Properties Of Polyvinyl Acetate Research Articles

Evaluation the influence of cesium 137 source on some physical properties and molecular weight of poly vinyl acetate at room temperature

Abstract Radiation influence on some rheological properties of polyvinyl acetate (PVAC) in chloroform solution (CHCl3) was studied. Capsule shape samples of PVAC were irradiated using cesium 137; γ = 661.66 kev and β = 513.97 kev (as a radioactive element) for 10, 20, 30 and 40 min. PVAC/chloroform diluted solutions were prepared at room temperature. The results showed that there is a direct relationship between the amount of radiation and viscosity values (shear, relative, specific and reduced). In particular, a pronounced reduction in the viscosity values starts to be observed for a radiation period of 10 min. After that, the increase in viscosities continues with radiation time up to 40 min. Once PVAC was subjected to the gamma radiation, the crosslinking was endorsed with radiation time increasing and reached the highest limit at 40 min radiation as shown by the values of the average viscosity molecular weight. The molecular weight of polyvinyl acetate documented highest value which is 37077.07 at 40 minutes’ period. The findings of this study confirmed that radiation dose has an effective influence on polymer chemical structure, therefore, its properties are a function of radiation dose.

Effect of Shell Growth on the Morphology of Polyvinyl Acetate/Polystyrene Inverted Core-Shell Latex Fabricated by Acrylonitrile Grafting.

A novel strategy for fabricating inverted core-shell structured latex particles was implemented to investigate the morphology and properties of polyvinyl acetate (PVAc)-based latex. In this study, active grafting points were synthesized onto the surface of PVAc latex cores via grafting acrylonitrile (AN) to obtain a controllable coating growth of the shell monomer, styrene (St). The effect of shell growth on the morphological evolvement was explored by tuning the time of shell monomer polymerization. Unique particle morphologies, transferring from “hawthorn” type, over “peeled pomegranate” type, to final “strawberry-like” type, were observed and verified by electron microscopy. The morphological structure of latex particles exerted a significant effect on the particle size, phase structure, and mechanical properties of the obtained emulsions. The water-resistance of PVAc-based latex was also evaluated by the water absorption of latex films. More importantly, the experimental results provided a reasonable support for the controlled growth of St monomer, that is, the self-nucleation of dispersive St monomer can be transformed to in-situ coating growth on the PVAc core surface depending on the AN-active grafting points. This fabricating approach provides a reference for dynamical design and control of the latex particle morphology.

Development of exfoliated nanocomposite prepared from vinyl acetate and montmorillonite

To improve the chemical, physical, mechanical and thermal properties of polyvinyl acetate (PVAc), montmorillonite (MMT) was added and polymerised with vinyl acetate to prepare an exfoliated nanocomposite of PVAc–MMT. Linear macromolecular chains of PVAc were formed between MMT layers and they exfoliated MMT into layers or sheets of nanoparticles. Both PVAc and PVAc–MMT were pseudoplastic non-Newtonian fluids, and possessed the normal stress effect (or Weissenberg effect) that was the pole climbing phenomenon. PVAc–MMT’s static tensile properties were better, and PVAc’s glass transition temperature was lowered by MMT. Both PVAc and PVAc–MMT possessed cold crystallisation, and their pyrolysis were similar, because MMT had no obvious effect on pyrolysis temperatures but mainly delayed thermal degradation processes.

Preparation and characterization of PVAc–NMA–MMT

To further improve and enhance the performances and properties of polyvinyl acetate (PVAc), montmorillonite (MMT) and N-hydroxymethyl acrylamide (NMA) were introduced together to polymerize with vinyl acetate (VAc). The exfoliated nanocomposite of PVAc–NMA–MMT was prepared through different synthesis precursors. Linear macromolecular chains of PVAc–NMA were formed in MMT layers. MMT was exfoliated into layers or sheets of nanoparticles and dispersed randomly in PVAc–NMA matrix. Both PVAc–NMA and MMT had small particles with a diameter of 50–100 nm. They dispersed together randomly. PVAc–NMA–MMT was a pseudo-plastic non-Newtonian fluid and possessed the normal stress effect (or Weissenberg effect from the pole-climbing phenomenon. With the change of different synthesis precursors and the increase of NMA content and MMT content in the synthesis system, the molecular weight of PVAc–NMA–MMT increased. PVAc–NMA–MMT had good dispersion, excellent storage stability and high static tensile at 6.47–6.85 MPa.

Preparation and characterization of exfoliated nano-composite of polyvinyl acetate and montmorillonite

To improve the chemical, physical, and mechanical properties of polyvinyl acetate (PVAc), montmorillonite (MMT) was added in the synthesis of PVAc in conventional lab conditions. The final product was studied mainly by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), static tensile, and the rheology was also investigated by the power-law function equation and the Cross-Williamson model viscous equation. The exfoliated nano-composite of PVAc-MMT was obtained. Linear macromolecular chains of PVAc were formed in MMT layers. MMT was exfoliated into layers or sheets of nano-particles, and randomly dispersed in PVAc matrix. The particle diameter of MMT ranged from 50 to 100 nm, while PVAc’s ranged from 250 to 500 nm, the smaller MMT particles were adsorbed around the larger PVAc particles to form the “Strawberry” structure. In addition, PVAc and PVAc-MMT were pseudo-plastic Non-Newtonian fluids, they all possessed the normal stress effect (or Weissenberg effect), that was the pole-climbing phenomenon. Key words: Polyvinyl acetate (PVAc), montmorillonite (MMT), chemical structure, dispersion, particles, rheology, static tensile.

Investigation of electrical and optical properties of polyvinyl acetate doped with some polymers

Polyglycerol (PG) and polytriethanolamine(PTEA) have been prepared. The electrical resistivity (ρ) and the optical absorption of polyvinylacetate (PVAc) doped with polyglycerol (PG), polyaniline (PA), and polytriethanolamine (PTEA) have been studied. It was found that the conduction was mainly ionic in the temperature range from 20 to 120°C. The resistivity decreased with the increase of the dopant cocentration. The optical absorption spectra were determined in the wavelength range 400–2500 nm. The analysis of the absorption spectra showed that the intensity of the bands is remarkably affected by the dopant concentration. The optical energy gap of pure PVAc and the samples containing different dopants were estimated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1558–1563, 2002

Interaction between Wood and Polymers. Pt. IV. Dielectric Properties of Polyvinyl Acetate Filled with Wood Components

Interaction between Wood and Polymers. Pt. IV. Dielectric Properties of Polyvinyl Acetate Filled with Wood Components

Polyvinyl Acetate and Portland Cement Mortars

Research on properties of polyvinyl acetate and on its use in concrete floor surfacing materials; applications made several years ago and their present conditions; advantages are excellent bonding, high tensile strength, self curing in presence of air and light, and easy mixing; disadvantages are: cannot be subjected to continuous exposure to water and it shows cracks when applied in thicknesses over 1/2 in.

The Electrical Properties of Polyvinyl Acetate

The Electrical Properties of Polyvinyl Acetate