It is increasingly important to understand the dynamic response of polymers and polymer composites as their engineering application increases. This work aims to investigate the effects of additions to thermoplastic carbon chains on the response of the resulting polymer at the continuum scale. Polyethylene, polyvinyldichloride, and polymethylmethacrylate are shocked, and their equation of state and strength properties is presented. An explanation is sought for the greater hardening observed in polymethylmethacrylate by looking at tacticity and electronic attractive forces, as well as entanglement of chains as a result of the large pendent side group. It is concluded that this entanglement has the greatest effect upon the observed strengthening in these thermoplastics. © The Minerals, Metals amp; Materials Society and ASM International 2007.