Supermolecular morphology of polypropylene filled with nanosized silica

Abstract

The supermolecular morphology of injection-molded SiO 2 /polypropylene (PP) nanocomposites was investigated via thin sections analyzed under polarized light and the systematic development of an appropriate etching technique, which allowed the study of the supermolecular morphologies with light microscopy (LM) and high-resolution field emission scanning electron microscopy (FESEM). In parallel, information regarding the dispersion, distribution state, and morphology of SiO 2 particles was investigated via transmission electron microscopy (TEM) and scanning electron microscopy (SEM) of the ion-polished and fractured surfaces of SiO 2 -filled PP. The TEM/SEM results demonstrated an almost homogeneous dispersion and distribution of SiO 2 particle agglomerates in the PP matrix. With polarized transmitting LM, reflecting LM, and FESEM, the spherulitic structure of the nanocomposites could be visualized to obtain information on the nanoparticle influence on the crystallization and structural behavior. The size and size distribution of the spherulites analyzed with transmitting light (thin sections) and reflecting light (etched specimens) showed an excellent correlation. With increasing filler loading, the mean size of the spherulites decrease as did the degree of crystallinity. This was a clear indication that the particles acted as nucleation agents and, on the other hand, hindered the arrangement of the molecules during the crystallization. As a result, the particles were most likely located in three areas: the center of the spherulites, the areas between the highly crystalline branches, and the spherulite boundaries. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39655.

Correlation between morphology and electrical breakdown strength of the polypropylene/maleic anhydride grafted polypropylene/nano‐ZrO2 ternary system

“…It can be seen in Figure (a) that when only nano‐ZrO 2 was added, the melting temperature increased slightly with nano‐ZrO 2 content. This can be understood as the enhancement of α‐crystal as discussed above, since the α‐crystal possesses a higher melting temperature of 165 °C compared with 154 °C for β‐crystal . In Figure (b), the melting peak splits into two peaks, one for PP (high‐temperature peak) and the other for PP‐g‐MAH (low‐temperature peak) .…”

“…The degree of crystallinity ( X c , %) can also be obtained from the DSC results based on eq. () : where Δ H s is the enthalpy of fusion calculated by the melting peak, and Δ H k is 209 J/g (literature data for the enthalpy of fusion of 100% crystalline polypropylene), while x is the weight proportion of nano‐ZrO 2 . The influence of nano‐ZrO 2 content on crystallinity is shown in Figure .…”

A novel functional silica/lignin hybrid material as a potential bio-based polypropylene filler

“…0.1 g) and 1 mg of the tested substance in a special steel ring under a pressure of 10 MPa. The investigation was performed over a wavenumber range of 4000-400 cm 21 (at a resolution of 0.5 cm 21 ).…”

“…Combining the lignin macromolecule, rich in various functional groups, with a commonly used inorganic support, offering particularly high chemical and thermal stability, enables the formation of an innovative hybrid material with improved physicochemical properties compared with those of the separate precursors (SiO 2 and lignin). A very good inorganic material used as an active filler in polymer composites is silica [14][15][16][17][18][19][20][21]. Numerous methods of obtaining silica are known, ranging from the sol-gel method [22][23][24] to precipitation methods in polar [25,26] and nonpolar media [27,28].…”

Supermolecular structure and nucleation ability of polylactide-based composites with silica/lignin hybrid fillers

“…Inorganic fillers such as silica are attractive reinforcements that are able to significantly improve thermal, mechanical and also chemical properties of PLA-based biocomposites [4,5]. Its valuable physicochemical properties along with high surface are the reasons for its widespread use [22,23]. Silica exhibits also a great potential for surface functionalization in terms of physical and chemical features and therefore gains even more possible applications [24][25][26][27][28][29][30].…”