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Solid state NMR investigation of antiplasticization of polystyrene by mineral oil
Author(s) -
Smith P. B.,
Delassus P. T.,
Ellaboudy A. S.,
Diedering D. E.,
Landes B. G.,
Anderson S. L.,
Grulke E. A.
Publication year - 1994
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19940860116
Subject(s) - polystyrene , materials science , flexural strength , polymer , mineral oil , plasticizer , flexural modulus , composite material , phase (matter) , polymer chemistry , chemical engineering , organic chemistry , chemistry , metallurgy , engineering
The effects of mineral oil plasticization of polystyrene were investigated as a function of polystyrene molecular weight and mineral oil concentration. Solid state NMR, thermo/mechanical methods and positron annihilation spectroscopy (PAS) were used to study the molecular dynamics and free volume effects of this blend. Antiplasticization was observed in the low (40,000) molecular weight polystyrene samples as an embrittlement of the system. In contrast, the flexural modulus was not affected by the presence of mineral oil in the higher (270,000) molecular weight polymers but a decrease in the flexural strength was observed with increasing mineral oil concentration. The NMR and PAS data indicated that the mineral oil was not dissolved in the polymer at ambient temperature, rather it phase separated even at very low concentrations. This caused antiplasticization in low molecular weight polymers because the small free volume holes were filled causing a densification of the system. With high molecular weight polystyrene, this phase separation was manifested as a decrease in the flexural strength.