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MATERIAL SELECTION CASE STUDIES

This post provides insights, with the help of three anonymous examples, into how we help clients with challenges involving material selection.  The required behavior during the fabrication process and the end use performance characteristics are defined first.  Price is also usually an important consideration, although in a few instances there have been applications of such high value that material price was not a factor.  Potential candidate materials are selected based on the specified processing, performance, and price criteria.  Samples are then obtained from material suppliers for experimental evaluation.

A client requested help with the selection of an FDA-compliant, non-outgassing, and chemical-resistant thermoplastic polymer for an injection molded thin-walled product that would need to withstand long-term use at a temperature of 250 oC.  The cost of the material could not exceed $ 10/lb for large volume purchases because of the assumed limit to how much customers may be willing to pay for the molded product.  Online databases of thermoplastic polymers (Omnexus, MatWeb, UL Prospector, and CAMPUS) were searched to obtain preliminary ideas on potential candidate materials.  More detailed product literature provided online by material suppliers was then studied to refine these preliminary ideas.  Customer technical service personnel at each company manufacturing a potential candidate material were contacted to discuss the client’s needs in detail and obtain recommendations of their specific commercial product grades considered most worthy of evaluation.  These recommendations were presented to the client in a report.  The client then molded product prototypes from each of the recommended thermoplastic polymers and evaluated these prototypes to determine the best thermoplastic polymer to use for the targeted application.

Omnexus

A client requested help with the selection of the reactive components to be used in a thermosetting formulation to manufacture a high-performance monolithic machine part.  The part was to be cast in place at room temperature within a cavity in the machine from a suitable thermosetting resin.  It was determined that the versatility of epoxy resin chemistry provides the best design space to seek suitable ingredients for use in manufacturing this product.  Customer technical service personnel at the three leading global providers of epoxy resins and related intermediates (Hexion, Huntsman, and Olin) were contacted to discuss the need in detail.  Each provider recommended a short list of combinations of its epoxy thermoset precursors (resin, curing agent, and in some formulations also a reactive diluent) for evaluation.  These recommendations were presented to the client in a report.  The client then evaluated the recommended formulations in laboratory experiments on smaller-scale samples to determine the optimum formulation for use in the machine part.

A client requested help with the selection of additives needed for a new product to achieve its performance targets.  The product was a thermoset nanocomposite.  The manufacturing method involved dispersing the nanoparticles uniformly in the unreacted monomer liquid and then polymerizing the monomer around the nanoparticles to convert the liquid into a rigid thermoset polymer matrix.  The fact that the nanoparticles and the monomer liquid were incompatible with each other meant that the nanoparticles were dispersed poorly, resulting in inferior mechanical properties for the fabricated product.  Our solution to this problem was to recommend the inclusion of two different types of additives in the formulation.  A polymeric dispersant would situate itself between the monomer and the nanoparticles, to render the thermodynamics of the system more favorable to providing uniform dispersion.  A polymeric coupling agent would react both with the polymer and with the nanoparticles, to improve the load-bearing performance by grafting the nanoparticles onto the thermoset polymer matrix.  Recommendations of product grades worthy of experimental evaluation were obtained from the leading suppliers of such additives. The recommended additives were then evaluated to determine the best dispersant and coupling agent to use and the optimum percentage of each additive to include in the formulation.

Call Bicerano & Associates Consulting, LLC at (912) 235-2238 or use our online form or email us at info@polymerexpert.biz today!

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