UPR-Based Nanocomposites

Nanoparticles added to thermoplastic polymers improve the mechanical properties, increase Tg and enhance fire retardancy. Nanoparticles in UPRs bring similar effects [217]. Montmorillonite (MMT) was used to obtain polymer nanocomposites [218]. That general approach was applied to the UPR-layered MMT nanocomposites. The structure of the nanocomposites was investigated by XRD and TEM. Organophilic MMT was applied dodecylammonium-bromide treated MMT was used. A UPR synthesized 

In the UPR-based nanocomposites, the styrene monomer was replaced with the polar hydroxypropyl acrylate [224]. X-ray and mechanical test data indicated that mixing of the components for an extended period of time is essential to improve the physical properties of nanocomposites in the UP/Cloisite 6A system. This phenomenon was attributed to the high polarity of hydroxypropyl acrylate which may disturb the preintercalation of UPR into the galleries of montmorillonite. The UPRs with a styrene monomer were used in dispersions with polymerizable quaternary ammonium-modified montmorillonite [225]. An increase in tensile and impact strength and heat resistance (Table 29) was found when 2-5 wt % organophiHc montmorillonite was added. 

The effect of organophiHc MMT is particularly advantageous, when the organic substituent is copolymerizable. 

A different method of incorporating organophiHc MMT into the molecule of UP consists of when a MMT functionalized with hydroxyl groups copolymerizes ionically with maleic anhydride, phthaHc anhydride, and 

Modified montmorfllonite (MMT), 4 wt. % Tensile strength [MPa] Impact strength [kj/m2] Hardness [Barcol] HDT [°C] 

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