An imaging spectrometer with a 256 element InGaAs diode array was combined with a high throughput optical arrangement for recording high quality NIR spectra (824 nm to 1700 nm) of plastics from a distance of 25 cm within 6.3 milliseconds. The considered spectral region was assessed to be suitable for plastic identification.

Hyphenated rapid real-time dynamic mechanical analysis (RT-DMA) and time-resolved nearinfrared spectroscopy (RT-NIRS) have allowed simultaneous monitoring of acrylate photopolymerizations with regard to both their chemical conversion and mechanical properties. Up to 374 NIR spectra and up to 50 DMA data points can be accumulated within a second. We observe that modulus buildup does not linearly follow chemical conversion of acrylate bonds. The gel point is detected after passing a certain critical acrylate conversion. Beyond the gel point (determined when the phase angle drops below 45°) network formation proceeds exponentially with acrylate conversion. Experimental data reveal a critical dependence of the mechanical property development during the later stage of acrylate conversion. The experimental results across the modulus-conversion plot reveal the importance of final acrylate bond conversion as opposed to the early part of the conversion vs time (maximum rate of polymerization R p) when considering the rate of development of mechanical properties (cure speed).

The reactivity ratios of various UV-copolymerizing systems were determined employing RT-FTIR spectroscopy, combined with advanced and alternative multivariate-statistical data analysis techniques. For complex mixtures peak identification as well as peak deconvolution has been increased significantly by employment of 2-dimensional correlation spectroscopy, based on the Hilbert transform. As an advantage, kinetic reaction profiles of homo-and copolymerization reactions have been extracted and have been separated without any additional measurement. The following reactivity ratios were obtained: fumarate/vinyl ether r 1 ) 0, r2 ) 0; maleate/vinyl ether r1 ) 0, r2 ) 0; fumarate/allyl ether r1 ) 0, r2 ) 0; maleate/allyl ether r1 ) 0, r2 ) 0; fumarate/methacrylate r1 ) 0, r2 ) 1.3; fumarate/acrylate r1 ) 0, r2 > 50; methacrylate/vinyl ether r1 ) 16, r2 ) 0; methacrylate/allyl ether r1 > 100, r2 ) 0; methacrylate/acrylate r1 ) 1.6, r2 ) 0.15; methacrylate/N-vinylcaprolactam r1 ) 7.3, r2 ) 0.01; and acrylate/ N-vinylcaprolactam r1 ) 1.3, r2 ) 0.01. Kinetically, the fumarate-vinyl ether copolymerization can be regarded as the homopolymerization of a CT complex while the fumarate allyl ether copolymerization should be regarded as a perfect alternating copolymerization. The HEA-NVC copolymerization has to be regarded as a terpolymerization between HEA, NVC, and the HEA-NVC charge-transfer complex.

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An optical setup consisting of a high-throughput near-IR (NIR) spectrograph with an InGaAs-array detector and specially designed collection optics is used to record spectra from post consumer packages located on an industrial conveyor belt. NIR spectra of packages of different polymers (PE, PET, PP, PS, and PVC) and of a cardboard/plastic compound are recorded between 900 and 1700 nm with 6.3-ms integration time. The visual distinction between the spectra is demonstrated by aid of principal component analysis (PCA) plots. The spectra are further classified by a FuzzyARTMAP neural network. The method is assessed to be suitable for on-line identification under industrial conditions.