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.

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 Thermal characterization of novel aliphatic polyesters with ether and thioether linkages

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Soccio ◽  
N. Lotti ◽  
L. Finelli ◽  
A. Munari
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Chemical Structure ◽  
Room Temperature ◽  
Crystallization Rate ◽  
Thermal Characterization ◽  
Scanning Calorimetry ◽  
Aliphatic Polyesters ◽  
Good Thermal Stability

AbstractSeveral novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s were synthesized for comparison and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of the presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the Tgvalue, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions

scholarly journals Polystyrene Nanocomposites Reinforced with Novel Dumbbell-Shaped Phenyl-POSSs: Synthesis and Thermal Characterization

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1475 ◽  
Author(s):  
Abate ◽  
Bottino ◽  
Cicala ◽  
Chiacchio ◽  
Ognibene ◽  
...  
Keyword(s):  
In Situ Polymerization ◽  
Thermal Characterization ◽  
Sem Analysis ◽  
Morphological Properties ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Scanning Calorimetry ◽  
Filler Reinforcement ◽  
Aromatic Bridge ◽  
Very High

Two series of novel dumbbell-shaped polyhedral oligomeric silsesquioxanes (POSSs), fully functionalized with phenyl groups at the corner of the silicon cages, were used to prepare polystyrene (PS) nanocomposites through the method of in situ polymerization. The percentage of the molecular filler reinforcement was set as 5% w/w of POSS and was checked by 1H-NMR spectroscopy. The obtained nanocomposites were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Thermal and morphological properties were evaluated and compared among the nanocomposites obtained using the two different series of dumbbell-shaped POSSs and with the net PS. The thermal parameters for the prepared nanocomposites were very high when compared with those of neat PS, and they evidenced significant differences when an aliphatic or aromatic bridge was used to link the silicon cages. SEM analysis results allow us to hypothesize a justification for the different resistance to thermal degradation showed by the two series of molecular reinforcement.

Thermal and Mechanical Properties of Unvulcanized Polypropylene Blends with Different Elastomers: Ethylene-Propylene-Diene Terpolymer, Nitrile-Butadiene Copolymer and Chlorinated Polyethylene

2013 ◽  
Vol 559 ◽  
pp. 93-98
Author(s):  
Ingars Reinholds ◽  
Valdis Kalkis ◽  
Janis Zicans ◽  
Remo Merijs Meri ◽  
Agnese Grigalovica
Keyword(s):  
Upper And Lower Bounds ◽  
Tensile Behaviour ◽  
Component Ratio ◽  
Scanning Calorimetry ◽  
Chlorinated Polyethylene ◽  
Ethylene Propylene ◽  
Polypropylene Blends ◽  
Pp Blends ◽  
Ethylene Propylene Diene Terpolymer ◽  
Elastomer Blend

In this work, composites of isotactic polypropylene (PP) with three unvulcanized elastomers – terpolymer of ethylene-propylene-dicyclopentadiene (EPDM), chlorinated polyethylene (CPE) and copolymer of acrylonitrile-butadiene (NBR) – have been investigated. The purpose of the investigation was to create PP/elastomer blend composites of significantly different compositions (with an excess of PP, intermediate ones, and with an excess of elastomer) and to study the dependence of tensile behaviour and elastic properties on the blends with different component ratio. Tensile properties have been recognized from the stress-strain curves. The changes of elastic modulus have been characterized with respect to the Hashin-Shtrikman upper and lower bounds and the Davies equation. Calorimetric properties of PP blends with elastomers (crystallinity and melting behaviour of polypropylene phase) have also been investigated with the method of differential scanning calorimetry (DSC).

Thermal characterization of novel aliphatic polyesters with ether and thioether linkages

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Soccio ◽  
N. Lotti ◽  
L. Finelli ◽  
A. Munari
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Chemical Structure ◽  
Room Temperature ◽  
Crystallization Rate ◽  
Thermal Characterization ◽  
Scanning Calorimetry ◽  
Aliphatic Polyesters ◽  
Good Thermal Stability

AbstractSeveral novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s for comparison were synthesized and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the Tg value, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions.

scholarly journals Effect of Alkyl Chain Length in POSS Nanocage on Non-Isothermal Crystallization Behavior of PCL/Amino-POSS Nanocomposites

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1719 ◽  
Author(s):  
Fernández ◽  
Guzmán ◽  
Ramos ◽  
Fernández
Keyword(s):  
Size Distribution ◽  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Crystallization Process ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Degree Of Crystallinity ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Scanning Calorimetry ◽  
Oligomeric Silsesquioxane

The study of the non-isothermal crystallization behavior of polymers is of great importance due to the effect of degree of crystallinity and crystallization process on the polymer properties. The effect of aminopropylisobutyl polyhedral oligomeric silsesquioxane (APIBPOSS) and aminopropylisooctyl polyhedral oligomeric silsesquioxane (APIOPOSS) on poly(ε-caprolactone) (PCL) crystallization is studied by differential scanning calorimetry (DSC) under non-isothermal conditions and polarized optical microscopy (POM). The crystallization kinetics is analyzed using the Avrami and Mo models, and effective activation energies are evaluated by the Friedman isoconversional method. The results show that the compatibility between polyhedral oligomeric silsesquioxanes (POSS) and PCL and POSS loading affect the crystallization process. A higher crystallization temperature, a narrower size distribution of crystallite, and a faster crystallization rate are obtained in the presence of all the studied contents of APIBPOSS and at lower contents of APIOPOSS. At APIOPOSS contents higher than 2 wt %, the crystallization temperature is lowered, the size distribution of crystallite is broadened, and the crystallization process is retarded. The presence of POSS leads to an increase in the number of nucleation sites, and a reduction in the size of the crystallite and the overall degree of crystallinity, as a result of the confinement of PCL chains caused by POSS nanoparticles.

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 Effect of Post-Cure on the Static and Viscoelastic Properties of a Polyester Resin

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1927
Author(s):  
Marco P. Silva ◽  
Paulo Santos ◽  
João M. Parente ◽  
Sara Valvez ◽  
Paulo N. B. Reis ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Room Temperature ◽  
Bending Strength ◽  
Polyester Resin ◽  
Thermal Characterization ◽  
Unsaturated Ester ◽  
Bending Properties ◽  
Scanning Calorimetry ◽  
Bending Tests ◽  
Three Point Bending

This work intends to study the effect of the curing parameters on the mechanical properties of a polyester resin without a complete curing reaction process. For this purpose, cures at room temperature, 40 °C, and 60 °C, and post-cures at 40 °C and 60 °C, with different exposure times, were considered. Three-point bending tests were performed to assess the bending properties and both stress relaxation and creep behavior. The degree of crosslinking was estimated by evaluating the C = C ester bond, by Fourier infrared spectroscopy and complemented with the thermal characterization made by differential scanning calorimetry. The results showed that higher curing temperatures are preferable to methods involving curing and post-curing, which can be confirmed by the higher degree of conversion of unsaturated ester bonds at 60 °C. Compared to the resin cured at room temperature, the bending strength increased by 36.5% at 40 °C and 88.6% at 60 °C. A similar effect was observed for bending stiffness. In terms of stress relaxation and creep strain, the lowest values were obtained for samples cured at 60 °C.

Solvent-assisted osmium staining of butyl acrylate and ethylene-propylene-diene in a styrene acrylonitrile matrix

1993 ◽  
Vol 51 ◽  
pp. 900-901 ◽  
Author(s):  
Gudrun A. Hutchins
Keyword(s):  
Butyl Acrylate ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Staining Procedure ◽  
Reactive Site ◽  
Ethylene Propylene ◽  
Minimal Distortion ◽  
Styrene Acrylonitrile ◽  
Engineering Polymers ◽  
Effective Reaction

In order to optimize the toughening effect of elastomers in engineering polymers, it is necessary to characterize the size, morphology and dispersion of the specific elastomer within the polymer matrix. For unsaturated elastomers such as butadiene or isoprene, staining with osmium tetroxide is a well established procedure. The residual carbon-carbon double bond in these materials is the reactive site and forms a 1,2-dilato complex with the OsO4. Incorporation of osmium tetroxide into the elastomer not only produces sufficient contrast for TEM, but also crosslinks the elastomer sufficiently so that ultramicrotomy can be accomplished at room temperature with minimal distortion.Blends containing saturated elastomers such as butyl acrylate (BA) and ethylene propylene diene monomer (EPDM) cannot be stained directly with OsO4 because effective reaction sites such as C=C or -NH2 are not available in sufficient number. If additional reaction sites can be introduced selectively into the elastomer by a chemical reaction or the absorption of a solvent, a modified, two-step osmium staining procedure is possible.

Sign in / Sign up

Export Citation Format

Share Document