Mechanical Properties of Orthodontic Thermoplastics PETG/ PC2858 after Blending.

Objective: To characterise and compare the tensile characteristics after multi-proportional blending, to determine the proper blending ratio for new thermoplastic material and to compare its mechanical performance with commercial thermoplastics.
Methods: PETG and PC2858 aggregates were blended in five different ratios. Standard specimens of each ratio were molded and tested to determine their mechanical performance. Then the new material with the proper blending ratio was chosen and compared against commercial thermoplastics.
Results: With the increase of PC2858 content, the tensile and impact strength increased but elongation at break decreased. When blending ratio (wt %) was 70/30, the PETG/PC2858 exhibited optimal mechanical properties, with a tensile strength of 63.42 ± 1.67 MPa, and a stress relaxation rate of 0.0080 ± 0.0005 N/s, which exceeded those of Erkodur and Biolon.
Conclusion: By blending PETG and PC2858 at the weight ratio 70/30, we obtained new thermoplastic material which outperformed commercial products.