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.

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_008491.pdf

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

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

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

Examples from nature: Examples from synthetic chemistry:

http://pslc.ws/macrog.htm

Commodity (most commonly used) recyclable plastics (Who is PETE?)

The “polymer revolution” Step growth polymerization

B.S. Chemistry, Tarkio College, 1920 Ph.D. U. Illinois, 1924 Organic chemistry Instructor Harvard U., 1926-1928 Dupont’s Central Research & Development (1928-1937) (then 3 Ph.D. scientists and $20K, now >1500 Ph.D. level scientists and $1.3Billion

Wallace Carothers 1896-1937

1930: Neoprene 1930: Polyesters 1934: Polyamides 1935: Nylon 1938: Teflon 1959: Spandex(Lycra) 1965: Tyvek 1967: Nomex 1971: Kevlar

The “polymer revolution” Step growth polymerization

B.S. Chemistry, Tarkio College, 1920 Ph.D. U. Illinois, 1924 Organic chemistry Instructor Harvard U., 1926-1928 Dupont’s Central Research & Development (1928-1937) (then 3 Ph.D. scientists and $20K, now >1500 Ph.D. level scientists and $1.3Billion

Wallace Carothers 1896-1937

1930: Neoprene 1930: Polyesters 1934: Polyamides 1935: Nylon 1938: Teflon 1959: Spandex(Lycra) 1965: Tyvek 1967: Nomex 1971: Kevlar

neoprene

spandex

Tyvek

PET

Polyamides

Nylon 6

Nylon 6,6

Polyamides Step growth polymerization

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.

Polyamides Step growth polymerization

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

Polyamides Step growth polymerization

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

Synthesis of polyamides by interfacial polymerization Step growth 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.

Synthesis of polyamides by interfacial polymerization Step growth 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.