Scale-up Preparation Of Benzoxazine-based Polymer Spheres

Carbon spheres with tunable size and surface functionality show great potential for applications in adsorption, catalysis, drug delivery, energy storage and conversion, which are usually prepared by carbonization of polymer analogues. However, polymer precursors are required to be able to form carbon residue after a high-temperature pyrolysis. In this case, benzoxazine-based polymer spheres are attractive because of their excellent performance characteristics such as high-temperature resistance, thermal abrasiveness, and high yield of carbon conversion.On the basis of the results in our previous works, we have optimized the synthesis of polymer spheres based on the benzoxazine chemistry. Polymer spheres are first synthesized through precisely programming the reaction temperatures, using monomers including resorcinol, formaldehyde,1,6-diaminohexane. With the design and selection of large-scale reactor, we produce plenty of benzoxazine-based polymer spheres at one session through a simple and low-cost process.Firstly, by analyzing the theory and procedure in course of fabricating polymer spheres, a suitable large-scale reactor has been designed both in type and size. Ultimately, a vertical double-flat glass reactor with volume 10 L and volume charge coefficient 0.8-0.85 is selected to be used, of which volume is 40 times as much as that of solvent before... Secondly, with the reactor and process, highly uniform monodisperse polymer spheres are produced, the size is 325±25 nm. SEM results indicate that the solid content of each doubling of the average size of the polymer growth of about 100nm, and accompanied by a wider particle size distribution. The results of SEM show that there is an increase in average sphere size and a broadening in the distribution with the solid content increasing. The sphere tended to agglomerate or bridge to each other when the solid content reaches 2.32%. Finally, based on the results above, a feasibility analysis on the approach of large-scale preparation of benzoxazine polymer sphere has been carried out. The conversion rate of the polymer is nearly 100%, the yield is more than 80%, operating time circle is 9 h, and the assessment suggests that it is safe enough to realize large-scale production of benzoxazine-based polymer spheres by method illustrated above.