Originally Published MDDI September 2002
BULLETIN BOARD
Thermally conductive plastic enhances performance of heat-measuring devices. A liquid crystalline polymer (LCP) developed by Cool Polymers (Warwick, RI; 603/863-5005) has been used to mold a part for a device measuring heat flow. The LCP provides a thermal conductivity of 50 W/mK. Cool Polymers tested a prototype of the LCP against an aluminum prototype to ensure that the plastic would meet heat transfer requirements. The company's line of thermally conductive plastics is available in a variety of base resins and ranges in thermal conductivity from 2 to 100 W/mK.
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Low fluorescent adhesives serve as critical bonding tools. Low autofluorescent adhesives reduce the possibility of undesirable background fluorescence in microfluidic devices. Adhesives Research Inc. (Glen Rock, PA; 717/235-7979) has developed the adhesives to provide minimal fluorescence and good assay compatibility. Used alone or in conjunction with an assay platform, the adhesives will adhere to the base plate without creating voids or gaps, and will not flow into microfluidic channels or interfere with chemical reagents used in the microchannels and reservoirs. The adhesives are dimensionally stable, provide resistance to moisture and temperature, and are chemically compatible with electrophoretic separation. These clear adhesives can be either flexible or rigid, and can incorporate hydrophilic properties to enhance the flow of liquid through microfluidic channels.Cyclic olefin copolymer chosen for vascular catheter manifold. Boston Scientific (Natick, MA; 800/225-3226) has redesigned its imaging catheter to include Topas 8007, a cyclic olefin copolymer (COC). Topas COC, manufactured by Ticona (Summit, NJ; 908/598-4000), is a medically compatible material that eliminates the need for adhesive, while reducing material cost and assembly. Unlike polyolefins, urethanes, and nylon copolymers, Topas COC creates a sturdy part without damaging the insert-molded lumen tube, and allows for the consolidation of five nylon elements into a single clear part. The polymer is 92% transparent, flows well at low pressures and temperatures, has a low coefficient of friction, and can undergo E-beam sterilization. The catheter manifold is made in a single-cavity tool. Because Topas COC shrinks less than 0.7% during molding, the part is stable and retains its dimensions while cooling. The manifold has a smooth finish and no rough edges, thereby eliminating secondary finishing.
Technical booklet highlights Ricon, SMA, and Poly bd resins. A booklet offering extensive product information on inks, coatings, rubber, adhesives, and sealants formulators is available from Sartomer Co. (Exton, PA; 610/363-4100). Your Single Source for Specialty Chemicals includes a breakdown of Sartomer's new structure, as well as an overview of new technical resources. Resin overviews focus on SMA, Poly bd, and Ricon resins. The booklet includes the most complete line of polybutadiene polymers and coatings available. Other specialty chemicals include functional liquid and metallic monomers, oligomers, photoinitiators, and Norsolene hydrocarbon resins.
Low cyclic dimer reduces scaling and promotes long run times. UDEL P-3500 LCD contains a low level of cyclic dimer, which is produced during polysulfone manufacturing and can lead to scaling within the vessels and pipes used in the membrane manufacturing process. The LCD polysulfone improves stability and shelf life of the dope solution, and offers high fiber strength for consistent filtration and fewer fiber breaks and surface defects. Manufactured by Solvay Advanced Polymers (Alpharetta, GA; 800/621-4557), UDEL P-3500 is designed specifically for membranes and is typically used in medical filtration.
Unbacked membrane for rapid assays is now available.A membrane intended for highly sensitive rapid diagnostic assays provides consistency and high surface quality. Unbacked Hi-Flow Plus 180 has a powder-free surface that prevents interference, making it suitable for infectious-disease testing, drug testing, and cardiac-marker diagnostic test kits. Hi-Flow Plus 180 provides a nominal flow rate of 180 seconds across 4 cm of membrane, a flow rate variance of 25%, and a thickness variance of 10%. A master roll average specification of ±11% for capillarity and ±6% for thickness ensures membrane consistency. The membrane, manufactured by Millipore (Cork, Ireland; 800/645-5476), compliments the company's other existing Hi-Flow Plus membranes. The backed membranes provide lateral flow rates of 65, 75, 90, 120, 135, 180, and 240 seconds across 4 cm of membrane. A clear polyester material increases tensile strength.
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