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The impact of polyaniline in phosphorus flame retardant ethylene-propylene-diene-rubber (EPDM)
(2019)
Usually elastomers are loaded with high amounts of flame retardants to fulfill fire safety requirements. In this study the potential char precursor polyaniline (PANI) and the established fire retardant pentaerythritol (PER) were implemented in ethylene-propylene-diene monomer rubber (EPDM). PANI and PER were used in low loadings (7 phr) and combined with two phosphorous flame retardants, Ammonium polyphosphate (APP) and a piperazine-pyrophosphate/phosphoric acid compound (FP), to boost their performance. A comprehensive study is presented, explaining the impact of PANI on curing and mechanical properties, including compensation for the plasticizer-like effect of APP in EPDM, and improved flame retardancy. In the cone calorimeter test, the combination of EPDM/FP/PANI reduced the effective heat of combustion by 20%. All nine EPDM rubber compounds were investigated with the LOI and UL 94 tests, cone calorimeter, FMVSS 302 and glow wire testing to quantify fire performance. The PANI containing EPDM rubbers, EPDM/APP/PANI and EPDM/FP/PANI outperformed the corresponding PER containing, EPDM/APP/PER and EPDM/FP/PER rubbers in various tests. Moreover, the study investigated the impact of PANI and PER on the mode of action of the phosphorus species and showed that the addition of PANI increased the amount of phosphorus in the condensed phase. To receive a broader understanding of the flame retardant mode of action of PANI in combination with APP and FP, calculations were carried out to estimate the impact of PANI on the protective layer effect.
Alkali-silica reaction (ASR) is a serious Problem concerning the deterioration of concrete. This leads to significant maintenance and reconstruction costs for concrete infrastructures all over the world. The geographical regions, which play a major role in concrete deterioration, are for example coastal Areas or in general, areas with a high air humidity/salinity due to closeness of rivers or lakes.
These exemplary results show, the application of Raman spectroscopy establishes a valuable approach for characterizing the chemical and structural composition of ASR-products. The results prove the potential to trace the kind of reaction products, developing in dependence on the aggregate and to follow up its local alteration from origin of the gel.
Superglassy polymers with a large fractional free volume have emerged as novel materials with a broad range of applications, especially in the field of membrane separations. Highly permeable addition-type substituted polynorbornenes with high thermal resistance and chemical stability are among the most promising materials. The major obstacle for extending the practical membrane application is their strong tendency to physical aging, leading to a partial decline in their superior transport performance over time. In the present study, broadband dielectric spectroscopy with complementary X-ray scattering techniques were employed to reveal changes in microporous structure, molecular mobility, and conductivity by systematic
comparison of two polynorbornenes with different numbers of trimethylsilyl side groups. Their response upon heating (aging) was compared in terms of structure, dynamics, and charge transport behavior. Furthermore, a detailed analysis of the observed
Maxwell−Wagner−Sillars polarization at internal interfaces provides unique information about the microporous structure in the
solid films. The knowledge obtained from the experiments will guide and unlock potential in synthesizing addition-type polynorbornenes with versatile properties.
Polymers of Intrinsic Microporosity (PIMs) of high performance have developed as materials with a wide application range in gas separation and other energy-related fields. Further optimization and long-term behavior of devices with PIMs require an understanding of the structure-property relationships including physical aging. In this context the glass transi-tion plays a central role, but with conventional thermal analysis a glass transition is usually not detectable for PIMs be-fore their thermal decomposition. Fast scanning calorimetry provides evidence of the glass transition for a series of PIMs, as the time scales responsible for thermal degradation and for the glass transition are decoupled by employing ultrafast heating rates of tens of thousands K s-1. The investigated PIMs were chosen considering the chain rigidity. The estimated glass transition temperatures follow the order of the rigidity of the backbone of the PIMs.
Polymeric membranes represent a low-cost, energy efficient solution for gas separation. Recently polymers of intrinsic microporosity (PIMs) have emerged as prestigious membrane materials featuring a large concentration of pores smaller than 1 nm, a BET surface area larger than 700 m2/g and high gas permeability and selectivity. Unusual chain structure combining rigid segments with sites of contortion gives rise to the intrinsic microporosity. However, this novel class of glassy polymers are prone to pronounced physical aging. The initial microporous structures approach a denser state via local small scale fluctuataions, leading to a dramatic reduction in the gas permeabilities. For the first time, dielectric relaxation spectroscopy with state-of-the-art high-resolution analyzers was employed to investigate three representative PIMs with a systematic change in chain rigidity: PIM-EA-TB 〉 PIM-1 〉 PIM-MDPH-TB. The molecular mobility, the charge transport and their response upon heating (aging) in the polymers were measured in a broad temperature range through isothermal frequency scans during different heating / cooling cycles. Multiple dielectric processes following Arrhenius behavior were observed for the investigated polymers. Local fluctuations, Maxwell-Wagner-Sillars (MWS) polarization and structural relaxation phenomena were discussed and attempted to be correlated with the structural features of PIMs. Moreover, all PIMs showed conductivity in the glassy state. The significant increase in the conductivity with increasing temperature far below the glass transition temperature of PIMs is explained in terms of the loosely packed microporous structure and the formation of local intermolecular agglomerates due to interaction of π-electrons in aromatic moieties of the polymer backbone.
High performance polymers of intrinsic microporosity (PIMs) have emerged as novel materials with broad applications from gas separation to electronic devices. Sufficiently rigid, even contorted polymer chains show only limited molecular mobility, therefore undergo inefficient packing and give rise to intrinsic microporosity with pore size generally smaller than 1 nm and BET surface areas larger than 700 m2/g. Further performance optimization and long-term stability of devices incorporating PIMs rely on our understanding of structure-processing-property relationships and physical aging, in which glass transition plays a key role. Up to now no glass transition temperature (Tg) of PIMs could be detected with conventional thermal analysis techniques before degradation. Decoupling the time scales responsible for the glass transition and the thermal decomposition is a reliable strategy to overcome this. This was achieved by employing fast scanning calorimetry (FSC) based on a chip sensor, which is capable to heat and cool a small sample (ng-range) with ultrafast rates of several ten thousand K/s. FSC provides definitive evidence of glass transition of a series of PIMs with a special consideration on the chain rigidity. The determined glass transition temperature of these PIMs follows the order of the rigidity of their backbone structures. FSC provides the first clear-cut experimental evidence of the glass transition of PIM-EA-TB with a Tg of 663 K, PIM-1 of 644 K and PIM-DMDPH-TB of 630 K at a heating rate of 1Χ104 K/s. Local fluctuations are featured in glass transition of highly rigid PIMs. As conformational changes are prevented by the backbone rigidity, the glass transition must rather be assigned to local small scale fluctuations.
Für Bauteile (Komponenten) von Versorgungsanlagen für flüssige Brenn- und Kraftstoffe muss die Beständigkeit der metallenen Werkstoffe und Polymere nachgewiesen werden. Im Anwendungsfall von Heizöl mit 20 % biogenen Anteilen in Form von Rapsölfettsäuremethylester (FAME, Biodiesel) ist es für eine konservative Beurteilung des Korrosionssystems Werkstoff/Medium/Umgebung wichtig, die Alterungseffekte des Mediums einzubeziehen.
Entwicklung eines Prüfverfahrens für die Untersuchung der Beständigkeit von metallenen Werkstoffen und Polymeren in Heizöl und Heizöl-FAME-Blends, das für eine Vorauswahl der Werkstoffe und zum Nachweis der Beständigkeit im Hinblick auf die bauaufsichtlichen Zulassungsverfahren geeignet ist. Ein Schwerpunkt wird bei den metallenen Werkstoffen auf der Erprobung von Messmethoden liegen, mit denen sich in kurzer Versuchszeit ein Korrosionsangriff detektieren lässt.
Metallene Werkstoffe:
Weder örtliche Korrosion noch erhöhte Flächenkorrosion (Korrosionsrate:< 0,1 m/Jahr) sind bei den bisher geprüften Werkstoffen: Aluminium,
C-Stahl 1.0037, austenitischer CrNi-Stahl 1.4301, Kupfer und Messing in Heizöl und B20 (Heizöl mit 20% Biodiesel) aufgetreten. Diese Werkstoffe sind in den Prüfmedien Heizöl und B20 als beständig zu bewerten.
Es wurde keine signifikante Veränderung des pH-Wertes der Prüfmedien gemessen.
Polymere:
Massebestimmung:
Die Prüfkörper der Elastomere ACM, HNBR und PUR sowie in geringerem Maße PE neigten zur Quellung in Heizöl und B20 nach 42 d und 84 d Auslagerung; für PA 6, POM und PVC wurde keine Masseänderung gemessen. Die Masseänderung der Prüfkörper in Heizöl und B20 ist mit Ausnahme von PUR vergleichbar. Bei PE traten Verfärbungen durch die Brennstoffe auf.
Zugeigenschaften:
ACM, HNBR, PE und PVC sind in Heizöl und B20 beständig, da die Änderung der Zugfestigkeit und der Reißdehnung < 15 % beträgt. PA und POM sind bedingt beständig, da die Änderung der Zugfestigkeit und der Reißdehnung < 30% beträgt.
Compatibility of polymeric materials with heating oil/biodiesel blends at different temperatures
(2019)
Materials compatibility is a major concern whenever the fuel composition is changed. The question arises of whether polymeric materials are resistant to heating oil with admixtures of 10 % biodiesel (B10) and 20 % biodiesel (B20).
The polarity of biodiesel increases its solvency and facilitates permeation and extrac-tion. Solvation, swelling and/or extraction lead to changes in the physical properties and chemical changes of polymeric materials.
The objective of this research was to determine the resistance of frequently used sealing materials such as FKM, EPDM, CR, CSM, NBR, IIR, VMQ, FVMQ, PA and PUR in up to four-year aged B10 for 84 days at 20 °C, 40 °C and 70 °C.
The polymeric materials: ACM, FKM, HNBR, PA, PE; POM, PUR and PVC were ex-posed to B20 for 84 days at 40°C and 70°C in another research project.
Mass, tensile strength, breaking elongation and Shore hardness A (D) of the test specimens were determined before and after the exposure for 84 (42) days in the heating oil blends B10 and B20.
There is not determined a threshold for the reduction in tensile properties and Shore hardness in the international standards. Therefore, a threshold of 15 % was deter-mined for the evaluation of the compatibility.
Measurements of the variations in mass, tensile properties and Shore hardness after exposure of the polymers in non-aged and aged heating oil B10 showed clearly that FKM, FVMQ and PA were the most resistant materials in B10. The elastomers CR, CSM, EPDM, IIR, NBR and VMQ were generally not resistant to B10. Damage to the materials increased with higher test temperatures and the age of B10.
FKM, POM and PVC showed high compatibility in B20 at 40°C and 70 °C. ACM, HNBR and PA were evaluated as resistant in B20 at 40 °C but not at 70°C.
Für Bauteile (Komponenten) von Versorgungsanlagen für flüssige Brenn- und Kraftstoffe muss die Beständigkeit der metallenen Werkstoffe und Polymere nachgewiesen werden. Im Anwendungsfall von Heizöl mit 20 % biogenen Anteilen in Form von Rapsölfettsäuremethylester (FAME, Biodiesel) ist es für eine konservative Beurteilung des Korrosionssystems Werkstoff/Medium/Umgebung wichtig, die Alterungseffekte des Mediums einzubeziehen.
Entwicklung eines Prüfverfahrens für die Untersuchung der Beständigkeit von metallenen Werkstoffen und Polymeren in Heizöl und Heizöl-FAME-Blends, das für eine Vorauswahl der Werkstoffe und zum Nachweis der Beständigkeit im Hinblick auf die bauaufsichtlichen Zulassungsverfahren geeignet ist. Ein Schwerpunkt wird bei den metallenen Werkstoffen auf der Erprobung von Messmethoden liegen, mit denen sich in kurzer Versuchszeit ein Korrosionsangriff detektieren lässt.
Die untersuchten Werkstoffe Aluminium, Stahl 1.0037, 1.4301, Kupfer, Messing (CuZn40Pb) und Zink (ZP0410) sind in B0, B20, B100 und in 6 Jahre altem B100 beständig.
Auch in einem Jahr alten B20 und in einem Jahr alten B100 sind die Werkstoffe beständig.
Bei Kupfer blieb die Korrosionsrate in der Flüssigphase sowohl in B20 (0 μ m/ a) als auch in B100 (4 μ m/ a) nach einem Jahr unverändert. Für das 6 Jahre alte B100 stieg die Korrosionsrate des Kupfers an (16 μ m/a). Im Gegensatz dazu sank bei Messing die Korrosionsrate in der Flüssigphase mit dem Alter des Brennstoffs, nach einem Jahr für B20 von 4 μ m/ a auf 1 μ m/a und für B100 von 36 μ m/ a auf 6 μ m/ a, im 6 Jahre alten B100 lag die Korrosionsrate des Messings bei 0 μ m/ a.
In 8 Jahre altem B10 trat bei Zink in der Flüssigphase Flächenkorrosion auf, es ist in dem Medium demnach nicht beständig. Messing zeigte örtliche Korrosion in der Gasphase, es ist folglich unbeständig und für den Einsatz in stark gealterten B10 nicht geeignet.
Aluminium, 1.0037, 1.4301 und Kupfer sind in dem 8 Jahre alten B10 beständig.
Die Änderung der Zugfestigkeit und der Reißdehnung von ACM, HNBR und FKM in Heizöl, B20 und gealterten B10 beträgt < 15 %. Diese Werkstoffe sind in Heizöl, B20 und in gealterten B10 unter Berücksichtigung des von der BAM zur Beurteilung der Beständigkeit festgelegten Grenzwertes von 15 % bei 40 °C als beständig zu bewerten.
PUR ist bei 40 °C nicht beständig in B20 und in gealtertem B10. Bei 70 °C ist HNBR nicht in B20 beständig aufgrund der Verringerung der Zugfestigkeit (40 %) und der Reißdehnung (50 %). FKM ist bei 70 °C in Heizöl und in B20 beständig.
Biodiesel is subject to degradation processes like oil and grease. The oxidative degradation products of vegetable oil esters in biodiesel particularly lead to enhanced sedimentation in blended fuels.
The polarity of biodiesel increases its solvency and facilitates permeation and extraction. Solvation, swelling and/or extraction lead to changes in the physical properties and chemical changes of polymeric materials. It also accelerates the degradation (hydrolysis and oxidation) of these materials with the loss of additives and stabilizers.
The objective of this research was to determine the resistance of frequently used polymeric materials such as ACM, EPDM, FKM, FVMQ, CR, CSM, IIR, HNBR, NBR, PA, PE; POM, PUR, PVC and VMQ in biodiesel and heating oil with 10 %/20 % biodiesel (B10/B20) at 40°C and 70°C.
Mass, tensile strength and breaking elongation of the test specimens were determined before and after the exposure for 84 days in the biodiesel heating oil blends. The visual examination of some elastomer test specimens clearly showed the great volume increase until break or partial dissolution. Shore hardness A and D were determined before and after exposure of the test specimens in the biofuels for 42 days.
The elastomers CR, CSM, EPDM, IIR, NBR and VMQ were generally not resistant to biodiesel and B10 at 40°C and 70°C. FKM, ACM, HNBR, PA, PE, POM, and PVC showed high compatibility in B10/B20 at 40°C. A lower compatibility was determined for ACM in biodiesel. ACM and HNBR were not resistant in B20 at 70°C.