SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 58: Polymer Networks and Elastomers

CPP 58.3: Talk

Friday, March 31, 2023, 10:15–10:30, ZEU 255

Strain hardening of hydrogenated acrylonitrile butadiene rubber — •Christoph Gögelein¹ and Marjan Hemstede - van Urk² — ¹Arlanxeo Deutschland GmbH, Kaiser-Wilhelm-Allee 40, 51369 Leverkusen — ²Arlanxeo Netherlands B.V., Urmonderbaan 24, 6167 RD Geleen, The Netherlands

Therban hydrogenated acrylonitrile butadiene rubber (HNBR) is a specialty elastomer used in the automotive and oil and gas markets. It is well known that HNBR with acrylonitrile (ACN) contents above 39 wt% shows strain-induced crystallization (SIC), caused by the crystallization of alternating ethylene-ACN units (Obrecht, 1986). For HNBR polymers with ACN contents lower than 36 wt%, crystallization occurs in longer ethylene units derived from hydrogenated butadiene sequences (Uschold & Finlay, 1974). Besides these well-established findings, there is an ongoing debate up to which temperature SIC occurs for HNBR (Narynbek Ulu, et al., 2017) (Shaw, 2019). Therefore, crystallization of the polymers was studied, using regular and isothermal differential scanning calorimetry at varying storage times. Furthermore, we investigated strain hardening behavior of HNBR networks with varying ACN contents from room temperature (RT) up to 100 °C, as well as at varying crosslink densities and filler loadings. Our results show that there is a significant strain hardening behavior for HNBR vulcanizates with high ACN content, i.e. for > 39 wt% ACN content. The effect is still observed at 60 °C, but not at 80 °C. Surprisingly, strain hardening doesn't enhance the fatigue lifetime for the samples under investigation.