PCB cushion pads generally combine silicone rubber and fiberglass. They offer heat and pressure resistance, cushioning, flatness, reusability, electrical insulation, thermal conductivity, easy installation, and high voltage resistance. However, some aspects of their elastic response remain unresolved.

Molecular networks made by conventional methods contain chains of varying lengths. Numerically,

short chains predominate. The effect of this uneven chain-length distribution on network elasticity, particularly under large deformation,

requires further investigation. This is related to short-chain elasticity. These chains exhibit non-Gaussian

behavior, making their conformational statistics difficult to analyze. Nevertheless, such analysis is necessary

for a realistic study of network chains.

Network topology also needs more detailed treatment, including crosslink functionality, spatial

distribution, and loop formation. The tube model for uncrosslinked polymers provides an explanation of

molecular interactions in the condensed state, but its application to network structures appears incomplete. A key issue

is the stress response of highly filled elastomers. Filled elastomers are not purely elastic;

their stress–strain relationship is irreversible, so a strain-energy function is not an appropriate way to describe

their stress response. They also appear to become anisotropic after stretching and release.

The molecular processes involved in deformation, and the mathematical framework needed to describe them, remain unclear.