Thermo-oxidative Stability Research Articles

Testing of diesel oil containing 10% (V/V ) FAME and cetane package in terms of thermo-oxidative stability

W artykule na podstawie wyników testów i badań przedstawiono wpływ nowego dodatku cetanowo-detergentowego Energocet® na stabilność oksydacyjną i podatność na utlenianie uszlachetnionych olejów napędowych B10 według metody PN-EN 15751:2010 (Rancimat) i PN-EN 16091:2011 (PetroOXY). Przed przystąpieniem do prac przeprowadzono przegląd literatury dla rozeznania tego tematu. Przechodząc do realizacji badań, postawiono cele do osiągnięcia, którymi były skomponowanie nowoczesnego pakietu cetanowo-detergentowego o nazwie Energocet® i pokazanie oddziaływania tego dodatku cetanowego na stabilność termooksydacyjną skomponowanych olejów typu B10 na podstawie wyników badań liczby nadtlenowej oraz stabilności skomponowanych paliw. Badania wykonano w oparciu o surowce, produkty i komponenty dostępne na polskim rynku paliw i biopaliw. Dla sprawdzenia skuteczności i wpływu nowego pakietu dodatków Energocet® na jakość komponowanych paliw w badaniach wykorzystano jeden typowy bazowy olej napędowy oraz dwa komponenty FAME różnych producentów. W badaniach do przygotowania bazowych paliw badawczych B10 użyto jednego bazowego oleju napędowego A oraz dwóch rodzajów estrów metylowych kwasów tłuszczowych oleju rzepakowego (RME), oznaczonych jako B i C. Praca miała charakter technologiczno-analityczny. Na podstawie uzyskanych wyników badań dodatku cetanowo-detergentowego Energocet® w olejach napędowych zawierających FAME w ilości 10% (V/V) (B10) oznaczono ich stabilność termooksydacyjną po trzech i sześciu tygodniach przechowywania w warunkach testów. Dodatkowo wyznaczono optymalny poziom dozowania pakietu cetanowo-detergentowego Energocet® w ilości 1500 mg/kg w olejach napędowych B10 z udziałem RME-B i RME-C. Przedstawiono również skłonność uszlachetnionych badanych paliw do generowania wolnych rodników w czasie sześciotygodniowego przechowywania próbek w temperaturze 43°C, oznaczonych w postaci liczby nadtlenkowej. Otrzymane wyniki potwierdziły, że dodatek cetanowo-detergentowy Energocet® korzystnie oddziałuje na parametry jakościowe paliw typu B10, w tym również na stabilność termooksydacyjną.

Властивості насіння та олії соняшнику олеїнового типу вітчизняної селекції

Goal. To study domestic sunflower seeds of line X526B with a high content of oleic acid glycerides and oil obtained from it by the method of one-time pressing. To determine the physical-mechanical properties and quality of seed shearing. To establish the oxidative stability of the oil. Methods. The results of measuring the linear sizes of seeds were processed by methods of mathematical statistics to obtain variation series and distribution curves. The evaluation of the thermooxidative stability of the oil was performed by the method of differential scanning calorimetry. Results. The frequency of X526B sunflower seeds of the same length, width, and thickness is 31, 28, and 40%, respectively, which will have a positive effect on the purification of seed mass from waste and oil impurities before the seeds enter production. The X526B sunflower seed width distribution curve differs slightly from the length and thickness distribution curves because it has several frequency peaks (28 and 23%), which can complicate the process of selecting sieves to separate waste. The husk content of this line of sunflower seeds is at the level of 24%, which coincides with the characteristics of classical seeds (25-30%). The number of non-grinded seeds decreases with the increasing number of stages of shaking. The period of induction of oxidation of this oil at a temperature of +110°C does not exceed the period of induction of classical sunflower oil and is 321 minutes. Conclusions. The technology of shearing sunflower seeds of the oleinic type is similar to the technology of shearing classic sunflower seeds, namely, the main influence on quantitative and qualitative indicators of shearing is the thickness of the air layer and the strength of the shell. The technological process parameters (seed moisture and rotation of the seed rotor) are secondary. The oil obtained from X526B sunflower seeds is more resistant to oxidation than the classic one, and can therefore be used for cooking at higher temperatures.

Toughening of natural rubber nanocomposites by the incorporation of nanoscale lignin combined with an industrially relevant leaching process

Strong and tough nanocomposite materials based on natural rubber (NR) latex demonstrate increasing potential to be used in advanced engineering applications and personal care products. Among many approaches for improving the toughness of NR-based products, the use of renewable and bio-based nanofillers is persuaded by environmental and economic trends. In this study, we report the preparation and incorporation of nanoscale organosolv lignin (OSL) particles in NR latex to improve its mechanical properties. We showed that the tensile strength, toughness, and Shore hardness of NR films reinforced with 5 wt % nanoscale OSL were improved by 39 %, 53 % and 12 %, respectively, while retaining high elongation at break (∼1800 %). This substantially improved mechanical property profile can be attributed to the enhanced nanoscale dispersion of OSL and the associated favourable interfacial adhesion of OSL with the NR matrix. Furthermore, the impact of an industrially applicable leaching process on the toughness and thermo-oxidative stability of rubber films is also discussed. For an instance, after the leaching process, the tensile strength, elongation, and toughness of 1 wt % OSL/NR were increased by 27 %, 9 %, and 32 %, respectively.

Potential of using basa catfish oil as a promising alternative deep-frying medium: A thermo-oxidative stability study

Basa catfish is a good source for fish oil extraction, which was believed to have good thermo-oxidative stability because of its similar fatty acid composition to that of palm olein (PO). The thermo-oxidative stability of PO, basa catfish oil (FO), and palm olein-basa fish oil blend (PO-FO; ratio 1:1) was evaluated after 75 frying cycles. No significant difference was observed in p-anisidine value, TOTOX value, conjugated trienes, monomeric oxidized triacylglycerols, and free fatty acids concentration after frying. Moreover, compared to PO, FO exhibited lighter color, lower acid value, conjugated dienes, polymerized triacylglycerol, and total polar content. The PO-FO blend also demonstrated a more favorable frying stability compared to the other two frying systems. These findings indicated that FO could be proposed as a promising alternative to common PO, and its blending with other vegetable oils at an appropriate ratio might improve the overall oil frying quality for future industrial applications.

Synthesis of novel aromatic polyamides containing cardo groups and triphenylphosphine oxide structures by a heterogeneous palladium-catalyzed carbonylation and condensation reaction

New aromatic polyamides containing cardo groups and triphenylphosphine oxide structures were synthesized by a heterogeneous palladium-catalyzed carbonylation and condensation of bis(4-(3-iodophenoxy)phenyl)phenylphosphine oxide (BIPPO), aromatic diamines bearing cardo groups, and carbon monoxide. Polycondensations were carried out in N,N-dimethylacetamide under 1 atm of CO at 120 °C in the presence of a magnetically recyclable heterogeneous palladium catalyst and 1,8-diaza-bicyclo[5,4,0]-7-undecene (DBU) and afforded novel aromatic polyamides with inherent viscosities between 0.72 and 0.76 dL/g. All the polyamides were quite soluble in dipolar aprotic solvents and pyridine and could be converted into transparent, flexible, and tough polyamide films by casting from DMAc solutions. These polymers exhibited high thermal and thermooxidative stability with the glass transition temperatures of 237 °C–256 °C, the temperatures at 5% weight loss of 448 °C–465 °C in air. All the phosphorus-containing polyamides self-extinguished as soon as the flame was removed, and the limited oxygen indices (LOIs) of these polymers were in the range of 39%–44%. The polymer films also showed good mechanical properties and high optical transparency.

Microwave-assisted phosphorylation of organosolv lignin: new bio-additives for improvement of epoxy resins performance

The search for bio-additives for enhancing the thermal and optical performance of epoxy resins has been increasing constantly. Lignin represents an interesting alternative for such purposes. Therefore, the aim of this work was promote the valorization of acetosolv coconut shell lignin (ACSL) and phosphorylated acetosolv coconut shell lignin (P-ACSL) as bio-additives in epoxy resins, evaluating their effects on the thermal and UV-blocking properties of the thermosetting materials. The phosphorylation of ACSL was carried out at 60 °C during 5, 10, and 20 min under microwave irradiation. ACSL and P-ACSL were characterized by TGA, DSC, GPC, and 1H and 31P NMR analyses. ACSL and P-ACSL were added to diglycidyl ether of bisphenol A (DGEBA) and isophoronediamine (IPDA) at 0, 0.5, 1.0, 2.5, 5.0, and 10 wt%, being cured at room temperature during 24 h. The neat and additivated epoxy resins were characterized by TGA, DSC, and UV-Vis analyses. It was observed a notorious enhancement of the thermal (≈ 9 °C for ACSL and P-ACSL) and thermo-oxidative (≈ 8.5 and 15 °C for ACSL and P-ACSL, respectively) stabilities of the thermosetting materials using both lignins, as well as for their glass transition temperatures (Tg), which presented a slight increase of 2.1 and 3.5 °C for ACSL and P-ACSL, respectively. Furthermore, ACSL and P-ACSL exhibited UV stabilizer properties through the complete absorption of UV light in the UV-A and UV-B regions. It can be concluded that P-ACSL could represent an alternative bio-additive that can be easily produced through a clean and fast methodology, capable of improving the thermal, optical, and chemical resistance properties of epoxy resins.

Melt extrusion and additive manufacturing of a thermosetting polyimide

Abstract Additive manufacturing offers the ability to fabricate complex structures without the need for expensive tooling which is very attractive for manufacturing of structural composites. One limitation of additive manufacturing technologies hindering their adoption in high-performance structural composites is the lack of compatible high operating temperature thermosetting resins with robust thermo-oxidative stability. To address this limitation, a reactive melt extruded thermosetting polyimide filament was printed via fused filament fabrication (FFF). A crosslink chemistry has been designed with slow reaction kinetics at the printing temperature which allows printing in a similar manner to engineering thermoplastic filaments. A cure cycle for the as-printed uncrosslinked articles was developed to achieve full cure without loss of shape. The glass transition temperature of the fully cured resin is 250 °C. Comparing longitudinal and transverse tensile strengths of printed and cured coupons showed highly anisotropic behavior. Transverse and through-thickness properties for both uncured and cured printed coupons were nearly identical. The average measured tensile strength of printed and fully cured material was 86 MPa; 73% of fully cured compression molded strength. These results demonstrate the ability to 3D print high performance thermosets without changing commercially available FFF machines.

Impact of Olive Extract Addition on Corn Starch-Based Active Edible Films Properties for Food Packaging Applications.

Active edible films based on corn starch containing glycerol as a plasticizer and an olive extract obtained from Spanish olive fruit (Olea europaea) by-products (olive extract; OE) at different concentrations (0, 0.05, 0.1 and 0.2 wt%) were prepared by using the casting technique and further solvent-evaporation. OE showed high total phenolic and flavonoids contents and antioxidant activity, which was evaluated by using three different methods: free radical scavenging assay by (1,1-dipheny l-2-picrylhydrazyl) DPPH, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) ABTS radical inhibition and ferric reducing antioxidant power (FRAP). The incorporation of OE into the corn starch/glycerol matrix underlined the antioxidant potential and antimicrobial effect against E. coli and S. aureus of these novel active films, being noticeable for films added with 0.2 wt% OE. The developed active films showed a clear thermo-oxidative stability improvement with OE incorporation, in particular at 0.2 wt% loading with an increase of around 50 °C in the initial degradation temperature (Tini) and oxidation onset temperature (OOT). The functional properties of control films were also improved with OE addition resulting in a decrease in Young’s modulus, elongation at break, shore D hardness and water vapor permeability. The present work suggested the potential of the developed corn starch-based edible films as low-price and sustainable food packaging systems to prevent the oxidative deterioration of packaged foodstuff while reducing also the generation of olive by-products.

Improvement in Thermo-oxidative Stability and Mechanical Strength of Carbon Foams for Thermal Management of Reusable Launch Vehicles

Carbon foams were prepared and coated with silicon carbide (SiC) by chemical vapour infiltration (CVI) technique and tested for improvement of oxidation stability and compressive strength, compared to virgin carbon foams. Microstructural and morphological characterisation of SiC-coated carbon foam samples proved the formation of stoichiometric high strength, crystalline β-SiC over amorphous carbon which enables the ceramic foam to take high compressive loads. The final ceramic foam was successfully tested for oxidation stability up to a maximum temperature of 1650 °C under air atmosphere. The weight loss of SiC-coated carbon foam was found to depend on the final density, which depends on the SiC coating thickness. The functional property of reducing the back wall temperature of ceramic matrix composites (CMC) based light weight thermal protection systems (TPS) using SiC-coated carbon foam as the core material was validated by carrying out the plasma testing under atmospheric re-entry conditions. The process is noted for the cost-effective method of imparting desired ceramic property of SiC to less-expensive carbon foam structure.

Properties of Nanocomposites of High-Pressure Polyethylene with Metal-Containing Nanofillers

The effect of nanofiller (NF) additives containing copper oxide nanoparticles (NPs) stabilized by a polymer matrix of maleated polyethylene (MAPE), obtained by the mechanochemical method, on the properties of composites based on high-pressure polyethylene (LDPE) has been investigated by X-ray diffraction (XRD) and thermographic (TGA) analysis. The improvement in strength, deformation, and rheological properties, as well as the thermo-oxidative stability of the obtained nanocomposites, has been revealed, which is associated with the synergistic effect of the interaction of copper nanoparticles with maleic groups of MAPE. It has been shown that LDPE-based nanocomposites can be processed both by pressing and by injection molding and extrusion, which expands the scope of its application.

Natural antioxidant from bamboo leaves for the processing stability of polypropylene

The antioxidant of bamboo leaves (AOB) was used firstly to stabilize polypropylene (PP). Thermogravimetric analysis, oxidation onset temperature and oxidation induction time tests were carried out to test the thermal and thermo-oxidative stability of samples. The melt flow rate and yellowness index were used to characterize the processing stability and color of samples. Field emission scanning electron microscopy was used to determine the distribution of additives. Results showed that AOB improved the thermo-oxidative stability and processing stability of PP. The efficacy of AOB was comparable with that of Irganox 1010 in protecting PP. However, due to the dark yellow color of AOB, the problem of the discoloration of the polymer matrix was not solved.

Influence of substrate and temperature on the biodegradation of polyester-based materials: Polylactide and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as model cases

The extended use of polymers from renewable resources such as aliphatic polyesters or polyhydroxyalkanoates boosted the necessity to understand their behaviour in an end-of-life scenario. Although they can be degraded in reasonable shorter times than traditional polymers, understanding the degradation mechanisms under dissimilar conditions will contribute to further developments in this field. This work aimed to study the effect of temperature and substrate in the degradation of polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) in a simulated laboratory scale to ascertain their contribution, separately or in combination. For this purpose, nine parallel degradation assays were performed by means of the combination of mesophilic (25 °C), thermophilic (58 °C) and hyperthermophilic (80 °C) temperatures with enriched synthetic medium, compost and standardised soil substrates. Although the analysis of the surface morphology, the thermal properties and the thermo-oxidative stability revealed changes as a function of time, the evaluation of the molar mass allowed for a more precise determination of the degradation. In general, chain scission was perceived in all cases as a function of time. The effect of temperature was critical, significantly more important than the effect of the substrate, which showed a less significant contribution, especially in terms of molar mass reduction. While for the PLA, biodegradation at 58 °C and thermal degradation at 80 °C resulted in similar consequences, for the PHBH the hyperthermophilic temperature of 80 °C was the most severe condition, regardless of the substrate. From a technological perspective, it may be highlighted that biodegradation at 58 °C may be the most cost-effective condition due to the lower energy supply required and the valuable contribution of the microorganisms.

Thermal oxidative stability of yttrium containing oligomeric silazanes with organoelement substituents and multiceramics on their basis

Characteristics of thermal transformations of oligomeric silazanes with organoelement substituents at the N atoms (M-OESs) containing one element M = Y, Zr, or Hf or a pair of elements, viz., Zr and Y or Hf and Y, in air in the temperature range 200–1500 °C were investigated. The introduction of yttrium into zirconium- or hafnium-containing oligosilazanes results in an increase in the mass loss at the stage of ceramization and to a decrease in the mass loss in the formed ceramics during subsequent stepwise heat treatment up to 1500 °C. The combination of yttrium with hafnium or zirconium in M-OESs results in a synergistic effect of overall mass loss reduction. The (Zr, Y)-OES and (Hf, Y)-OES multiceramics outperform ceramics modified with one metal in this parameter. The obtained multiceramics is characterized by high thermo-oxidative stability in the temperature range 1100–1500 °C. It is also found that yttrium-containing oligosilazane (Zr, Y)-OES exhibits oleophilic properties with respect to carbon materials.

Bio-Based Polyamide 1010 with a Halogen-Free Flame Retardant Based on Melamine-Gallic Acid Complex.

This work aims at developing polyamide 1010 (PA1010) composites with improved fire behavior using a halogen-free flame-retardant system based on melamine (Me) and gallic acid (GA) complexes (MA). The MA complexes were formed by hydrogen bonding, starting from 1:2, 1:1, 2:1 Me:GA molar ratios. PA1010 composites were obtained by melt mixing, followed by compression molding. MA provided a plasticizing effect on the PA1010 matrix by decreasing the glass transition temperature. The influence of MA on PA1010 chain packaging was highlighted in the X-ray diffraction patterns, mainly in the amorphous phase, but affected also the α and γ planes. This was reflected in the dynamic mechanical properties by the reduction of the storage modulus. H-bonds occurrence in MA complexes, improved the efficiency in the gaseous form during fire exposure, facilitating the gas formation and finally reflected in thermal stability, thermo-oxidative stability, LOI results, and vertical burning behavior results. PA1010 containing a higher amount of GA in the complex (MA12) displayed a limiting oxygen index (LOI) value of 33.6%, much higher when compared to neat PA1010 (25.8%). Vertical burning tests showed that all the composites can achieve the V-0 rating in contrast with neat PA1010 that has V-2 classification.

THE INFLUENCE OF BIOCARBON ADDITIVES ON GREASE FUNCTIONALITY

The article presents the results of tests on tribological and physicochemical properties of plastic greases, in which the dispersing phase was highly refined mineral oil and the dispersed phase (thickener) lithium stearate. The functional additives were biocarbon, which were obtained in the pyrolysis process of waste of natural origin, i.e. stems with corn leaves, wheat straw, flax straw, and cherry stones. The compositions containing 5% m/m biocarbon were prepared. Their evaluated on the functional properties of plastic greases was assessed. Tribological characteristics of the greases compositions were determined using the T-02 tester in accordance with the requirements of the subject standards. The effect of biocarbon used on anti-wear (Goz) and anti-seizing (Pt, poz) plastic greases was determined. An assessment was also made of the effect of plant biocarbon on changes in basic physicochemical properties of the composition of plastic greases, i.e. penetration, dropping temperature, and thermo-oxidative stability. It was found that some of the biocarbon significantly improve the tribological properties of plastic greases without significantly affecting the change of key physicochemical parameters. The most beneficial impact of the tested additives on the operational properties of plastic greases was observed when using biocarbon from wheat straw. In some cases, a lower oxidative resistance of biocarbon grease is observed compared to grease without the addition of biocarbon.

Thermal behavior study and degradation mechanism by TG/MS/FTIR technique of some poly(aryl ether ether ketone)s

This study assesses the thermal and thermo-oxidative stability of some aromatic poly(aryl ether ether ketone)s as well as the degradation mechanism by the TG/MS/FTIR technique (simultaneous mass spectrometry and Fourier transform infrared spectroscopy of off-gases from thermogravimetric analyzer), in two working atmospheres, air and helium. This type of polymers is used in many applications in the electronic, automotive and aerospatial fields. The polymers were synthesized by polycondensation reaction of 4,4′-difluorobenzophenone with several bisphenols, such as 9,9-bis(4-hydroxyphenyl)fluorene, 4,4′-cyclohexylidenebisphenol, 2-(bis[4-hydroxyphenyl]methyl)benzoic acid (phenolphthalin) and 2,5-bis(4-hydroxyphenyl)-1,3,4-oxadiazole. They were characterized by FTIR and 1H NMR spectroscopy, solubility, inherent viscosity and thermogravimetric analysis. Moreover, the main products of polymer thermal decomposition were determined in air and in inert atmosphere (helium). The degradation mechanism of the analyzed samples is influenced by their structure and working atmosphere. Molecular dynamics simulation was also used to evaluate thermal stability of the polymers.

Multi-phenyl structured aromatic hydrocarbon polymer

Multi-phenyl structured random polymer was synthesized via condensation polymerization reaction by applying different monomer ratios and characterized by various spectroscopic methods (FT-IR, 1H NMR). The prepared polymers showed good thermooxidative stability up to 400 ºC. The surface morphology was studied by FESEM that showed the good linkage among the polymer chains. The EDS data of poly(fluorenylene ether ketone), PFEK; demonstrated that all the monomers participated in the copolymerization reaction. Inherent viscosity values of the polymers were obtained in the range of 0.76∼1.12 dL g-1. The polymers’ yield was within 85~90%. The obtained results indicate that the multi-phenyl structured polymer will be the good candidates to prepare the effective aromatic hydrocarbon polymer electrolyte membrane.
 Bangladesh J. Sci. Ind. Res.55(2), 139-146, 2020

Sulfonation and Characterization of Tert-Butyl Styrene/Styrene/Isoprene Copolymer and Polypropylene Blends for Blood Compatibility Applications.

Hydrogenated styrenic block copolymers (HSBCs) have been used in medical tubing for many years due to their high clarity, flexibility, kink resistance, and toughness. However, when it comes to blood storage applications, HSBC compounds’ market has been limited because of their high hydrophobicity, which may trigger platelet adhesion when contacting with blood. HSBC needs to be physically or chemically modified in advance to make it blood compatible; however, HSBC has strong UV/ozone resistance, thermooxidative stability, and excellent processing capability, which increases the difficulty of the chemical modification process as unsaturated dienes has been converted to saturated stable midblocks. Moreover, medical HSBC-containing compounds primarily make up with the non-polar, hydrophobic nature and benign characteristics of other common ingredients (U.S. Pharmacopeia (USP) grades of mineral oil and polypropylene), which complicates the realization of using HSBC-containing compounds in blood-contacting applications, and this explains why few studies had disclosed chemical modification for biocompatibility improvement on HSBC-containing compounds. Sulfonation has been reported as an effective way to improve the material’s blood/platelet compatibility. In this study, hydrogenated tert-butyl styrene (tBS)-styrene-isoprene block copolymers were synthesized and its blends with polypropylene and USP grades of mineral oil were selectively sulfonated by reaction with acetyl sulfate. By controlling the ratio of the hydrogenated tBS-styrene-isoprene block copolymer in the blend, sulfonated films were optimized to demonstrate sufficient physical integrity in water as well as thermal stability, hydrophilicity, and platelet compatibility.

Comparison of the thermo-oxidative stability of murici oil (Byrsonima crassifolia L. Kunt) obtained by enzymatic hydrolysis assisted by ultrasound and classical method

The extraction of oil from various raw materials by enzymatic process has received great importance for being considered clean technology. In addition, the product obtained by enzymatic action has better yields as well as better chemical quality parameters, also better stability conditions. Thus, the objective of the present work was to optimize the murici pulp oil extraction process by enzymatic hydrolysis and to compare the thermo-oxidative stability of murici oil extracted by ultrasound-assisted enzymatic hydrolysis and the oil obtained by the classic method (Soxhlet). The results obtained showed a dependence on the dependent variable - yield (%) - as a function of the independent variables - enzyme concentration (%) and exposure time on ultrasound (min). From the applied statistical analysis, it was observed that the oil extracted by enzymatic hydrolysis showed greater thermal stability (400 °C) compared to that obtained by the classical method (384 °C). The analysis of oxidative stability showed greater propensity to oxidation the oil obtained by classical method compared to that obtained by enzymatic hydrolysis in 6 hours of induction at 110 °C. Thus, the oil obtained by enzymatic hydrolysis has properties superior to that obtained by the classical method and, thus, with better thermo-oxidative stability.

Features of Structural Transformations and Properties of Polycaproamide Modified with Polyfluorated Alcohol Immobilized on Montmorillonite

The effect of 1,1,9-trihydroperfluorononanol-1 immobilized on montmorillonite nanoclay on the nature of structural transformations and the properties of polycaproamide composites was studied. Using the methods of electron, atomic force microscopy and differential scanning calorimetry, we established the features of changing the diameter and height of spherulites in non-oriented films of this heterochain polymer, as well as the reorganization of its polymorphic composition due to the introduction of a fluorine-containing modifier. The stabilizing effect of the additive used on the mechanical properties and thermo-oxidative stability is shown.