On cryogenic milling of primary recycled ABS: Rheological, morphological, and surface properties

Abstract

The primary (1°) recycled acrylonitrile butadiene styrene (ABS) is one of the most acceptable thermoplastic for 3D printing applications. For ascertaining rheological and dimensional features of 3D printed functional prototypes, one must have control on feed stock filament volume and its melt flow index (MFI). Some studies have reported investigations on mechanical and thermal properties along with dimensional features and MFI of 1° recycled ABS. But hitherto little has been reported on effect of cryogenic milling (CM) on rheological, morphological, and surface properties of feed stock filament (for possible 3D printing). This article reports the effect of CM on 1° recycled ABS for 3D printing applications. The effects of CM input parameters such as vibration frequency (Hz), CM time (min), and weight of grinding media (g) have been investigated for rheological (MFI, sample volume), surface (Shore D hardness, porosity), and morphological (based upon photomicrographs) properties. Based upon analysis of variance for sample volume and MFI of the 1° recycled ABS, grinding frequency was observed as most significant factor (91.88% for sample volume and 76.59% for MFI) at 95% confidence level in the present case study. The results of study suggest that sample volume and MFI observations are in line with Shore D hardness and porosity.