Title: Effect of Process Variables on the Uncured Handleability and Formability of Stretch Broken Carbon Fiber

Authors: Riad Morshed Rezaul, Cecily Ryan, Roberta Amendola, Dilpreet Bajwa, Douglas Cairns

DOI: 10.33599/nasampe/c.22.0161

Abstract: Carbon fiber reinforced polymer composites find extensive application in the aerospace industry due to their outstanding strength and stiffness. When manufacturing components with complex geometries, discontinuous carbon fibers offer superior formability compared to continuous carbon fibers. Stretch broken carbon fiber (SBCF) is a type of discontinuous carbon fiber generated by stretch breaking the fibers at their natural flaws. The resulting fibers are shorter in length compared to the continuous fibers. Uncured SBCF tows can be challenging to handle due to lack of fiber continuity. As with continuous fiber tows, a thin polymeric coating known as sizing can be applied to the SBCF. In SBCF, this coating serves to increase handleability as measured via tensile strength. The objective of this work is to investigate how the process variables during the stretch breaking process (sizing bath concentration, stretch ratio, nip force, and line speed) can be tuned to generate SBCF reliably and with consistent properties. The preliminary evaluation of the generated SBCF tows with a sizing bath concentration of 10 wt.% resulted in 1.75 wt.% sizing deposition on the tow, which meets the target sizing deposition of 1.5 wt.% to 2 wt.% in our present work. The room temperature tow tenacity of 290.86 N suggests the potential of the SBCF tows to provide desired tow handleability and back-tension ability during the prepreg production. The elevated temperature tow tenacity of 10.11 N indicates the potential formability of the SBCF tows. Replication of these results over multiple batches in SBCF generation also supports the reproducibility of these values under consistent processing conditions. From the fiber length distribution of the SBCF, it was observed that the fiber length ranges from 22 mm to 43 mm (mean fiber length is ~32 mm).

References: [1] J. C. Janicki, D. S. Bajwa, D. Cairns, R. Amendola, C. Ryan, and A. Dynkin, “Gauge length and temperature influence on the tensile properties of stretch broken carbon fiber tows,” Compos. Part A Appl. Sci. Manuf., vol. 146, no. February, p. 106426, 2021, doi: 10.1016/j.compositesa.2021.106426. [2] G. Jacobsen, “Mechanical characterization of stretch broken carbon fiber materials - IM7 fiber in 8552 resin,” Int. SAMPE Symp. Exhib., no. December 2007, 2010. [3] Chris Ridgard, Douglas Cairns, “Advances in the development of stretch broken carbon fiber for primary aircraft structure,” CAMX Anaheim CA, October, 2022. [4] H. Zheng et al., “Recent advances of interphases in carbon fiber-reinforced polymer composites: A review,” Compos. Part B Eng., vol. 233, no. January, p. 109639, 2022, doi: 10.1016/j.compositesb.2022.109639. [5] H. Lyu, N. Jiang, J. Hu, Y. Li, N. Zhou, and D. Zhang, “Preparing water-based phosphorylated PEEK sizing agent for CF/PEEK interface enhancement,” Compos. Sci. Technol., vol. 217, no. June 2021, p. 109096, 2022, doi: 10.1016/j.compscitech.2021.109096. [6] E. Laukmanis et al., “Effect of the interplay between fiber surface chemistry and sizing reactivity on fiber matrix interaction in carbon fiber reinforced epoxy resin reinforced epoxy resin,” Compos. Interfaces, vol. 00, no. 00, pp. 1–31, 2022, doi: 10.1080/09276440.2022.2068249. [7] G. Jacobsen and W. C. Schimpf, “Process development and characterization of stretch broken carbon fiber materials.” [8] R. L. Zhang , Y. D. Huang, N. Li, L. Liu, and D. Su, “Effect of concentration of the sizing agent on the carbon Fibers surface and interface properties of its composites,” Journal of Applied Polymer Science, vol 125, pp 425-432, 2012, doi: 10.1002/app.35616. [9] Yoni Shchemelinin, Jared W. Nelson, Cecily Ryan, Dilpreet Bajwa, Douglas Cairns, “Bulge and dome testing to investigate the formability of continuous and stretch broken carbon fiber prepreg laminates,” CAMX Anaheim CA, October, 2022. [10] Matthew C. Egloff, Roberta Amendola, Douglas Cairns, Dilpreet Bajwa, Cecily Ryan, Bridget Powers, “A predictive forming model for stretch-broken carbon fiber composites as a function of state of stress, forming rate, and resin viscosity,” CAMX Anaheim CA, October, 2022. [11] Dalton B. Nold, Dilpreet Bajwa, Douglas Cairns, Roberta Amendola, Cecily Ryan, “Tensile properties of stretch broken carbon fiber prepreg,” CAMX Anaheim CA, October, 2022. [12] Tasnia J. Nur, Zachary T. White, Brendon Bossert, Matthew C. Egloff, Cecily Ryan, Dilpreet Bajwa, Roberta Amendola, “Novel experimental unit to evaluate inter-ply and tool-ply friction in carbon fiber reinforced polymer composites prepregs,” CAMX Anaheim CA, October, 2022.

Conference: CAMX 2022

Publication Date: 2022/10/17

SKU: TP22-0000000161

Pages: 18

Price: $36.00