Preparation and Effectiveness of Slow-release Polymeric Fertilizer Containing Multiple Nutrients Special for Maize

Slow-release polymeric fertilizer containing multiple nutrients was synthesized through condensation polymerization from raw materials of homemade low-molecular urea-formaldehyde and the compounds of potassium dihydrogen phosphate and phosphoric acid. Adjustment of the proportion of raw materials makes the ingredients of the fertilizer are N:P_2O_5:K_2O =1:0.75:0.13, which satisfy the nutritional requirement for maize growth. Field-experiment results prove that the yield of maize increases by 16.56% when using the polymeric fertilizer special for maize alone, by 56.51% when applying the polymeric fertilizer special for maize plus farmyard manure, and by 49.11% when applying the SV fertilizer special for maize plus manure.

Study on the Properties of Microcapsulated Chlorocyclophosphazene Polypropylene Composites

Microcapsulated chlorocyclophosphazenes were synthesized,and then microcapsulated chlorocyclo- phosphazene/polypropylene(PP)composites were prepared.The results showed that microcapsulated chlorocyclo- phosphazene had good high thermal stability through thermogravimetric analysis(TGA).The flammability and mechanical properties of microcapsulated chlorocyclophosphazene/polypropylene composites were investigated by limiting oxygen index experiment,UL 94V flame retardancy test,cone calorimetry,tensile experiment,and impact test,respectively.It was shown that the microcapsulated chlorocyclophosphazene/PP composites had better tensile strength,impact strength,flame retardant properties and smoke suppress properties compared with chlorocyclo- phosphazene/PP composites.

Highly Efficient Adsorption of Copper Ions by a PVP-Reduced Graphene Oxide Based On a New Adsorptions Mechanism

Polyvinylpyrrolidone-reduced graphene oxide was prepared by modified hummers method and was used as adsorbent for removing Cu ions from wastewater. The effects of contact time and ions concentration on adsorption capacity were examined. The maximum adsorption capacity of 1689 mg/g was observed at an initial p H value of 3.5 after agitating for 10 min. It was demonstrated that polyvinylpyrrolidone-reduced graphene oxide had a huge adsorption capacity for Cu ions, which was 10 times higher than maximal value reported in previous works. The adsorption mechanism was also discussed by density functional theory. It demonstrates that Cu ions are attracted to surface of reduced graphene oxide by C atoms in reduced graphene oxide modified by polyvinylpyrrolidone through physisorption processes, which may be responsible for the higher adsorption capacity. Our results suggest that polyvinylpyrrolidone-reduced graphene oxide is an effective adsorbent for removing Cu ions in wastewater. It also provides a new way to improve the adsorption capacity of reduced graphene oxide for dealing with the heavy metal ion in wastewater.

Effect of Electric Field Intensity on the Morphology of Magnetic-field-assisted Electrospinning PVP Nanofibers

Polyvinylpyrrolidone （PVP） nanofibers were processed by magnetic-field-assisted electrospinning （MFAES） technique. Since electric field intensity was one of the most important parameters influencing fiber morphology, the research aimed to study how electric field intensity affects fiber morphology in MFAES technique. The experimental results revealed that the distribution of diameter widened while the average diameter of PVP fibers decreased and the degree of the alignment reduced with the increase of electric field intensity. However, the fibers would be conglutinated together when the electric field intensity was too low. Also, the increase of working distance made the average diameter and the degree of the alignment increase slightly under the same electric field intensity, but the fibers could be partially curved instead of being fully straight if the working distance was too long. It was also indicated that maintaining the electric field intensity at 1 kV/cm With the voltage-distance combinations of 12 kV-12 cm （for 12wt% PVP） and 15 kV-15 cm （for 14wt% PVP） among all other combinations would result in the optimal alignment as well as a narrow size distribution of the fibers.