Nanocomposites of silica reinforced polypropylene: Correlation between morphology and properties

Abstract

Polypropylene/fumed hydrophilic silica nanocomposites were prepared via melt mixing method using a single‐screw extruder. Comparative study with and without compatibilizing copolymer agent (maleic anhydride grafted polypropylene: PP‐g‐AM) was conducted. The obtained results were interpreted in terms of silica nanoparticle–silica nanoparticle and silica nanoparticle‐polymer interactions. These results have shown that the addition of nanofillers improves the properties of the nanocomposites. From transmission electron microscopy, it was found that agglomerations of silica particles into the PP matrix increased in average size with increasing silica contents, except in presence of the copolymer. Storage modulus values of the nanocomposites measured by dynamic mechanical thermal analysis were sensitive to the microstructure of the nanocomposites. Higher silica contents resulted in higher storage modulus, revealing that the material became stiffer. By adding the compatibilizer, a further increase of storage modulus was observed due to the finer dispersion of the filler in the matrix and the increased interfacial adhesion. Crystallization rates were found to increase with the increase of silica nanoparticles as well as PP‐g‐MA content. In addition, silica nanoparticles and the compatibilizing agent present centers of germination and nucleation of crystallites. Thus, the use of the coupling agent resulted in a further enhancement of mechanical properties of the nanocomposites due to the reduction of silica agglomeration. POLYM. ENG. SCI., 54:2187–2196, 2014. © 2013 Society of Plastics Engineers

High shear dispersion of tracers in polyolefins for improving their detection

“…For example, high screw speed can give rise to the development of nanostructured blends with properties impossible to reach with classical processing techniques (twin-screw extruder, internal mixer, etc.). Concerning high shear extrusion, Louizi et al [24,25] and Bouaziz et al [26] have recently shown that the final morphology of polymer blends is significantly influenced by extrusion parameters such as mean residence time and screw rotation speed. Moreover, the specific mechanical energy "SME", which characterizes the extrusion process (with parameters such as torque, temperature, rotation speed, and throughput), can be correlated with the quality of the final product.…”

Maleated glycidyl 3-pentadecenyl phenyl ether with styrene: synthesis and application as compatibilizer in SBR/silica composite

“…Twenty‐first century materials will be made and tailored to target specification by combining disparate multiple materials to achieve new functionality. Maleic anhydride (MAH) grafting is approved as an effective additive to improve dispersion of silica in non‐polar matrix . Among the grafting techniques, free‐radical melt grafting during extrusion has been considered as one of the most practical and cost‐effective methods.…”

Polypropylene/silica micro‐ and nanocomposites modified with poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene)

“…10 On the contrary, steady increase of Young's modulus with increased silica content indicates preferable reinforcing effect of stiffer silica particles. Additional enchancement of tensile and impact strength was achieved by addition of maleated polypropylene (PP-g-MAH) as a compatibilizer for binary iPP/SiO 2 composites presented in papers by Bikiaris et al and Bouaziz et al 12,13 The hydroxyl groups on the surface of silica nanoparticles react with maleic anhydride groups of PP-g-MAH leading to higher adhesion between iPP matrix and silica particles and finer dispersion of individual SiO 2 nanoparticles with reduced agglomeration. Additional enchancement of tensile and impact strength was achieved by addition of maleated polypropylene (PP-g-MAH) as a compatibilizer for binary iPP/SiO 2 composites presented in papers by Bikiaris et al and Bouaziz et al 12,13 The hydroxyl groups on the surface of silica nanoparticles react with maleic anhydride groups of PP-g-MAH leading to higher adhesion between iPP matrix and silica particles and finer dispersion of individual SiO 2 nanoparticles with reduced agglomeration.…”

“…[7][8][9][10][11] However, in order to improve the interfacial stress transfer and to balance the toughness and stiffness in polymer composites an appropriate compatibilizer and/or a rubber toughening agent should be added. 12,13 While the compatibilization of binary and ternary iPP composites was widely explored, [12][13][14][15][16][17][18][19][20][21][22] there are few papers dealing with V C 2014 Wiley Periodicals, Inc. 12,13 While the compatibilization of binary and ternary iPP composites was widely explored, [12][13][14][15][16][17][18][19][20][21][22] there are few papers dealing with V C 2014 Wiley Periodicals, Inc.…”

“…Because SEBS grafted with maleic anhydride (SEBS-g-MAH) forms preferentially compartmentalized and inverse core-shell morphology morphology as reported in our previous investigation in the iPP/SiO 2 /SEBS composites very distinctive morphologies could be expected in the case of block copolymer without reactive MAH group-SEBS elastomer. [11][12][13][14][15][16][17][18][19][20][21][22][23] Thereby, the comparison of the effects of four silica fillers differing in size (nano-vs. micro-) and in their surface properties-new hydrophobic nanosilica (Aerosil R7200) vs. hydrophilic parent (Aerosil 200) and hydrophobic microsilica (Sipernat D17) vs. hydrophilic parent (Sipernat 120), e.g. The relation between interfacial properties and composite morphology will be analyzed by models calculated from adhesion parameters.…”