Properties and structure of composites polypropylene/clay
Jolanta Janik Politechnika Szczecińska, Instytut Polimerów, ul. Pułaskiego 10, 70-322 Szczecin
Annals 4 No. 10, 2004 pages 2005-211
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abstract This paper presents of research on possibility producing of thermoplastics nanocomposites with inorganic filler. Composites of polypropylene (PP-matrix) with clay-organic modified bentonite (filler) under the direction of optimisation technological parameters their produce and their properties was studied. The effect of commercial compatibilizers like graft polypropylene of maleic anhydrite (PP-g-MA) on composites PP/clay properties (static mechanical properties, thermal properties and structure) was investigated. The concentration of bentonite (OB) in the composites in a range 10, 15 and 20 wt.% was kept. The composites using a two-screw, corotating extruder were compounded. The research show that tensile strength σM and flexural strength σ fM of composites PP/clay (10, 15, 20 wt.%) clay are lower than for PP (Figs. 1, 3) and modulus of elasticity at tensile Et and modulus of elasticity at bending Ef are higher than PP (Figs. 2, 4). Composite PP/clay are brittle, what was related with decreasing of elongation at break εB and Charpy notched an in comparison with PP (Figs. 5 i 6). Addition of compatibilizing agents (PP-g-MA: PB 3002 and Exxelor) to PP/clay improves considerably mechanical properties in comparison with PP, but with PB 3002 increase is higher than with Exxelor. For example composite PP/20%OB/PB3002 demonstrate higher Ef (about 87%) and σ fM (about 60%) than PP. Composites PP/20%OB and with compatibilizing agents characteristics higher bending modulus E’ (DMTA) than PP (Fig. 7), and composites with PB 3002 demonstrate the highest values E’. Composite PP/clay characteristics lower glass temperature then PP (Fig. 8, Tab. 1). TG and DTG research (Fig. 9, Tab. 2) demonstrate improve thermal resistance of PP after addition of compatibilizers. Compatybilizing composites demonstrate higher thermal resistance than PP (Fig. 9). SEM pictures show (Figs. 10 and 11), that PB 3002 is a good compatibilizer, in composites PP/clay improve dispersion and reduce the size particle of filler (bentonite) in PP matrix. Key words: polymer nanocomposite, composite, polypropylene, clay, bentonite, compatibilizer