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Mechanical characterization of polyhedral oligomeric silsesquioxane/polypropylene blends
Author(s) -
Baldi Francesco,
Bignotti Fabio,
Fina Alberto,
Tabuani Daniela,
Riccò Theonis
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.26142
Subject(s) - silsesquioxane , materials science , polypropylene , crystallinity , differential scanning calorimetry , composite material , ultimate tensile strength , alkyl , modulus , yield (engineering) , dynamic mechanical analysis , polymer chemistry , polymer , chemistry , organic chemistry , physics , thermodynamics
Polypropylene blends with polyhedral oligomeric silsesquioxanes (POSS) bearing different alkyl groups were investigated to elucidate the effect of the alkyl group length on the mechanical behavior of the blends. In particular, blends of polypropylene (PP) with either octamethyl‐POSS, octaisobutyl‐POSS, or isooctyl‐POSS were studied. Differential scanning calorimetry evidenced only minor changes in the degree of crystallinity compared to neat PP. Uniaxial tensile tests showed that the incorporation of octamethyl‐POSS induces an increase in Young's modulus and a reduction of the yield strength in comparison with unfilled PP. By contrast, upon the incorporation of octaisobutyl‐POSS and isooctyl‐POSS, both Young's modulus and the yield strength were found to decrease by increasing the POSS content. It is suggested that POSS behave as particles having a siliceous hard‐core surrounded by a hydrocarbon soft‐shell, which limits the stress transfer from the matrix to the core in dependence on the length of the alkyl groups. Finally, the essential work of fracture method was employed to study the fracture behavior of octamethyl‐POSS/PP blends, with different POSS contents (0, 3, and 10 wt %). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007