Synthesis and properties of responsive self-healing polyurethane containing dynamic disulfide bonds

2021 ◽  
pp. 095400832110228
Author(s):  
Qiqi Qu ◽  
Hua Wang ◽  
Jing He ◽  
Yunsheng Da ◽  
Menghan Zhu ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Meaningful Work ◽  
Hexamethylene Diisocyanate ◽  
Self Healing ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
Raman Scattering Spectroscopy ◽  
Ph Response ◽  
Healing Efficiency

The polymers with pH responsiveness and temperature sensitivity exhibit important applications in many fields. To endow the responsive polymers with self-healing is meaningful work, which contributes to increase their service life and reduce waste of resources significantly. In this research, a series of pH-responsive polyurethanes containing dynamic disulfide bonds and carboxylic acid functional groups were prepared by mixing polycaprolactone diol (PCL), hexamethylene diisocyanate (HDI), 2,2-dimethylolbutyric acid, and bis(2-hydroxyethyl) disulfide. The structure of the polymer was confirmed by some characterization methods such as infrared absorption spectroscopy, Raman scattering spectroscopy, X-ray diffraction, and differential scanning calorimetry. Many performances of the polymer such as the contact angle, thermal stability, mechanics, and self-healing properties can be adjusted by changing the functional units of polyurethanes. The dynamic disulfide bonds in the main chain were observed no harm to the pH response performance, instead which were beneficial to the promotion of heat resistance, tensile properties, and self-healing performance of polyurethane. The elongation at break and the tensile strength are increased by 85.3% and 54.9%, respectively. All the polyurethane exhibited considerable self-healing effects at 110°C, with the highest healing efficiency reaching 93.7%, as a result of the dissociation of hydrogen bonds and the exchange reaction of disulfide bonds.

scholarly journals High Throughput Screening and Characterization Methods of Jordanian Oil Shale as a Case Study

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3148 ◽  
Author(s):  
Ziad Abu El-Rub ◽  
Joanna Kujawa ◽  
Esra’a Albarahmieh ◽  
Nafisah Al-Rifai ◽  
Fathieh Qaimari ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Oil Shale ◽  
Analytical Techniques ◽  
Economic Feasibility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
X Ray ◽  
Hydrogen Mass

Oil shale is an important possible solution to the problem of energy in Jordan. To explore the technical and the economic feasibility of oil shale deposits, numerous samples are analyzed using the standard Fischer Assay (FA) method. However, it would be useful to develop faster, cheaper, and reliable methods for determining the oil content of oil shale. Therefore, the aim of this work was to propose and investigate rapid analytical techniques for the screening of oil shale deposits and to correlate them with the FA method. The Omari deposit located east of Jordan was selected as a case study for analysis using thermogravimetric analysis (TGA) coupled with Fourier-transform infrared (FTIR), differential scanning calorimetry (DSC), elemental analysis, X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. Results obtained from the TGA method were linearly correlated with FA with high regression factor (R2 = 0.99); a quadratic correlation (R2 = 0.98) was maintained between the FA and the elemental hydrogen mass content, and a quadratic correlation (R2 = 0.97) was found between the FA and the aliphatic hydrocarbons (FTIR peak at 2927 cm−1) produced in the pyrolysis zone. Although other techniques were less correlated, further investigation might lead to better results. Subsequently, these correlated techniques can be a practical alternative to the conventional FA method when, in particular, specific correlation is made for each deposit.

scholarly journals Self-Healing Photocurable Epoxy/thiol-ene Systems Using an Aromatic Epoxy Resin

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Ricardo Acosta Ortiz ◽  
Omar Acosta Berlanga ◽  
Aída Esmeralda García Valdez ◽  
Rafael Aguirre Flores ◽  
José Guadalupe Télles Padilla ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Epoxy Resins ◽  
Room Temperature ◽  
Gel Permeation Chromatography ◽  
Mechanical Analysis ◽  
Hypervalent Iodine ◽  
Self Healing ◽  
Healing Efficiency ◽  
Kinetics Of ◽  
Epoxy Groups

A rapid and efficient method to obtain self-healing epoxy resins is discussed. This method is based on the use of a thiol-disulfide oligomer obtained by partial oxidation of a multifunctional thiol using a hypervalent iodine (III) compound as oxidant. The oligomer was characterized by Fourier transform infrared spectroscopy (FTIR), Raman and nuclear magnetic resonance spectroscopies, and gel permeation chromatography (GPC). The oligomer was a joint component of the thiol-ene system along with a tetra-allyl-functionalized curing agent. The kinetics of the photopolymerization of diglycidylether of bisphenol A (DGEBA) revealed that conversions of the epoxy groups as high as 80% were achieved in only 15 minutes by increasing the concentration of the thiol-ene system in the formulation. The disulfide bonds introduced in the copolymer using the thiol-disulfide oligomer allowed the repairing of the test specimens in as little as 10 minutes when the specimens were heated at 80°C or for 500 minutes at room temperature. The analysis of the mechanical properties using dynamic mechanical analysis (DMA) showed that the specimens displayed a healing efficiency up to 111% compared with the unhealed specimens, depending on the amount of polythioethers present in the copolymer.

Comparison and Thermodynamic Analysis of Crystallinity of Noncrosslinking and Crosslinking Fluorinated Acrylate Copolymers Films

2011 ◽  
Vol 239-242 ◽  
pp. 1391-1395
Author(s):  
Hui Qin Chen ◽  
Bing Wu ◽  
Zhi Qi Cai ◽  
Pi Hui Pi ◽  
Xiu Fang Wen ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermodynamic Analysis ◽  
Hexamethylene Diisocyanate ◽  
Hydroxyethyl Methacrylate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Fluorinated Acrylate ◽  
X Ray ◽  
Ethyl Methacrylate ◽  
Dsc Curves

In this manuscript two different fluorinated acrylate copolymers films, one was non-crosslinking Stearyl acrylate/2-(perfluorooctyl) ethyl methacrylate (SA/FOEMA) and another was cross-linked SA/2-hydroxyethyl methacrylate(HEMA)/FOEMA/hexamethylene diisocyanate trimers (N3300), were prepared and their crystallinities were investigated by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It can be shown from the XRD results that the value of crystallinities of SA/FOEMA and SA/HEMA/FOEMA/N3300 copolymer were 80.95% and 84.02%, respectively. Based on DSC curves and theoretical thermodynamic analysis , it is indicated that crosslinking can improve crystallinity of copolymer composed of SA and FOEMA.

Mechanochemical Synthesis of Nanocrystalline CeO2: The Effect of Annealing Temperatures on the Particle Size

2006 ◽  
Vol 517 ◽  
pp. 252-256 ◽  
Author(s):  
Abdul Hadi ◽  
Iskandar Idris Yaacob ◽  
Lee Seok Ling
Keyword(s):  
Annealing Temperature ◽  
Gas Adsorption ◽  
Weight Ratio ◽  
X Ray Diffraction ◽  
Treatment Results ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
X Ray ◽  
Annealing Temperatures ◽  
Adsorption Desorption

Cerium dioxide (CeO2) nanoparticles were synthesized by a novel mechanochemical process. The precursors of Ce2(CO3)3.xH2O and NaOH were mixed at a weight ratio of 4 to 1. The mixtures were milled using a planetary ball mill with ball to powder ratio of 10:1. The products were then characterized using a battery of characterization methods, including X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and gas adsorption-desorption measurement. The as-prepared particles were largely amorphous with an average specific surface area of about 119.94 m2/g. Nanocrystalline CeO2 with crystallite size of 4.5 nm was obtained when the sample was annealed in air at 350 oC. The heat treatment results showed that the crystallinity of nanocrystalline CeO2 increased with increasing annealing temperature.

scholarly journals Research on synthesis and self-healing properties of interpenetrating network hydrogels based on reversible covalent and reversible non-covalent bonds

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Xiaowen Huang ◽  
Xiaofei Wang ◽  
Chuanying Shi ◽  
Yang Liu ◽  
Yanyan Wei
Keyword(s):  
Hydrogen Bonds ◽  
Disulfide Bonds ◽  
The Self ◽  
Self Healing ◽  
Complex Environment ◽  
Interpenetrating Network ◽  
Covalent Bonds ◽  
Healing Efficiency ◽  
Potential Applications ◽  
Reversible Covalent

AbstractFirst of all, we will provide a brief background on the self-healing hydrogels we produced which are suitable for the complex environment of nature. In this paper, disulfide bonds and acylhydrazone bonds can be combined in SH-WPU and hydrogen bonds existed in PAMAM. And the hydrogel can achieve self-healing under acid, alkaline, neutral or light environment.Self-healing for 1 h, 24 h and 48 h, the self-healing efficiency is 31.58%, 49.84% and 87.35% respectively. This effect achieved the desired effect and the repair effect is more obvious than previous research results. The hydrogels have potential applications in the field of biomaterials.

scholarly journals Improvement of the optical and photocatalytic properties of ZnAl2O4: 1% La3+, x% Pb2+ nanoparticles synthesized by citrate sol-gel route

2021 ◽  
Author(s):  
Hichem Filali ◽  
Nahman Boukheit ◽  
Rafika Bouhroum ◽  
Wassila Chekirou ◽  
Ahcène Karaali
Keyword(s):  
Raman Spectroscopy ◽  
Single Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Constant Amount ◽  
Pure Zinc ◽  
Characterization Methods ◽  
X Ray ◽  
Gel Technique

Abstract Samples of pure zinc aluminate (ZnAl2O4) and doped both with lead (Pb2+) at different ratios (0, 0.5, 1, 1.5, 2 and 2.5% mol) and a constant amount of lanthanum (La: 1% mol), were prepared by the citrate sol-gel technique, and then annealed at 900°C for 2h. In order to study the structural, optical and thermal properties; different characterization methods were used, such as: powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), TGA, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The Analyzes by XRD revealed the presence of the cubic single phase ZnAl2O4 for all samples, with a crystallites size between 19 and 25 nm. These results were confirmed using FTIR, Raman spectroscopy and SEM. Also, photocatalytic study for different samples of ZnAl2O4 shows that they can be used like as photocatalyst and good adsorbents for degradation of Hexamethyl crystallized violet dye in aqueous solution.

scholarly journals Novel Crosslinking System for Poly-Chloroprene Rubber to Enable Recyclability and Introduce Self-Healing

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3347
Author(s):  
Anureet Kaur ◽  
Julien E. Gautrot ◽  
Gabriele Cavalli ◽  
Douglas Watson ◽  
Alan Bickley ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Photoelectron Spectroscopy ◽  
Disulfide Bonds ◽  
Self Healing ◽  
Scanning Calorimetry ◽  
Polymer Backbone ◽  
Ene Reaction ◽  
X Ray ◽  
Chloroprene Rubber ◽  
Polysulfide Polymer

The introduction of dynamic bonds capable of mediating self-healing in a fully cross-linked polychloroprene network can only occur if the reversible moieties are carried by the cross-linker itself or within the main polymer backbone. Conventional cross-linking is not suitable for such a purpose. In the present work, a method to develop a self-healable and recyclable polychloroprene rubber is presented. Dynamic disulfide bonds are introduced as part of the structure of a crosslinker (liquid polysulfide polymer, Thiokol LP3) coupled to the polymer backbone via thermally initiated thiol-ene reaction. The curing and kinetic parameters were determined by isothermal differential scanning calorimetry and by moving die rheometer analysis; tensile testing was carried to compare the tensile strength of cured compound, healed compounds and recycled compounds, while chemical analysis was conducted by surface X-Ray Photoelectron Spectroscopy. Three formulations with increasing concentrations of Thiokol LP-3 were studied (2, 4, 6 phr), reaching a maximum ultimate tensile strength of 22.4 MPa and ultimate tensile strain of 16.2 with 2 phr of Thiokol LP-3, 11.7 MPa and 10.7 strain with 4 phr and 5.6 MPa and 7.3 strain with 6 phr. The best healing efficiencies were obtained after 24 h of healing at 80 °C, increasing with the concentration of Thiokol LP-3, reaching maximum values of 4.5% 4.4% 13.4% with 2 phr, 4 phr and 6 phr, respectively, while the highest recycling efficiency was obtained with 4 phr of Thiokol LP-3, reaching 11.2%.

Evaluation of properties of sulfur-based polymers obtained by inverse vulcanization: Techniques and challenges

2020 ◽  
pp. 096739112095407 ◽  
Author(s):  
Ali Shaan Manzoor Ghumman ◽  
Mohamed Mahmoud Nasef ◽  
M Rashid Shamsuddin ◽  
Amin Abbasi
Keyword(s):  
Elemental Sulfur ◽  
Complex Structure ◽  
X Ray Diffraction ◽  
Renewable Materials ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
X Ray ◽  
Characterization Techniques ◽  
Thermal Gravimetric Analyzer ◽  
Treatment Conditions

Sulfur-based polymers are unique renewable materials that are receiving a growing attention. The utilization of elemental sulfur with a variety of monomers in their preparation in the absence of solvents using the inverse vulcanization are granting them green nature and unique properties. Several characterization techniques have been used to evaluate the properties of sulfur-based polymers. However, the complex structure and lack of solubility undermine the applicability of some standard characterization techniques in the usual manners. This article reviews the characterization methods used for the evaluation of various properties of sulfur-based polymers such as chemical, morphological, structural, thermal, rheological and mechanical properties, all of which vary depending on the type of comonomer involved in the reaction and heat treatment conditions. The successful applications of different characterization techniques including Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, nuclear magnetic resonance (NMR), scanning electron microscopy/X-ray energy dispersion (SEM-EDX), X-ray diffraction (XRD), mechanical tester, rheometer, thermal gravimetric analyzer (TGA) and differential scanning calorimetry (DSC) are discussed. The challenges to the evaluation of the properties of sulfur-based polymers and the innovative applications of the conventional techniques to overcome them are also deliberated.

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