Upcycling of blending waste plastics as flexible growing substrate with superabsorbing property

Abstract

Converting blending waste plastics into lightweight growing substrate is an attractive approach for efficiently recycling low value-added waste plastics. In the current research, a universal and mild strategy for recycling blending waste plastics to fabricate blending plastic-g-growing substrate (BP-GS) with superabsorbing and flexible properties was developed. The incompatibility between blending waste plastics was successfully overcome, and the effects of several parameters on the synthesis and water absorption of BP-GS were established. Furthermore, the prepared BP-GS possessed high water-absorbing capacity (1188%), excellent porous structure and flexible properties. Mechanisms study demonstrated that the blending plastics formed uniform structure via crosslinking of macromolecular free radicals, and additives such as superabsorbent polymer (SAP) and polyolefin elastomer (POE) were grafted into the blending waste plastics by forming stable covalent bonds, generating hydrophilic and flexible BP-GS. Furthermore, the regulation of melt flow rate (MFR) was ascribed to the effect of POE on crystallinity and branching degree of the plastics. In addition, pot and slope experiments showed BP-GS could coordinate with soil to support plants growth for drought and landslide prevention. Meanwhile, sequencing analysis indicated a micro-ecosystem could be formed in the prepared BP-GS to support plants growth. Therefore, the synthesized superabsorbent has potential application in vertical greening and slope restoration. This high value-added and universal recycling method will promote eco-friendly, upcycling and circular development of blending waste plastics recovery.