Dual-Functional Organosilicon Additives Containing Methacrylate and Trimethoxysilyl Groups Enhancing Impact Toughness of Polylactide (PLA): Structure–Property Relationship

The demands of the green economy necessitate modern polymer materials that are not only environmentally friendly but also durable and capable of long service life. Bio-based polylactide (PLA) polyesters have gained significant traction in various industrial markets; however, their application in specialized sectors is hindered by high brittleness. This study extensively examines the effects of 1-5% of synthetically obtained tetracyclosiloxane (CS) and octaspherosilicate (OSS) derivatives with methacrylate (MA) and trimethoxysilyl (TMOS) groups as functional modifiers for PLA. The research provides a detailed characterization of PLA/CS and PLA/OSS materials, including a comparative analysis of mechanical properties such as tensile, flexural, and dynamic resistance. Notably, incorporating 5% CS-2MA-2TMOS into PLA resulted in a remarkable 104% increase in impact resistance. The study further evaluates the influence of these modifications on thermal properties (DSC, TGA), heat deflection temperature (HDT), and surface character (WCA). The miscibility between the organosilicon additives and PLA was assessed using oscillatory rheometry and SEM-EDS analysis. The melt-rheology analysis explained the mechanisms behind the interaction between the CS and OSS additives with the PLA matrix, highlighting their lubricating effects on the melt flow behavior. The study was complemented by XRD structural analysis and verification of the structure of PLA-based materials by optical microscopy and SEM analysis, demonstrating a plasticizing effect and uniform distribution of the modifiers. The findings strongly suggest that, even at low concentrations, organosilicon additives serve as effective impact modifiers for PLA.