Absorption spectra polycarbonates

Figure 1. UV absorption spectrum of Polycarbonate, Polybutylene terephtalate...

The other alternative for exciton quenching due to doping is Forster-type energy transfer towards a chromophore with bathochromatically shifted absorption spectrum so that the spectral overlap between the donor and acceptor absorption is larger. An example is fluorescence quenching in a film of poly(phenyl-pheny-lene-vinylene) (PPPV) blended with polycarbonate (PC) at a PPPV PC ratio of 20 80 per weight and doped by the 4-dicyanomethylenc-2-methyl-6-p-dimcthyla-... 

Fig. 22. Absorption spectrum of polycarbonate (concentration 0.51 g l-1 in chloroform, 0.5 cm cell) 1, unirradiated 2, irradiated 5 h 3, irradiated 30 h 4, irradiated 120 h 5, spectrum of the yellow product isolated after complete hydrolysis of irradiated polycarbonate [reproduced with permission from Ref. 108].

An IR absorption spectrum of the polycarbonate polymer used In these determinations Is shown In Fig. 5. A comparison can be made... 

Fig. 1S.12. Activation spectrum of a 700 pm filtered xenon lamp. Superimposed are the film of unstabilized bisphenol-A polycarbonate, spectral irradiance of the irradiation source based on the increase in absorbance at 310 nm and the UV-absorption spectrum of the after accelerated aging with a borosilicate-glass polymer redrawn from data in Ref. [35]).

Fig. 15.14. Quantum yield for chain scission (-o-), efficiency of photo-Fries rearrangement (- -), and absorption spectrum (—A-) of bisphenol-A polycarbonate [34],...

Figure 17.6. (a) Emission spectra of a 3-mm-thick polycarbonate sheet made by the TIRES technique and by uniformly heating the sample. A blackbody emission spectrum is shown below for comparison, (fo) Emittance spectra of polycarbonate derived from the upper panel spectra compared to an absorption spectrum of polycarbonate recorded by photoacoustic spectrometry. (Reproduced from [7], by permission of the American Chemical Society copyright 1990.)... 

Figure 8.7 (a) Absorption spectrum calculated by using the n(v) and k(y) spectra in Figure 8.6 and (b) absorbance spectrum of a cast film of polycarbonate (PC) deposited onto a germanium substrate. 

Figure 26 Emission spectra (PL, EL) in PC at room temperature of 40 wt% TPD donor solution with a 40 wt% of PBD acceptor added. The photoluminescence (PL) spectrum excited at 360 nm, the electroluminescence (EL) spectra (I, II) originate from the recombination radiation in a 60 nm thick film, taken at two different voltages. Absorption (Abs) and PL spectra (excitation at 360 nm) of (75wt% TPD 25wt% PC) and (75wt% PBD 25wt% PC) spin-cast films are given for comparison. Molecular structures of the compounds used are given in the upper part of the figure TPD [N,Nf-diphenyl-A v/V/-bis(3-methylphenyl)-l,l -biphenyl-4,4 diamine PBD [2-(4-biphenyl)-5-(4- er .-butylphenyl)l,3,4-oxadiazole PC[bisphe-nol-A-polycarbonate]. Adapted from Ref. 112.

Examination of curves of sample optical density demonstrated that when the NS concentration was 1% from polycarbonate mass, the visible-light spectrum was absorbed by about 4.2 per cent more when compared with the reference sample. When the nanocomposite concentration was 0.1 percent, the absorption decreased by 0.7 per cent. When the concentration was 0.01 per cent, the absorption decreased in the region 540-600 nm by 2.3 per cent, and in the region 640-960 nm - by 0.5 per cent. 

Hostavin B-CAP from Clariant is a new UV stabiliser for polycarbonate and PET, based on a benzylidene-bis-malonate type UV absorber. It has good absorption in the high-energy range of the UV spectrum, and reduces yellowing. It does not interact with residual metal ions, and therefore does not affect either the colour or transparency of the polymer. Clariant recommends combining this UV absorber with other stabilisers for the long-term protection of polycarbonate and PET. 

The infrared spectrum of the residue of polycarbonates subjected to pyrolysis at 500°C contains no bands characteristic of methyl groups the intensity of the absorption bands of the ester groups -C = O and -C-O-C-is significantly reduced, and the absorption bands corresponding to the benzene ring are intensified. 

The market introduction of 2-hydroxyphenyl triazine is considered a true innovation. This class of highly effective UV absorbers exhibits exceptionally high intrinsic absorption with high inherent light stability in the shortwave range of the UV spectrum. The product has proven itself in polycarbonate, thermoplastic polyesters, and polyamides. Fig. 3.7 [529]. 

On the other hand, the maximum absorption index of bands in the spectra of most organic molecules (including polymers) rarely exceeds 0.3 above 1000cm In these cases, ( 2 — 1) > and the reflection spectrum looks more like the n spectrum (see Figure Ab) than the k spectrum. The specular reflection spectrum of a polycarbonate polymer is shown in Figure 13.2. Few experienced spectroscopists would immediately recognize this spectrum as a polycarbonate. To convert this spectrum to the optical constant (n and k) spectra, the Kramers-Kronig... 

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