Amir Hosein Paryab - Department of Materials science and Engineering, Sharif University of Technology, Tehran, Iran
Sorosh Abdollahi - School of Material science and Engineering, Iran University of Science and Technology, Tehran, Iran
Rashid Khalilifard - Department of Materials science and Engineering, Sharif University of Technology, Tehran, Iran
Hamid Reza Madaah Hosseini - Department of Materials science and Engineering, Sharif University of Technology, Tehran, Iran

As an alternative to conventional fertilizers, e.g. NPK (the Nitrogen-Phosphorous-Potassium containing chemical fertilizers) which release their nutrients in a short period of time, due to high solubility in irrigation water, glass fertilizers are ideal as they release macro- and micronutrients for crops and plant nourishment. Also, despite conventional ones, they have no ground-water pollution. In the present study, glass fertilizers were synthesized via Polymer-Derived Ceramics (PDC) method. Despite the melt-casting procedure, PDC needs lower temperatures in heat treatment. The precursors consist of poly-siloxane and active fillers. Thus, thanks to gaseous release during heat treatment of the present active fillers, i.e. Ca(OH)۲, MgCO۳, and Al(OH)۳, a porous microstructure can be generated. In order to manipulate the pore size and specific surface area, fractions of active fillers were used as calcined. The experiments showed that upon increase of non-calcined active fillers, the specific surface area and the amount of porosity was increased due to more gaseous release during heat treatment. Thus, affected by microstructure, the release rate of macro and micro-elements was higher in the sample containing non-calcined active fillers, in comparison to other samples. Additionally, the porous samples were able to be loaded by extra nutrients containing Nitrogen, like KNO۳.

glass fertilizer, polymer-derive ceramics, slow release, active fillers