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Abstract The standard application of a chromatographic column is to use some stationary phases to separate and quantitate the composition of organic mixture. In the IGC method, the compositions of the stationary phase and the solutes are known and thus, the interactions between them are determined. Predominantly IGC has been used to determine the physico-chemical properties (weight fraction activity coefficient, Flory- Huggins interaction parameter, change in heat of adsorption (ΔH), change in free energy (ΔG), and change in entropy (ΔS)) of stationary phases at infinite dilution. In the case of polymer–solute systems this can be done using a column packed with inert particles that have been coated with the polymer. In our thesis, we aimed to establish a numerical study for interaction of poly ethylene glycol (8000, 12000) [PEG8, PEG12], poly ethylene glycol adipate [PEGA], and poly ethylene glycol succcinate [PEGS] with different groups of solutes. Moreover, we also prepared a new polymer poly (styreneco- p-chloromethylstyrene) [PS] with different properties and apply the former study to invistigate the interaction of this new polymer with the same group of solutes. This study included the calculation of thermodynamic parameters, weight fraction activity coefficient, Flory- Huggins interaction parameter. from our finding, Specific retention volume Vg decreased as temperature increased, as the interaction between the solutes and stationary phase generally decreased by elevating the temperature. Vg increased also by increasing the polarity of solute that interacts with polar polymer. This may be explained in view of the nature of the polymer. Thus the solubility of polar solutes is increased. This Leeds to longer retention time and, in turn, SUMMARY AND CONCLUSION 95 higher calculated Vg for these solutes. The oppsite is true for non polar solutes. Thus solubilities decreased leading to shorter retention time and lower calculated Vg for non polar solutes. It is well known, the smaller the ΔH, the greater is the interaction between the solute and polymer. ΔH gives us an impression about the interactions between the polymer and solute, but its values for some solutes are near (e.g. ΔH of carbon tetra chloride and n-hexane are -25.310 and -25.347, respectively). So, we used Flory-Huggins interaction parameter for more clarifying of the interactions between solute and polymer and to show which of solutes are more miscible with polymer (as found in χ12 of carbon tetra chloride and npentane that 0.051 and 2.214, respectively). Flory-Huggins interaction parameter (χ12) reflects the interaction between low-molecular-weight solvents and high-molecular-weight polymers. Miscibility occurs when χ12 is lower than a critical value, or lower than zero. Values lower than 0.5 indicate favourable interactions. The weight fraction activity coefficient method, to gives us more information about the interaction between solute and polymer. It devides the solute interaction with polymer to a three groups (firstly, Ω∞ 1<5 indicating that the solute has a good compatibility with the polymer, the second is 5< Ω∞ 1<10 indicating that the solute has a moderate compatibility with the polymer and the third is Ω∞ 1>10 that indicate the poor compatibility between the solute and polymer) For PEG 12000 and PEG 8000, the physicochemical interaction parameters showed that the two polymers has a good compatibility with polar solutes as chloroform and carbon tetra chloride and a moderate SUMMARY AND CONCLUSION 96 compatibility with the polarizable solutes such as BTEX, but have apoor compatibility with Alkanes, the physicochemical interaction parameters showed also that PEG 12000 is more polar than PEG 8000 and shows strong interactions with solutes higher than of PEG 8000. This phenomenon is due the higher molecular weight of PEG 12000 than of PEG 8000, which thus increase its polarity. PEG esters (Adipate, Succinate) have the same performance of PEG 8000 and PEG 12000 except for Cyclo compounds, where these solutes showed moderate polymer-solute interaction that help us to separate aromatic, cyclo-alkanes and parafins (e.g. Ω1 ∞ values of Toluene = 2.446, Methyl cyclo hexane = 5.266, N.Heptane = 13.128) from a mixture of them on gas chromatography, this behaviour due to its branched polymer. Also, from the physicochemical interaction parameters we observed that PEGS shows strong interactions with solutes higher than of PEGA. This phenomenon is due the higher polarity of PEGS than PEGA We developed a new stationary phase by preparing poly (styrene-cop- chloromethylstyrene) and confirmed its structure using NMR which displayed seven peaks, the peaks at 0.8 ppm and 1.2 ppm that assigned to the terminal groups form each side as depicted on the structure. The peaks at 1.5 ppm and 2 ppm can be attributed to CH2 groups in styrene moiety and in pchloromethylstyrene respectively. Two peaks attributed to CH of styrene and p-chloromethylstyrene can be seen at 2.5 ppm and 3.3 ppm. The most important peak that elucidates the formation of the copolymer comes from the methylene group in p-chloromethylstyrene since it appears at 4.2 ppm. IR that used for functional group determination, strong peak is displayed at 3026 cm-1 which is characteristic for asymmetric stretch of C=C-H on aromatic ring. The peak at 2923 cm-1 is attributed to the (CH) SUMMARY AND CONCLUSION 97 group that link monomer units to give polymer chains. A very important set of peaks appear from 1744 to 1943 cm-1. These peaks are due to the substituted aromatic rings in the polymer. Thermal Gravimetric Analysis showed that the polymer has a good thermal stability where, it decomposed at T= 400oK. Also, GPC informed us that average molecular weight of polymer is (58,550 g/mol). The physicochemical interaction parameters of PS showed that, the highest values of the Flory–Huggins interaction parameter for nonpolar test solutes, n-alkanes. These high values reflect the poor compatibility/miscibility of n-alkanes with the examined polymer. That was confirmed by the values of weight fraction activity coefficient. For polar test solutes, χ∞ 12 values are lower than those for nonpolar solutes reflecting the good miscibillity of them on PS, which appeared in Cyclohexane and Methyl cyclohexane because of its cyclic formula. Also, polarizable aromatic compounds, oxocompounds (Ketones, Esters, and Ethers) and pyridine have a good compatibility with polymer Generaly; the poly (styrene-co-p-chloromethylstyrene) can be successfully used in the separation of different polar families as Aromatic hydrocarbons, Cyclo-compounds, Esters, Ethers and Ketones by gas chromatography. |