Analysis Of Polymer Additives Research Articles

PIPELINE TRANSPORT OF HYDROCARBONS WITH POLYMER ADDITIVES IN THE ARCTIC CONDITIONS

The analysis of polymer additives under different conditions and concentrations is performed, and the coefficient of hydrodynamic drag force was found to decrease as the temperature decreases. Expediency and economic benefit of using polymeric additives for pumping of hydrocarbon fluids in the аrctic conditions is confirmed.

Gel permeation chromatography – Atmospheric pressure chemical ionization – Mass spectrometry for characterization of polymer additives

ABSTRACTThe study presents the possibility to use gel permeation chromatography (GPC) with atmospheric pressure chemical ionization (APCI)-mass spectrometry for the analysis of polymer additives having molecular weights up to 2,000 g mol−1. Irganox 1010, Irganox 1035, Irganox 1076, and Irganox 3114 were analyzed in chloroform using 2.1-mm-internal-diameter GPC columns at the optimum flow rate of 50 µL min−1. Based on the chemical formula, the APCI interface combined with chlorine ionization enabled us to predict the expected mass spectrum and to build libraries without needing to inject each additive separately. Quantification limits of about 100 µg of additive in 1 g of polymer (100 ppm) can be reached using single-ion-monitoring methods based on the calculated isotope distribution.

Rapid identification of polymer additives by atmospheric solid analysis probe with quadrupole time-of-flight mass spectrometry.

A method using an atmospheric solid analysis probe (ASAP) combined with quadrupole time-of-flight mass spectrometry (QTOFMS) assisted by a pre-built MS library was found to be efficient in fast and direct analysis of additives for polymers. By this method, sample pretreatment could be eliminated from the additives identification process. Some crucial parameters, such as desolvation gas temperature, corona current, sample cone voltage and collision energy, should be optimized. A MS library of 100 polymer additives, including phenols (Irganox 1010, Irganox 1076), hydroxyl phenyl benzotriazole derivatives (Tinuvin 326, Tinuvin 327, Tinuvin 328), hindered amines (Tinuvin 944, Tinuvin 770) and plasticizers, was built based on the optimized conditions. To verify the application of the MS library, the ASAP-QTOFMS method was applied to identify complex additives, a simulated polypropylene (PP) sample and a real polymethylmethacrylate (PMMA) sample purchased from a local market. By searching the exact mass, and comparing the MS and MS/MS spectra of samples with standards in the MS library, complex additives such as Irganox GX 2921, as well as additives in PP and PMMA samples, could be identified quickly and easily. The determination of mass accuracy increased the confidence of peak identification as well. Moreover, the results also provided information of the characterization for PP and PMMA polymers. A rapid identification method has been developed for polymer additives by ASAP-QTOFMS. A MS library of 100 polymer additives was built by this method. Using ASAP-QTOFMS assisted by the pre-built MS library, polymer additives can be quickly identified. This method was found to be a promising tool in the rapid analysis of additives in polymers and polymer matrices.

Quantitative Analysis of Polymer Additives with MALDI-TOF MS Using an Internal Standard Approach

MALDI-TOF MS is used for the qualitative analysis of seven different polymer additives directly from the polymer without tedious sample pretreatment. Additionally, by using a solid sample preparation technique, which avoids the concentration gradient problems known to occur with dried droplets and by adding tetraphenylporphyrine as an internal standard to the matrix, it is possible to perform quantitative analysis of additives directly from the polymer sample. Calibration curves for Tinuvin 770, Tinuvin 622, Irganox 1024, Irganox 1010, Irgafos 168, and Chimassorb 944 are presented, showing coefficients of determination between 0.911 and 0.990.

Rapid identification and semi-quantitative determination of polymer additives by desorption electrospray ionization/time-of-flight mass spectrometry

A fast and simple method for the direct qualitative and semi-quantitative determination of a set of four polymer additives in plastic samples by desorption electrospray ionization time-of-flight mass spectrometry (DESI-TOF-MS) is presented. After evaluation of crucial DESI parameters such as composition of spray solutions and spray voltages, a series of lab-made polypropylene samples containing Chimassorb 81 (2-hydroxy-4-n-octoxybenzophenone), Tinuvin 328 (2-(2-hydroxy-3, 5-ditert-pentylphenyl)-benzotriazole), Tinuvin 326 (2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chloro benzotriazole), and Tinuvin 770 (bis(2,2,6,6,-tetramethyl-4-piperidyl)sebaceate) in concentrations between 0.02% and 0.2% were analyzed, resulting in calibration graphs with R (2) better than 0.994. To demonstrate the applicability of the developed method for the investigation of real samples, liners for in-ground swimming pools and polypropylene granules were analyzed with respect to their content in the selected polymer additives. Two alternative methods, both well established in the fields of polymer additive analysis, namely HPLC with UV detection (after previous extraction) and thermodesorption gas chromatography/mass spectrometry have been employed for evaluation of the results from the DESI experiments.

Analysis of Polymer Additives in High-Temperature Liquid Chromatography

A high-temperature liquid chromatographic technique is employed for the separation of commercially available polymer additives to enhance the resolution and speed. Separation efficiencies and elution behaviors for seven phthalate plasticizers and five antioxidants are evaluated at elevated column temperatures and with a thermal gradient. Diamondbond C18 (octadecylsilica), Zirchrom PS (zirconia-based polystyrene), and Zirchrom PBD (zirconia-based polybutadiene) columns are selected for the study because of their thermal stability. The temperature programming is controlled with a column oven in conjunction with an independent mobile phase preheater and a post-column effluent cooling assembly. Van't Hoff plots show that the reverse-phase liquid chromatography mechanism is maintained over a wide range of column temperatures. A 1% increase of acetonitrile in the mobile phase is estimated to have a comparable effect as a 7-7.5 degrees C column temperature increase on the retention time changes.

Feasibility of supercritical fluid extraction with on-line coupling of reversed-phase liquid chromatography for quantitative analysis of polymer additives

An on-line analytical method for determining polymer additives which incorporates (a) sample preparation and concentration, (b) chromatographic separation, and (c) UV detection is presented. The on-line system which combines supercritical fluid extraction (SFE) and high-performance liquid chromatography (LC) allows analytes to first be extracted and transferred to the SFE sorbent trap, then desorbed from the trap and presented to the LC system. No UV detector interference from residual dissolved CO 2 in the mobile phase was observed since CO 2 is eliminated by a pre-wash of the sorbent trap with a small amount of water. Reversed-phase LC with a mobile phase gradient of acetonitrile–water was employed. The described method allows a complete analysis to be processed in less than 30 min.

Polymer additive analysis at the limits

Polymer/additive analysis is a complex problem. Analysis of additives in polymers takes advantage of all current instrumental tools featuring techniques based on low/high temperature, pressure, speed, wavelength, voltage, performance, sensitivity, selectivity, resolution, mass, fragmentation, dimensionality, orthogonality, equipment size, column technology, instrumental complexity, cost, timeliness, etc. with allowance for the use of extreme operating parameters in terms of volume, solvent use, temperature variation, time, speed, wavelength dependency, destructiveness, spatial resolution, remoteness, angular dependency, modulation, etc. Historically, analysis of polymer/additive packages has experienced a long series of tool development. Nowadays the experimentalist disposes of powerful tools with a proven record of being efficient in industrial problem solving. High-performance polymer/additive analysis does benefit from on-line, simultaneous analysis, fast screening, high sensitivity and high resolution. The future of in-polymer additive analysis will be strongly affected by developments in many instrumental disciplines. General trends are higher sensitivity, more information, faster and further automation. Some future needs are more reliable quantitation, reference materials and simplification of data management. A particular problem in additive analysis concerns accuracy and traceability. There are still many quantitative analytical methods waiting to be developed. It is here that the field will advance. The paper concludes with various proposals for (r)evolutionary developments in polymer/additive analysis.

Fast identification of polymer additives by pyrolysis-gas chromatography/mass spectrometry

Thermoanalytical methods are especially useful in the analysis of polymer additives. This paper describes a fast method for the qualitative identification of additives in polymers originating from electronic waste. The method is based upon a double-shot pyrolyzer coupled to a gas chromatograph with mass spectrometry detection. The pyrolysis products of two samples of recycled ABS were studied and compared to those of a virgin ABS sample as a function of the pyrolysis mode. The identification of the additives was achieved on the basis of their mass spectra (MS) and comparison with standard MS-libraries.

Analysis of additives in polymers by thin-layer chromatography coupled with Fourier transform-infrared microscopy

A new, fast and convenient method based on coupled thin-layer chromatography (TLC) and Fourier transform-infrared (FT-IR) microscopy is developed to separate, detect and identify the additives in polymers. After the TLC development, the analytes were transferred on to a barium fluoride (BaF 2) salt plate via a special capillary technique and analysed by FT-IR microscopy. The additives used for stabilization of polypropylene and the plasticisers used for poly(vinyl chloride) were analysed as examples to illustrate this technique. The overall time taken for the experiment including transferring three marked spots and then identifying them was about 20 min. An amount as small as 0.5 μg can be easily detected and identified. It was a very convenient and reliable method to separate and evaluate complex additives for polymers without the interference from TLC adsorbent, because of a special transferring and identifying method, which is suitable to FT-IR microscopy.

Analysis of Polymer Additives by Matrix‐Assisted Laser Desorption Ionization/Time of Flight Mass Spectrometer Using Delayed Extractionand Collision Induced Dissociation

AbstractMatrix‐assisted laser desorption/ionization (MALDI) in combination with mass spectrometry proved to be a viable method for identifying additives in polyethylene ex tracts. The MALDI mass spectra of additives standards were found to be very simple consisting of [M+H]+ and/or [M+Na]+ pseudo molecular ions with little fragment ions. For real samples, which of ten contain more than one additive, the production of only one or two ions for each additive makes the tentative assignment much easier. Collision induced dissociation (CID) of the pseudomolecular ion is used to confirm the tentative assignment. The analysis of highmolecular weight additives, such as Chimassorb 944 and Tinuvin 622 indicated that MALDI was superior to other ionization techniques such as electrospray ionization (ESI), desorption chemical ionization (DCI) and fast atom bombardment (FAB) in the analysis of high molecular weight polymer additives. Sample preparation was found to be more critical than DCI in the analysis of real sample. The signals were interfered by the low molecule weight polyethylenemolecules, which were co‐extracted with the additives. This problem was partially overcome by using acetone in stead of methanol to precipitate the low molecular weight polyethylenemolecules.

Polymer characterization: physical techniques

The seperation and analysis of additives in polymers. NMR. Characterization of polymers. Vibrational spectroscopy. Molecular weight determination. Chromatographic methods. Thermal analysis. Small angle neutron scattering and neutron reflectometry. Mechanical and rheological testing. Polymer microscopy. The characterization of polymer surfaces by XPS and SIMS.

Polymer additive analysis by pyrolysis–gas chromatography: IV. Antioxidants

Antioxidants are important additives in polymers. Because of the low level of antioxidants normally used, they cannot be analyzed directly by common spectroscopic or thermal chemical techniques. However, antioxidants as well as other additives in polymers can be qualitatively analyzed by pyrolysis–gas chromatography (Py–GC) after separating the polymers and additives. In this study, several antioxidants have been investigated to demonstrate that Py–GC is a viable tool to analyze them. The advantages of using Py–GC in the analysis of antioxidants have also been discussed.

Polymer additive analysis by pyrolysis–gas chromatography: III. Lubricants

Lubricants are widely used in thermoplastic polymers to increase the overall rate of processing or to improve surface release properties. Because of the low level of lubricants normally used in a polymer, it may not be possible to analyze the additive directly by common spectroscopic or thermal chemical techniques. However, lubricants as well as other additives in the polymer can be qualitatively analyzed by pyrolysis–gas chromatography (Py–GC) after extraction. In this work, several lubricants have been studied to demonstrate that Py–GC is a viable tool to investigate lubricants. The advantages of using Py–GC in the analysis of lubricant have also been discussed.

Polymer additive analysis by pyrolysis–gas chromatography: II. Flame retardants

Flame retardants are widely used in thermoplastic polymers for household and transportation applications. Flame retardants as well as most of the other additives in the polymer can be qualitatively analyzed by pyrolysis–gas chromatography (Py–GC) simultaneously with the polymer composition. The key to successful analysis of flame retardants not only requires a thorough knowledge of the various types of flame retardants but also necessitates an understanding of the parent polymer and its targeted applications. In this study, several flame retardants in different polymer matrices have been studied to demonstrate the utility of Py–GC for the analysis of flame retardants. The advantages of Py–GC for flame retardants analysis have also been discussed.

Polymer additive analysis by pyrolysis–gas chromatography: I. Plasticizers

Plasticizers are widely used in thermoplastic polymers to modify their physical properties and processibility. Plasticizers as well as most of the other additives in the polymer can be qualitatively analyzed by pyrolysis–gas chromatography (Py–GC) simultaneously with the polymer composition. The key to the successful analysis of plasticizers not only requires a comprehensive understanding of commercial plasticizers but also requires knowledge of the polymer and its applications, as well as the Py–GC technique. In this study, several plasticizers in different polymeric systems were studied to demonstrate the utility of Py–GC as a good tool for the characterization of these systems. The advantages of using Py–GC for plasticizer analysis are also discussed.

Identification and analysis of polymer additives using packed-column supercritical fluid chromatography with APCI mass spectrometric detection

Packed-column supercritical fluid chromatography (pSFC) with detection using atmospheric pressure chemical ionisation (APCI) mass spectrometry (MS) provides a versatile method for the detection and quantification of 20 polymer additives, including common antioxidants, light stabilisers and slip agents. Using MS with APCI in both positive and negative ion modes both molecular mass data and informative fragmentation patterns were obtained. The pSFC-MS technique was shown to be linear over a wide concentration range (0.05–25 µg ml–1) and picogram limits of detection with positive ion APCI (single ion monitoring) were determined for Tinuvin 327 (68 pg) and Irganox 1010 (390 pg). The corresponding figures for negative ion APCI were 150 and 470 pg, respectively. Standard mixtures of additives could be separated in less than 15 min with a high degree of resolution. Experiments on additives extracted from polyethylene confirmed these observations, and it was possible not only to identify a number of the additives, but also, in the case of the antioxidant Irgafos 168, an oxidation product.

Utilising precursor ion and second-generation product ion scanning techniques in a four-sector mass spectrometer for the analysis of polymer additives

The analysis of organic polymer additives by means of mass spectrometry (MS) has been shown to be aided by the utilisation of precursor ion and second-generation product ion (MS3) scanning experiments. These techniques have been used to determine the fragmentation pathways of these materials under high-energy conditions. A four-sector mass spectrometer was employed to generate precursor ion and MS3 spectra which indicated that the routes of dissociation for the generation of many fragment ions, observed as intense peaks in the product ion spectra, were relatively complex. Fragmentation schemes are proposed to account for the data observed in the spectra.

The application of electrospray ionisation and tandem mass spectrometry to the analysis of polymer additives

Electrospray ionisation (ESI) has been employed in conjunction with tandem mass spectrometry (MS/MS) on a tandem quadrupole mass spectrometer for the analysis of five common organic polymer additiv...

Spatially Resolved in-Situ Analysis of Polymer Additives by Two-Step Laser Mass Spectrometry

Two-step laser mass spectrometry has been employed for the direct in-situ analysis of a variety of additives in different polymers. Because of the high sensitivity and optical selectivity of this approach, mass spectra can be obtained directly from the polymer material. The effects of CO2 laser irradiation (λ = 10.6 μm) on samples of poly(oxymethylene) (POM), poly(vinyl chloride) (PVC), polypropylene (PP), and poly(ethylene terephthalate) (PET) and the mechanism of additive desorption have been examined. Several hydroxyphenylbenzotriazole (Tinuvin) UV stabilizers as well as a phenolic antioxidant (Santo White) were successfully detected in typical industrial polymers. The detection limit for Santo White antioxidant in POM was found to be as low as 28 ppm. Finally, depth profiling by stepwise CO2 laser ablation was carried out for a POM injection bar containing 0.1 wt % antioxidant. These spatially resolved measurements established that the near surface concentration of antioxidant was 40% lower than in th...