Application of a Multiple Linear Regression Model to Fixed Bands IR Detector Data in GPC‐IR Analysis of Polyolefins

Ortín, A.; Monrabal, Benjamín; Montesinos, Javier Vallejo; Hierro, P.

doi:10.1002/masy.200950807

Cited by 14 publications

(16 citation statements)

References 3 publications

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“…In both cases, there is a very good linear relationship between the SCB content and the intensity ratios with excellent fitting factors, R 2 > 0.999, even though some authors have suggested that a quadratic function results in better results in their cases. [ 14 ]…”

Section: Resultsmentioning

confidence: 99%

“…[ 9–12 ] In this paper, we report a new polyethylene SCB distribution determination technique developed in our group using an IR5‐detected GPC (GPC‐IR5) system, wherein IR5 is a fixed‐band infrared spectrometer that is equipped with a thermoelectric‐cooled mercury‐cadmium‐telluride (MCT) detector and optical filters set at five frequency regions for C─H stretching bands (thus IR5). [ 13,14 ] We will first describe SCB calculation algorithms and the detector calibration method, which will be followed by error analysis and discussion of practical aspects in application of this technique. A comparison of SCB results determined via this technique to those via other techniques will also be given.…”

Section: Introductionmentioning

confidence: 99%

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A Short‐Chain Branching Distribution Determination Technique for Polyethylene Using IR5‐Detected GPC

2020

Macromolecular Symposia

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In this paper, a robust short-chain branching (SCB) determination technique recently developed using IR5-detected GPC (GPC-IR5) for polyethylene resins is reported, wherein the IR5 detector is an infrared detector equipped with five filters set at different frequency ranges and a mercury-cadmium-telluride detector with thermoelectric cooling capability. Both intensity ratios of methyl/methylene and methyl/all C─H groups have very good linear relationship with the SCB content. Based on these relationships, an excel spreadsheet method is developed to deduce the SCB distribution across the molecular weight distribution using in-house developed algorithms. The uncertainty of SCB determination using the GPC-IR5 technique is found to be chromatographic signal-to-noise ratio dependent and can be explicitly expressed and calculated slice by slice. The SCB uncertainty is also found to be a function of experimental conditions and environment, which can affect not only the signals but also the noise levels at different IR bands. At a given polymer concentration, the higher the SCB content, the smaller the relative error bars. The SCB detection limit of this GPC-IR5 technique is found to be at ≈0.5-1.0 SCB per 1000 TC for all samples tested. Some practical aspects for application of this technique are also discussed in this paper.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Short‐Chain Branching Distribution Determination Technique for Polyethylene Using IR5‐Detected GPC

2020

Macromolecular Symposia

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“…By combining GPC‐IR with a spectroscopic technique like infrared spectroscopy, the comonomer composition along the MWD can be obtained. This is normally done by GPC‐IR . The CCD of polyethylene can be measured either by fractionation techniques based on chain crystallizability, such as crystallization analysis fractionation, temperature rising elution fractionation (TREF), and crystallization elution fractionation, or by fractionation techniques based on adsorption of the polymer on a stationary phase, including solvent gradient interaction chromatography , and temperature gradient interaction chromatography .…”

Section: Polymer Reaction Engineeringmentioning

confidence: 99%

A Methodology for Estimating Kinetic Parameters and Reactivity Ratios of Multi‐site Type Catalysts Using Polymerization, Fractionation, and Spectroscopic Techniques

Touloupidis

Albrecht

Soares

2018

Macro Reaction Engineering

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This work describes a polymer reaction engineering framework for understanding how catalyst kinetic parameters affect the microstructure of polyolefins made with single‐ or multi‐site catalysts. Moreover, a methodology for deconvolution and kinetic parameters estimation is presented to estimate the reactivity ratios of multi‐site catalysts based on the combination of polymerization, fractionation, and spectroscopic techniques, namely, gel permeation chromatography‐IR and carbon‐13 nuclear magnetic resonance spectroscopy. The methodology capabilities are then demonstrated and validated using a case study simulated via a Monte Carlo model including random noise in order to better represent experimental result uncertainties. The methodology can reverse engineer experimental results and estimate all relevant reaction performance parameters.

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“…Three types of coupling high temperature (HT) GPC to IR detection approaches for PO analysis have been described in literature: (i) off‐line coupling to FTIR, in which the eluent from the GPC is deposited on a rotating germanium disk, and the solid obtained after solvent evaporation is subsequently analyzed off‐line by FTIR for branching content, (ii) on‐line coupling to FTIR where branching levels in eluent are measured in a heated flow‐through cell placed inside an FTIR spectrometer, and (iii) on‐line coupling to a filter‐based IR detector . The off‐line FTIR method is most powerful for qualitative studies of complex mixtures, given that the whole sample spectrum is available for analysis once the solvent is removed, but it has limitations for quantitative application, mainly due to the difficulties with solvent evaporation and consistent deposition of the solute on the rotating disk.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Chemical Composition along the Molar Mass Distribution in Polyolefin Copolymers by GPC Using a Modern Filter‐Based IR Detector

Ortín¹,

Montesinos²,

López³

et al. 2013

Macromolecular Symposia

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Summary Gel permeation chromatography (GPC), also known as size exclusion chromatography (SEC), is the technique routinely used at high temperature to analyze the molar mass distribution in polyolefins. The distribution of comonomer along the molar mass distribution in a copolymer is a key microstructural feature that determines the macroscopic properties of the material, and thus, its range of possible applications and performance. The direct coupling of a modern filter‐based infrared (IR) detector to a high temperature GPC instrument, by means of a heated flow‐through cell, is here described. The analyses are carried out by recording the continuous IR absorbance chromatograms at selected bands, which show different sensitivities to the different monomer units. A slice‐by‐slice ratio of the IR bands is further calculated to determine the average chemical composition of each molar mass fraction, after GPC separation. The high sensitivity of this IR detection method allows the injection of low concentrations of sample and the use of standard GPC analysis conditions, so that chromatographic quality is not compromised even in cases where very high molar mass fractions are present. The analysis of comonomer variations along the molar mass distribution in polyolefin copolymers is discussed. Selected applications of the method to polyethylene and poly(propylene) copolymers are presented.

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Application of a Multiple Linear Regression Model to Fixed Bands IR Detector Data in GPC‐IR Analysis of Polyolefins

Cited by 14 publications

References 3 publications

A Short‐Chain Branching Distribution Determination Technique for Polyethylene Using IR5‐Detected GPC

A Short‐Chain Branching Distribution Determination Technique for Polyethylene Using IR5‐Detected GPC

A Methodology for Estimating Kinetic Parameters and Reactivity Ratios of Multi‐site Type Catalysts Using Polymerization, Fractionation, and Spectroscopic Techniques

Characterization of Chemical Composition along the Molar Mass Distribution in Polyolefin Copolymers by GPC Using a Modern Filter‐Based IR Detector

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