摘要:
A low cost method of fabricating bipolar plates for use in fuel cells utilizes a wet lay process for combining graphite particles, thermoplastic fibers, and reinforcing fibers to produce a plurality of formable sheets. The formable sheets are then molded into a bipolar plates with features impressed therein via the molding process. The bipolar plates formed by the process have conductivity in excess of 150 S/cm and have sufficient mechanical strength to be used in fuel cells. The bipolar plates can be formed as a skin/core laminate where a second polymer material is used on the skin surface which provides for enhanced conductivity, chemical resistance, and resistance to gas permeation.
摘要:
The present invention is directed to in situ reinforced thermoplastic fibers having improved mechanical properties and a method of making same. These composites have improved tensile strength and tensile moduli that exceed that predicted by composite theory under the rule of mixtures. The in situ composites can be used in woven preforms.
摘要:
Reacting carbonyls, such as aldehydes and ketones, with amines produces a ketimine or aldimine and a water byproduct. When the ketimine or aldimine reaction occurs in a polymer composition, the polymer becomes foamed due to the evolution of water. Hence, carbonyl and amine containing compounds may be introduced into a polymeric composition to serve as an in-situ blowing agent. The carbonyl and amine containing compounds may be different polymers which will be combined through a ketimine or aldimine linkage to form a graft co-polymer, they may be small molecular weight additives that are placed in the composition with a polymer that is to be foamed as a byproduct of a ketimine or aldimine reaction of the additives, or they may be a polymer containing a carbonyl or amine moiety and a small molecular weight additive compound that will react with the moiety on the polymer to form a ketimine or aldimine.
摘要:
A method for blending polymeric materials includes the steps of producing a melt stream of a first polymer from a first extruder (12) and a separate melt stream of a second polymer from a second extruder (14), joining the melt streams at a T-junction (16), distributing the first polymer within said second polymer using a static mixer (10), and extruding the blend through a die (18). In particular, using this method liquid crystal polymer fiber reinforcement can be formed in-situ within a matrix material.
摘要:
Maleated polyolefins such as maleated polypropylene, maleated polyethylene, and the like can be used as compatibilizing agents for producing a polymer alloy of polyolefins, such as polypropylene, and liquid crystal polymers. The polymer alloys have improved stiffness, strength, and surface appearance characteristics.