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

Abstract

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‐SiO2 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‐SiO2 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.

Poly(vinyl alcohol)/sodium alginate polymer membranes as eco‐friendly and biodegradable coatings for slow release fertilizers

“…The saturated nutrient solution concentration ( C sat ) in the PCU granules was 0.603 g mL −1 , the density of the PCU granules ( ρ s ) was 1.335 g cm −3 , the radius of the PCU granules ( r ) was approximately 0.35 cm and the thickness of the coating membrane ( l ) was approximately 0.015 cm. The critical volume fraction ( γ ) of voids filled with water in the PCU granules was approximately 0.05, which was determined with the same method reported previously 37 . Hence, the duration of the lag period ( t ′) and the linear release period ( t* ) can be calculated and Table 2 shows the calculated results.…”

“…P s and P h represent the permeability of the nutrient and water through the coating membrane of the PCU granules, respectively. They were tested by using a self‐made device as described previously 37 …”

“…The critical volume fraction (γ) of voids filled with water in the PCU granules was approximately 0.05, which was determined with the same method reported previously. 37 Hence, the duration of the lag period (t 0 ) and the linear release period (t*) can be calculated and Table 2 shows the calculated results. Moreover, the specific equations of the fractional release for the three stages (lag period, linear release period and decaying release period) can be expressed.…”

Preparation and characterization of compatibilized and toughened polylactic acid/cellulose acetate films by long‐chain hyperbranched polymers

“…In addition, since CA was a hydrophilic material, LCHBPs could reduce the contact angle and improve the hydrophilicity by improving the surface roughness of CA. 61 However, the uniform distribution of CA particles and the reduction of particle size were not conducive to reducing the contact angle, but the hydrophilicity of the PLA/CA blends was improved significantly by introduction of PEG chains. It can be seen from the results that the addition of LCHBPs reduced the hydrophobicity and increase the hydrophilicity of the PLA/CA blends.…”

Preparation of multifunctional silicon‐phosphorus acrylate particles for the simultaneous improvement of the flame retardancy and mechanical performance of polylactic acid

“…[13][14][15] PLA, a biodegradable plastic derived from biomass, is expected to replace petroleum based plastics. [16][17][18] However, its ubiquitous application has been significantly hampered by its low fire resistance and poor brittleness. 19 Chen et al 20 improved the fire performance of PLA by using the synergistic effect of heax-[N,N 0 ,N 00 -tris-(2-amino-ethyl)- [1,3,5] triazine-2,4,6-triamine] cyclotriphosphazene (HTTCP), ammonium polyphosphate (APP), and nano ZnO.…”