No abstract

Polyvinyl acetate (PVAc) is considered to be a type of environmental friendly adhesive, and montmorillonite (MMT) is a cheap and accessible natural nanomineral. MMT was first organically activated by dioctadecyl dimethyl ammonium bromide (DOAB). The intercalated nanocomposite of MMT-DOAB was added during the synthesis of PVAc in conventional laboratory conditions. The PVAc-MMT-DOAB was mainly studied by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, static tension, and the rheology was also investigated by the power-law function equation and the Cross—Williamson model viscous equation. The exfoliated nanocomposite of PVAc-MMT-DOAB could be obtained. Linear macromolecular chains of PVAc were formed in the layers of MMT-DOAB. MMT-DOAB was exfoliated into nanoparticles of layers or sheets, randomly dispersed in the matrix of PVAc. The particle diameter of MMT-DOAB ranged from 25 to 75 nm, they randomly dispersed with PVAc particles. In addition, the smaller MMT-DOAB particles were adsorbed around the bigger PVAc particles; they formed the ‘strawberry’ structure. PVAc and PVAc-MMT-DOAB were pseudo-plastic non-Newtonian fluids and they all possessed the normal stress effect (or Weissenberg effect), that was the pole-climbing phenomenon. The reasonable addition of MMT-DOAB in polymerization was found to be not more than 2.0 wt.% of VAc.

No abstract

Electrically conductive vinyl ester resin–silver micro-flake adhesives, combined with intense pulsed light, present ultra-fast photonic curing within a second.

No abstract

ABSTRACT:To improve the chemical, physical, and mechanical properties of polyvinyl acetate (PVAc), an organic montmorillonite (OMMT) was first prepared by montmorillonite (MMT) and octadecyl trimethyl ammonium bromide (STAB), and then it was added to synthesized PVAc under conventional laboratory conditions. The influence of its variable addition on the properties of PVAc OMMT was investigated mainly by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and static tension, and the rheology was also investigated by the power-law function equation and the Cross-Williamson model viscous equation. The exfoliated nanocomposite of PVAc OMMT was obtained; linear macromolecular chains of PVAc were formed in the layers of OMMT, and no chemical bonding appeared between OMMT and PVAc, but there were some physical effects. The dispersion of PVAc OMMT was better than PVAc. OMMT was exfoliated into layers or sheets of nanoparticles and was randomly dispersed in the matrix of PVAc. The particle diameter of OMMT ranged from 50 to 100 nm, whereas PVAc's diameter ranged from 250 to 500 nm; the smaller OMMT particles were adsorbed around the bigger all PVAc particles and formed a "strawberry" structure. PVAc and PVAc OMMT were both pseudoplastic non-Newtonian fluids; they possessed the normal stress effect (or the Weissenberg effect), that is the pole-climbing phenomenon. The static tension properties of PVAc OMMT were much better than PVAc, and the addition of OMMT in polymerization was reasonable and not more than 2

No abstract

No abstract