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Your search keyword '"Mays, Jimmy W."' showing total 19 results
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19 results on '"Mays, Jimmy W."'

17. Solution properties and chain flexibility of poly(p-tert-butylstyrene)

Author

Mays, Jimmy W., Ferry, William M., Hadjichristidis, Nikos, Funk, Walter G., and Fetters, Lewis J.

Abstract

The dilute solution properties of anionically synthesized poly(p-tert-butylstyrene) (PtBS) were studied in tetrahydrofuran, cyclohexane 1,4-dioxane, 1-nitropropane and 2-octanol. Cyclohexane and tetrahydrofuran are good solvents for PtBS, 1,4-dioxane is of intermediate solvent power, and 1-nitropropane and 2-octanol are theta solvents. The unperturbed dimension results show PtBS to be a more extended chain than polystyrene. These observations are interpreted in light of rotational isomeric state (RIS) models for polystyrene and poly(p-chlorostyrene) and experimental data available for polystyrene and its substituted derivatives.

Published
1986
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19. Fabrication and characterization of poly(l-lactic acid) gels induced by fibrous complex crystallization with solvents.

Author

Yasuhiro Matsuda, Akinobu Fukatsu, Yangyang Wang, Miyamoto, Kazuaki, Mays, Jimmy W., and Shigeru Tasaka

Subjects
*POLYLACTIC acid, *DIMETHYLFORMAMIDE, *TEMPERATURE effect, *SOLVENTS, *CRYSTALLIZATION, *MICROFABRICATION, *FIBERS, *GELATION
Abstract

Complex crystal induced gelation of poly(l-lactic acid) (PLLA) solutions was studied for a series of solvents, including N,N-dimethylformamide (DMF). By cooling the solutions prepared at elevated temperatures, PLLA gels were produced in solvents that induced complex crystals (ε-crystals) with PLLA. Fibrous structure of PLLA in the gel with DMF was observed by polarizing optical microscopy, field emission electron microscopy, and atomic force microscopy. Upon heating, the crystal form of PLLA in the DMF gel changed from ε-crystal to α-crystal, the major crystal form in common untreated PLLA films, but the morphology and high elastic modulus of the gel remained until the α-crystal dissolved at higher temperature. In addition, a solvent exchanging method was developed, which allowed PLLA gels to be prepared in other useful solvents that do not induce ε-crystals without losing the morphology and mechanical properties. [ABSTRACT FROM AUTHOR]

Published
2014
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