I am happy to announce the publication of a new book that I co-edited, Thermal Analysis of Polymers: Fundamentals and Applications (J. D. Menczel and R. B. Prime, eds.), John Wiley and Sons, 2009. This book emphasizes the practical application of thermal analysis based on fundamental principles. It is written for a broad audience, including those new to thermal analysis, experienced thermal analysts wishing to refresh their skills, and professional scientists and engineers who depend on good thermoanalytical data and its correct interpretation. Each chapter includes basic principles, calibration, how to perform an experiment, and applications to the characterization of polymeric materials and their processes. Some chapters also present case studies where thermal analysis was instrumental in solving real industrial problems. Chapters include Differental scanning calorimetry, Thermogravimetric analysis, Thermomechanical analysis and thermodilatometry, Dynamic mechanical analysis, Dielectric analysis, and Micro- and nano-scale local thermal analysis. For more information and to purchase click here
This website is intended to be a resource for anyone interested in thermosets and the characterization of thermosetting materials and processes by thermal analysis techniques (DSC, DMA, TGA, TMA). I will try to answer basic thermoset questions where I can. For specific applications and problems, for customizing of Excel spreadsheets for specific applications, or to arrange for in-house education or training, please request rates which can range from short term consultation or training to long range projects. I have collaborations with commerial analytical laboratories that may be of interest to organizations without their own facilities. Contact me at firstname.lastname@example.org.
Thermosets are network forming polymers. They include epoxy, phenolic, unsaturated polyester, polyurethane, dicyanate, bismaleimide, acrylate and many others. Unlike thermoplastics, chemical reactions are involved in their use. As a result of these reactions the materials first increase in viscosity and eventually cross-link and become set, i.e. they can no longer flow or dissolve. Cure is most often thermally activated, hence the term thermoset, but network forming materials whose cure is light or radiation activated are also considered to be thermosets. Some thermosetting adhesives cross-link by a dual cure mechanism, that is by either heat or light activation. For a more detailed introduction to thermosets, click here: introtothermosets.pdf
Because thermosets need to be cured, the kinetics of these chemical cure reactions are important. Cure kinetics generally fall into two categories. First, aging or storage kinetics after reactants have been mixed but prior to their use: reaction of prepregs, premixed and frozen adhesives, and powder coatings during storage fall into this category. And secondly, the cure of the thermoset after the prepreg has been formed into an aerospace structure or the adhesive joint has been formed. Included here are the characterization, design and optimization of cure processes, where issues such as the optimum time to apply pressure in an autoclave process, the time/temperature to reach full cure, and the increase in temperature required to reduce the cycle time by 50% are considered. Development of a kinetic equation is often needed for software that models the thermal cure process. Aging of cured thermosetting systems may also be considered but they generally consist of different chemical or physical processes.
There are three approaches to cure kinetics: traditional kinetic analyses, model-free kinetics, and time-temperature superposition or TTS kinetics. Traditional kinetics involves chemically-based models such as nth order and autocatalytic, fits conversion-time data or conversion-rate of conversion-time data taken at several temperatures to these models to determine reaction orders and measure rate constants, and measures the activation energy E from the Arrhenius equation. Model-free kinetics performs an isoconversional analysis on DSC taken at three or more heating rates, where activation energy is allowed to vary with temperature. I have been one of the pioneers of TTS kinetics and its application to the characterization of cure as well as to the monitoring and control of systems which cure according to complex time/temperature profiles. A tenet of TTS kinetics is that cure can be described by a single or overall constant activation energy, which is a reasonable assumption for most thermosetting systems. TTS kinetics can treat Tg-time data as well as conversion-time data, which are equivalent through the Tg-conversion relationship. To read a paper using a hybrid approach of TTS and traditional kinetics (see "Selected Publications", item #2 below), click here: kineticspaper.pdf
I am a consultant to industry and government, and a frequent lecturer at short courses. I am also a member of the InnoCentrix team, an organization that specializes in polymers and innovation (www.innocentrix.com) and a collaborator with the Polymeric Composites Laboratory at the GloCal Network Corporation (www.glocalcorp.net). I have over 40 years experience developing polymeric materials and their processes. My work is focused on two areas: thermal analysis and the cure and properties of cross-linked polymer systems such as coatings, adhesives and electronic materials. This work is documented in over 50 publications, in the chapter on Thermosets listed below, and in the recently published book on Thermal Analysis of Polymers, also listed below. I have a B.S. in chemistry from Loyola Marymount University and a Ph.D. in chemistry from Rensselaer Polytechnic Institute with Bernhard Wunderlich. I spent 30 years at IBM where I led teams that developed polymeric systems and their processes for printer and information storage technologies. I retired as a Senior Scientist from the IBM Materials Laboratory in San Jose, CA. In 1980 I co-founded the Golden Gate Polymer Forum (GGPF, www.ggpf.org), a San Francisco Bay Area polymer group which holds monthly dinner meetings and 1-2 symposia or short courses per year. I am on the board of directors of GGPF and a fellow of SPE and NATAS and was the 1989 recipient of the international Mettler Toledo Award in Thermal Analysis. Below is a list of selected publications and lectures.
Recent Lectures & Classes:
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