Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2006-04-04
2006-04-04
Hightower, P. Hampton (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S125000, C528S126000, C528S128000, C528S170000, C528S171000, C528S172000, C528S173000, C528S174000, C528S176000, C528S179000, C528S183000, C528S185000, C528S220000, C528S229000, C528S310000, C528S350000, C528S351000, C528S353000, C528S373000, C525S420000, C525S422000, C525S432000, C525S436000
Reexamination Certificate
active
07022810
ABSTRACT:
A new class of hybrid organic-inorganic materials, and methods of synthesis, that can be used as a proton exchange membrane in a direct methanol fuel cell. In contrast with Nafion® PEM materials, which have random sulfonation, the new class of materials have ordered sulfonation achieved through self-assembly of alternating polyimide segments of different molecular weights comprising, for example, highly sulfonated hydrophilic PDA-DASA polyimide segment alternating with an unsulfonated hydrophobic 6FDA-DAS polyimide segment. An inorganic phase, e.g., 0.5–5 wt % TEOS, can be incorporated in the sulfonated polyimide copolymer to further improve its properties. The new materials exhibit reduced swelling when exposed to water, increased thermal stability, and decreased O2and H2gas permeability, while retaining proton conductivities similar to Nafion®. These improved properties may allow direct methanol fuel cells to operate at higher temperatures and with higher efficiencies due to reduced methanol crossover.
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Hampton Hightower P.
Sandia Corporation
Watson Robert D.
LandOfFree
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