Performance adjustable porous polylactic acid-based membranes for controlled release fertilizers

摘要

Here, the phase inversion method using a mixture of chloroform and acetone as a solvent was adopted to fabricate a series of porous polylactic acid (PLA)-based membranes for controlled release fertilizers (CRFs). Cellulose acetate (CA) was used as an additive; polyethylene glycol (PEG) and nano-SiO(2)were used as porogens. Our first interest is to investigate effects of the amount of additive and porogen and type of porogens on the resulting membranes' performance. Results show the dialysis coefficient for membrane M1-3 (CA content of 2%) is nearly 20 times higher than that for M0-1 (CA content of 0%), suggesting that the addition of CA can promote the membrane's permeability. Porogens can increase membranes' hydrophilicity, dialysis coefficient and nutrient release rate. However, there is no obvious performance difference between membranes with different porogens. Secondly, M1-2 (no porogen), M2-2 (nano-SiO(2)content of 0.5%) and M3-2 (PEG content of 0.5%) were selected to coat urea granules. Results show the nutrient release rate of urea coated by M2-2, M3-2 is much higher than that of urea coated by M1-2. This research suggests the resulting membranes' performance is easily adjustive and they can be applied to prepare various CRFs to fertilize various crops.