Polymer Bulletin 37, 221-228 (1996) Polymer Bulletin 9 Springer-Verlag 1996 FT-Raman analysis of the effects of -radiation on nylon 6-12 filaments M. Olivares 1, H. L6pez-Valdivia 2, G. V~izquez-Polo 1, M.A. Mondrag6n 1, R. Lima 1, E. Martinez 3, V.M. Castafio 1,. 1 Instituto de Fisica, UNAM, Apdo. Postal 20-364, 01000 Mrxico, DF, Mrxico z Instituto de Investigaciones Nucleares, Aparatado Postal 18-1027, 11801 Mrxico DF, Mrxico 3 Industrias Negromex, S.A. de C.V., Bosque de Ciruelos 180, 11700 Mrxico, DF, M6xico Received: 9 February 1996/Revised version: 9 April 1996~Accepted: 15 April 1996 SUMMARY FT-Raman spectroscopy of commercial amorphous and crystalline nylon 6-12 filaments subjected to various y-radiation doses are presented. The results show that a difference exists in the interaction of ?-radiation with these polyamides, depending on the crystallinity which can be evaluated by measuring the CH- stretching/CH-bending Raman band intensity ratio as a function of applied ,/-dose. INTRODUCTION Nylons constitute a big family of versatile engineering polyamides with a wide range of applications in various fields [1]. In particular, fibers produced by different types of crystalline and semi-crystalline nylons are routinely used as reinforcing elements in FRP (Fiber-Reinforced Plastics) and as bristle materials [ 1,2]. In every case, physical, chemical and mechanical properties are considerably dependent on the degree of cristallinity of the specific nylon employed and various methodologies, including DSC [2], WAXS [3] and spectroscopic approaches [4-5] have been explored for understanding and predicting nylon properties. Various nylons present a temperature-induced crystalline phase transition, the so- called Brill transition [6-7], whose precise mechanisms are still to be determined. Polyamides are also relevant because of their structure is a close relative to that of peptides or proteins [8] and various vibrational spectroscopies are used as tools for understanding some of the characteristics of both nylons and biomolecules [9- l l].Specifically, Raman spectroscopy offers promising analytical posibilities because a number of the most relevant molecular events taking place in nylons are Raman-active. Until recently, however, the use of Raman spectroscopy was limited because of strong fluorescence overlapping the significant peaks. The development of FT-Raman instruments in which the laser-excitation of the sample is within the near IR range, allows now to renew the interest in exploring Raman effects in polymeric materials [8-12]. Irradiation of polymers is an active area of research because radiation modification of polyamides can lead to an improvement in their properties [13,14] and because these studies can provide insight into the * Correspondingauthor