Vermiculite

About: Vermiculite is a research topic. Over the lifetime, 2320 publications have been published within this topic receiving 37142 citations.

Novel Preparation and Properties of Polypropylene−Vermiculite Nanocomposites

Abstract: A novel approach to the preparation of polymer nanocomposites utilizing a low-molecular-weight reactive modifying reagent has been developed in this study. This is the first report on the fabrication of in situ nanocomposites using maleic anhydride as a reactive reagent that acts both as a modifying additive for the polymeric matrix and as a swelling agent for the silicate. Accordingly, polypropylene−vermiculite nanocomposites with an intercalated or exfoliated structure can be achieved by simple melt mixing of maleic anhydride-modified vermiculite with polypropylene. The nanocomposite structure is evidenced by the absence of vermiculite reflections in the X-ray powder diffraction patterns. Tensile tests show that the tensile modulus and strength of the nanocomposites tend to increase dramatically with vermiculite addition. Such enhancement in mechanical properties results from the formation of intercalated and exfoliated vermiculite reinforcement in the composites. Finally, the thermal properties of the ...

Biochar characteristics relate to its utility as an alternative soil inoculum carrier to peat and vermiculite

Abstract: Biochar materials have greatly variable physical and chemical properties, which will affect their abilities to serve as carriers for introducing bacteria into soils. Here we examined biochars made from 5 feedstocks produced at 2 highest treatment temperatures (HTT's) by slow pyrolysis. Peat and vermiculite, which are traditional inoculum carriers, and liquid inoculum with no carrier, were included for comparison. All of the carriers were inoculated with a liquid suspension of the plant growth promoting rhizobacterial (PGPR) strain, Enterobacter cloacae UW5, carrying a green fluorescent protein (GFP) marker. Inoculum survival was determined using quantitative PCR to enumerate the GFP markers in DNA extracted from non-sterilized soils directly after incorporation of the inoculated carriers and after a 4-week incubation. The biochars were characterized with respect to carbon and nitrogen content, specific surface area, pH, electrical conductivity, water holding capacity, pore opening diameters, and hydrophobicity to identify specific attributes that influence the survival of the inoculant after introduction into soil. The results indicated that chemical properties of biochar, particularly nitrogen and pH, were among the most important characteristics affecting initial inoculum survival and hence likely the shelf life. However, once incorporated into soil, physical features, including surface area, pore opening diameters, and water-filled pore spaces, were more closely associated with inoculum survival. All biochars tested performed as well as vermiculite and none demonstrated detrimental effects on the UW5 population. The best biochar was that made from pinewood at a HTT of 600 °C (Pine600), which performed as well as peat and sustained higher population densities than vermiculite. The Pine600 biochar was further tested to assess its effect on the expression of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and auxin synthesis, both of which were unaffected by the presence of biochar at 2% or 5% (w/v) concentrations.