NMR relaxation reveals modifications in rubber phase dynamics during long-term degradation of high-impact polystyrene (HIPS)

作者：Vilaplana Francisco; Karlsson Sigbritt; Ribes Greus Amparo; Schade Christian; Nestle Nikolaus^*

来源：Polymer, 2011, 52(6): 1410-1416.

DOI：10.1016/j.polymer.2011.02.005

• High-impact polystyrene (HIPS)
• Nuclear magnetic resonance relaxation
• Polybutadiene rubber

The microstructure of rubber-modified polystyrene after thermal ageing at 90 C and multiple extrusion was analyzed by time-domain nuclear magnetic resonance (TD-NMR) in a non-destructive manner. The transverse magnetization decay behaviour observed in TD-NMR was related to the total rubber fraction and its cross-linking density. The data reveal different mechanisms of long-term rubber degradation in high-impact polystyrene (HIPS) during then-no-oxidation and multiple processing: Multiple processing causes a slight increase in the cross-linking density of the rubber phase, without appreciably altering the total amount of rubber fraction. Thermo-oxidation is accompanied by a significant overall decrease of the rubber fraction, an increase of the cross-linking density, and a pronounced increase of the non-crosslinked fraction (chain ends and fragmented segments). The NMR results correlate well with spectroscopic observations and moderately with macroscopic mechanical properties.

• 出版日期2011-3-10