Poly Vinyl Formal Pvf Foam

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Poly vinyl formal pvf foam.

2 shows the infrared absorption spectra of 12 mm thick polyvinyl formal foil irradi ated with 900 mev au ions at room temperature rt. The sound absorption coefficient α of the pvf foam largely increased with the decreasing pore size especially in the frequency range of 800 2500 hz. The state key laboratory of polymer materials engineering polymer research institute of sichuan university chengdu 610065 china new materials r d center institute of chemical material china academy of engineering physics mianyang 621900 china. Outstanding solution absorbing performance unique high rate hydroexpansivity and promising biocompatibility.

Scanning electron microscopy showed that the pvf foams had two kinds of pore structures closed and open cell. Morphology observation showed that the porous structure of pvf foams was successfully created using water as the blowing agent and it was strongly affected by the crosslinking agent and polymer concentration leading to an easily tuned pore size from hundreds of microns to few microns. The pvf foams could be used as sound absorbing materials because of the open cell multiporous structures. And the highest α value of 0 98 was obtained at 2000 hz for pvf 3 0.

A very broad characteristic absorption peak centred at about 3490. Formvar refers to any of several thermoplastic resins that are polyvinyl formals which are polymers formed from polyvinyl alcohol and formaldehyde as copolymers with polyvinyl acetate they are typically used as coatings adhesives and molding materials. Through the help of images taken by a scanning electron microscope the formation process of the present pvf foam will be discussed in terms of the spinodal decomposition sd phase separation principle. By changing the concentration from 10 to 20 wt of pva solution pvf foams were successfully obtained.

The modulus of the composite increased 1857 and the highest volume expansivity reached 2150. It was found that a higher pva concentration prevented foam volume shrinkage and the best concentration was 16 wt. Ir spectroscopy results on pvf and its polymeric subunits pva and pvac are discussed in detail. Developed a double crosslinking sodium alginate sa polyvinyl formal pvf composite with ipn structure.

Poly vinyl formal pvf of 90 acetalization was prepared by acid catalysed homogeneous formalization of pva of molecular weight 14 000 with paraformaldehyde.