Effects of crosslinking modes on the film forming properties of kelp mulching films

To solve the serious environmental pollution caused by traditional plastic mulching film, a biodegradable kelp mulching film (KMF) with excellent film forming properties was fabricated using kelp as the raw material. In this paper, the effects of different crosslinking modes with Ca2 + and H+ on the film formation of KMF were investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) results indicated that the synergistic gelation of calcium alginate and alginic acid existed in Ca2 +-H+-KMF, implying that the KMF simultaneously crosslinks with Ca2 + and H+. And the Ca2 +-H+-KMF exhibited the best physical and mechanical properties among the five differently crosslinked KMFs. Studied results suggested that KMF simultaneously crosslinked by 2% Ca2 + and 1% H+ for 15 min had the best overall performance. The maximum tensile strength (TS) and elongation at break (EB) were 66.72 MPa and 7.68%, at the same time, the water vapour permeation (WVP) and water solubility (WS) were 8.05 × 10− 11 g/(m·s·Pa) and 7.75%. Using kelp in agricultural mulching films reflects the ecological concept of making full use of resources, thus the KMF can be regarded as a sustainable ecological alternative to traditional plastic mulching films in agriculture.