Studies On Preparation And Properties Of Bio-based Epoxy Coated Fertilizers

Compared with traditional water-soluble chemical fertilizers,controlled-release fertilizers can significantly increase the utilization of fertilizers and reduce the adverse effects of fertilizer leaching on the environment.However,the high cost of controlled-release fertilizers and the difficulties in the degradation of coating materials have hindered their large-scale production applications in agriculture.Therefore,this research used low-cost,biodegradable materials including bagasse,lignin as a raw material for the preparation of controlled-release fertilizers coating materials,and developed two kinds of coating materials with low cost,biodegradable,and excellent controlled release properties.And they were sprayed onto the surface of the urea granules by the drum coating technique,respectively.Finally we obtain two new coated controlled release fertilizers with smooth surface,compact structure,and good controlled release properties.1.A novel controlled release fertilizer was successfully produced by coating urea particles with bagasse-based epoxy（EPCU）.Firstly,the liquefied bagasse were prepared from the wasted bagasse in the presence of catalyst and liquefier.Secondly,the controlled-release fertilizers coated bagasse-based epoxy synthesized from the liquefied bagasse（LB）and bisphenol-A diglycidyl ether（BDE）with the different mole ratios of LB to BDE were obtained.The structure of coating materials and microscopic morphology of EPCU were examined by FTIR,¹H NMR,SEM.Moreover,the nutrient release behaviors and its mechanism of EPCUs were also discussed in detail.Results showed that EPCU3 coating had uniform、smooth surface,compact structure,and improved the thermal stability by 60.3℃(T_10%),increased the nutrient release longevity by 12 times,and raised the water contact angle of surface by 12%compared with other EFCUs,and then significantly slowed the nitrogen release rate of the EPCU.This work indicated that the environment-friendly EPCU with superior controlled release properties could be especially useful in horticultural and agricultural applications.2.The phenolated lignin was used to synthesize lignin-based epoxy resin,and lignin-based epoxy resin coated urea were obtained.Firstly,the lignin was modified and phenolated to obtain the phenolated lignin.Secondly,controlled-release fertilizers coated by lignin-based epoxy resin（EFCU）synthesized from phenolated lignin and bisphenol A diglycidyl ether（BDE）with the different ratios of FAL to BDE were successfully prepared.The nutrient release properties of controlled-release fertilizers were studied in detail.The chemical structure and microstructure of EFCU were analyzed by means of FTIR and SEM.The results showed that EFCU3 with the 1:5 of FAL to BDE had compact structure and excellent properties,and improved the thermal stability by 70.6°C(T_10%),extended the nutrient release life by 3.5 times,and increased the surface water contact angle by 32.6%compared with EFCU1,which significantly slowed the nitrogen release rate of EFCU3.This research shows that the EFCU with good controlled release property has broad prospects in horticulture and agricultural applications.