Design, synthesis and characterization of hybrid materials produced by grafting or mixing hybrid polyhedral oligomeric silselsquioxanes onto natural rubber and starch films

Martinez Pardo, I 2018, Design, synthesis and characterization of hybrid materials produced by grafting or mixing hybrid polyhedral oligomeric silselsquioxanes onto natural rubber and starch films, Doctor of Philosophy (PhD), Science, RMIT University.


Document type: Thesis
Collection: Theses

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Title Design, synthesis and characterization of hybrid materials produced by grafting or mixing hybrid polyhedral oligomeric silselsquioxanes onto natural rubber and starch films
Author(s) Martinez Pardo, I
Year 2018
Abstract The advantage of using nanomaterials as structure-property modifying agents is that they have substantially different physicochemical properties than those of their macroscale or bulk counterparts. Among nanomaterials, silica-based polyhedral oligomeric silsesquioxanes (POS or POSSTM) have shown to improve several physicochemical properties such as hydrophobicity and thermal stability when they are incorporated in polymers through chemical reaction or physical mixing. POS are highly versatile materials as they enable alteration or tailoring of the pendant groups. For this reason, POS are gaining popularity in polymer industry. However, their technological potential has not been adequately utilised in many important applications such as modifying the surface of starch films to introduce hydrophobicity and improving thermo-mechanical properties of natural rubber (NR).

Starch films have intrinsic natural affinity for water on their surface as well as in the bulk. This affinity is due to the hydroxyl groups in starch structure. This high affinity for water is the main reason that starch-only films are not used widely in packaging applications. It is a technological challenge to introduce any hydrophobic agent into hydrophilic matrix of starch. However, because of unique nature of POS, they can be tailored to physically mix with starch to increase hydrophobicity and avoid dispersion and segregation problems.

Natural rubber, so far, is one of the most versatile elastomeric materials with quite wide application including in medical devices, adhesives and tyres. Nevertheless, its weak thermo-mechanical stability and relatively low temperature resistance have limited its applications. POS is capable of improving the above-mentioned properties as observed in other elastomers such as polyurethanes and non-elastomeric materials such as epoxy resins.

In this context, the overall objectives of this research were to increase the hydrophobicity of thermoplastic starch films and improve the thermo-mechanical properties of NR. These two desired characteristics were brought to starch and NR by tailoring different POS and then incorporating them into NR and starch films by chemical grafting or physical mixing.
Degree Doctor of Philosophy (PhD)
Institution RMIT University
School, Department or Centre Science
Subjects Food Packaging, Preservation and Safety
Keyword(s) Polyhedral oligomeric silsesquioxanes
Starch
Natural rubber
Water-resistant
Computer modeling
Nanocomposite
Hybrid material
Rheology
Rheologically complex
Master curve
Click chemistry
Generalized model
Saving computational resources
Topology prediction method
Hydrophobicity
Mechanical properties
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Created: Tue, 16 Apr 2019, 16:07:43 EST by Keely Chapman
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