Study On Bio-based Resin Coated Controlled Release Fertilizers

The traditional coated controlled release fertilizers have many problems such as high cost、long degradation period and strong dependence on petrochemical resources,especially organic polymer coating materials,which seriously affect the sustainable development of coated controlled release fertilizers.Therefore,the development of coatings with low-cost,biodegradable,excellent controlled release properties is a hot research topic in the field of coated controlled release fertilizers.The development of bio-based resin coated controlled release fertilizers using biomass materials is a new way to study environmentally friendly coating materials.Therefore,low-cost,biodegradable and widely available materials such as D-glucose derivatives D-glucose diacid and waste leftovers were used as raw materials of coatings.Two kinds of bio-based coating materials with low-cost,biodegradable and water resisting properties were developed in this paper.The novel coated controlled release fertilizers with smooth surface、dense structure and excellent controlled release properties were obtained by the drum coating technique.1.A novel controlled release fertilizers was developed using interpenetrating polymer network(IPN)as the coating material.The IPN was successfully sprayed on the surface of the urea particles to form IPN coated controlled release fertilizers(IPNCU).The IPN was synthesized by bio-based polyamide(PA)from D-glucaric acid and epoxy(EP)through network interpenetrating.The chemical structure and microscopic morphology characteristics of IPN were examined byFTIR,~1H-NMR,and SEM.The property of IPN with the different mass ratios of PA to EP were investigated and compared with that of EP-coated fertilizers(EPCU).The nutrient release behaviors and its mechanism of IPNCU in water and soil were discussed in detail.The results showed that the IPNCU with 5%PA content increased the nitrogen release longevity by 41 days,raised the water contact angle of surface by 23.98°,and then significantly slowed the nitrogen release rate of the IPNCU compared with EPCU.This work indicated that the environment-friendly IPN with superior controlled release properties could be especially useful in horticultural and agricultural applications.2.The novel bio-based polyurethanes were synthesized by using bio-based polyol derived from leftovers and isocyanate for the preparation of controlled release fertilizers(CRFs).The chemical structure and surface elemental compositions and distribution were examined by FTIR,EDX and XPS.The microscopic morphology of coating materials were examined by SEM.The nutrient release behaviors of bio-based polyurethane coated urea in water were detected.The results showed that the FPUs coating materials had a denser structure and better controlled release ability.This work indicated that using leftovers as coating materials of environment-friendly CRFs had great potential,which would be widely used in agricultural and horticultural fields.