Polyallyl diglycol carbonate

Structural formula
General
Surname	Polyallyl diglycol carbonate
other names	CR-39 PADC Polydiethylene glycol diallyl biscarbonate
CAS number	95567-48-9
Monomers / partial structures	Diallyl diglycol carbonate
PubChem	8879
Type of polymer	synthetic homopolymer, thermoset
properties
Physical state	firmly
density	1.31 g cm −3
safety instructions
GHS labeling of hazardous substances no classification available H and P phrases H: see above P: see above
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Polyallyl diglycol carbonate (PADC) is a polymer that is used, among other things, to manufacture eyeglass lenses and is also known as CR-39 .

Manufacturing

The monomer diallyl diglycol carbonate (ADC) used for polymerization can be produced by reacting diethylene glycol , phosgene and allyl alcohol :

The thermoset is created by adding a radical initiator to the monomer (often: diisopropyl peroxydicarbonate , IPP) and then heating it. The units marked with “ m ” and “ n ” in the structural formula of the info box represent different polymer chains that are spatially linked by the diisopropyl peroxydicarbonate . This structure leads to the thermoset behavior of the plastic.

History and use

The Columbia Southern Chemical Company was looking for synthetic resins as part of a project around 1940 , as various materials based on natural products became scarcer due to the Second World War . Sample 39 of 180 promised favorable properties, resulting in the abbreviation CR-39 for "Columbia Resin # 39". The first applications were light, self-healing fuel tanks (glass fiber reinforced), sight tubes and lenses for searchlights in war aircraft. From 1947 spectacle lenses were made from it. Sheets for welding screens, crane cabin windows and protective goggles were later made.

Use as a particle detector

CR-39 can be used as a nuclear track detector (SSNTD, solid state nuclear track detector or more precisely PNTD, plastic nuclear track detector). An impinging particle of ionizing radiation penetrates the detector and forms a latent particle track along which radicals are formed as a result of the ionization. If the irradiated CR-39 is etched with 5-7 molar sodium hydroxide solution, typically 70 ° C, then the areas where radicals occur are etched faster than the surrounding material. The number of holes thus formed per unit area is then determined using a microscope. In connection with a so-called converter made of LiF or PE , the neutron fluence can also be determined by measuring the fluence of the charged recoil particles .

Individual evidence

1. ↑ PPG: CR-39 monomeric , accessed April 8, 2019.
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
3. ^ Antonio Mendez-Vilas: Recent Advances in Multidisciplinary Applied Physics. Proceedings of the First International Meeting on Applied Physics, October 13-18th, 2003, Badajoz, Spain . Elsevier, Amsterdam 2005, ISBN 0-08-048056-X , pp. 880 ( limited preview in Google Book search).
4. ↑ Herbert Bartl, Jürgen Falbe (ed.): Methods of organic chemistry (Houben-Weyl) , Volume E20, Macromolecular substances. Georg Thieme Verlag, Stuttgart 1978, p. 1016 ( limited preview in the Google book search).
5. ↑ Safety data sheet diallyl diglycol carbonate at ppg.com (PDF).
6. ↑ Sina Ebnesajjad: Adhesives Technology Handbook . 2008, ISBN 978-0-08-094729-7 , pp. 108 ( limited preview in Google Book search).
7. ^ PA Mosier-Boss, S. Szpak1, FE Gordon, LPG Forsley: Characterization of tracks in CR-39 detectors obtained as a result of Pd / D Co-deposition . In: The European Physical Journal Applied Physics . Vol. 46, No. 3 , June 2009, doi : 10.1051 / epjap / 2009067 (English).