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- 2016 (3) (entfernen)
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- Biodiesel (2)
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- PE-HD (2)
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- differential scanning calorimetry (DSC) (1)
- epoxy resin (1)
- in situ near-infrared (NIR) spectroscopy (1)
Eingeladener Vortrag
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The application of epoxy resins is variating from low cost adhesive to high performance plastics. As a result, the choice of monomer, hardener and in particular the curing treatment define the final product properties. For process optimization and ensuring product quality the curing kinetics of epoxy resin needs to be known. This is usually done by use of differential scanning calorimetry (DSC) or rheology measurements.
In the presented study, we will approve the applicability of the heatable near-infrared (NIR) cell 1 as alternative method to determine cure kinetics. This spectroscopic method in the NIR region enables following the cure progress by the characteristic oxirane absorption band 2,3. According to the reactivity of this functional group, the consumption of it should be a key factor for cross linking density and hence the mechanical performance of the material. Kinetic parameters will be provided by non-isothermal heating rates and predicted epoxy conversion for a typical cure treatment (Figure 1). The verification of the investigated cure kinetics is ensured by multiple step curing processes in the in situ NIR heating cell and ex situ on real samples.
In this presentation, we will introduce the heatable near-infrared (NIR) cell to investigate kinetic parameters for various epoxy resins, using diverse curing processes. Advantages and disadvantages of the method will be described as well as the comparison with DSC results.
Renewable resources become more and more relevant to maintain energy demands for an increasing global population. Biosynthetic fuels like biodiesel might replace conventional petrochemical fuels, such as diesel. However, more research is needed to characterize the interaction between the different fuels and the polymeric material, especially with respect to ageing and degradation.
The poster will present several interaction and degradation phenomena of high density polyethylene (PE-HD) induced by diesel and biodiesel 1-3. Also the possible influence of microbial growth (fungi and bacteria) is considered. The chosen PE-HDs are typical thermoplastic resins for container and storage tank applications. Degradation of PE-HD will be investigated by changes of the mechanical properties – with main emphasis on the Charpy impact strength 2. Furthermore, with alternating sorption and desorption cycles in combination with oven ageing the co-oxidation 3 of PE-HD in contact with biodiesel will be addressed.
Mechanical characterization of high-density polyethylene in contact with diesel and biodiesel fuels
(2016)
Renewable resources become more and more relevant to maintain energy demands for an increasing global population. Biosynthetic fuels like biodiesel might replace conventional petrochemical fuels, such as diesel. However, more research is needed to characterize the interaction between the different fuels and polymeric materials widely used in the fuel infrastructure as well as for automotive parts. Especially changes in the structural properties and mechanical behavior of the polyethylene (PE-HD) have to be addressed.
The presented work comprises the direct interaction of high density polyethylene (PE-HD) with diesel and biodiesel, resulting in swelling and plasticization. Also long-term degradation phenomena will be discussed.
The chosen PE-HD types are typical thermoplastic resins for container and storage tank applications. The impact of diesel and biodiesel in PE-HD is investigated by changes in the mechanical properties with emphasis on the Charpy impact strength. Furthermore, structural and dynamic influences on the polymeric material induced by diesel and biodiesel are proven in Dynamic Mechanical Analysis (DMA). Both methods, Charpy impact strength and DMA, reveal softening effects due to the migration of diesel and biodiesel into the amorphous regions of PE-HD.
Since biodiesel is more prone to oxidative degradation compared to diesel, the fuel/air/polymer-interaction is studied for partly immersed tensile test specimens. Main focus of the evaluation is the co-oxidation. Here, the accelerated deterioration of PE caused by the sorption of the facile oxidation of biodiesel into the solid polymer might be a major degradation mechanism in this context.