Utilizing “Reverse Compatibility” to Construct Interface Interlocking Structures to Improve the Mechanical Properties and Degradability of PBAT/HDPE and Application in Sewage Treatment

Inspired by the mortise and tenon structure in ancient Chinese architecture, the polymer composites with interfacial interlocking structures were developed by utilizing the “reverse compatibility” between polymers and inorganic fillers, and the porous materials were obtained for wastewater purification after degradation of the composites. In detail, the PBATT or HDPEF composites were prepared by poly (butylene adipate-co-terephthalate) (PBAT) or high-density polyethylene (HDPE) blended with montmorillonite (MTT) or Mica flour (MF) possessing opposite compatibility. Afterward, the mass ratios of 1/9 or 2/8 for PBATT and HDPEF were re-blended to obtain PBATT/HDPEF composites with a “zipper” or “mortise and tenon” interface interlocking structure. Firstly, compared to PBAT/HDPE-2/8 composites, PBATT/HDPEF-2/8 exhibited excellent mechanical properties, including tensile strength enhanced by 25% and tear strength improved by 14.1%. Moreover, the interlocking structure formed by inorganic fillers advanced the hydrophilicity, water permeability, and degradation properties of the composites. Remarkably, the smaller water contact angle (WAC) (65.9°), the more considerable WAC difference within the same period (6.1°), and the more significant weight loss (4.5%) of PBATT/HDPEF-2/8 composites were displayed than other samples. More interestingly, the preparation cycle of porous materials was shortened by the excellent degradation properties, and the inorganic fillers at the interface were more conducive to the purification of wastewater and the adsorption of heavy metal ions.