It is remarkable that the as-received UHMWPE fibers/NR composites gives the highest energy dissipation in the temperature region over the glass transition temperature. This can be attributed to the very weak fiber/polymer bond in the composite [25]. As-received UHMWPE fibers/NR composites give an increase in E0 in both the rubbery region and glassy region, treated UHMWPE fibers/NR composites only in the rubbery region. For instance, at 40 C the storage modulus of the NR and the composites with as-receivedand treated UHMWPE fibers are 3.3, 20.7 and 16.1 MPa,respectively.