Elongation is associated with the uncoiling of polymer molecules and their movement relative to other molecules. Highly crosslinked polymers have a low elongation relative to linear polymers. Elongation can vary widely among polymers and is usually expressed as a percent of the original length of the sample. Flexural strength is measured by supporting a sample test bar of uniform cross-section at each end, in a horizontal position. The sample is then subjected to a vertical stress until it yields or breaks.
Crosslinked polymers are more rigid and have a higher flexural strength than linear polymers.
Impact resistance is a measure of the toughness of a polymer. It can be determined by striking a vertical sample with a weighted pendulum and measuring the distance the pendulum travels after the sample breaks. Dispose of materials as instructed by your teacher. Weigh down or clamp the base of the ring stands for stability. See figure below.