Ž . Vibrational Spectroscopy 24 2000 171–180 www.elsevier.comrlocatervibspec Two-dimensional Fourier-transform Raman and near-infrared correlation spectroscopy studies of poly ž / methyl methacrylate blends ž / 1. Immiscible blends of poly methyl methacrylate and atactic polystyrene Akira Matsushita a , Yanzhi Ren b , Kimihiro Matsukawa c , Hiroshi Inoue c , Yukio Minami a , Isao Noda d , Yukihiro Ozaki b, ) a Forensic Science Laboratory, Osaka Prefectural Police Headquarters, Honmachi, Chuo-ku, Osaka 541-0053, Japan b Department of Chemistry, School of Science, Kwansei Gakuin UniÕersity, Nishinomiya 662-8501, Japan c Plastics Department, Osaka Municipal Technical Research Institute, Morinomiya, Joto-ku, Osaka 536-8553, Japan d The Procter and Gamble Company, Miami Valley Laboratories, PO Box 538707, Cincinnati, OH 45253-8707, USA Received 26 October 1999; received in revised form 21 February 2000; accepted 28 February 2000 Abstract Ž . Ž . Ž . Fourier-transform FT Raman and near infrared NIR spectra have been measured for poly methyl methacrylate Ž . Ž . PMMA and its immiscible blends with atactic polystyrene PS of small PS contents from 1 to 10 wt.%. Generalized Ž . two-dimensional 2D correlation spectroscopy has been applied to analyze the composition-dependent FT-Raman and NIR spectral variations of the immiscible blends. The synchronous 2D FT-Raman correlation analysis separates the Raman bans of the minority PS from those due to the majority PMMA. It detects the bands due to PS at 2900, 2856, 1562, 1494, 1201, 1184, 1156, 1130, 1097, 1069, 964, 904, 796, and 759 cm y1 , which are too weak to be observable from the one-dimensional blend spectra. The synchronous 2D Raman-NIR hetero-correlation analysis further separates NIR bands of PS from those of PMMA. It detects the bands at 6082, 5972, 5937, 5920, 4834, and 4663 cm y1 due to PS, which are virtually unidentifiable from the one-dimensional blend spectra. These results are further proved by the synchronous 2D NIR correlation analysis. q 2000 Elsevier Science B.V. All rights reserved. Ž Keywords: Generalized two-dimensional correlation spectroscopy; FT-Raman spectroscopy; Near infrared spectroscopy; Poly methyl . methacrylate ; Polystyrene; Immiscible blends ) Corresponding author. Tel.: q 81-798-54-6380; fax: q 81-798- 51-0914. Ž . E-mail address: ozaki@kwansei.ac.jp Y. Ozaki . 1. Introduction Ž . Generalized two-dimensional 2D correlation wx spectroscopy 1 , an extension of the original 2D correlation spectroscopy proposed by Noda in 1986 0924-2031r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S0924-2031 00 00062-X