Abstract
This paper is devoted to a systematic study of composite materials based on industrial and recycled polypropylene (PP) with controlled operational, technological, and environmental characteristics. The results of experimental studies aimed at forming functional structures of various natures in the PP matrix are summarized: cellulose fibers, microcrystalline cellulose, nanodispersed silica, intumescent flame retardants, and antioxidant stabilizers. Approaches have been implemented to reduce PP crystallinity and shrinkage through in situ sol-gel synthesis of SiO2 in the melt, increase mechanical rigidity and biodegradability through cellulose reinforcement, impart fire resistance through the use of expandable graphite and IFR systems, and stabilize regenerated PP with vitamin E. It has been shown that a combination of these methods enables the production of composites tailored to the needs of additive manufacturing (FDM printing), injection molding, structural and thermal insulation products for construction applications, and the recycling of polymer waste.