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 135 °C were carried out using micro-sized specimens with a thickness of 100 µm. 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 4000 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 ( 90%) of the absorber sheet.

中文翻译：

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碳纳米管对太阳能集热器吸收体β-成核聚丙烯无规共聚物整体老化行为的影响

摘要 本文研究了碳纳米管（CNT）对过热保护太阳能集热器用β-成核聚丙烯无规共聚物吸收材料的基本特性和整体老化行为的影响。使用厚度为 100 µm 的微型样品在 135 °C 的高温下进行热空气老化实验。未老化试样的抗氧化剂含量和机械和热性能被表征。CNT 颜料影响半结晶形态（β 含量较少）并显着增加刚度。老化指标断裂应变、平均摩尔质量、主要抗氧化剂含量和氧化温度被监测长达 4000 小时。对于具有 CNT 的化合物，推断出更显着的降解。与炭黑改性等级相比，CNT 化合物的劣化率更高。CNT 的量应保持在吸收片的低水平（90%）。