Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11011417 | Solar Energy | 2018 | 5 Pages |
Abstract
This paper deals with the effect of carbon nanotubes (CNT) on the basic characteristics and the global aging behaviour of β-nucleated polypropylene random copolymer absorber material for overheating protected solar thermal collectors. Hot air aging experiments at an elevated temperature of 135â¯Â°C were carried out using micro-sized specimens with a thickness of 100â¯Âµm. The unaged specimens were characterized as to the antioxidant content and the mechanical and thermal properties. The CNT pigment affected the semi-crystalline morphology (less β-content) and increased the stiffness significantly. The aging indicators strain-at-break, average molar mass, primary antioxidant content and oxidation temperature were monitored for up to 4000â¯h. A more pronounced degradation was deduced for the compounds with CNT. Compared to carbon black modified grades a higher deterioration rate was ascertained for the CNT compounds. The amount of CNT should be kept at low levels (<0.1â¯wt%) just needed to achieve sufficient solar absorbance (>90%) of the absorber sheet.
Related Topics
Physical Sciences and Engineering
Energy
Renewable Energy, Sustainability and the Environment
Authors
Gernot M. Wallner, Michael K. Grabmann, Clemens Klocker, Wolfgang Buchberger, David Nitsche,