Influence of octyl substituted octakis(dimethylsiloxy)octasilsesquioxane on the morphology and thermal and mechanical properties of low density polyethylene

Abstract

Low density polyethylene (LDPE) was melt blended with octyl substituted octakis(dimethylsiloxy)octasilsesquioxane (AS8) prepared in high yield by hydrosilylation of octene with octakis(hydrodimethylsiloxy)octasilsesquioxane. Two procedures were used to incorporate AS8 into LDPE at nanolevel and their efficiency was investigated by X-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy (AFM), differential scanning calorimetry, thermogravimetry and mechanical characterization. A slight increase of crystallite mean dimensions was observed by XRD in both types of LDPE-AS8 composites compared with neat LDPE. Better AS8 dispersion was observed by AFM in the composite prepared by the first procedure and the increase of both tensile strength and elongation at break in this composite confirmed the nanolevel dispersion and interface improvement in this case. AS8 influence in the final stages of polyethylene fracture was illustrated by AFM of elongated tensile specimens and a new mechanism of AS8 action was suggested. An interesting behavior consisting of simultaneous improvement of elastic modulus, strength and ductility was detected in the low range of polyhedral oligomeric silsesquioxane concentration in LDPE (0.5 wt%).

Morphology and mechanical properties of high density polyethylene-POSS hybrid nanocomposites obtained by reactive blending

“…The improved thermo-oxidative stability of other nanocomposites with POSS, including those based on polypropylene [14,24,47] and polyethylene [33] have been reported in the past. Fina et al [14,47] explained the enhanced stability of similar PP-g-POSS hybrid nanocomposites as a result of gradual accumulation of POSS on the sample surface from early stages of PP-g-POSS degradation, which allowed POSS oxidation and then formation of a ceramic thermally stable phase (silica) which can act as a protective barrier, limiting the polymer volatilization rate [47].…”

“…The influence of POSS grafting reaction on the morphological characteristics and physical properties of obtained composites was studied. Nanocomposites based on polyethylene and POSS were studied by several authors [20,[28][29][30][31][32][33][34][35] in aspect of their microstructure, crystallization rheological, and thermal properties, yet the PE-POSS hybrids obtained by reactive blending have not been reported.…”

New Alternative to Produce Colored Polymer Nanocomposites: Organophilic Ni/Al and Co/Al Layered Double Hydroxide as Fillers into Low-Density Polyethylene

“…45 In the region of 2 to 4° (in 2θ) reflections of some organophilic LDH were observed, with the exception of NiUS and CoUS, where the absence of reflections suggests the delamination/exfoliation of the layered crystals in the LDPE matrix. The XRD patterns also showed an increase in interlayer distance for LDH intercalated with dodecylsulfate, laurate and palmitate in the nanocomposite compared to the neat organophilic LDH (compare Figure 8 with Table 1).…”

Silsesquioxane Derivatives as Functional Additives for Preparation of Polyethylene-Based Composites: A Case of Trisilanol Melt-Condensation

“…It has been proven that a choice of introduced functional groups plays a major role in miscibility of silsesquioxanes and polymer matrix and the additive tendency towards agglomeration, but also the processing method and parameters have an impact on the obtained additive dispersion in the final composite or nanocomposite [40]. For example, large, linear alkyl chains render silsesquioxanes well-compatible with PE on the basis of similarity to the polyolefin chains, while smaller or branched substituents decrease the additive miscibility with the polymer [40,53]. At the same time, silsesquioxane additives of limited dispersion abilities may form particles serving as a reinforcing phase and improving mechanical properties of the obtained (nano)composite [21,25,40].…”