
Pieter F. Craffert
Keyword(s):  
Healing Process ◽  
Placebo Response ◽  
Well Being ◽  
Faith Healing ◽  
Self Healing ◽  
Health Providers ◽  
Human Beings ◽  
Nocebo Effect ◽  
Potential Health ◽  
Adaptive Trait

Abstract As biopsychosocial beings, humans have developed numerous mechanisms that regulate and sustain life and well-being, one of which is self-healing. The term placebo response, to be understood as a meaning response and self-healing mechanism, refers to an evolutionary adaptive trait that developed as an integral part of human beings as biocultural and socially embodied beings in search of ways of overcoming assaults on wellness. As embodied beings humans function as biopsychosocial organisms where body, culture and society interact in order to bring about well-being. The placebo response is one such response by the organism and can have positive or negative effects on the organism. When the organismic response to assaults on well-being facilitates positive outcomes such as healing and well-being, it is called the placebo effect, and when it operates as a negative force as in producing or enhancing sickness and distress, it is referred to as the nocebo effect. An understanding of these organismic responses is essential for an appreciation of all health care systems and healing modalities, and consequently, for the evaluation of the efficacy and quality of potential health providers and promoters of well-being. It can also be used to evaluate the potential of complementary and alternative medicine (CAM), including faith healing and distant healing. Ultimately, an appreciation of the organismic response to bring about either the placebo or nocebo effect provides insight into who and what we are as human beings.

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