CS242188B1 - A method for separating components from a mixture of styrene acrylate copolymers and polymethyl methacrylate - Google Patents

Abstract

The subject of the invention is a process for the separation of components from a mixture of styrene acrylate copolymers and polymethyl methacrylate with a minimum content of 50 wt. % styrene in the copolymer, which allows * 1H NMR analysis of the composition of the copolymer and the total mixture. The separation is carried out by adding an equal amount of C6 to C11 n-alkanes to the mixture of copolymer and homopolymer after its dissolution in toluene, thereby selectively precipitating polymethyl methacrylate and the styrene acrylate copolymer remains dissolved in the solution.

Description

242188

The present invention relates to a process for separating components with a mixture of styrene acrylate copolymers and polymethyl methacrylate with a minimum content of 50% by weight. styrene in copolymer for analytical purposes. In the case of multicomponent block-type polymers or mixtures thereof, conventional methods of analysis, such as infrared and 1 H-NMR spectroscopy, are not able to determine whether the mixture is a mixture of homopolymers or copolymers, or a copolymer and a homopolymer. In addition, because of the overlapping of the characteristic signals in the si NMR spectra of the polymers, it is often not possible to determine the quantitative representation of the individual components.

These problems can be solved by a combination of separation procedures and subsequent spectral analysis of compounds isolated.

In general, the separation techniques utilize the solubility dependency of the polymers of the structure, composition, or molar mass. Dissolution of polymers is not determined by general rules, but by scores of empirical findings. Usually a selective solvent for one polymer is used, which simultaneously coagulates the species of the mixture component. R. Urwin, J. Stearne: Macromol. Chem. 78, 194, (1964), H, Okuuma, T. Kotaka, H. Inagaki: Polymer 10, 501 (1969)] extraction of the polymerization reaction mixture of styrene and methyl methacrylate with acetonitrile, which is a selective solvent for polymethyl methacrylate and a prepolystyrene precipitator.

According to the present invention, the components are separated from a mixture of styrene acrylate copolymers and polymethylametacrylate with a minimum content of 50% by weight. styrene in the copolymer, which allows the 1 H NMR analysis of the copolymer and the total mixture to be added by adding an equal amount of C 6 to C 8 n-alkane to the copolymer / homopolymer mixture after dissolution in toluene, thereby selectively precipitating polymethacrylate and the styrene acrylate copolymer remains dissolved in the solution.

For the 1 H NMR analysis of the composition of the polymethyl methacrylate composition, since its methoxy group signal overlaps with the methyleneoxy signal of the styrene acrylate copolymer and makes it impossible to determine the composition. After separation of the polymethylmethacrylate from the mixture, the copolymer can be analyzed and its composition determined. From the results of this analysis and analysis of the aqueous mixture by the HD NMR method, the composition can be calculated.

The procedure for separating the components of the mixture and the results of determining the composition of the mixture by 1 HNMR analysis are given in the following examples. Example 1 not 50 wt. The styrene-containing styrene-butyl acrylate copolymer and the polymeric methacrylate are dissolved in 5 ml of toluene at 70 ° C with stirring. After cooling the mixture to room temperature, 5 ml of n-hexane was added to selectively precipitate the polymethyl methacrylate. The mixture is centrifuged and the solid is decanted with 5 ml of n-hexane and centrifuged again. The precipitated polymethyl methacrylate is dried and analyzed by 1 H NMR spectroscopy. Analysis results: styrene 0% by weight butyl acrylate 0% by weight methyl methacrylate 100% by weight.

The centrifuged solutions are combined, the solvent is evaporated off and the dry matter is analyzed by NMR spectroscopy. Analysis results: styrene 76.6% by weight butyl acrylate 23.4% by weight. From the composition data of the copolymer and from the ratio of the signal areas in the Ή NMR spectrum of the flood), the total composition of the blend-copolymer-copolymer: 23 wt. % styrene 7 wt. butyl acrylate 70 wt. methyl methacrylate. Example 2 2.2 to 0.3 g of a mixture II consisting of at least 50 wt. styrene-containing styrene-2-ethylhexyl acrylate copolymer and polymethylmethacrylate are dissolved in 5 ml of toluene at 70 ° C with stirring. Cooling the mixture to room temperature adds 5 mL of n-octane to selectively precipitate polymethyl methacrylate. The next procedure is the same as <in Example 1.

Analysis of the precipitated polymethyl methacrylate by 1 H NMR spectroscopy: styrene 0% by weight 2-ethylhexyl acrylate 0% by weight methyl methacrylate 100% by weight.

Analysis of the isolated copolymer: styrene 61.7 wt. 2-ethylhexyl acrylate 38.3 wt.

Total composition of the mixture: styrene 30.8 wt. 2-ethylhexyl acrylate 19.2 wt. % methyl methacrylate 50 wt. 0.2 to 0.3 g of a mixture I composed of

Claims (1)

242183 SUBSTANCE The method of separating components from the styrene-acrylate copolymer and polymethylmethacrylate with a minimum content of 50% by weight. styrene in a copolymer allowing 1 H NMR analysis of the copolymer composition of the total mixture, characterized in that an equal amount of Co to C 8 n -alkane is added to the mixture of copolymer and homopolymer after dissolution in toluene, thereby selectively precipitating polymethyl methacrylate and styrene -acrylate copolymer remains dissolved in the solution. REPAIR TO PVAO ě. 242188 Int. Cl.4 C 08 L 33/12, G 01 N 24/00 The correct name of the second author of the invention is: ... STŘEŠINKOVÁ DAGMAR ing.