Papers by Anastasia Koutsomitopoulou
Journal of Applied Polymer Science, 2014
ABSTRACT The purpose of the present study is to investigate the quasi-static and the viscoelastic... more ABSTRACT The purpose of the present study is to investigate the quasi-static and the viscoelastic behavior of epoxy resin reinforced with starch powder. An increase in the elastic modulus on the order of 42% was achieved; a behavior that was predicted by the modulus prediction model (MPM). Next, the composite was subjected to flexural relaxation experiments, in order to determine the relaxation modulus, at different filler-weight fractions and flexural deflections imposed. The viscoelastic models of the standard linear solid, the power law model and the residual property model (RPM) were applied in order to simulate/predict the stress relaxation curves. Predicted values derived from the application of the above models were compared to each-other as well as to respective experimental findings. From the above comparison it was proved the superiority of the RPM model in predicting both the linear and the nonlinear viscoelastic response of the materials investigated. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41697.
Green Composites from Natural Resources, 2013
Powder Technology, 2014
This study is focused on recycling potential of some waste materials, such as olive pits, i.e. th... more This study is focused on recycling potential of some waste materials, such as olive pits, i.e. the solid phase derived from an olive oil mill, blended with thermoplastic polymers and used for the production of new materials applied in manufacturing containers and formworks. The olive pit powders are described and characterized. Then the powder is introduced in a bio-based and biodegradable matrix (polylactic acid, PLA) at various percentages. In this study, a comparison of the size distribution and the densities of olive pit powders according to the grinding methods (planetary mill and centrifugal mill) was made. The analyses showed that olive pits can be further studied as additive for the production of green materials. The development of an agricultural based polymer matrix compatible with olive pits and consequently a fully biodegradable composite system is the future and ultimate goal of the research undertaken. For that purpose, composite samples made out of PLA matrix, reinforced with olive pit powders were manufactured and mechanically characterized. With filler loading, an increase in the tensile modulus but a decrease of the flexural strength may be due to the poor interfacial bonding between olive pit powder and PLA.
Journal of Materials Science, 2012
ABSTRACT In this investigation, specimens of MWCNT-epoxy nanocomposites were prepared by two diff... more ABSTRACT In this investigation, specimens of MWCNT-epoxy nanocomposites were prepared by two different dispersion methods including the use of ultrasonication, and high speed shear mixing. The dispersion degree between MWCNT and polymer resin was analyzed after completing the curing reaction, by scanning electron microscopy. The effect of the nanotubes dispersion achieved on the properties of the manufactured nanocomposite was analyzed through static three point bending tests and dynamic mechanical thermal analysis. Interesting results concerning the dispersion effect of MWCNTs added to the polymer matrix on the storage and loss moduli as well as on tan delta and T (g) values of the specimens manufactured by the sonication and high speed shear mixing methods were derived.
Journal of Applied Polymer Science, 2012
ABSTRACT This study is focused on the investigation of the effect of thermal shock cycling on the... more ABSTRACT This study is focused on the investigation of the effect of thermal shock cycling on the mechanical properties of cellulose based reinforced polymer composites. Polymer composites reinforced with olive pits powder at different filler-volume fractions were manufactured. An increase in the bending modulus on the order of 48% was achieved. On the other hand, results showed that the bending strength remained almost unaffected from the amount of filler introduced. Next, the effect of thermal shock cycling on the mechanical behaviour of the thus manufactured composites was investigated. Theoretical predictions for both the properties variation with number of thermal shock cycles applied as well as with filler-volume fraction were derived using the residual properties model (RPM) and the modulus predictive model (MPM), respectively. Predicted values were compared with respective experimental results. In all cases, a fair agreement between experimental findings and theoretical predictions was found. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite co... more Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite components are to be economically viable material choices for high production volumes in the automotive industry. Manufacturing process variants of resin transfer moulding (RTM) target a reduction of in-mould manufacture time by reducing the time to infuse and cure components using fast curing resin systems with time to cure completion of about 5 minutes at processing temperature. The present study involves a new three part epoxy system supplied by Hexion designed for use with short cycle time RTM processes. Following the establishment of a cure kinetics model for this resin, the potential of dielectric cure monitoring for characterising the flow and cure of the resin in the mould was investigated and is reported here.
Uploads
Papers by Anastasia Koutsomitopoulou