Research On Synthesis Of Triazine And Silane-containing Hyperbranched Polyphosphonate And Its Flame-retardant Performances For PP

Phosphorus and nitrogen-containing hyperbranched polymers (HBP) have great potential in exploring environment-friendly flame retardant system which holds high molecular weight components and good durability. However, so far they are still far away from industrial fire retardant applications, mainly because that the mass production processes for them is not mature and they are mostly immiscible with most polymers due to their high polarity.In this study, according to the industrial design requirements, we optimized the synthesis process of hyperbranched polyphosphonate (HBPPO) based on our previous laboratory-test results aiming to provide theoretical support for HBPPO pilot and industrial production. On this basis, we also explore the silylation process of HBPPO in order to break through the current application bottleneck of phosphorus-nitrogen-contained HBP. In the end, a novel flame retardant synergist of hyperbranched polyphosphate (TMHO) was successfully synthesized in mass, and it was used to investigate the synergistic effect of silicon, nitrogen and phosphorus in designing flame-retardant polypropylene (PP), as well as the synergistic effect of phosphorus, nitrogen, silicon and metal ion. This work is aimed to build a new intuescent flame retardant system with high molecular weight components and high performances. In addition, all the resulting intermediates and target products were characterized by elemental analysis, Fourier transform infrared spectra (FT-IR),1H NMR and 29Si NMR spectroscopy. Charring capability of flame retardants and combustion properties of PP flame retarded by them were studied by UL-94 test, limiting oxygen index (LOI), cone calorimeter test (CCT) and scanning electron microscopy (SEM) and so on.The results show that:(1) It is really feasible for the optimization of process parameters obtained to be used in bulk synthesis of HBPPO and TMHO; (2) Introducing three flame-retardant elements of phosphorus, nitrogen and silicon into TMHO allows it to play multiple roles as flame retardant, compatilizer and toughening agent given that it is in multicomponent mixed system; (3) Synergistic complex of TMHO/APP/metal ion can not only get a good flame retardant effect, but also have some smoke suppression function, which makes the flame retardant system from them more secure and efficient. (4) TMHO has better rubber and plastic-processing stability than HBPPO, indicating it may be a potential excellent charring flame retardant synergist with more good comprehensive performances.