The combination of high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polypropylene (PP) is frequently found in polymer waste streams. Because of their similar density, they cannot be easily separated from each other in the recycling stream. Blending of PP/ polyethylenes (PEs) in different ratios possibly eliminate the sorting process used in the regular recycling process. PP has fascinating properties such as excellent processability and chemical resistance. However, insufficient flexibility limits its use for specific applications. Blending of PP with relative flexible PEs might improve its flexibility. This is a unique approach for recycling or upcycling, which aims to maintain or improve the properties of recycled materials. The effects of the branched-chain structures of PEs on the crystallization behavior and the related mechanical properties of such blends were investigated. The overall kinetics of crystallization of PP was significantly influenced by the presence of PEs with different branched-chain structures. The presence of LDPE was found to decrease the overall crystallization rate while the addition of HDPE accelerated the crystallization process of the blends. No negative effect on the mechanical performance and the related crystallinity was observed within the studied parameter range.

Additive manufacturing, the so‐called three‐dimensional (3D) printing, is a revolutionary emerging technology. Fused filament fabrication (FFF) is the most used 3D printing technology in which the melted filament is extruded through the nozzle and builds up layer by layer onto the build platform. The layers are then fused together and solidified into final parts. Graphene‐based materials have been positively incorporated into polymers for innovative applications, such as for the mechanical, thermal, and electrical enhancement. However, to reach optimum properties, the graphene fillers are necessary to be well dispersed in polymers matrix. This study aims to emphasise the interest of producing ABS/graphene oxide (GO) composites for 3D printing application. The ABS/GO composite filaments were produced using dry mixing and solvent mixing methods before further melt extruded to investigate the proper way to disperse GO into ABS matrix. The ABS/GO composite filament with 2 wt.% of GO, prepared from the solvent mixing method, was successfully printed into a 3D model. By adding GO, the tensile strength and Young’s modulus of ABS can be enhanced. However, the ABS/GO composite filament that was prepared via the dry mixing method failed to print. This could be attributed to the aggregation of GO, leading to the die clogging and failure of the printing process.

Until now, only a few materials are available for additive manufacturing technologies that employ photopolymerization, such as stereolithography (SLA) and digital light processing (DLP) 3D printing systems. This study investigates a newly formulated resins as an alternative 3D printing materials with tunable mechanical properties to expand the potential applications of advanced engineering products such as wearable devices and small reactors. A commercial acrylate-based resin was selected as a standard resin (STD). The resin was formulated by combining various volume ratios of a low-cost polypropylene glycol (PPG) having various molecular weights (400, 1000, and 2000 g/mol) with the STD resin. The printability of the formulated resins was optimized using the digital light processing (DLP) 3D printing technique. The effects of the PPG contents on the properties of the printed parts were studied, including printability, thermal properties, mechanical properties, and thermo-mechanical properties. As a result, the formulated resins with 5–30%vol of PPG could be printed while higher PPG content led to print failure. Results suggest that increasing the PPG contents reduced the dimensional accuracy of the printed parts and decreased the mechanical properties, including the flexural strength, flexural modulus, impact strength, hardness, and elastic modulus. interestingly, at small loading, 5%vol, the mechanical performance of the printed specimens was successfully enhanced. These results are intriguing to use a tunable mechanical acrylate-based resin for a specific application such as a microreactor.