Discussion on the peculiar behavior of polyolefins filled with nano-sized silica

Discussion on the peculiar behavior of polyolefins filled with nano-sized silica

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Effect of silica nano-filler on the deformation response and morphology of low- and high-density polyethylene (HDPE, LDPE) and isotactic polypropylene (PP) modified with fumed silica was investigated. The dynamic-mechanical thermal spectroscopy, differential scanning calorimetry, optical microscopy and density measurements were carried out to determine the temperature dependence of storage and loss moduli as well as nanocomposite morphology. It was demonstrated that the degree of matrix reinforcement is considerably affected by the extent of matrix crystallinity, especially, in the temperature range from (Tm-130C) to Tm. Based on experimental evidence and literature review; it is proposed that this phenomenon may be attributed to the alpha mechanical relaxation process occurring above matrix Tg. As a result of adding silica into the melted matrix, mobility of chains in contact with silica particles became reduced. This caused substantial changes in morphology of these semicrystalline nanocomposites.

Effect of silica nano-filler on the deformation response and morphology of low- and high-density polyethylene (HDPE, LDPE) and isotactic polypropylene (PP) modified with fumed silica was investigated. The dynamic-mechanical thermal spectroscopy, differential scanning calorimetry, optical microscopy and density measurements were carried out to determine the temperature dependence of storage and loss moduli as well as nanocomposite morphology. It was demonstrated that the degree of matrix reinforcement is considerably affected by the extent of matrix crystallinity, especially, in the temperature range from (Tm-130C) to Tm. Based on experimental evidence and literature review; it is proposed that this phenomenon may be attributed to the alpha mechanical relaxation process occurring above matrix Tg. As a result of adding silica into the melted matrix, mobility of chains in contact with silica particles became reduced. This caused substantial changes in morphology of these semicrystalline nanocomposites.

polyolefin, nanocomposites, immobilization, morphology, relaxation

polyolefin, nanocomposites, immobilization, morphology, relaxation

KALFUS, J.; JANČÁŘ, J.

11.09.2007

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Brno

978-80-214-3495-0

CD: Main topic: Polyolefin Composites for special purposes (micro-fillers, fire-resistant, conductive etc.)

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