Testing and sampling technology of polymer materia

Detection and sampling technology of polymer materials for drug packaging

after the molecular compounds in drug packaging containers are irradiated by infrared radiation, the molecular vibration and rotation will transition from a lower energy level to a higher energy level, resulting in the selective absorption of a certain frequency of infrared radiation, forming a characteristic infrared absorption spectrum

infrared spectroscopy is an effective means to identify substances and analyze the chemical structure of drug packaging. It has been widely used in qualitative identification and phase analysis of substances; Similarly, infrared spectroscopy plays an important role in identifying the information of various functional groups of polymer compounds and determining the composition of materials. The European Pharmacopoeia also prefers infrared spectroscopy for the control of polymer materials. In order to control the formula of pharmaceutical packaging materials by strengthening the control of materials, and ensure the safety and reliability of drug use. To this end, the State Drug Administration issued 34 national standards for drug packaging containers (materials) in 2002. In these standards, infrared spectroscopy is widely used for the control of polymer materials

in order to understand the requirements of the standard and master the infrared detection technology, next, combined with the phase of polymer compounds in drug packaging, several commonly used detection methods and sample preparation technologies are introduced:

infrared spectroscopy measurement technology is divided into two categories. One refers to detection methods: such as transmission method (British Pharmacopoeia, European Pharmacopoeia method), multiple internal reflection method (MIR), attenuated total emission method (ATR) (USP method), diffuse reflection method, photoacoustic spectroscopy method, polarized infrared method, specular reflection method, etc. The other refers to the sample preparation technology. In the analysis of polymer compounds, the commonly used sample preparation technologies include: direct method, solvent evaporation film method, solution method, slicing method, thermal cracking method, etc

direct method: take two sheet samples, cut them into appropriate sizes (so that they can be put into the detection device), dip a flannelette in absolute ethanol, wipe the surface of the sample to remove surface moisture (or dry it with appropriate methods, such as blowing it with dry nitrogen), and measure it with transmission method or internal surface reflection method. If the sample is too thick and the transmittance of the strongest absorption peak is less than 10% when measured by the transmission method in accordance with the national standard gb/t8809, the hot pressing method should be used to make the sample thinner

solvent evaporation film forming method: dissolve the sample in a suitable solvent and heat it if necessary. For example, Professor Martin Dunn, another person in charge of the project (now the dean of the school of engineering and Applied Sciences at the University of Colorado Denver), said: "in general, toluene can be used as the solvent for PE, and polyvinyl chloride (PVC) can be used as the material Dimethylformamide can be used as solvent. Take the above solution and drop it on the potassium bromide chip. After the solvent volatilizes and forms a thin mucosa, measure it by transmission method

solution method: dissolve the sample in a suitable solvent to form a solution, and then put 1 PC into a sealed absorption tank for determination

slicing method (applicable to multi-layer composite materials): place the sample on the slicer, cut it into thin slices with appropriate thickness by hand, and observe it under the microscope. Each layer should be clearly distinguished, and determine it by infrared microscopic transmission method

thermal cracking method (applicable to thermosetting materials): cut the sample into fine particles, take out an appropriate amount, place it at the bottom of the test tube, heat it horizontally on an alcohol lamp, remove the cracking solution at the mouth of the test tube, apply it to the potassium bromide or sodium chloride wafer, and determine it by transmission method

transmission method: the thickness is 50 μ For polymer compound diaphragm samples below m, the diaphragm spectrum can be directly determined by transmission method

total reflection method: samples such as thick diaphragm, opaque diaphragm or coating can be measured by total reflection method

mirror reflection method: for polymer compounds coated on the metal surface, if the coating is thin, the metal surface will produce a certain reflection, and the mirror reflection method can be used to determine the spectrum

polarized infrared spectroscopy method: refers to the infrared spectroscopy method for samples with certain spatial orientation by changing the vibration direction of light with a polarizer on the infrared measurement optical path. Generally, the angles adjusted by the polarizer are 00, 450, 900, etc. By comparing the infrared spectra measured from different angles, the spatial orientation of the sample can be determined (applicable to polymer compounds with spatial orientation, such as unidirectional or biaxial polypropylene, polyester, polyamide, etc.)

infrared characteristic absorption peaks of common polymer materials: 2917, 2849, 1472, 1463, 730, 719cm-1pe. 2951, 2920, 2870, 2840, 1457, 1376, 1167, 998, 973, 841 cm-1pp. For pet1716, 1340, 1245, 1101, 1020, 873, 726 cm-1. 2941, 1429, 1333, 1250, 1099, 960, 690, 615 cm-1pvc

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