Preparation and Physical Properties of Melamine Polyphosphate/Montmorillonite/Nylon 6 Nanocomposites

• Main Authors: Po-Shuan Wu, 吳博軒
• Other Authors: Jeng-Yue Wu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/9jf5up

碩士 === 國立中興大學 === 化學工程學系所 === 101 === In this study, melamine polyphosphate (MPP) was prepared and served as Clay modifier. The montmorillonite (MMT) with the characteristics of negative surface charge was modified by MPP via chemical reactions in the aqueous solution. The modified montmorillonite (MPP/Clay) was further introduced to Nylon 6 matrix by melt blending method. Thermal properties and flame retardant properties of (MPP/Clay)/Nylon 6 nanocomposites were studied. The synthesis of MPP was performed by the combination of melamine with phosphoric acid. Melamine phosphate (MP) was first prepared with positive charge in surface that can serve as the modified Clay precursor. After 300 ℃ thermal treatment, the MP molecules went through dehydration polymerization to generate MPP. Fourier transform infrared spectroscopy (FT-IR) indicated melamine polyphosphate wereobserved at 3133.8 cm-1 and 2843.7 cm-1 assigned to the vibration absorption of -NH3+, 2696.7 cm-1assigned to the vibration absorption of O-H groups, 1385.4 cm-1 assigned to the vibration of C-N groups of the triazine rings, 1282.12 cm-1 and 1178.8cm-1 assigned to the vibration of P=O bonds, 970.2cm-1 assigned to the vibration absorptions of P-O in P-O-H groups, and 888.7 cm-1 assigned to the vibration of P-O-P bonds. The modified montmorillonite (MPP/Clay) was prepared via melamine acidification and adsorb on the MMT surface firstly. Next, phosphoric acid was added to generate MP on the Clay surface. It was observed that the increase of MP concentration could further increase the platelet distance to the extent of featureless XRD pattern (none of peaks). The generated MPP particles with diameter less than 100 nm immobilized on the MMT surface was observed by field emission scanning electronic microscopy (FE-SEM). After melt blending, the (MPP/Clay)/Nylon 6 nanocomposites were prepared. Differential scanning calorimetry (DSC) results indicated that modified MMT does not affect the melting point of the polymer matrix. Found that the crystallization temperature of the composites occurred early in the first cooling, add modified montmorillonite has heterogeneous nucleation. Thermogravimetric analysis (TGA) showed that the incorporation of modified MMT (30 wt%) significantly enhanced the residue to 19.53 wt% at 800 ℃. Furthermore, LOI (limiting oxygen index) value increases from 25.3 to 37.4 indicating that (MPP/Clay)/Nylon 6 nanocomposites possess excellent flame retardant properties. FESEM analysis can be observed that the post-combustion of the (MPP/Clay)/Nylon 6 nanocomposites forms compact coke layer structure, thus prevents the inner polymer burning further to achieve the derived flame retardant purpose.