Effect of Stoichiometric Ratio on the Interfacial Polymerization Of

Home , DuPont Central Research, Kevlar, Wallace Carothers

Effect of stoichiometric ratio on the interfacial polymerization of polyamides Why worry about polymer science? John Droske Polymer Education "Approximately 50% of all chemists will work with polymers at some time in their careers," says John Droske, professor of chemistry at the University of Wisconsin–Stevens Point and director of the POLYED National Information Center for Polymer Education. "Because polymer science touches on many areas, it is important for chemists to be trained in polymer science." The POLYED has been working with a National Science Foundation grant to develop materials for polymer chemistry courses at the undergraduate level. http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_ARTICLEMAIN &node_id=1188&content_id=CTP_003399&use_sec=true&sec_url_var=region1

Students should be exposed to the principles of macromolecules across foundation areas, which could then serve as the basis for deeper exploration through in depth course work or degree tracks ACS Guidelines for Undergraduate Professional Education in Chemistry http://portal.acs.org/portal/fileFetch/C/WPCP_008491/pdf/WPCP_0084 91.pdf

What is a polymer (a.k.a macromolecule)? Poly-mer Two latin roots: πολυ (poly)? µεροζ (meros)?

Polymers are everywhere (and we did not come up with the concept)

Examples from nature: Examples from synthetic chemistry:

http://pslc.ws/macrog.htm

Commodity (most commonly used) recyclable plastics (Who is PETE?) Step growth polymerization The “polymer revolution”

Wallace Carothers 1896-1937 B.S. Chemistry, Tarkio College, 1920 1930: Neoprene Ph.D. U. Illinois, 1924 1930: Polyesters Organic chemistry Instructor 1934: Polyamides Harvard U., 1926-1928 1935: Nylon Dupont’s Central Research & Development (1928-1937) 1938: Teflon (then 3 Ph.D. scientists and $20K, now 1959: Spandex(Lycra) >1500 Ph.D. level scientists and 1965: Tyvek $1.3Billion 1967: Nomex 1971: Kevlar

Step growth polymerization The “polymer revolution”

spandex

neoprene

Polyamides

Tyvek

Nylon 6

PET Nylon 6,6 Step growth polymerization Polyamides

Commercial applications

Fibers, Engineering plastics.

Clothing, films, food packaging, tapes (audio, video), steel and aluminum replacement for autoparts and electrical appliances, toys, power tools, sporting equipment

Nylon 6+ Nylon 6/6 : 90% of polyamide fiber market Cotton is now only 25% of U.S. fiber market, the remaining 75% consists of PET, Nylon and Rayon fibers.

Step growth polymerization Polyamides

Experimental conditions a) Solution b) Bulk (melt) c) Interfacial polymerization Step growth polymerization Polyamides

Experimental conditions a) Solution b) Bulk (melt) c) Interfacial polymerization

Step growth polymerization Synthesis of polyamides by interfacial polymerization

Stoichiometry: From the greek words stoicheion (element) and metron (measure). For chemical purposes it is the study of the proportions at with elements and molecules react

Goal for this experiment: Evaluate the effect of stoichiometric ratio on the amount of isolated polyamide. Step growth polymerization Synthesis of polyamides by interfacial polymerization

Procedure: a)Add solution of diamine (in 5% aq.KOH) b) Add solution of diacid chloride (in cyclohexane) c) Pull fiber from the interface until no more polymer is formed d)Stir the mixture to mix the organic and aqueous phases. e)Collect all the polymer formed and weight it. f) Compare the amount of isolated polymer with the amount expected according to the amount of added (limiting) reagents.