The circular economy promotes plastic recycling, waste minimization, and sustainable materials. Hence, the use of agricultural waste and recycled plastics is an eco-friendly and economic outlook for developing eco-designed products. Moreover, new alternatives to reinforce recycled polyolefins and add value to agroindustrial byproducts are emerging to develop processable materials with reliable performance for industrial applications. In this study, post-consumer recycled high-density polyethylene (rHDPE) and ground rice husk (RH) of 20% w/w were blended in a torque rheometer with or without the following coupling agents: (i) maleic anhydride grafted polymer (MAEO) 5% w/w, (ii) neoalkoxy titanate (NAT) 1.5% w/w, and (iii) ethylene–glycidyl methacrylate copolymer (EGMA) 5% w/w. In terms of processability, the addition of RH decreased the specific energy consumption in the torque experiments with or without additives compared to neat rHDPE. Furthermore, the time to reach thermal stability in the extrusion process was improved with EGMA and MAEO compatibilizers. Tensile and impact test results showed that using coupling agents enhanced the properties of the RH composites. On the other hand, thermal properties analyzed through differential scanning calorimetry and thermogravimetric analysis showed no significant variation for all composites. The morphology of the tensile fracture surfaces was observed via scanning electron microscopy. The results show that these recycled composites are feasible for manufacturing products when an appropriate compatibilizer is used.

The circular economy promotes the recycling of plastics to develop new materials and products. The blends of immiscible plastics increase the availability of raw materials. This research aims to process and relate the morphology, rheological and thermo-mechanical properties of recycled high density polyethylene (rHDPE) and recycled polypropylene (rPP) modified by the addition of commercial organoclays (OMMT) and olefin block copolymer (OBC) compatibilizer. Given amounts of post-consumer blends of rHDPE coming from packing and rPP from lids were mixed in a torque rheometer. Mixes of virgin HDPE and PP in percentages of 0, 20, 40, 60, 80, 100 wt% were prepared to determine the concentration of these plastics in the blends. The corresponding DSC calibration curve of enthalpy of fusion versus weight percent was obtained. The resultant mixture of rHDPE/rPP (-83 wt%/-15 wt %) was melted with two organoclays (Cloisites20A and Cloisite 93A) (3 wt%) and with or without the presence of OBC (D5541) (5 wt%). Intercalated structures were observed in both clay nanocomposites, but Cloisite 20A showed greater basal spacing than those of Cloisite 93A. It was found that the organoclays and the OBC decreased the crystallinity on rHDPE and rPP. Rheological measurements using a plate-plate rheometer showed a viscosity increase of blends in the presence of both organoclays, at low shear rates (- 10 s⁻¹), being the Cloisite 20A the one that showed the highest values. On the other side, the OBC decreased the viscosity in all composite blends, at higher shear rates (60-100 s⁻¹). Both organoclays increased the stiffness of the rHDPE/rPP, but the OBC in conjunction with the organoclays declined the stiffness. The impact resistance was improved in the presence of the organoclays and the OBC. Based on these results, it can be concluded that the two organoclays used in this study can be used as compatibilizers for rHDPE/ rPP blends.

Plastic waste is a global concern due to its influence on health, the environment, and economic development. Ecuador is in the line to reduce plastic waste, representing 11% of the urban waste generated. Ecuador is making several efforts to achieve a circular economy model that encourages plastic waste management, recycling, and reuse. This review outlines the current state of plastic waste management, legislation, the recycling industry, and research challenges in Ecuador. Although the current legal framework is explicit about incorporating recycled plastic in single-use products, the plastics industry has few options for quality recycled materials. Also, the present law includes "extended producer responsibility" for the plastics industry to be involved directly in the PET recycling process, which proved to have a successful application model. However, since waste separation is implemented in around 33% of the country, most recyclates end up in landfills. Still, plastic manufacturers are looking for ways to comply with the regulations and incorporate circular economy policies within their companies. Finally, local academic research has proven the feasibility of alternative methods of plastics recycling, such as polymer blends and natural agrowaste-reinforced recycled plastic composites to meet circular economy trends.