Plasticization of poly(styrene-b-isobutylene-b-styrene) ionomers by acid salts of 2-ethylhexyl-p-dimethylaminobenzoate
Polymers and High Performance Materials
Poly(styrene-b-isobutylene-b-styrene) block copolymer ionomer (overall molecular weight = 71,200 g/mole; 25.5 wt % polystyrene, 4.7% sulfonation of phenyl units, 100% neutralized with KOH) was compounded with various organic and inorganic acid salts of 2-ethylhexyl-p-dimethylaminobenzoate (ODAB) to explore the efficacy of these compounds as ionic plasticizers. Results were compared to the same polymer plasticized by zinc stearate. Plasticizers were added to the polymer at levels of approximate to 5 wt%. Films were prepared by solution casting from tetrachloroethylene. Thermogravimetric analysis (TGA) showed all ODAB derivatives to have lower decomposition temperatures than zinc stearate. Dynamic mechanical analysis (DMA) of the films showed varying degrees of ionic plasticization as evidenced by a lowering of the temperature at which the onset of flow occurred. With the exception of the stearic acid salt of ODAB, all ODAB derivatives were more efficient ionic plasticizers than zinc stearate. Among the ODAB derivatives, the degree of ionic plasticization varied, with the methane sulfonic and p-toluene sulfonic acid salts being most effective, leading to the conclusion that processing temperatures could be tailored to specific applications by choice of plasticizer and level of incorporation.
POLYMER ENGINEERING AND SCIENCE
Storey, R. F.,
(1999). Plasticization of poly(styrene-b-isobutylene-b-styrene) ionomers by acid salts of 2-ethylhexyl-p-dimethylaminobenzoate. POLYMER ENGINEERING AND SCIENCE, 39(7), 1328-1334.
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