Abstract
In this report, high molecular weight polyvinyl alcohol (PVA) was prepared by emulsifier-free emulsion polymerization, using the redox initiator of potassium persulfate (KPS) / N,N-dimethyl ethanolamine (DMEA). The structure and property of PVA were studied by using ubbelohde viscometer, fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (1H-NMR), X-ray Diffraction (XRD), differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA). The results showed that the viscosity-average degree of polymerization (DP) of PVA 7506, which was much higher than that of PVA commonly used in industrial production. The syndiotacticity and crystallinity of PVA was 54.2 % and 35.6 %, respectively.
Highlights
High-performance polyvinyl alcohol (PVA) fibers show additional advantages, such as good acid resistance, high Young’s modulus, strong adhesion and good dispersion [1, 2]
The branching degree (BD) for acetyl group of Polyvinyl acetate (PVAc) was calculated by using eq (2) [7]
Where DP1 was the Pn of PVAc and DP2 was the Pn of PVA saponified of PVAc
Summary
High-performance polyvinyl alcohol (PVA) fibers show additional advantages, such as good acid resistance, high Young’s modulus, strong adhesion and good dispersion [1, 2]. The preparation method of industrial production of PVA is free radical polymerization with vinyl acetate (VAc) as raw material and azodiisobutyronitrile or benzoyl peroxide as initiator. This method is difficult to get high molecular weight PVA because of chain transfer. In order to prepare high molecular weight PVA, many researchers used suspension polymerization, solution polymerization, emulsion polymerization or radiation polymerization to control chain transfer [5]. These methods have some disadvantages, such as complex process conditions, impurity residues and so on. The structure and property of PVA were investigated by using ubbelohde viscometer, fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (1H-NMR), X-ray Diffraction (XRD), differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA)
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