Temperature Effect on Low Velocity Impact of Nanoclay Reinforced Polymers

The main objective of this study is to ascertain the effect of temperature on nanoclay reinforced polymers subjected to low velocity impact loads. Most of the studies for low velocity drop weight tests are on fiber or fabric reinforced polymers. In recent years nanoadditives such as nanoclay have been used to improve the fire retardation of composites. The low velocity drop weight testing undertaken under this research has the digtinct goal of obtaining base line data for impact analysis of nanoclay reinforced polymers. First, polypropylene 3371 (PP) resin specimens with dimensions of 4 '' x4 '' x(1/8)'' reinforced with varying weight fractions of nanoclay (0%, 0.2%, 1%, 3%, 6% and 10%) and instrumented with strain gages were subjected to low velocity impact tests. The low velocity impact tests were carried out at an energy level appropriate for nanoadditive reinforced polymers and at various temperatures, from -65 degrees F (-54 degrees C) to 160 degrees F (71 degrees C). The variation of contact force, specimen deflection and energy imparted to the specimen with time and the variation of contact force with displacement were obtained at each temperature. Depending on the drop height, the weight used and the percentage of nanoclay reinforcement, the following was observed: some specimens were penetrated (P), some cracked (F) and some visually remained virtually intact (NP), that is, they were not penetrated. The results of the low velocity impact tests indicate that high temperatures affect polypropylene significantly and practically eliminate the effect of nanoclay reinforcement. As a consequence the specimens show ductile behavior and were not penetrated. However, at room and low temperatures the effect of nanoclay reinforcement is discernable and addition of nanoclay makes the specimens more brittle, resulting in penetration of most of them.