A comparison of mechanical properties of recycled high‐density polyethylene/waste carbon fiber via injection molding and 3D printing

Abstract

Recycled high‐density polyethylene (r‐HDPE) was combined with waste carbon fiber by loading 6 k, 12 k, and 24 k tows through an extruder to create thermoplastic/carbon pellets with fiber volume fractions of 11.2%, 18.9%, and 29.5%, respectively. Tensile and flexural coupons were subsequently produced via injection molding and novel 3D printing. The addition of carbon into r‐HDPE in all cases showed increased mechanical properties. Maximum increases were observed through the inclusion of 29.5% fiber volume fraction. Increases in tensile and flexural modulus of up to 2.9 GPa (+505.9%) and 5.8 GPa (+711.0%) respectively were observed for r‐HDPE/carbon fiber (CF) samples. Increases in tensile and flexural strengths of up to 57.9 MPa (+311.8%) and 47.7 MPa (+188.0%) respectively were observed for 29.5% r‐HDPE/CF samples. Some variance in mechanical performance between injection molded and 3D printed samples was observed indicating production methodology might influence final material performance.

Advancing Plastic Recycling: Challenges and Opportunities in the Integration of 3D Printing and Distributed Recycling for a Circular Economy

“…These pellets are then dried to remove moisture as it affects the production process. Next, pellets are melted and injected into a mold, where they form the desired product [156]. However, there are several advantages to using injection molding with recycled plastic.…”

Scalable methods for directional assembly of fillers in polymer composites: Creating pathways for improving material properties

“…Moving forward, additive manufacturing (AM) processes are now becoming an emerging technology with enormous potential for mass production and rapid prototyping. [281][282][283][284][285][286][287] AM has several distinct advantages over conventional manufacturing methods, including design flexibility, [288][289][290][291] and significant reduction in overall processing time, [292,293] energy consumption, [294][295][296] and waste generation, [297][298][299] making it very compelling for the polymer industry. Over the past decade, intensive research efforts have been focused on improving printing resolution, [300,301] accelerating printing rate, [302,303] and enabling the precise structural control across multiple length scales.…”

Mechanical Response and Processability of Wet-Laid Recycled Carbon Fiber PE, PA66 and PET Thermoplastic Composites

“…Thomason [10] and Vaidya [11] illustrated the importance of fiber aspect ratio of discontinuous fibers. Polyamide (PA), polyethylene (PE) and polyethylene terephthalate (PE) are of continued interest as thermoplastic matrices in reinforced composites due to their recyclability and superior mechanical properties [12][13][14].…”