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 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 The effect of dynamic vulcanization on the morphological and mechanical properties of the toughened poly (lactic acid)/epoxidized natural rubber

2018 ◽  
Vol 14 (3) ◽  
pp. 348-352 ◽  
Author(s):  
Nur Amira Sahirah Abdullah ◽  
Zurina Mohamad
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Impact Strength ◽  
Natural Rubber ◽  
Crosslinking Agent ◽  
Epoxidized Natural Rubber ◽  
Poly Lactic Acid ◽  
Dynamic Vulcanization ◽  
The Impact

Poly (lactic acid)/epoxidized natural rubber (PLA/ENR) was prepared by using counter-rotating twin-screw extruder. For dynamic vulcanization process, ENR was compounded with 3 phr of N, N’-m-phenylenebismaleimide (HVA-2) as a crosslinking agent. The aim of this study is to determine the effect of unvulcanized and dynamically vulcanized of ENR on the properties of PLA/ENR blend. The blending of PLA with ENR was prepared with the various composition of ENR (0 wt% to 30 wt%). The morphology and mechanical properties of the blends were investigated by using scanning electron microscope (SEM), tensile test, and impact test. The unvulcanized blend produced a co-continuous morphology of PLA and ENR and the dynamically vulcanized blend shows the dispersed ENR rubber particles in PLA continuous matrix.  For both systems, the tensile strength value was dropped with the increasing amount of ENR content. The impact strength of both systems shows the maximum value at 20 wt% of ENR content. However, dynamically vulcanized PLA/ENR blend shows a better tensile strength and impact strength value as compared with unvulcanized blend.

scholarly journals Effect of Urea-Formaldehyde (UF) with Waterborne Emulsion Microcapsules on Properties of Waterborne Acrylic Coatings Based on Coating Process for American Lime

2020 ◽  
Vol 10 (18) ◽  
pp. 6341 ◽  
Author(s):  
Xiaoxing Yan ◽  
Wenting Zhao ◽  
Xingyu Qian
Keyword(s):  
Urea Formaldehyde ◽  
Paint Film ◽  
Coating Process ◽  
Self Healing ◽  
Waterborne Coatings ◽  
Aging Resistance ◽  
Acrylic Coatings ◽  
Waterborne Emulsion ◽  
The Impact ◽  
Good Coating

The purpose of this paper is to explore the effect of urea-formaldehyde (UF) with waterborne emulsion microcapsules on the optical, mechanical and aging resistance properties of waterborne coatings from the perspective of coating process. In this paper, the microcapsules were prepared with UF resin as the wall materials and waterborne emulsion as the core materials. Based on the coating process, the optical, mechanical and aging resistance properties of the waterborne acrylic coatings with microcapsules for American lime were tested. The good coating process is three layers of primer, two layers of topcoat, and adding microcapsules into primer. The results showed that the coating process had little effect on the color difference of the paint film with microcapsules, the gloss of the paint film prepared by the good coating process was basically not changed, and the mechanical properties of the paint film were good. At this time, the hardness grade of the paint film was 3H, the adhesion was grade 0, the impact resistance was 110.0 N·cm−2, and the elongation at break was 29.7%. The microcapsules added to the primer had better liquid resistance than those added to the topcoat. The paint film had good stability and aging resistance, and could inhibit the generation of microcracks to a certain extent. The paint film prepared by the good coating process had better comprehensive performance. This work provides a technical reference for self-healing of the waterborne coatings on American lime.

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

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.

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

scholarly journals The Impact of Coating Ingredients on the Aging Resistance of Topcoat Paints by Model Trees

2020 ◽  
Author(s):  
Tzu-Tsung Wong ◽  
Shih-Hsuan Hung
Keyword(s):  
Linear Regression ◽  
Regression Models ◽  
Prediction Method ◽  
Linear Regression Models ◽  
Key Factors ◽  
Model Trees ◽  
Factors Affecting ◽  
Aging Resistance ◽  
Before And After ◽  
The Impact

Topcoat paint is mainly composed of resin and pigment and hence its quality highly depends on the type and proportion of these two ingredients. This study aims at testing the formula of the topcoat paint for finding one that can achieve better quality for anti-aging. Various formulas of paint are applied on boards that will be put into ultraviolet accelerated test machines to simulate weathering tests. The gloss and color, before and after the tests, are collected and numerical prediction method M5P is used to grow model trees for discovering the key factors affecting aging. Based on the structure and the linear regression models in the trees, a better topcoat paint should be composed of a high proportion of resin and generally a low proportion of pigment. Good types of resin and pigment are also identified for keeping color and gloss.

Study on Aging Resistance Properties of Natural Rubber Dried by Microwave

2013 ◽  
Vol 706-708 ◽  
pp. 266-269
Author(s):  
Yong Zhou Wang ◽  
Fu Quan Zhang ◽  
Mao Fang Huang ◽  
Mei Chen ◽  
Hong Xing Gui ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Oxidative Degradation ◽  
Rate Of Change ◽  
Thermal Oxidative Degradation ◽  
Oxidative Aging ◽  
Degradation Temperature ◽  
Hot Air ◽  
Aging Resistance ◽  
Before And After ◽  
Thermal Oxidative Aging

In this work, thermogravimetry (TG) and Wallace plastometer were used to study the thermal-oxidative aging resistance properties of natural rubber (NR) dried by microwave and hot-air. Showed from the results, thermal degradation temperature, primary thermal-oxidative degradation temperature, the value of P0, PRI and VR for NR dried by microwave were higher than those of NR dried by hot-air; the thermal-oxidative aging resistance properties of NR vulcanizes dried by microwave improved significantly, and the rate of change for elongation at break (-26.76%) and tensile strength (-38.6%) of NR vulcanizes dried by microwave before and after aging were apparently higher than those of NR vulcanizes dried by hot-air, which were (-60.29%) and (-82.11), respectively.

scholarly journals Alleviating Molecular-Scale Damages in Silica-Reinforced Natural Rubber Compounds by a Self-Healing Modifier

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 39
Author(s):  
Bashir Algaily ◽  
Wisut Kaewsakul ◽  
Siti Salina Sarkawi ◽  
Ekwipoo Kalkornsurapranee
Keyword(s):  
Natural Rubber ◽  
Zinc Acetate Dihydrate ◽  
Crosslinking Agent ◽  
Annealing Treatment ◽  
Self Healing ◽  
Rubber Compounds ◽  
Healing Efficiency ◽  
Molecular Scale ◽  
Transesterification Catalyst ◽  
Natural Rubber Vulcanizates

The property retentions of silica-reinforced natural rubber vulcanizates with various contents of a self-healing modifier called EMZ, which is based on epoxidized natural rubber (ENR) modified with hydrolyzed maleic anhydride (HMA) as an ester crosslinking agent plus zinc acetate dihydrate (ZAD) as a transesterification catalyst, were investigated. To validate its self-healing efficiency, the molecular-scale damages were introduced to vulcanizates using a tensile stress–strain cyclic test following the Mullins effect concept. The processing characteristics, reinforcing indicators, and physicomechanical and viscoelastic properties of the compounds were evaluated to identify the influences of plausible interactions in the system. Overall results demonstrate that the property retentions are significantly enhanced with increasing EMZ content at elevated treatment temperatures, because the EMZ modifier potentially contributes to reversible linkages leading to the intermolecular reparation of rubber network. Furthermore, a thermally annealing treatment of the damaged vulcanizates at a high temperature, e.g., 120 °C, substantially enhances the property recovery degree, most likely due to an impact of the transesterification reaction of the ester crosslinks adjacent to the molecular damages. This reaction can enable bond interchanges of the ester crosslinks, resulting in the feasibly exchanged positions of the ester crosslinks between the broken rubber molecules and, thus, achievable self-reparation of the damages.

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