Polymer Testing 85 (2020) 106447 Available online 20 February 2020 0142-9418/© 2020 Published by Elsevier Ltd. Analysis Method FT-IR/UATR and FT-IR transmission quantitative analysis of PBT/PC blends Ana Carolina Ferreira a, b , Milton Faria Diniz c , Ana Cl� elia Babetto Ferreira d , Nat� alia Beck Sanches e , Elizabeth da Costa Mattos a, c, ** a Instituto Tecnol� ogico de Aeron� autica (ITA), Praça Marechal Eduardo Gomes, 50 – Vila Das Ac� acias, CEP 12228-901, S~ ao Jos� e Dos Campos, SP, Brazil b General Motors Do Brasil (GM), Av. Goi� as, 2769 – Santa Paula, CEP 09550-051, S~ ao Caetano Do Sul, SP, Brazil c Instituto de Aeron� autica e Espaço (IAE), Divis~ ao de Propuls~ ao, Praça Marechal Eduardo Gomes, 50 – Vila Das Ac� acias, CEP 12228-904, S~ ao Jos� e Dos Campos, SP, Brazil d Instituto SENAI de Inovaç~ ao Em Materiais Avançados, CEP 09861-000, S~ ao Bernardo Do Campo, SP, Brazil e Universidade Guarulhos (UNG), R. Eng. Prestes Maia, 88 – Centro, CEP 07023-070, Guarulhos, SP, Brazil A R T I C L E INFO Keywords: MIR Polymer blends Quantifcation Transmission UATR ABSTRACT Polymer blends are produced to achieve properties that pure polymers are unable to. The qualitative analysis of these blends is not always satisfactory to point out failures in the fnal product and, therefore, the determination of their content might be required. The aim of this study is to develop quantitative methodologies using Fourier transform infrared spectroscopy (FT-IR), refection mode with the universal attenuated total refectance acces- sory (UATR) and transmission techniques, for the determination of the content of each polymer present in the polymer blend poly (butylene terephthalate) (PBT) and polycarbonate (PC). FT-IR/UATR presented better results using the relative band (A 1772 /A 1716 ). FT-IR/UATR presented error of 2.30%, which is a little higher than the accuracy limit of the spectrometer (�2%), but still adequate for industrial applications. 1. Introduction PBT/PC is a polymer blend that fnds wide use in different industrial sectors, such as aeronautics and automotive. Polymer blends charac- teristics can be improved by incorporating load materials and by the curing process. Both modify and enhance mechanical and thermal properties, and turn them into engineering plastics [1]. Engineering plastics are stable for defned periods of time. They can consequently endure mechanical, thermal, electrical, chemical or environmental stress. Plastic blends are more expensive than regular plastics because of their more complex manufacturing process. Polymers used in a plastic blend are selected for their processability and fexibility, characteristics that can provide complex designs with good dimensional stability and excellent resistance to corrosion in chemical hostile environments. The blend PBT/PC used in this study is of great importance due to the properties acquired during the blend formation. Such properties include impact resistance, thermal and electrical resistance, allied to good chemical resistance, especially to stress-cracking when in contact with products used in automobiles, such as oils and gases [2]. Fig. 1 shows the PBT chemical structure. PBT is a semi-crystalline polymer produced by the polycondensation of 1,4-butanediol and dimethyl terephthalate [3]. The repetition unit in the molecular chain is formed by two distinct and chemically different parts. Terephthalate provides strong intermolecular bonds, whereas butane delivers fexi- bility and mobility of the molecular chain that is responsible for the PBT crystallinity. Several types of additives, fllers, and reinforcing agents can be added to achieve good mechanical, dielectric and solvent-resistant properties [2]. PBT has a high melting point (T m ¼ 225 � C), which is attributed to the molecular rigidity generated by the p-phenylene groups, especially because they are bonded to carbonyls that make the entire group reso- nates as one unit. It has great chemical resistance when in contact with aliphatic hydrocarbons, alcohols, gasoline, detergents, mineral acids, greases, and oils. However, they present low resistance to alkalis [2,4]. PBT chain has four methylene groups (from 1,4-butanediol), which in- crease the polymer fexibility and provide fast crystallization [4]. Low fracture toughness is a major disadvantage of PBT, and reduces the impact resistance of the polymer. The addition of elastomer in contents superior to 20% and the dispersion of impact modifers of the * Corresponding author. Instituto Tecnol� ogico de Aeron� autica (ITA), Praça Marechal Eduardo Gomes, 50 – Vila das Ac� acias, CEP 12228-901, S~ ao Jos� e dos Campos, SP, Brazil. E-mail address: elizabethecm@fab.mil.br (E. da Costa Mattos). Contents lists available at ScienceDirect Polymer Testing journal homepage: http://www.elsevier.com/locate/polytest https://doi.org/10.1016/j.polymertesting.2020.106447 Received 20 November 2019; Received in revised form 6 February 2020; Accepted 15 February 2020