(180c) Preparation, Structure, and Properties of Nanoparticles and Long Fibers Reinforced Thermoset Composites

Nanoparticles, such nanoclay and carbon nanofibers, are promising candidates for reinforcing various polymer matrices. The polymer nanocomposites have some unique properties, such as good barrier properties and excellent thermal performance. Although fiber-reinforced plastics (FRP) have good mechanical properties, water or other small molecules may diffuse onto the interface between the polymer matrix and fibers, causing substantially drop of interfacial strength and adhesive failure may occur. Under tension, compression, shear, or impact, failure of the polymer matrix may also take place. On the other hand, although nanoparticles may reinforce the polymer matrix and slow down water uptake, the loading of nanoparticles often cannot reach high level (<10 wt%) in polymer nanocomposites due to the dispersion difficulty. Thus, mechanical properties of polymer nanocomposites are relatively low compared with those of highly loaded fiber-reinforced plastics (>50 wt%). We try to combine the advantages of both polymer nanocomposites and fiber-reinforced plastics to produce a new composite with superior properties.

In this study, epoxy, phenolic, and unsaturated polyester resins, the most important thermoset polymers, are used as polymer matrices. Polymer composites with various long fibers and nanoparticles are synthesized by different processes. Then, the dispersion of nanoparticles in the composites and the adhesion between long fiber and polymer matrix are characterized by electron microscopy. The mechanical or thermal properties of these composites are compared with both continuous fiber-reinforced composites and polymer nanocomposites. The optimal conditions of sample preparation and processing are also investigated to achieve the good dispersion of nanoparticles in the polymer matrix and excellent properties of the hybrid composites.