Waste to high performance materials: Self-assembly of short carbon fiber polymer composites

Traditional manufacturing of carbon fiber/polymer composite parts is restricted to non-complex geometries and remains expensive due to costly carbon fiber production, laborious processing steps, and generates 20–30% short fiber waste. We present an inexpensive method of aligning and consolidating short (waste) fibers into needle-like building blocks for composite part manufacturing that capitalizes on the anisotropy of short fibers. The method consists of mixing suspended short fibers with a secondary phase that induces self-assembly of the short fibers into an overlapping needle-like bundle with polymer binder distributed in the interstitial sites. The process can achieve high volume fraction of fiber comparable to that of high-performance composites. These self-assembled building blocks can be consolidated to form large scale parts, and they offer several advantages over traditional continuous fiber manufacturing, such as forming complex geometries, utilizing less expensive short fibers, simplifying processability, and increasing fiber recyclability.