Correlation Between the Mechanical Strength and Crystallinity of 3D- Printed PEEK Materials

Poly-ether-ether-ketone (PEEK) materials have high thermal resistance, high mechanical strength, good chemical stability, and high friction resistance. Therefore, PEEK materials are considered as high-performance engineering plastics suitable for use in various fields, such as the automotive, aviation, medicine, and electronics fields. A low-temperature FDM 3D printer, a widely used type of printer, was modified to become a high-temperature 3D printer for the successful printing of PEEK materials. A simple model was established to explain the correlation between the mechanical strength and crystallinity of 3D-printed PEEK materials, and for experimental verification, 3D-printed PEEK materials were heat treated at 250 ^oC in air for two hours. The correlation between the mechanical strength and internal structure before and after the heat treatment of the 3D-printed PEEK materials was analyzed by tensile and flexural strength measurements and wide-angle X-ray diffraction (WAXRD). The mechanical strength measurements showed an increase of 20% in the flexural strength and the tensile strength compared to those values in without a heat treatment. The intensity and diffraction angle of the top plane and bottom plane of the printed PEEK, which was heat treated, were nearly identical from WAXRD. We will present the detailed experiment results and other analysis results for improved 3D printed samples.<br/>This work was supported by a grant from the “National Research Council of Science & Technology (NST) of the Korean government (MSIT) (No. CRC-19-02-ETRI),” the “Technology Innovation Program (No. 20005139)” funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea) and by an “Electronics and Telecommunications Research Institute (ETRI) grant funded by the Korean government, 21YU1100,” for the development of 4D structures and biodegradable materials for high-speed reactions within the body-temperature range.