| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 5<\/td>\n | Plastics\ufffd\u2014 Polyurethane raw materials\ufffd\u2014 Determination of isocyanate content <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | Contents Page <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | Foreword <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | Plastics\ufffd\u2014 Polyurethane raw materials\ufffd\u2014 Determination of isocyanate content 1\ufffd\ufffd\ufffd Scope 2\ufffd\ufffd\ufffd Normative references 3\ufffd\ufffd\ufffd Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | 4\ufffd\ufffd\ufffd Principle 4.1\ufffd\ufffd\ufffd Method\ufffdA 4.2\ufffd\ufffd\ufffd Method\ufffdB 5\ufffd\ufffd\ufffd Application 6\ufffd\ufffd\ufffd Interferences 7\ufffd\ufffd\ufffd Sampling <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 8\ufffd\ufffd\ufffd Test conditions 9\ufffd\ufffd\ufffd Reagents 9.1\ufffd\ufffd\ufffd Acetone 9.2\ufffd\ufffd\ufffd Toluene 9.3\ufffd\ufffd\ufffd di- 9.4\ufffd\ufffd\ufffd di- 9.5\ufffd\ufffd\ufffd Aqueous hydrochloric acid 9.6\ufffd\ufffd\ufffd Methanolic hydrochloric acid 9.7\ufffd\ufffd\ufffd Bromophenol blue indicator solution 9.8\ufffd\ufffd\ufffd 1,2,4-Trichlorobenzene 9.9\ufffd\ufffd\ufffd Methanol 10\ufffd\ufffd\ufffd Apparatus 10.1\ufffd\ufffd\ufffd Potentiometric titrator 10.2\ufffd\ufffd\ufffd Syringes 10.3\ufffd\ufffd\ufffd Magnetic stirrer 10.4\ufffd\ufffd\ufffd Analytical balance <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 10.5\ufffd\ufffd\ufffd Iodine flask 10.6\ufffd\ufffd\ufffd Conical flask 10.7\ufffd\ufffd\ufffd Volumetric pipettes 10.8\ufffd\ufffd\ufffd Measuring pipette 10.9\ufffd\ufffd\ufffd Graduated cylinders 10.10\ufffd\ufffd\ufffd Beaker 10.11\ufffd\ufffd\ufffd Burette 11\ufffd\ufffd\ufffd Method\ufffdA \u2014 Toluene\/dibutylamine with aqueous HCl 11.1\ufffd\ufffd\ufffd Procedure 11.1.1\ufffd\ufffd\ufffd Using a volumetric pipette ( 11.1.2\ufffd\ufffd\ufffd Weigh a sample of the product to be analysed to the nearest 11.1.3\ufffd\ufffd\ufffd After complete dissolution, allow to react for 11.1.4\ufffd\ufffd\ufffd Using a graduated cylinder ( 11.1.5\ufffd\ufffd\ufffd Titrate the excess dibutylamine using one of the two following procedures: 11.1.5.1\ufffd\ufffd\ufffd Potentiometric titration (recommended) 11.1.5.2\ufffd\ufffd\ufffd Colorimetric titration <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 11.1.6\ufffd\ufffd\ufffd Conduct a blank determination under identical conditions, except omit the test portion. 11.2\ufffd\ufffd\ufffd Expression of results 11.2.1\ufffd\ufffd\ufffd Calculate the %\ufffdNCO as follows: 11.2.2\ufffd\ufffd\ufffd The amine equivalent may be calculated as follows: 11.2.3\ufffd\ufffd\ufffd For isocyanates based on a single isomer or isomer mixture (for example, \u201cpure\u201d TDI or … 11.2.4\ufffd\ufffd\ufffd The number of equivalents per kilogram (equiv\/kg) may be calculated as follows: <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 11.2.5\ufffd\ufffd\ufffd In refined isocyanates, acidic impurities are usually present in such low amounts that … 11.3\ufffd\ufffd\ufffd Precision and bias 11.3.1\ufffd\ufffd\ufffd Precision 11.3.2\ufffd\ufffd\ufffd Bias 11.4\ufffd\ufffd\ufffd Test report 12\ufffd\ufffd\ufffd Method\ufffdB \u2014 Toluene\/TCB\/DBA with methanolic HCl 12.1\ufffd\ufffd\ufffd Procedure 12.1.1\ufffd\ufffd\ufffd Introduce <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 12.1.2\ufffd\ufffd\ufffd Transfer the approximate amount of sample required, weighed to the nearest 12.1.3\ufffd\ufffd\ufffd Cover the flask and swirl the contents until the solution is homogeneous. The reaction … 12.1.4\ufffd\ufffd\ufffd Let the reaction mixture stand until it reaches room temperature ( 12.1.5\ufffd\ufffd\ufffd Titrate potentiometrically with 12.1.6\ufffd\ufffd\ufffd Prepare a blank exactly as described above, but without adding the test portion. Titrat… 12.1.7\ufffd\ufffd\ufffd If a potentiometric titrator is not available, the titration can be performed using a c… 12.2\ufffd\ufffd\ufffd Expression of results 12.2.1\ufffd\ufffd\ufffd As required, calculate the %\ufffdNCO, amine equivalent, or equivalents per kilogram followi… 12.2.2\ufffd\ufffd\ufffd In refined isocyanates, acidic impurities are usually present in such low amounts that … <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 12.2.3\ufffd\ufffd\ufffd The amine equivalent, corrected for acidity, may be calculated as follows: 12.3\ufffd\ufffd\ufffd Precision and bias 12.3.1\ufffd\ufffd\ufffd Use the following criteria to judge the acceptability of results for crude or modified … 12.3.1.1\ufffd\ufffd\ufffd Repeatability (single analyst) 12.3.1.2\ufffd\ufffd\ufffd Reproducibility (multilaboratory) 12.3.2\ufffd\ufffd\ufffd Use the following criteria to judge the acceptability of results for MDI isomers: 12.3.2.1\ufffd\ufffd\ufffd Repeatability 12.3.2.2\ufffd\ufffd\ufffd Reproducibility 12.3.3\ufffd\ufffd\ufffd TDI isomers were evaluated. However, there were insufficient degrees of freedom to make… 12.3.4\ufffd\ufffd\ufffd Bias is the difference between the expectation of the test results and an accepted refe… 12.4\ufffd\ufffd\ufffd Test report <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Plastics. Polyurethane raw materials. Determination of isocyanate content<\/b><\/p>\n |