Preparation Of Dendritic Melamine Phosphine Modified Organic Montmorillonite And Its Applicaion Into Rubber Composites

In this study, different generations of dendrimers were synthesized from cyclotriphosphazene-core and then added the ethylenediamine. The Michael addition reaction was conducted in methanolic added methylacrylate. The organic modification of Na-montmorillonites(Na-Mt) was achieved by exchanging the cations with methacryloxyethyl-trimethyl ammonium chloride(DMC) which structure contains double bonds that lead to the addition reaction with different generations of dendritic polymer, then the organic-montmorillonites(DMC-OMt) was prepared. Different generations of flame-retardant dendritic macromolecules modified DMC-OMt,flame-retardant dendritic montmorillonite were prepared. Though the characterization the flame retardant, the better dendritic montmorillonite was applied to the natural rubber(NR). Their flame retardant and mechanical properties were researched. The research focused on the following three aspects:(1) Preparation of dendritic polymer. Different generations of dendrimers, G1.0,G2.0 and G3.0 were synthesized from cyclotriphosphazene-core. Characteristics of these dendrimers were studied by Fourier transform infrared(FTIR),1H nuclear magnetic resonance(1H-NMR), ultraviolet(UV-Vis) spectroscopy and intrinsic viscosity(IV). FTIR analysis revealed that the main absorption peaks of phosphonitrilic chloride trimer(PCT) was P-Cl bond which was observed at 581 cm-1.This peak disappeared at the absorption peaks of G1.0,G2.0 and G3.0 resulting from the substitution of chlorine atom. UV-Vis test showed that with the increase ofdendrimer generations, the number of the end functional groups increased exponentially. IV test showed that the intrinsic viscosity of the dendritic polymers increased obviously with the increase of generations. The all above tests shown that the different generations of dendritic polymer have been synthesized successfully as expected.(2) Preparation of dendritic flame retardant montmorillonites. Firstly, organic montmorillonites(DMC-OMt) was prepared via ion-exchange reactions between Na-Mt and quaternary ammonium salt, DMC. Different generations of flame-retardant dendritic macromolecules modified DMC-OMt, G1.0-OMt, G2.0-OMt and G3.0-OMt were prepared.The interlayer space, interlamellar structure, thermal stability, and surface morphology of these dendritic montmorillonites were investigated by Fourier transform infrared(FT-IR) spectroscopy, thermogravimetric analysis(TGA), X-ray diffraction(XRD) and scanning electron microscopy(SEM) as well as energy dispersing spectrometer(EDS). XRD revealed that the interlayer spacing of G1.0-OMt,G2.0-OMt and G3.0-OMt was 1.77, 1.36 and 1.32 nm, respectively. TGA results illustrated that thermal stability of G1.0-OMt, G2.0-OMt and G3.0-OMt was obviously improved with the increase of generations compared with that of Na-Mt. SEM also revealed a tendency towards exfoliation, lump formation and agglomeration of the dendritic montmorillonite particles.(3) Application of dendritic montmorillonites in NR. The different proportion of the G3.0-OMt added to the NR and flame retardant composite material was prepared.The vulcanization curve of the composite, the tensile strength, elongation at break and hardness, abrasion, thermal stability and flame retardant properties were tested. The result shows that the tensile strength of NR composites increased with the increased amount of G3.0-OMt. The maximum value was increased to 18.8MPa when 15 phr of G3.0-OMt was added which was increased by 16.7% compared with 0phr. The results of TGA showed that the residual quantity increased with the increasing amount of flame retardant, the largest residual amount was 13.67 when 20 phr of G3.0- OMt was added.The maximun value of burning time was 230 s, and it was improved about54% compared with that of the blank NR.