thermoset polymer particles are used in many applications requiring lightweight particles possessing high stiffness , strength , temperature resistance , and / or resistance to aggressive environments . the present invention relates to the use of two different methods , either each by itself or in combination , to enhance the stiffness , strength , maximum possible use temperature , and environmental resistance of such particles . one method is the application of post - polymerization process steps to advance the curing reaction and to thus obtain a more densely crosslinked polymer network . in general , its main benefits are the enhancement of the maximum possible use temperature and the environmental resistance . the other method is the incorporation of nanofillers , resulting in a heterogeneous “ nanocomposite ” morphology . in general , its main benefits are increased stiffness and strength . nanofiller incorporation and post - polymerization heat treatment can also be combined to obtain the benefits of both methods simultaneously . the present invention relates to the development of thermoset nanocomposite particles . it also relates to the optional further improvement of the heat resistance and environmental resistance of said particles via post - polymerization heat treatment . furthermore , it also relates to processes for the manufacture of said particles . finally , it also relates to the use of said particles in the construction , drilling , completion and / or fracture stimulation of oil and natural gas wells ; for example , as a proppant partial monolayer , a proppant pack , an integral component of a gravel pack completion , a ball bearing , a solid lubricant , a drilling mud constituent , and / or a cement additive .