Spin-label study of immiscible polymers—II. Influence of polyisoprene on end-labelled polystyrene
Abstract Electron spin resonance spectra of blends of polyisoprene (PIP) and polystyrene (PS), carrying a nitroxide spin-label, show that the PIP exerts a plasticizing influence on the labelled chain-ends of PS. This effect presumably occurs at the interphase where certain of these chain-ends appear to be in a predominantly PIP environment. Treating the labelled PS as a macromolecular spin probe shows that the effective volume of an inner PS segment is ca 1.6 times greater than that of a labelled chain-end and ca 1.7 times greater than that of an inner PIP segment. Comparing the results with previously published data for spin-probed PS suggests that rotation of the chain-end label involves more than one styrene unit along the chain.
The goals of the paper are to understand the impact damage behavior and identify the effect of surface protective materials on impact resistance in filament wound composite pressure vessels. For these, a series of low velocity impact tests was performed on specimens cutting from the full scale pressure vessel by the instrumented impact testing machine. The specimens are classified into two types, which are with and without surface protective material. The visualization for impact damage by two different impactors is made by metallurgical microscope. Based on the impact force history and damage, the impact resistance parameters were employed,rod its validity in identifying the damage resistance of filament wound composite pressure vessel was reviewed. As the results, the impact resistance of the filament wound composites and its dependency on the surface protective material were evaluated quantitatively