scholarly journals Stabilization Effects of Natural Compounds and Polyhedral Oligomeric Silsesquioxane Nanoparticles on the Accelerated Degradation of Ethylene-Propylene-Diene Monomer

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4390
Author(s):  
Traian Zaharescu ◽  
Ignazio Blanco
Keyword(s):  
Antioxidant Properties ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Natural Antioxidants ◽  
Rosemary Extract ◽  
Γ Irradiation ◽  
Ethylene Propylene ◽  
Radical Intermediates ◽  
Accelerated Degradation ◽  
Evaluation Procedures ◽  
Oligomeric Silsesquioxane

In this work the analysis on the stabilization activities of some natural antioxidants (rosemary extract, capsaicin, quercetin or oleanolic acid) is presented. A similar contribution of an inorganic structure—polyhedral oligomeric silsesquioxane (POSS) nanoparticles—is also evaluated. The stabilization effects on the oxidation protection were investigated for several formulations based on ethylene-propylene-diene-terpolymer (EPDM). The samples were examined in pristine state or after γ-irradiation, when the accelerated degradation scission of polymer macromolecules followed by the mitigation of oxidation. Three evaluation procedures: chemiluminescence, FTIR spectroscopy and thermal analysis were applied for the characterization of stability efficiency. The delaying effect of oxidative aging in EPDM matrix is illustrated by the values of activation energy, which are correlated with the type and concentration of embedded compounds. The durability of studied EPDM formulations is discussed for the assessment of material life. The improved behavior of structured hybrids useful for the optimization application regimes is essentially based on the antioxidant properties of polyphenolic components in the cases of natural antioxidants or on the penetration of free radical intermediates into the free volumes of POSS.

scholarly journals Stability Efficiencies of POSS and Microalgae Extracts on the Durability of Ethylene-Propylene-Diene Monomer Based Hybrids

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 187
Author(s):  
Traian Zaharescu ◽  
Carmen Mateescu
Keyword(s):  
Thermal Stability ◽  
Accelerated Aging ◽  
Inorganic Filler ◽  
Ethylene Propylene Diene Monomer ◽  
Γ Irradiation ◽  
Ethylene Propylene ◽  
Accelerated Degradation ◽  
Improvement Effect ◽  
Aging Conditions ◽  
Oligomeric Silsesquioxane

The EPDM (ethylene-propylene-diene monomer) hybrids with improved thermal and radiation strengths containing 1 and 5 phr of polyhedral oligomeric silsesquioxane (vinyl-POSS, Ov-POSS) and/or 2 phr of microalgae (Chlorella vulgaris (CV) and Spirulinaplatensis (SP)) powders were investigated in respect to their thermal stability after γ-irradiation. The material durability under accelerated degradation was qualified by chemiluminescence and gelation, which prove the contribution of inorganic filler and microalgae extracts on the increase of hybrid thermal stability, as well as the interaction between added components (POSS and CV or SP). The activation energies and the durabilities under accelerated degradation were calculated, indicating their suitable usage as appropriate materials in various applications. The reported results indicate the improvement effect of both microalgal powders on the oxidation strength, but the contribution of Spirulinaplatensis grabs attention on its efficient effects upon the prevention of degradation under accelerated aging conditions. The thermal performances of the tested EPDM based hybrids are remarkably ameliorated, if the certain formulation includes Ov-POSS (5 phr) and Spirulinaplatensis (2 phr), certifying its suitability for the pertinent applications.

scholarly journals The effect of polyhedral oligomeric silsesquioxanes (POSSs) incorporation in ethylene-propylene-diene-terpolymer (EPDM): a thermal study

2021 ◽  
Author(s):  
Ignazio Blanco ◽  
Traian Zaharescu
Keyword(s):  
Room Temperature ◽  
Thermal Characterization ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Dsc Analysis ◽  
Γ Irradiation ◽  
Scanning Calorimetry ◽  
Ethylene Propylene ◽  
Oligomeric Silsesquioxane ◽  
Ethylene Propylene Diene Terpolymer ◽  
Dynamic Heating

AbstractA series of ethylene-propylene-diene-terpolymer (EPDM)/polyhedral oligomeric silsesquioxane (POSS) composites at different percentage of POSS were prepared and subjected to γ-irradiation. Both irradiated and non-irradiated EPDM and composites were investigated by the means of thermal analysis to verify if the presence of POSS molecules is able to reduce the oxidation level of free radicals generated during the degradation and to evaluate the effects of the irradiation. EPDM composites at 1, 3 and 5 mass% of POSS were thus degraded in a thermogravimetric (TG) balance in dynamic heating conditions (25–700 °C), in both inert and oxidative atmosphere by flowing nitrogen and air respectively. Thermal characterization was then completed by carrying out Differential Scanning Calorimetry (DSC) analysis from sub-ambient to better highlight the melting of the polymer and polymer composites occurring just above the room temperature. FTIR spectroscopy was also performed for the prepared samples to check the presence of the molecular filler in the composites and for the TG’s residue at 700 °C, in order to evaluate its nature. DSC and TGA parameters were detected and discussed to have information about the effect of the degradation’s environment, the effect of irradiation on polymer stabilization and the effect of POSS content in the polymer matrix.

Physical gelation in ethylene–propylene copolymer melts induced by polyhedral oligomeric silsesquioxane (POSS) molecules

Polymer ◽  
2003 ◽  
Vol 44 (5) ◽  
pp. 1499-1506 ◽  
Author(s):  
Bruce X. Fu ◽  
Michael Y. Gelfer ◽  
Benjamin S. Hsiao ◽  
Shawn Phillips ◽  
Brent Viers ◽  
...  
Keyword(s):  
Polyhedral Oligomeric Silsesquioxane ◽  
Ethylene Propylene ◽  
Copolymer Melts ◽  
Physical Gelation ◽  
Oligomeric Silsesquioxane

Model Polyhedral Oligomeric Silsesquioxane Thin Films for Coating Applications

2002 ◽  
Author(s):  
Brent Viers ◽  
Shawn Phillips ◽  
Timothy Haddad ◽  
Alan Esker ◽  
Joe Polidan
Keyword(s):  
Thin Films ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Oligomeric Silsesquioxane

Polyhedral Oligomeric Silsesquioxane /Platelets Rich Plasma/Gelrite-Based Hydrogel Scaffold for Bone Tissue Engineering

2020 ◽  
Vol 26 (26) ◽  
pp. 3147-3160
Author(s):  
Saeedeh Ahmadipour ◽  
Jaleh Varshosaz ◽  
Batool Hashemibeni ◽  
Leila Safaeian ◽  
Maziar Manshaei
Keyword(s):  
Bone Fractures ◽  
Compressive Strain ◽  
Gelation Time ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Local Drug Delivery ◽  
Gelling Agent ◽  
Control Group ◽  
Hydrogel Scaffold ◽  
Alizarin Red ◽  
Oligomeric Silsesquioxane

Background: Polyhedral oligomeric silsesquioxane (POSS) is a monomer with silicon structure and an internal nanometric cage. Objective: The purpose of this study was to provide an injectable hydrogel that could be easily located in open or closed bone fractures and injuries, and also to reduce the possible risks of infections caused by bone graft either as an allograft or an autograft. Methods: Various formulations of temperature sensitive hydrogels containing hydroxyapatite, Gelrite, POSS and platelets rich plasma (PRP), such as the co-gelling agent and cell growth enhancer, were prepared. The hydrogels were characterized for their injectability, gelation time, phase transition temperature and viscosity. Other physical properties of the optimized formulation including compressive stress, compressive strain and Young’s modulus as mechanical properties, as well as storage and loss modulus, swelling ratio, biodegradation behavior and cell toxicity as rheometrical parameters were studied on human osteoblast MG-63 cells. Alizarin red tests were conducted to study the qualitative and quantitative osteogenic capability of the designed scaffold, and the cell adhesion to the scaffold was visualized by scanning electron microscopy. Results: The results demonstrated that the hydrogel scaffold mechanical force and injectability were 3.34±0.44 Mpa and 12.57 N, respectively. Moreover, the scaffold showed higher calcium granules production in alizarin red staining compared to the control group. The proliferation of the cells in G4.5H1P0.03PRP10 formulation was significantly higher than in other formulations (p<0.05). Conclusion: The optimized Gelrite/Hydroxyapatite/POSS/PRP hydrogel scaffold has useful impacts on osteoblasts activity, and may be beneficial for local drug delivery in complications including a break or bone loss.

Punica granatum as a Source of Natural Antioxidant and Antimicrobial Agent; a Comprehensive Review on Related Investigations

2020 ◽  
Vol 17 ◽  
Author(s):  
Atefeh Jalali ◽  
Mohammadreza Kiafar ◽  
Masih Seddigh ◽  
Mohammad M. Zarshenas
Keyword(s):  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Natural Antioxidants ◽  
Punica Granatum ◽  
Antimicrobial Activities ◽  
Natural Antioxidant ◽  
Antiviral Activities ◽  
Natural Foods

Background: The consumption of natural antioxidants is increasing due to the demand and tendency to natural foods. Punica granatum L. [Punicaceae] is a fruit with various bioactive ingredients. The effectiveness of this plant has been proved against various disorders such as hyperglycemia, hyperlipidemia, blood coagulation, infections, cancer, and dentistry. Among them, there are numerous researches on antimicrobial and antioxidant properties. Subsequently, the present study aimed to compile a review of those properties to outline this herb as a possible natural antioxidant and preservative. Methods: Synchronically, keywords "Punica granatum" with antimicrobial, or antibacterial, antifungal, antiviral, antioxidant and radical scavenging were searched through "Scopus" database up to 31st September 2019. Papers focusing on agriculture, genetics, chemistry, and environmental sciences were excluded and also related papers were collected. Results: Among 201 papers focusing on related activities, 111 papers have dealt with antioxidant activities focusing based on DPPH assay, 59 with antibacterial, on both gram+ and gram- bacteria, 24 with antifungal effects, mostly on Aspergillus niger and Candida albicans, and 7 papers with antiviral activities. There were about 50 papers focusing on in-vivo antioxidant activities of this plant. Conclusion: Taken together, botanical parts of P. granatum have possessed notable radical scavenging and antimicrobial activities that with these properties, this plant can be introduced as a natural safe source of preservative and antioxidant. Accordingly, P. granatum can be applied as excipient with the aforementioned properties in the pharmaceutical and food industries.

scholarly journals Polyhedral oligomeric silsesquioxane (POSS)-modified phenolic resin: Synthesis and anti-oxidation properties

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 316-326
Author(s):  
Bing Wang ◽  
Minxian Shi ◽  
Jie Ding ◽  
Zhixiong Huang
Keyword(s):  
Phenolic Resin ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Synthesis Process ◽  
H Nmr ◽  
Chemical Structures ◽  
Carbon Fiber Fabric ◽  
Oxidation Properties ◽  
Tg And Dtg ◽  
Oligomeric Silsesquioxane ◽  
Fiber Fabric

Abstract In this work, octamercapto polyhedral oligomeric silsesquioxane (POSS-8SH) and octaphenol polyhedral oligomeric silsesquioxane (POSS-8Phenol) were successfully synthetized. POSS-8Phenol was added into the synthesis process of liquid thermoset phenolic resin (PR) to obtain POSS-modified phenolic resin (POSS-PR). Chemical structures of POSS-8SH, POSS-8Phenol, and POSS-PR were confirmed by FTIR and 1H-NMR. TG and DTG analysis under different atmosphere showed that char yield of POSS-PR at 1,000°C increased from 58.6% to 65.2% in N2, which in air increased from 2.3% to 26.9% at 700°C. The maximum pyrolysis temperature in air increased from 543°C to 680°C, which meant better anti-oxidation properties. XRD results confirmed both POSS-8Phenol and POSS-PR-generated crystalline SiO2 in air, which could explain the improvement of anti-oxidation properties. SEM showed that the POSS-PR had phase separation during curing process. Finally, carbon fiber fabric-reinforced POSS-PR (C-POSS-PR) was prepared to verify the anti-oxidation properties of POSS-PR.

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