Introduction of Macromolecular Science/Polymeric Materials into the Foundational Course in Organic Chemistry

Organizer: Bob A. Howell, Department of Chemistry, Central Michigan University, Mt. Pleasant, MI 48859-0001, tel: (989) 774-3582, Email: bob.a.howell@cmich.edu

The purpose of the symposium was to explore methods by which the current ACS Committee on Professional Training guideline provision that “students should be exposed to the principles of macromolecules across foundational areas” is being implemented for the beginning organic chemistry course.  Speakers from widely different types of institutions – from community colleges to four-year colleges to major universities – provided many innovative and successful ways that polymers can be incorporated into the foundational organic course.  Incorporation of polymeric materials emphasizes the importance of organic chemistry in the daily lives of students, enhances interest in the course, generates enthusiasm, and improves student performance. 

The first speaker in the morning session was Charles Carraher of Florida Atlantic University who presented Macromolecule/Polymer Foundational Content in Organic Chemistry.  He discussed the various initiatives of the Polymer Education Committee (PolyEd) to facilitate the inclusion of polymers across the curriculum.  The beginning organic course is a natural fit for polymeric materials.

Bob Howell, Central Michigan University, presented Incorporation of Polymeric Materials to Enhance Interest and Learning in the Foundational Organic Chemistry Course.  A discussion of alkenes usually occurs early in the first organic course and offers a wonderful opportunity to engage the student.  The most important societal/commercial reaction of alkenes is vinyl polymerization.  Discussion of vinyl polymerization permits the introduction of radical chemistry in a relevant, easily appreciated manner.  More importantly, it can be used to illustrate the importance of polymeric materials in the daily lives of student.  Common examples include: poly(acrylonitrile) [Orlon] for clothing [almost always one or more students will be wearing a sweater made from Orlon (“synthetic wool”)] or carpeting and as a precursor to carbon fiber for composite fabrication for aerospace; poly (vinyl chloride) [PVC] for siding for home construction, floor tile, plumbing pipe, and many other uses; poly(acrylates) as coatings; poly(styrene) for inexpensive wine tumblers, culterary, light cours, etc.  A bit of history can be included here as well: low-density poly (ethylene) for radar insulation during WW II; poly(methyl methaerylate) [PMMA, Plexiglass] for the fabrication of canopies for fighter aircraft during WWII [this also offers an opportunity for a brief description of the origins of the Rohn and Haas Company].  Examples of this kind tend to strongly engage the interest of students [generates an appreciation of how organic chemistry impacts their well-being and “hooks” them on the course]. 

Eric Bosch of Missouri State University presented Extrapolation from Small Molecules to Polymers: A Simple and Effective Way to Promote Interest in Both Organic Chemistry and Polymer Chemistry.  The incorporation of several examples of small molecule reactions that could lead to polymer formation by a simple change of conditions was illustrated.  For example, esterification can first be demonstrated for a monofunctional alcohol plus a monofunctional acid, then for a difunctional alcohol and a monofunctional acid, and finally for a difunctional alcohol and a difunctional acid.  Through this progression, the student can readily appreciate how the polymer repeat unit is formed.  It is also clear that the reaction for small molecule esterification and polymerization is the same.  Similarly, an example from early in the course comes from the study of alkenes.  Treatment of isobutylene with water and acid generates isobutyl alcohol via a carbocation intermediate.  The question, “What happens if no water is present?,” can then be raised.  The same carbocation is generated by protonation of the alkene but this time isobutylene rather than water acts as the nucleophile to add to the carbocation.  This, in turn, generates another cation which adds isobutylene, etc., such that poly(isobutylene) is formed.

David Bergbreiter of Texas A&M University presented Using Polymer Synthesis, Reactions and Properties as Examples of Concepts in Beginning Organic Chemistry.  Several examples of simple organic reactions that lead to polymer formation were utilized to illustrate concepts basic to the beginning organic chemistry course.  Of particular note was the change in properties as a function of molecular weight.  A good illustration of the impact structure on properties was provided using three balls made of poly(isoprene).  The first was from the all cis isomer, the second from the trans isomer, and the third from the polymer resulting from predominately 1,2- addition.  When thrown against the wall, the ball from the all cis isomer bounded back in much the same way as a tennis ball would, the ball from the trans isomer dropped directly to the floor with a thud, the ball from the polymer resulting from 1,2- addition to the diene monomer came away from the wall in erratic fashion (“dying rabbit”).

Mark Green from the Polytechnic Institute of New York University presented Industrially Important Polymers Offer an Excellent Didactic Tool for Learning Many of the Fundamental Principles of Organic Chemical Structure and Reactivity.  In an “upside down” approach Professor Green’s course starts with cellulose, considers the structural features of cellulose and starch as isomeric glucose polymers, and works down to the monomeric unit which then permits a discussion alcohols, acetals, and the thermodynamics of ring formation.  Subsequent discussions begin with another polymer with an analogous treatment.  In this way, all the fundamental principles of organic chemistry are covered but with the students having a “front-end” appreciation for why they are important.

Sarah Goh of Williams College discussed Polymer Chemistry in an Undergraduate Curriculum in which she illustrated how polymer chemistry, both lecture and laboratory, can readily be included in the undergraduate curriculum.

John Droske of the University of Wisconsin – Stevens Point presented Integrating Macromolecules into Undergraduate Organic Chemistry Courses – it’s Important and There is Room.  Polymers fit naturally into functional group discussions and permit an illustration of the change in physical properties which accompany a change in molecular weight.  The beginning organic course can be enhanced in many ways by inclusion of polymeric materials.

David Baker of Delta College presented Polymers in Organic Chemistry – a Fine Balance.  Most community colleges can only teach a single organic course which must contain some polymer chemistry (for students who may work in industry with an associates degree), some biology (for preprofessional students) and cover all the fundamentals of organic chemistry such that credit for the course will transfer to a four-year college.  Several creative ways to incorporate polymeric materials into the community college organic chemistry course were illustrated. 

Abby Parrill of the University of Memphis presented Polymer Concepts Illustrated in the Context of Biopolymers and described an interesting change in the undergraduate chemistry curriculum at the University of Memphis.  The beginning organic course has been restructured to permit an increased emphasis on polymeric materials, particularly biopolymers.  This coincides nicely with the proposed changes for premedical education.

Bob Howell of Central Michigan University presented Use of Historical Events and Personalities to Facilitate the Incorporation of Polymeric Materials into the Beginning Organic Chemistry Course.  Numerous opportunities exhist to enhance interest in the foundational organic chemistry course by providing an historical context (the impact of the development of poly(ethylene), nylon, poly(methyl methaerylate) and poly(dimethysiloxane) on the outcome of WW II, for example) or some background on prominent individuals responsible for major discoveries (Staudinger, Carothers, Mark, Flory, Semon, Plunkett, Kwolek, etc.).  Students identify with these evetns/personalities and can relate them to the principles being discussed.  Course performance can be significantly improved by some incorporation of history/background.

Warren Ford of Portland State University presented Radical Chain Reactions in Foundational Organic Chemistry.  Instead of basing a discussion of radical chain processes on the chlorination of alkanes (which students tend to find not very exciting) the polymerization of styrene is used.  All the principles of radical processes can be illustrated for the formation of a material that students are familiar with and encounter regularly in their daily lives (inexpensive cutlery, wine tumblers, light covers, etc. – and as a formed product, coffee cups and home insulation).

Laura Kosbar of IBM presented The Importance of Macromolecules in Instursy – the Case for Inclusion in the Undergraduate Curriculum.  Most students who major in chemistry will ultimately work in industry (whether at the B.S., M.S. or Ph.D. level) and most of those will work in a polymer or polymer-related area.  Students who enter industry with some polymer background compete at an advantage with respect to those who do not.  It is vital that the undergraduate chemistry curriculum include polymeric materials.  The foundational organic is ideally suited for and is enhanced by the inclusion of polymers. 

Steven Fleming of Temple University presented Including Polymers in Organic Chemistry.  Opportunities for including polymers in the foundational organic course abound.  Professor Fleming, a textbook author, has developed several aides to facilitate the inclusion of polymeric materials and to promote an understanding of the fundamentals of organic chemistry.

Leslie Sperling of Lehigh University presented Inclusion of Polymer Concepts in Organic and Other Undergraduate Chemistry Books.  The principles of polymer chemistry can be used to enhance virtually any course in the undergraduate curriculum.  This is particularly the case for the foundational course in organic chemistry.  Polymers should be appropriately incorporated into all undergraduate chemistry textbooks. 

Bob Howell of Central Michigan University presented Enhancement of the Laboratory Component of the First Course in Organic Chemistry through the Incorporation of Polymeric Materials.  There are many good polymer experiments that may be utilized to illustrate the principles of organic synthesis, structure and spectroscopy.  A popular experiment that serves to generate student interest, illustrate interfacial synthesis, and provides an opportunity to discuss the development of “synthetic silk” is the synthesis of nylon 6,10.  In this case the product is removed from the interface between an aqueous basic solution of hexamethylenediamine and a methylene chloride solution of sebacoyl chloride as it is formed.  It may be conveniently rolled onto an empty paper towel roller.  This is the most remembered experiment when students are surveyed years after the course has been completed.  The polymerization of lactide using tin octanoate as initiator and benzyl alcohol as initiator, provides a great opportunity to introduce the generation of materials from a renewable biosource, to discuss acid catalysis, and illustrate nucleophilic addition-elimination at acyl carbon.  However, the strongest feature of this experiment is determination of structure using spectroscopy.  Proton NMR spectroscopy can be used to determine the number average molecular weight by end-group analysis.  Comparison of the peak area for the phenyl protons of the initiator fragment with that of the methylene protons of the polymer mainchain readily provides the number of mer units in the chain.  The preparation of poly(aspartic acid) provides an example of a truly green experiment.  No organic solvents are used, the monomer, an edible amino acid, is simply heated in a beaker.  After hydrolysis (by warming in aqueous base) of the poly(succinimide) initially formed, polymer molecular weight may be determined by titration with standard aqueous hydrochloric acid solution.  Poly(aspartic) acid is used commercially as a biodegradable scale inhibitor in steam lines.  Its synthesis provides a ready bridge to a discussion of naturally-occuring poly(amino acids).