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Study on Synthesis and Property of Water-soluble Polyelectrolyte

Author: WeiChaoQiao
Tutor: ZhaoHongChi
School: Hebei University
Course: Polymer Chemistry and Physics
Keywords: Polyallylamine Polyacrylic acid Polyacrylamide Polyvinylamine Hofmann downgrade Thermal stability Relative viscosity
CLC: O631.3
Type: Master's thesis
Year: 2009
Downloads: 79
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Abstract

Polyallylamine (PAH), polyacrylic acid (PAA), polyacrylamides (PAM) and polyethylene amine (PVAm) are all water-soluble polyelectrolyte, since the polymer molecular chains, respectively, with the amino, carboxyl, and amide groups reactive group, so in the polymer preparation and modification as well as the actual application, has a very important significance. The main contents are as follows: (1) as monomers, allyl amine hydrochloride (AH) and ammonium persulfate (APS) / sodium hydrogen sulfite as a redox initiator system, was synthesized by solution polymerization of PAH. The use of Fourier transform infrared spectroscopy the meter (FTIR), nuclear magnetic resonance spectrometer (NMR), thermal gravimetric analysis (TGA) were used to characterize the structure and performance of the PAH. Initiator type, amount of initiator, monomer concentration and reaction temperature on the relative viscosity of the polymerization reaction conversion rate and PAH. The results showed that: FTIR spectra 998cm-1 Chu C = C bond peak shape of the characteristic absorption of the polymer and monomer in the disappearance of the peak, and 1H-NMR spectra, the peak area and the chemical shift is significantly different, have proven AH polymer produced a of PAH; the of PAH thermal decomposition in two stages, and is completely decomposed at 700 ℃ has a higher thermal stability. Increases with the amount of initiator, monomer conversion increased the PAH relative viscosity reduced; monomer conversion increases with increasing monomer concentration and PAH were increased relative viscosity. (2) with acrylic acid (AA) as monomers, APS as initiator by solution polymerization of the neutralized product of PAA was prepared. The use of FTIR to characterize the structure of the PAA. Examine the reaction temperature, initiator dosage, monomer concentration of PAA solids content and viscosity average molecular weight. The intrinsic viscosity of PAA solution under different pH conditions. The results showed that: FTIR spectra at 1600-1650cm-1 C = C bond stretching vibration of the disappearance of the characteristic absorption peak, AA polymerized to form a neutralized product of PAA. As the monomer concentration increases the PAA solid content and viscosity-average molecular weight were increased; increase the solid content to increase the viscosity-average molecular weight decreases as the concentration of initiator; PAA solution intrinsic viscosity increases with the pH value of the solution first increases and then decreases in the pH ≈ 8 reached the maximum intrinsic viscosity. Under the experimental conditions for the initiator concentration 0.3% monomer concentration of 13%, pH value 6.0, the polymerization temperature is 70 ℃, reaction time 2h, of PAA solid content (13%) of its viscosity-average molecular weight of up to 100 million. (3) to the APS / sodium bisulfite redox initiator system, the aqueous solution polymerization of acrylamide (AM) were prepared polyacrylic amide (PAM), and using the PAM Hofmann downgrade reaction to give the polyvinyl amine (PVAm), and polyethylene amine hydrochloride (PVAm-HCl). FTIR and TGA were used to characterize the structure and properties of the polymer. Reaction temperature, monomer concentration, initiator dosage and pH of the system affect the average molecular weight of the monomer conversion rate and viscosity of the PAM. The results showed that: The FTIR spectra of the 998cm-1 C = C double bond of the characteristic absorption peak disappeared proved that the and AM polymerization generates PAM at 1670cm-1 carbonyl extinction of absorption proved synthesized PVAm. Decreased the PVAm thermal stability than PAM. Increase with the amount of initiator and monomer concentration to reduce the viscosity average molecular weight PAM reduced; monomer conversion increases with increasing temperature; increase the pH of the reaction system into the first increases and then decreases, pH value of the conversion rate of 7:00 reaches a maximum. Under the experimental conditions as the initiator concentration of 0.4%, the monomer concentration is 10%, reaction temperature 50V, the pH value of 7, the resulting PAM viscosity average molecular weight of 20 to 30 million.

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