聚合物及塑料中CHNS/O元素含量分析检测方案(有机元素分析)

thermoscientific APPLICATION NOTE 42230 Elemental Analysis： CHNS/O characterizationof polymers and plastics Dr. Liliana Krotz and Dr. Guido Giazzi Thermo Fisher Scientific. Milan， Italy Keywords CHNS/O， Dumas method， Plastics， Polymers This application note showsCHNS/O determination forpolymers and plastics with theFlashSmart EA， needed formaterial quality control. The chemical composition of polymers and plastics is connected with theirchemical， physical， mechanical properties. The development and productionof polymers and plastics requires quality control of raw materials， additives，stabilizers， intermediate and finished products. The analysis of the behaviorof polymers and plastics during molding and the evaluation of their lifetimecontribute to define their quality. For the material characterization and the qualitycontrol testings of polymers and plastics， nitrogen， carbon， hydrogen， sulfur andoxygen are determined. Nitrogen determination is crucial， and the importanceof sulfur determination has increased also. Nitrogen containing compoundsare used in the production process of polymers and plastics to trigger apolymerization reaction. They can also be used as additives for the addition ofspecific properties to polymers and plastics. As additives， nitrogen containing compounds provide the final product withspecific properties， and they act as： stabilizing emulsion polymers， chaintransfer agents and other polymerization modifiers to control molecular weight，plasticizers to increase flexibility， stabilizers to prevent polymer degradation，crosslinkers used to modify polymer networks. As the demand for material characterization testing has grown in recent yearsand elements are present at trace levels， the classical analytical methodsshowed to be no longer suitable， for their time-consuming sample preparationand for their use of hazardous reagents. For this reason an automated techniqueproviding accurate data at trace levels is the requirement for modern laboratoriesdealing with routine analysis. The Thermo ScientificFlashSmartElemental Analyzer(Figure 1)， meets laboratory requirements such asaccuracy， day to day reproducibility and high samplethroughput. It improves the productivity of the laboratoryover traditional methods， as it is automated and modular.CHNS determinations can be performed in a singleanalysis run and oxygen determination by pyrolysis ina second run. The FlashSmart EA can be configuredto perform a single nitrogen determination or tracesulfur analysis when coupled to the Flame PhotometricDetector (FPD). This note presents data on CHNS/O determination inpolymers and plastics to show the performance of theFlashSmart Elemental Analyzer. For CHNS or CHN determination the FlashSmartElemental Analyzer operates with dynamic flashcombustion of the sample. Samples are weighed in tincontainers and introduced into the combustion reactorvia the Thermo ScientificMAS Plus Autosamplerwith oxygen. After combustion， the produced gasesare carried by a helium flow to a layer containingcopper， then swept through a GC column， whichprovides the separation of the combustion and finally，detected by a Thermal Conductivity Detector (TCD). Figure 2. CHNS/O configuration. Figure 3. Sulfur configuration by FPD Detector. Figure 1. Thermo Scientific FlashSmart Elemental Analyzer. Total run time less than 10 minutes (Figure 2). For tracesulfur determination， the gases produced by combustionare carried by a helium flow to a layer containing copper，then swept through a water trap， a short GC column andfinally the sulfur is measured by the Flame PhotometricDetector (FPD). Total run time is 5 minutes (Figure 3). For oxygen determination， the system operates inpyrolysis mode. Samples are weighed in silver containersand introduced into the pyrolysis chamber via the MASPlus Autosampler. The reactor contains nickel coatedcarbon at a temperature of 1060℃. The oxygen inthe sample， combined with the carbon， forms carbonmonoxide which is chromatographically separatedfrom other products and detected by the TCD Detector(Figure 2). For nitrogen determination， the Elemental Analyzer operatesby dynamic flash combustion of the sample. Samplesare weighed in tin containers and introduced into thecombustion reactor via the MAS Plus Autosampler withoxygen. After combustion， the produced gases are carriedby a helium flow to a second reactor containing copper，then swept throughCO， and H，O traps， and a GC column，and finally， detected by a Thermal Conductivity Detector(TCD). Total run time less than five minutes (Figure 4). Figure 4. Nitrogen configuration. Element N% C% H% S% 0% 3.483 61.108 2.642 3.950 20.304 3.494 61.092 2.629 3.910 20.213 3.478 61.168 2.620 3.943 20.236 Average 3.485 61.123 2.630 3.934 20.251 RSD% 0.235 0.066 0.421 0.543 0.234 Table 2. NCS data of polymers powders. Sample N% RSD% C% RSD% S% RSD% 1 15.829 54.983 0.221 15.770 0.303 54.950 0.158 0.223 0.548 15.756 54.819 0.223 2 13.775 49.014 3.266 13.763 0.054 48.889 0.129 3.282 0.270 13.777 48.971 3.267 Table 3. CHN/O data of polyacrilonitriles. Sample N% RSD% C% RSD% H% RSD% 0% RSD% 23.17 64.26 5.73 4.79 A 23.35 0.45 64.35 0.12 5.76 0.71 4.59 2.25 23.17 64.42 5.68 4.63 22.77 64.65 5.73 5.31 B 22.54 0.75 64.23 0.33 5.66 0.98 5.37 0.71 22.44 64.41 5.62 5.30 24.97 64.88 5.67 2.99 C 24.8824.88 0.21 65.2065.23 0.30 5.665.70 0.37 3.012.98 0.51 Table 4 shows the nitrogen data of polymers in pellets.The system was calibrated with 10-12 mg atropinestandard using K factor as calibration method. Samples1 and 2 were weighed at 200-250 mg. For samples3 to 5 the calibration was performed with 5-6 mgatropine and samples were weighed at 30-40 mg.Table 5 shows the nitrogen data of polycarbonatepolymers in pellets analyzed in duplicate. The systemwas calibrated with 25-30 mg atropine using K factor ascalibration method. Sample was weighed at 150-170 mg. additives. The calibration was performed with 25-30 mgof atropine using K factor as calibration method. Sampleswere weighed at 25-30 mg. Table 6. Nitrogen data of polyethylene films. Table 6 shows nitrogen data of polyethylene films.As standard， 3-4 mg atropine was analyzed using Kfactor as calibration method. Samples were weighed at20-25 mg. Table 7 shows the nitrogen data of plastics Table 4. Nitrogen data of polymers (pellets). Sample N (ppm) RSD% 2410 1 2410 0.312 2397 1569 2 1590 1.212 1552 1072 3 1040 1.573 1064 781 4 779 0.604 788 492 5 500 0.841 494 266 6 252 5.556 238 220 7 213 1.646 218 114 8 103 5.038 107 Sample N (ppm) RSD% 1 985 982 998 1.589 1002 1029 999 1005 1001 1008 1031 331 332 2 324 328 1.236 326 334 346 335 327 339 967 3 971 0.206 969 439 4 427 2.300 447 91 5 89 1.111 90 Table 7. Nitrogen data of plastics additives. Table 5. Nitrogen data of polycarbonate polymers (pellets). Sample 1 2 3 4 5 N% 0.675 0.656 0.617 0.113 0.110 0.678 0.651 0.622 0.111 0.111 RSD% 0.314 0.541 0.571 1.263 0.640 Sample N% RSD% 18.141 Raw Material 1 18.136 0.022 18.144 19.639 Raw Material2 19.631 0.087 19.606 13.414 Raw Material3 13.407 0.039 13.417 2.242 Raw Material 4 2.241 0.569 2.219 12.799 Raw Material(Dimeric Benzotriazole) 12.808 0.057 12.814 0.642 Polycarbonate + DimericBenzotriazole 0.645 0.483 0.639 5.767 Raw Material (HinderedAmine Light Stabilizer) 5.753 0.231 5.740 White Polystyrene Granules (Contains Hindered Amine 0.506 0.501 0.808 Light Stabilizer) 0.509 For trace sulfur determination by FPD Detector， thesystem was calibrated with Thermo Scientific Pasta andSoil Reference Materials with 0.135 S% and 0.032 S%，respectively using quadratic fit as calibration method. Table 8 shows the sulfur data of a polyethylene filmsample. Table 9 shows the sulfur data of plastic powderswhile Table 10 shows the sulfur data of polymers. Thesamples were cut into small pieces and the samples wereweighed at 0.5-3 mg. Table 8. Sulfur data of polyethylene film sample. s(ppm) RSD% 571 573 540 2.792 542 558 Table 9. Sulfur data of plastic powders. Sample S(ppm) RSD% 562 1 582 1.857 566 58 2 54 5.329 60 39 3 42 10.657 48 2366 4 2335 0.813 2370 Conclusion The Thermo Scientific FlashSmart Elemental Analyzerenables to perform accurate and reproducible CHNS/Odetermination in polymers and plastics samples. No matrix effect was observed when changing the sampleand element content indicating the complete combustionof the samples. Nitrogen only analyses， simultaneous CHNS， NCS， CHNand oxygen can be performed on the Thermo ScientificFlashSmart Elemental Analyzer with a simple upgrade.Trace sulfur determination can also be performed whencoupled to the FPD Detector The FlashSmart Elemental Analyzer meets laboratoryrequirements in terms of automation， high samplethroughput. 2017 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific and itssubsidiaries. This information is presented as an example of the capabilities of Thermo Fisher Scientific products. It is not intendedto encourage use of these products in any manners that might infringe the intellectual property rights of others. Specifications，terms and pricing are subject to change. Not all products are available in all countries. Please consult your local salesrepresentatives for details. AN42230-EN 1017S 聚合物和塑料的化学成分与其化学、物理和机械性能有关。聚合物和塑料的开发和生产需要对原材料、添加剂、稳定剂、中间产品和成品进行质量控制。对聚合物和塑料在成型过程中的行为分析对其使用寿命进行评估来定义它们的质量好坏。为了对聚合物和塑料的材料特性和质量控制测试，需要测定氮、碳、氢、硫和氧的含量。氮的测定至关重要，硫的测定也越来越重要。含氮化合物，用于聚合物和塑料的生产过程中触发聚合反应。它们还可以作为添加剂，作为添加剂，含氮化合物为最终产品提供特定性能，它们起到稳定乳液聚合物、链转移剂和其他聚合改性剂的作用，用以控制分子量，增塑剂以增加弯曲程度，稳定剂防止聚合物降解，交联剂用于改性聚合物原型。 随着近年来对材料特性测试的需求不断增长，元素含量都是微量的，经典分析方法已不再适用于，例如耗时的样品制备和危险试剂的使用。因此，自动化技术以及在痕量水平上可以提供准确的数据等成为现代化实验室处理常规分析的要求。