Plasticstrends

Of the many ways one can modify traditional polymers, electron beam irradiation (EBI) is one of the most attractive technique to the scientific and the industrial community, since it can profoundly affects the molecular structure providing polymeric materials with unique properties^1-5.                           

The process has revolutionized the application of polymeric material in diverse areas including sterilization of medical devices, pollution control (treatment of sewage and sludge), food preservation, curing of cable insulations, manufacture of heat-shrinkable polymers, in orthopaedics, tire manufacturing and on^{1-4, 6,7}.  The process is carried out with electron accelerators (EA) that provide energies between 75 eV and 10 MeV2,8,9. The radiation interacts with the polymeric material, knocking-off labile atoms from the polymer to generate radicals1, 2 on the carbon backbone of the polymer.   These radicals initiate reactions such as polymerization (e.g. curing of coatings), and cross-linking. Polymerization is possible with monomers having chemical unsaturations and proceeds through free-radical initiated addition reactions. Cross-linking results when two polymeric-radicals unite.   The target of the article is to summarize applications of the EB process to polymeric materials, describing the important benefits, how the process is quantified, how the best results can be achieved, current application trends and where the future lies.

What did Alexander Pope say? "A little learning is a dangerous thing; Drink deep, or taste not the Pierian Spring; there shallow thoughts intoxicate the brain; and drinking largely sobers us again." But the poet never had to think about drinking spring water out of a polycarbonate bottle, did he?

Bisphenol A (BPA), a chemical that can leach out of polycarbonate bottles, is clearly the "toxin du jour."

Polyvinylidene fluoride (PVDF) is a material of choice in the chemical process industry (CPI) for many reasons such as high resistance to harsh chemicals combined with its stability against UV light and heat, high electrical resistance and its high purity.  These properties make it a good material for insulating electrical wires, especially ones that get hot during it's use.  PVDF is used in the manufacturing of thick wall pipes, fittings and other components used in the transportation and storage of aggressive chemicals. In fact, high purity of PVDF allows its use in the semi-conductor business for transportation and storage of ultra-high purity water.

 

Each year, Society of Plastics Engineers (SPE) honors outstanding contributors to our field with the International Award.  Recently, such men as Alan MacDiarmid (Nobel Laureate), Chris Macosko, Glenn Beall, and Greg McKenna, among others were so recognized.  Well forty or so years ago, the International Award was bestowed on an equally illustrious group.  There were Paul Flory (Nobel ), Herman Mark, Gulio Natta (Nobel), Arthur Tobolsky, Charles Overberger, (later ACS president), and Turner Alfrey, to pick out a few. During the '40s to the '60s,the Polytechnic Institute of Brooklyn (now Polytechnic Institute of New York) was a center of polymer/plastics activity.  Herman Mark, before Hitler an I.G. Farbenindustrie research director, headed up PIB's Polymer Institute.  He drew Alfrey, Overberger, and Tobolsky to the  Institute's staff.  I was fortunate enough to be a student under these three men, and to spend more than a few evenings after class having a beer or two with them in a bar conveniently across the street from PIB.

 

Imagine a future in which we wear clothing that is self-cleaning.  Imagine painting your living-room wall to display a real-time image of another part of the world; or utiliz­ing greenhouse gas to make value-added products; or designing surfaces that selectively destroy viruses and pathogenic bacteria; or a sur­geon placing a removable stent that changes shape inside an artery of a patient’s body; the list goes on. What materials could provide all the prop­erties necessary for these and other future applications? Plastics!  My previous article1 covered a series of developments in specific areas of plastics technology—includ­ing advances in plastics nanocom­posites, plastics electronics, the self-assembly process, fuel cells, tissue engineering, and high-throughput techniques. As these areas keep maturing, other areas where plastics may be used are gaining attention. This article highlights some of the current activities that have commer­cial and social implications, and also offers a glimpse into the future.