Polymers, formaldehyde Composition

Chapter 11 - In work the synthesis technology of zinccontaining polymer - inorganic composite on the basis of products of secondary raw material processing at joint precipitating with carbamide and formaldehyde (ZnCFO) is described. 

Blending of inert materials with ion-exchange resins to an extent that the desirable properties such as thermal stability and exchange capacity are not affected can partially replace the polymer content thereby reducing the production cost. Vasudevan et al. reported the preparation of phenol-formaldehyde composite ion-exchange... 

Actually, one of the first nanocomposites of this kind, although the purpose was not to improve the mechanical properties of polymers, was prepared by Kirkland, and Her and McQueston, [38] when they synthesized polymer-silica composites with average diameters ranging from 500 nm to 20 p,m by copolymerisation of either melamine or urea with formaldehyde in the presence of a silica sol. Calcination yielded microporous silica spheres, which were used as chromatographic column packing under the trade name Zorbex . 

FIGURE 15.14 Influence of cross-linking on the dynamic mechanical response of phenol-formaldehyde resin. Concentrations of the cross-linking agent hexamethylenetetramine are shown alongside the appropriate curve. (After Nielsen, E., Mechanical Properties of Polymers and Composites, Marcel Dekker, 1974.)... 

Singha, A. S., Thakur, V. K., Mishra, B. N. (2009). Study of grewia optiva fiber reinforced urea-formaldehyde composites, J. Polym. Mater, 26(1), 81-90. 

In polymerization-induced colloidal aggregation (PICA) processes, a reactive monomer, generally urea formaldehyde, is mixed with a stable, submicrometer diameter metal oxide sol and undergoes an acid-catalyzed polymerization that results in porous, uniformly sized polymer-oxide composite microspheres [24,25], PICA has been applied to a variety of metal oxide systems, primarily silica, but also alumina, titania, zirconia, ferric oxide, and antimony pentoxide [24,25]. The process is affected strongly by solution acidity [26]. At lower pH, polymerization is more rapid and a more porous but mechanically weaker particle is formed. 

Oksman K (2001) Mechanical properties and morphology of flax fiber reinforced melamine-formaldehyde composites. Polym Compos 22(4) 568—578 Oomah D (2001) Flaxseed as a functional food source. J Sci Agric 81(9) 889-894 Opoku A, Panigrahi S, Tabil L (2007) Frictional properties of natural and chemically treated flax fiber. In 2007 AS ABE Annual International Meeting, vol 13, Technical Paper NumbCT 076188 Minneapolis, MN, 17—20 June 2007... 

Sreekala MS, Kumaran MG, Thranas S (2000) Effect of chemical modifications on the mechanical performance of oil pabn fibre remfoicedphtmol formaldehyde composites. In natural polymers and composites. In Capparelli Mattoso LH et al. (ed) Embrapa Instrumentacao Agropecuaria,... 

Zapeiropoulos NE, Baillie CA, Matthews FL (2001) A study of transcrystallinity and its effect on the interface in flax fibre reinforced composite materials. Compos A 32(3) 525-543 Hagstrand PO, Oksman K (2001) Mechanical properties and morphology of flax fiber reinforced melamine-formaldehyde composites. Polym Comp 22(4) 568-578 Vazquez A, Dominguez V, Kenny JM (1999) Bagasse-fiber-polypropylene based composites. J Therm Compos Mater 12 477-497... 

M.S. Sreekala, S. Thomas, and G. Groeninckx, Dynamic mechanical properties of oil palm fiber/phenol formaldehyde and oil palm fiber/glass hybrid phenol formaldehyde composites. Polym. Compos. 26,388-400 (2005). 

B. Oztiirk, Hybrid effect in the mechanical properties of jute/rockwool hybrid fibres reinforced phenol formaldehyde composites. Fibers Polym. 11(3), 464-473 (2010). 

Pt alloys such as Pt-Ru were also deposited onto conductive polymer/polyelectrolyte composite particles by reducing a mixture of H2PtCl6 and RuCls using either formaldehyde or hydrazine at reflux [26]. Yields for Pt-Ru alloys were somehow lower than those for Pt. Also, when poly(vinylsulfate) was used as the polyelectrolyte, the yields were lower than when polystyrenesulfonate was used. The loss of the electronic conductivity of the polymer composite was more severe when hydrazine was used as the reducing agent than formaldehyde during the catalyst deposition step. 

Joseph S, Thomas S. Electrical properties of banana fiber-reinforced phenol formaldehyde composites. J Appl Polym Sci 2008 109 256. 

Most processors of fiber-reinforced composites choose a phenol formaldehyde (phenoHc) resin because these resins are inherently fire retardant, are highly heat resistant, and are very low in cost. When exposed to flames they give off very Htde smoke and that smoke is of low immediate toxicity. PhenoHc resins (qv) are often not chosen, however, because the resole types have limited shelf stabiHty, both resole and novolac types release volatiles during their condensation cure, formaldehyde [50-00-0] emissions are possible during both handling and cure, and the polymers formed are brittle compared with other thermosetting resins. 

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