Preparation and properties of polyethylene-based blended films base on mesoporous nano-SiO₂ antioxidant active assembly

The mesoporous nano-SiO₂ carrier was prepared with cetyltrimethylammonium bromide (CTAB) that served as template. Then α-tocopherol (α-TCP) was integrated into the carrier to form antioxidant active assembly. Low-density polyethylene (LDPE) active films were prepared by flat extrusion. Linear low-density polyethylene (LLDPE) and polyolefin thermoplastic elastomer (POE) were used as modified resin to regulate the films for better performance. The assembly and α-TCP were introduced into the films, serving as antioxidant active factor. The structure of the nano-SiO₂ carrier was studied by TEM, XRD and nitrogen adsorption/desorption apparatus. The thermal stability of the assembly was investigated by thermal gravimetric analysis (TGA). The physical and controlled release properties of the films were determined by mechanical performance test, release performance test, etc. Meanwhile, the additives’ synergistic effects on the films were studied. The results show that the active films’ thermal processing, mechanical and controlled release properties are significantly improved with introduction of the additives. The assembly’s insulating effect leads to thermal resistant temperature of α-TCP, which is integrated into assembly, increase by 70% when compared with the bared α-TCP. As compared with pure LDPE film, the mechanical properties of the active films are significantly improved by the additives. The tensile strength increase rate of the film modified by POE and assembly is more than 2.5 times as other samples’. As compared with the films modified with the bared α-TCP, the assembly reduces the diffusion coefficient of α-TCP by 45%-47%, which shows the remarkable controlled release property of the active films. The films’ crystallinity is negatively correlated with release rate of the antioxidant substance. As a result, the prepared materials can be used to regulate active substances’ release rate of antioxidant active package. And it shows a good potential for strengthing and toughing package films.