Letter from the editor

Miller, Wallace T.

doi:10.1016/0037-198x(91)90025-j

Cited by 24 publications

(37 citation statements)

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“…[1][2][3][4][5][6][7][8][9][10] However, this field has made remarkable progress within the last five years or so because of advances in NIR spectrometers, detectors, optical light fibers, software, and spectral analysis methods. For example, the development of a variety of NIR instruments has made NIR spectroscopic measurements of polymers much easier and more precise than before.…”

Section: Introductionmentioning

confidence: 99%

Discrimination of various poly(propylene) copolymers and prediction of their ethylene content by near‐infrared and Raman spectroscopy in combination with chemometric methods

Furukawa

Watari

Siesler

et al. 2002

J of Applied Polymer Sci

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Near-infrared (NIR) diffuse reflectance (DR) spectra and Fourier-transform (FT) Raman spectra were measured for 12 kinds of block and random poly(propylene) (PP) copolymers with different ethylene content in pellets and powder states to propose calibration models that predict the ethylene content in PP and to deepen the understanding of the NIR and Raman spectra of PP. Band assignments were proposed based calculation of the second derivatives of the original spectra, analysis of loadings and regression coefficient plots of principal component analysis (PCA) and principal component regression (PCR) (predicting the ethylene content) models, and comparison of the NIR and Raman spectra of PP with those of linear low-density polyethylene (LLDPE) with short branches. PCR and partial least squares (PLS) regression were applied to the second derivatives of the NIR spectra and the NIR spectra after multiplicative scatter correction (MSC) to develop the calibration models. After MSC treatment, the original spectra yield slightly better results for the standard error of prediction (SEP) than the second derivatives. A plot of regression coefficients for the PCR model shows peaks due to the CH 2 groups pointing upwards and those arising from the CH 3 groups pointing downwards, clearly separating the bands due to CH 3 and CH 2 groups. For the Raman data, MSC and normalization were applied to the original spectra, and then PCR and PLS regression were carried out to build the models. The PLS regression for the normalized spectra yields the best results for the correlation coefficient and the SEP. Raman bands at 1438, 1296, and 1164 cm Ϫ1 play key roles in the prediction of the ethylene content in PP. The NIR chemometric evaluation of the data gave better results than those derived from the Raman spectra and chemometric analysis. Possible reasons for this observation are discussed.

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Section: Introductionmentioning

confidence: 99%

Discrimination of various poly(propylene) copolymers and prediction of their ethylene content by near‐infrared and Raman spectroscopy in combination with chemometric methods

Furukawa

Watari

Siesler

et al. 2002

J of Applied Polymer Sci

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“…20 However, it must be kept in mind that in the case of NIR spectrosthe melting point is still very rare. 5,7 Figure 8 shows a PLS regression calibration model for precopy we used only one factor, while two factors were employed for the Raman data. In this point, dicting the melting points of EVA copolymers from the NIR spectra in the 1100-2200 nm after the calibration by NIR may be better than that by Raman spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

Discrimination of ethylene/vinyl acetate copolymers with different composition and prediction of the content of vinyl acetate in the copolymers and their melting points by near-infrared spectroscopy and chemometrics

Shimoyama

Hayano²,

Matsukawa

et al. 1998

J. Polym. Sci. B Polym. Phys.

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“…In MID IR it is difficult to separate absorptions of free and hydrogen bonded hydroxyl groups because their absorption frequencies are close and absorptivity of bonded hydroxyl group is much higher than that of free. [14] The additional advantage of NIR spectroscopy is that these absorptions are more apart so it is less difficult to separate them. [14] As it is often the case in NIR spectroscopy, there are some uncertainties and an ambiguity as which absorption was caused by which functional group.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Upper Liquid-Liquid Transition in Unsaturated Polyesters by Near-Infrared Spectroscopy

Pucić¹,

Ranogajec

2001

Macromol. Chem. Phys.

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Near infrared (NIR) spectroscopy was used to investigate less familiar transition in amorphous polymer melts – upper liquid‐liquid transition, Tlρ. This transition is related to lower liquid‐liquid transition, Tll, both are caused by stepwise decrease of local order based on secondary valent interactions that remain above glass transition temperature and has been recently detected in a number of polymers. If hydrogen bonding is possible in a polymer, as it is the case in the unsaturated polyesters under consideration, it may enhance the short‐range order. The NIR spectroscopy was chosen as a method of investigation because it is sensitive to structural changes, distinction between hydrogen bonded and non‐bonded hydroxyl groups is easier and thicker samples can be used than in MID region what is very important when concentration of measured species is low. The spectra of poly(1,3‐propyleneglycol maleate) with styrene and poly(1,6‐hexanediol maleate) were recorded at selected temperatures. Significant intensity changes of hydroxyl and carbonyl absorptions at 1 430 nm and between 1 900 nm and 2 100 nm accompanied by wavelength shifts occurred at Tlρ transition temperature while carbon‐hydrogen absorptions showed only minor changes. That confirmed our assumption that transition was caused by changes in hydrogen bonding.

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Letter from the editor

Cited by 24 publications

References 0 publications

Discrimination of various poly(propylene) copolymers and prediction of their ethylene content by near‐infrared and Raman spectroscopy in combination with chemometric methods

Discrimination of various poly(propylene) copolymers and prediction of their ethylene content by near‐infrared and Raman spectroscopy in combination with chemometric methods

Discrimination of ethylene/vinyl acetate copolymers with different composition and prediction of the content of vinyl acetate in the copolymers and their melting points by near-infrared spectroscopy and chemometrics

Investigation of Upper Liquid-Liquid Transition in Unsaturated Polyesters by Near-Infrared Spectroscopy

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