3D Printing with Waste High-Density Polyethylene

HDPE has widely been considered to be impossible to 3D print using fused filament fabrication (FFF). When HDPE is FFF printed, the printed object warps significantly and debonds off the print substrate. Therefore, it is difficult to preserve registry as the polymer filament is laid down layer by layer during FFF. We demonstrate a strategy for FFF of waste-derived HDPE. There are two aspects to our approach. (i) We formulate the HDPE by blending with dimethyl dibenzylidene sorbitol (DMDBS), that forms a nanofibrillar network in the HDPE melt as it cools and (≈ 10%) linear low density polyethylene (LLDPE). (ii) We use a thin “brim” around the printed object that helps it adhere to the print substrate using common paper glue. This dramatically reduces warpage, allowing FFF of HDPE objects with complex geometries. FEM simulations indicate that our approach decreases the stresses that develop due to crystallization induced shrinkage during cooling. Given the volume of HDPE that finds its way to the waste stream, our results have important implications for extending the use life of HDPE.