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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.
The first documentation of fuel biodeterioration dates back to the late 19th century. However, extensive studies concerning the microbial fuel contamination started in 1980’s. Polymeric fuel storage tanks containing diesel and biodiesel provide environmental conditions for microbial growth. Several studies demonstrated that bacteria, which were found in contaminated fuel systems, can use fuels as macronutrient; but such bacteria can also cause microbiologically influenced corrosion and fouling.
The aim of this study is to investigate the initial attachment behavior of bacteria, isolated from a diesel contamination, on neat and photooxidized high-density polyethylene (PE-HD). Two common PE-HD’s, less- and biodiesel-stabilized, were radiated to UV light representing a tank exposed to sunlight. The effect of photooxidiation on PE-HD’s surface were characterized chemically by Fourier-transform infrared spectroscopy (FTIR). The attached bacteria Pseudomonas aeruginosa and Bacillus subtilis on the polymer surface were evaluated by fluorescence microscopy and colony-forming unit tests (CFU).
PE-HD as a polymeric fuel storage tank material: Photooxidation, fuel sorption and long-term storage
(2018)
High-density polyethylene (PE-HD) is a commodity thermoplastic polymer which is typically used for packing of dangerous goods. Its good resistance against photooxidation, fuels, chemicals and other environmental factors in addition to low production costs makes PE-HD attractive for fuel storage applications. Typical engine fuels stored in polymer tanks are petrol, diesel and biodiesel that receives increasing attention as proper alternative to fossil fuels. One of the major problems with biodiesel is its susceptibility to oxidize due to its chemical composition of unsaturated fatty acids which also can cause polymer degradation.
The aim of this study is to investigate the influence of different environmental factors, UV radiation and commonly stored fuels, on the mechanical, physical and chemical properties of two types of PE-HD polymers (stabilized and non-stabilized). The influence on the mechanical properties was tested by Charpy and tensile tests, chemical and physical properties were evaluated by Fourier-transform infrared spectroscopy (FTIR) and by dynamical mechanical analysis (DMA) tests. Samples were characterized after varying exposure time of UV radiation and after fully and partially immersion in biodiesel. In addition, similar experiments were conducted using diesel for comparison.