Structural Investigations and Monitoring of Polymerisation by NIR Spectroscopy

Lachenal, G.

doi:10.1255/jnirs.150

Cited by 18 publications

(6 citation statements)

References 36 publications

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“…Given the use of organic chemicals, it was assumed that NIR spectroscopy 8 could be an adequate technique for monitoring the evolution of the curing process, because similar organic polymerisation reactions have been well documented in several other similar applications. [9][10][11][12] The adhesive chosen for this study was phenol formaldehyde resol resin. In order to get the best achievable NIR signal from the resin, it was decided not to use any abrasive material on the prepared samples.…”

Section: Resultsmentioning

confidence: 99%

“…be the relative deviation from 1, where n i is the number of predicted pixels and N i is the actual number of pixels expected in the time interval i. The deviation r i is calculated for each number of PLS components included in the model (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and for all time intervals, i. The optimal number of PLS components is indicated by that histogram where the shape of the relative pixel distribution is approximately uniformly distributed around 1.…”

Section: Pls Regression Of Curing Timementioning

confidence: 99%

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Hyperspectral near Infrared Image Analysis of a Phenol Formaldehyde Resin Curing Reaction

Lillhonga

Dahlbacka

Geladi

2012

Journal of Near Infrared Spectroscopy

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In the production of sandpaper, a phenol formaldehyde polymer bonds the abrasive material to a backing material made of paper or a textile. The reaction takes place at elevated temperatures (90-120°C) for a long time (at least eight hours) and is thereby a very energydemanding process step. A possible future application would be to use near infrared (NIR) hyperspectral imaging (1000-2498 nm) for (1) monitoring the curing reaction and determining an endpoint for it and (2) for identifying inhomogeneous regions with low adhesion in the final product. A feasibility study was carried out on four series of resin-coated backing materials without abrasives. These were imaged at half hour intervals for eight hours of curing using a NIR line scan imager. In order to analyse the influence of the backing material on the net NIR signal from resin-coated samples, spectra of the backing material (paper, textile) were also collected using a moving grating NIR spectrometer (1100-2498 nm). Results from principal components analysis of the hyperspectral images indicated that the reaction was stabilised after five to six hours, although it continued slowly for at least 16 more hours. A relevant question was when to finish the heating (curing) and still obtain a final product of high quality. Partial least squares regression models for predicting the curing time were thus also evaluated. A calibration made on image mean spectra was used for predicting the curing time of each pixel in the full set of hyperspectral images. The predicted images showed the curing progress, inhomogeneous regions where the reaction had progressed to a slower extent and other physical abnormalities (for example air bubbles). Pixel prediction distribution analysis of the images was found useful for determining the significant number of components of the proposed regression models.

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Section: Resultsmentioning

confidence: 99%

Section: Pls Regression Of Curing Timementioning

confidence: 99%

Hyperspectral near Infrared Image Analysis of a Phenol Formaldehyde Resin Curing Reaction

Lillhonga

Dahlbacka

Geladi

2012

Journal of Near Infrared Spectroscopy

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“…When combined with chemometric data analysis techniques, it offers a method of quantifying the relative concentrations of the constituent molecules. NIR is already widely accepted as a measurement technique within agriculture 1 , food industry 2 , pharmaceutical industry 3 and chemical industry 4 . Additionally, NIR spectroscopy has found applications in the medical sector [5][6][7] .…”

Section: Motivationmentioning

confidence: 99%

Development environments for an on-line FT-NIR spectrometer

et al. 2003

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This paper describes a software development environment suitable for advanced signal processing and feedback control algorithms for interferometry. The significance of software fast prototyping tools is illustrated where theoretically challenging algorithms are to be implemented. Specifically, a case is discussed where advanced control is deemed necessary for reliable operation of FT-NIR instruments in an on-line environment. In this particular case, an interactive test bed for new algorithmic approaches is developed, such that advanced theories and methods can be rapidly tested and validated with the real-world interferometer hardware. This development environment also allows new interfacing concepts with mechanical and optical hardware to be tested. Use of this environment is illustrated for the case of a novel Michelson NIR spectrometer operating in the range 800-2200 nm.

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“…A variety of methods— in situ , online and at‐line—are used for monitoring polymerization reactions, most of which focus on one aspect, such as monomer conversion. Widespread methods include infrared spectroscopy and Raman scattering 1–5. In most cases, empirical models must be developed to correlate reagent concentrations with spectral features.…”

Section: Introductionmentioning

confidence: 99%

Automatic continuous online monitoring of polymerization reactions (ACOMP)

Alb

Drenski

Reed

2007

Polymer International

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A brief overview of the principles and associated instrumentation used to monitor polymerization reactions by automatic continuous online monitoring of polymerization reactions (ACOMP) is presented. ACOMP can be used as an analytical method in R&D, as a tool for reaction optimization at the bench and pilot plant level and, eventually, for feedback control of full‐scale reactors. ACOMP measures in a model‐independent fashion the evolution of average molar mass and intrinsic viscosity, monomer conversion kinetics and, in the case of copolymers, also the average composition drift and distribution. A summary of areas of ACOMP application is given, which include free radical and controlled radical homo‐ and copolymerization, polyelectrolyte synthesis, heterogeneous phase reactions, including emulsion polymerization, adaptation to batch and continuous reactors, and modifications of polymers. Finally, a brief sketch of two novel complementary methods is given: automatic continuous mixing (ACM) and simultaneous multiple sample light scattering (SMSLS). Copyright © 2007 Society of Chemical Industry

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Structural Investigations and Monitoring of Polymerisation by NIR Spectroscopy

Cited by 18 publications

References 36 publications

Hyperspectral near Infrared Image Analysis of a Phenol Formaldehyde Resin Curing Reaction

Hyperspectral near Infrared Image Analysis of a Phenol Formaldehyde Resin Curing Reaction

Development environments for an on-line FT-NIR spectrometer

Automatic continuous online monitoring of polymerization reactions (ACOMP)

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