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GB/T 12008.3-2009: Plastics -- Polyether polyols -- Part 3: Determination of hydroxyl number Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB/T 12008.3: Historical versions
Similar standardsGB/T 12008.3-2009: Plastics -- Polyether polyols -- Part 3: Determination of hydroxyl number---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT12008.3-2009GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 83.080 G 31 Replacing GB/T 12008.3-1989 Plastics - Polyether polyols - Part 3.Determination of hydroxyl number (ISO 14900.2001, Plastics - Polyols for use in the production of polyurethane - Determination of hydroxyl number, NEQ) Issued on. JUNE 15, 2009 Implemented on. FEBRUARY 01, 2010 Issued by. General Administration of Quality Supervision, Inspection and Quarantine; Standardization Administration of the People's Republic of China. Table of ContentsForeword... 3 1 Scope... 5 2 Normative references... 5 3 Terms and definitions... 6 4 Method A - Phthalic anhydride method... 6 5 Method B - Near-infrared spectroscopy... 11 Annex A (informative) Precision of phthalic anhydride method... 16 Bibliography... 17ForewordGB/T 12008 “Plastics - Polyether polyols” consists of 7 parts. - Part 1.Designation system; - Part 2.Specification; - Part 3.Determination of hydroxyl number; - Part 4.Determination of sodium and potassium; - Part 5.Determination of acidity as acid number; - Part 6.Determination of degree of unsaturation; - Part 7.Determination of viscosity. This Part is Part 3 of GB/T 12008.The degree of consistency with ISO 14900.2001 “Plastics - Polyols for use in the production of polyurethane - Determination of hydroxyl number” and ASTM D6342.2008 “Standard Practice for Polyurethane Raw Materials. Determining Hydroxyl Number of Polyols by Near Infrared (NIR) Spectroscopy” is non-equivalent. This Part replaces GB/T 12008.3-1989 “Polyether polyols - Determination of hydroxyl number”. Compared with GB/T 12008.3-1989, the main changes in this Part are as follows. - changed the standard name; - added catalyst imidazole into phthalic anhydride acylation reagent (5.2 of Edition 1989, 4.3.3 of this Edition); - reduced reflow time (8.2 of Edition 1989, 4.5.2 of this Edition); - added Method B - Near infrared spectroscopy (Clause 5 of this Edition). Annex A of this Part is informative. This Part was proposed by China Petroleum and Chemical Industry Association. This Part shall be under the jurisdiction of Subcommittee on General Methods and Products for Plastic Resins of National Technical Committee on Plastics of Standardization Administration of China (SAC/TC 15/SC 4). Main drafting organizations of this Part. Jiangsu Chemical Research Institute Co., Ltd., Sinopec Group Asset Management Co., Ltd. Shanghai Gaoqiao Branch. The drafting organizations of this Part. Sinopec Group Asset Management Co., Ltd. Tianjin Petrochemical Branch, Jiangsu Zhongshan Chemical Co., Ltd., National Synthetic Resin Quality Supervision and Inspection Center. Main drafters of this Part. Liu Rong, Xu Yidong, Zhou Qinnan, Lu Wei, Qi Li, Du Xinlei, Wang Jiandong. Version of standard substituted by this Part is. - GB/T 12008.3-1989. Plastics - Polyether polyols - Part 3.Determination of hydroxyl number Warning - The personnel using this Part shall be familiar with the routine operation of the laboratory. This Part does not involve any security issues related to use. If there are any problems related to the use, the user is responsible for establishing appropriate safety and health measures and ensuring compliance with national regulations.1 Scope1.1 This Part of GB/T 12008 specifies two methods for the determination of the hydroxyl value of polyether polyols. 1.2 Method A is phthalic anhydride method. It is recommended for polyether polyols, polymer polyols and polyols with ammonia as initiator. But for polyols with steric hindrance, the result shall be lower. If corrective measures can be taken, other polyols can also apply this method. 1.3 Method B specifies the determination of hydroxyl value in polyether polyols by near infrared spectroscopy. It describes the steps of sample selection, data collection, establishment and verification of calibration models.2 Normative referencesThe provisions in following documents become the provisions of this Part of GB/T 12008 through reference in this Part. For dated references, the subsequent amendments (excluding corrigendum) or revisions do not apply to this Part, however, parties who reach an agreement based on this Part are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies. GB/T 601-2002, Chemical Reagent - Preparations of Standard Volumetric Solutions GB/T 2035-2008, Terms and definitions for plastics (ISO 472.1999, IDT) GB/T 6682-2008, Water for analytical laboratory use - Specification and test methods (ISO 3696.1987, MOD) ASTM D7253.2006, Standard Test Method for Polyurethane Raw Materials - Determination of Acidity as Acid Number for Polyether Polyols3 Terms and definitionsFor the purposes of this document, the terms and definitions defined in GB/T 2035-2008 as well as the followings apply. 3.1 polyurethane a polymer made by reacting organic diisocyanates or polyisocyanates with compounds containing two or more hydroxyl groups4 Method A - Phthalic anhydride method4.1 Principle The hydroxyl groups in the sample are esterified by refluxing in the pyridine solution of phthalic anhydride. 4.2 Interference 4.2.1 Excessive water shall destroy the esterification reagent and interfere with the determination. If the moisture content of the sample is greater than 0.2%, use a reagent that shall not introduce acid or alkali into the sample to dry. 4.2.2 Primary, secondary amino and long-chain fatty acids react with reagents to form stable compounds, which shall be included in the results. 4.3 Reagents Unless otherwise stated, only use analytical reagents. The test water shall conform to grade three water specification in GB/T 6682-2008. 4.3.1 Imidazole. 4.4 Instruments 4.4.1 Potentiometer or pH meter. the accuracy is not less than 0.1mV, equipped with a pair of electrodes or glass-calomel composite electrodes, a burette with a capacity of 100mL or a burette that can be automatically backfilled. 4.4.2 Syringe. 2mL, 5mL and 10mL, with a hole suitable for processing viscous polyols. 4.4.3 Magnetic stirrer 4.4.10 Erlenmeyer flask. 300mL, standard 24/40 ground mouth. 4.4.11 Air condenser. 400mm, standard 24/40 ground. 4.4.12 Oil bath. keep the temperature at (115±2)°C. 4.5 Steps 4.5.2 Accurately pipette 25mL of phthalic anhydride acylation reagent (4.3.3) into each test material and blank Erlenmeyer flask. Shake the flask until the test material dissolves. Each Erlenmeyer flask is connected to an air condenser (4.4.11). Put it in the (115±2)°C oil-bath (4.4.12) for 30min. 4.5.3 After heating, take the device out of the oil bath and cool to room temperature. Use 30mL of pyridine (4.3.2) to rinse the condenser and remove the condenser tube. Quantitatively transfer the solution to a 250mL beaker (4.4.8). Use 20mL of pyridine to rinse the Erlenmeyer flask. 4.5.4 Titrate the solution in one of the following methods. 4.5.5 Measure the acid value C according to ASTM D7253.2006.If the solution for determining the acid value is pink, follow the steps below to determine the base value L. 4.6 Result calculation and expression 4.6.1 Hydroxyl value OHV, in milligrams of potassium hydroxide consumed per gram of sample, is calculated according to formula (2). 4.7 Precision See Annex A for precision data. 4.8 Test report The test report shall contain the following.5 Method B - Near-infrared spectroscopy5.1 Principle Near-infrared spectroscopy is mainly generated when the molecular vibration transitions from the ground state to the higher energy level due to the non- resonance of the molecular vibration. 5.2 Instruments 5.2.1 Near-infrared hydroxyl value analyzer and supporting software. 5.2.2 Constant temperature unit. 5.2.3 Sample pool. 5.3 Application 5.3.1 General rules for use 5.3.2 Limitation 5.3.2.1 Before calibration, first determine the influencing factors of the near- infrared spectrum of the analyzed polyol. In order to properly select the sample, it is necessary to understand the chemical structure, interference, any non- linear relationships, the influence of temperature, and the interaction of the analyte with other components such as catalysts, moisture and other polyols, so as to simulate these uncontrollable factors. 5.4 Selection of calibration samples 5.4.1 The samples of the calibration set shall be selected according to the following guidelines as far as possible. 5.4.1.1 Sample selection includes all components expected to appear in the sample of interest. 5.5 Steps 5.5.1 Data collection 5.5.1.1 Chemical method data collection Measure the hydroxyl value of the polyether polyol sample according to Method A of this Part and use it as raw data for backup. 5.5.2 Spectrum collection 5.5.3 Model establishment Build a model according to the operating requirements of the instrument manual. Optimize the variables in the model. In the process of model calibration, use mathematical and statistical methods to identify outliers. And remove all outliers before the model is finalized. Correct the model. 5.5.4 Model verification Model verification is done by predicting the concentration of the analyte in the independent sample set and the known analyte concentration, and statistically analyzing the response of the model. Select the validation set samples according to the same conditions as the calibration set samples. In addition, the following conditions must be observed. 5.5.5 Conversion of calibration model 5.5.5.1 The conversion of the calibration model involves the steps of establishing the calibration model. It refers to the process of using the data obtained from the near-infrared hydroxyl value analyzer for spectral data collection and analysis. 5.5.5.2 When establishing a calibration model conversion, it is necessary to demonstrate it to ensure that the performance of the model does not degrade during the conversion process. Each calibration conversion step at least uses a converted model to conduct a complete verification. 5.6 Result expression Conduct parallel determination of the same sample. Report results in arithmetic average, to the nearest of 0.1. 5.7 Test report The test report shall contain the following. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
