Martin C. Hawley - US grants

9412783 Hawley ABSTRACT Education and Training Program in Composite Materials for DoD and Durable Goods Industries Michigan State University (MSU) and the University of Delaware (UD) will develop new courseware and software to advance the dual-use potential of low-cost composite manufacturing. Education delivery mechanisms to be used include computer-based simulations and interactive learning, broadcasting of classes over satellite networks, and workshops on design and processing of composites. Resources available to the universities include the National Science Foundation's Center for Polymer Processing at MSU and the Center for Composite Materials at UD, sponsored by the Army Research Office. These centers are also supported by large industrial consortia, and have excellent research and manufacturing facilities. Industry involvement in this effort will include guest lectures and planning workshops. ***

The global advantages of microwave processing over conventional heating include direct and volumetric heating, high selectivity, fast heating rate, and high controllability. The objective of this work is to study the fundamental interactions between microwaves and non-ionic chemical species. The research will: (1) determine the non-thermal effects during microwave-induced reaction by a comparative study of selected non-ionic reactions; (2) explore accurate temperature measurement techniques and determine the molecular temperature during microwave heating; (3) quantify the electric field and temperature distributions at the molecular level; and (4) study the effects of microwave reactor configuration and control on the reaction. To verify or disprove the non-thermal effects during microwave heating of non-ionic species, studies of both epoxy-amine polymerization and epoxy-amine model-compound organic reactions are planned using amines of different dipole moments. Systems of various dipole moments will be used because microwave effects occur primarily at the dipolar s ites for non-ionic reactions. The epoxide to be used for polymerization is diglycidyl ether of bisphenol A (DGEBA). The epoxides to be used for model-compound reactions are allyl glycidyl ether of bisphenol A (AGEBA) and phenyl glycidyl ether (PGE). The amines to be used will be meta phenylene diamine (mPDA), diaminodiphenyl methane (DDM), and diaminodiphenyl sulfone (DDS). Parallel isothermal reaction experiments will be carried out using microwave and conventional thermal heating. Microwave thermal mechanical analysis will be investigated to measure the segmental mobility of the dipolar groups. The electric field and temperature distributions at the molecular level will be modelled. The predicted temperatures will be compared to the measured temperatures.

The project develops a virtual prototyping facility for the design of mechanical assemblies containing polymer composites. Design approaches are investigated for lowering the cost of manufacturing, especially methods which replace mechanical subassemblies by a unitary composite part. A suite of automated design tools is developed for virtual prototyping of assemblies made of polymer composite materials AND making these tools accessible on the Internet. Industrial relevance is insured by direct participation of a midsized company specializing in advanced polymer composites design and fabrication.

Microwave processing of polymer composite materials is an increasingly important technology for the polymer industry and its customers. Polymer composites combine the best properties of its constituent parts, namely a polymer matrix along with a suitable filler such as glass, to achieve a new material that has superior properties to the original materials, including low cost. Desirable and achieved properties of polymer composite materials include improved strength and temperature tolerance among others. Microwave processing, as compared to convection processing, has been shown to yield superior mechanical properties as well as be more efficient in terms of energy requirements and time-to-manufacture. Microwave processing of polymer composites is similar to microwave heating of food in the ubiquitous microwave ovens. The electromagnetic energy within the microwave oven interacts with the material being processed and heats it throughout the volume rather than via surface heating. The temperature change causes a change in polymer composition (hence the curing process). This coupling between electromagnetic energy, temperature rise, and composition changes is not well understood resulting in unexplained over- and under-cured regions in the composite.

The Departments of Chemical Engineering and Materials Science, Electrical and Computer Engineering, and Mechanical Engineering are combining expertise in polymer processing, microwave energy, and thermal propagation to investigate the fundamental interaction between electromagnetic energy absorption, temperature change, and composition change. In addition, development of a multi-port microwave applicator is planned that will significantly reduce the cost of applicator construction due to the use of lower power microwave sources than is used in practice today. Both theoretical modeling of these coupled phenomena as well as experimental verification of results will be pursued. It is anticipated that the results of this project will be an improved microwave applicator and processing protocol that will significantly improve industrial polymer composite processing methods. The principal investigators are actively participating in a program at MSU to provide education and mentoring to underrepresented minority and women engineering students at both the undergraduate and graduate levels.