High clay composites

The compatibilization of clay with LDPE and HDFE is accomplished by the in situ polymerization of MAH or its precursor maleic acid, in the presence of a radical catalyst. The latter must be capable of initiating the homopolymerization of MAH, i.e. it must be present in high concentration and/or have a half-life of less than 30 min at the reaction temperature, e.g. t-butyl per-benzoate (tBFB) at 150°C. In a one-step process, the clay and PE are mixed with MAH-tBPB in the desired PE/clay ratio. In the preferred two-step process, a 70/30-90/10 clay/PE concentrate is prepared initially in the presence of MAH-tBPB and then blended with additional PE to the desired clay loading. The compatibil-ized or coupled PE-MAH-clay composites have better physical properties, including higher impact strengths, than unfilled PE or PE-clay mixtures prepared in the absence of MAH-tBPB. 

Allophane production. Allophane is a non-crystalline, hydrous aluminosilicate of highly variable composition, which forms as a common colloidal constituent of soils it may be an intermediate in the formation of some authigenic clay minerals. 

CAS 1332-58-7. A white-burning aluminum silicate that, due to its great purity, has a high fusion point and is the most refractory of all clays. Composition Mainly kaolinite (50% alumina, 55% silica, plus impurities and water). 

Roo Rooj, S., Das, A., Stockelhuber, K., Stocek, R., Reincke, K., GreUmann, W, Heinrich, G. A novel approach towards highly exfoliated natural rubber-clay composites PreparatiOTi and characterization. International Rubber Expo, 182nd Technical Meeting Educational Symposium, Cincinnati, OH, October 7-11, 2012, Paper No. 82, 1-20. 

If the nylon 6 clay nanocomposite is processed in an oxygen plasma, a uniform passivation film is formed. It was found that as the polymers are oxidized, highly oblique composites form, in which the clay concentration increases toward their surfaces, and that the clay layers in these composites function as polymer-protective layers. This indicates that the uniform passivation film may prevent the deterioration of the polymers [32]. 

If the same reason is applied to layered filler composite materials, they show very high strength. The clay composite with 4 wt% clay loading... 

Zeolite membranes indicate inorganic membranes with a selective/cata-lytic layer composed of a zeolite which is crystalline aluminosilicate with the feature of a high ordered porous structure with size comparable to molecular dimension. An example of the use of zeolites as a catalyst in a multi-phase membrane reactor can be found in Shukla and Kumar (2004) who have immobilized a lipase on a zeolite-clay composite membrane by using glu-taraldehyde as a bifunctional ligand in order to carry out the hydrolysis of olive oil. An application of a zeolite-based membrane in a three-phase membrane reactor has been reported by Wu et al. (1998), where TS-1 zeoUte crystallites were embedded in a polydimethylsiloxane (PDMS) membrane in order to catalyse the oxyfunctionalization of n-hexane (from a gas phase) with hydrogen peroxide (from a liquid phase). 

T and AH for the PCL decreased with increasing content of the modified montmorillonite in the blends. AH for the composite varied closely to that expected if the fractional crystallinity of the PCL was constant as its weight fraction decreased. That is, fractional PCL crystallinity appeared to be independent of clay content. Dimensions of PCL spherulites in the presence of the clay were smaller than in pure PCL. Crystallisation studies showed that, relative to the rate of crystallisation in pure PCL, 5 wt % clay enhanced the rate of crystallisation but above lOwt % clay the rate of crystallisation was decreased. It was proposed that clay enhanced the rate of nucleation but high clay contents hindered diffusion of polymer segments and, hence, of crystallisation. 

Nano-clay composites contain very thin, high aspect ratio, alumino-silicate platelets, derived from the stacks present in the parent clay. Two types of stmcture can be recognised, intercalated and delaminated. In the intercalated form, the stacks of platelets are still present, but with polymer chains present between clay platelets, pushing them apart. In the delaminated form, the original stacks are no longer present, and the platelets are fully dispersed. 

There are numerous bit types and compositions that are applicable to specific types of rock however, commercial diamond or diamond-impregnated bits are usually the preferred bit from a core recovery and quality standpoint. Tungsten carbide core bits can sometimes be used in weak rock or in high-clay-content rocks. A thin bentonite mud is the typical drilling fluid used for coring. Thick mud can clog the small bit ports and is typically avoided. 

An alternative route to the compatibilization of a filler such as clay with LDPE and HDPE, through the radical catalyzed polymerization of maleic anhydride (MAH) in the presence of the polymer and clay, has been shown to yield PE-g-MAH-clay composites having better mechanical properties than unfilled PE or PE-clay mixtures prepared in the absence of MAH and a radical catalyst, In the present paper, further improvements in the preparation and properties of HDPE-clay composites are described. These result from the use of high melt index HDPE as "coating PE" in the preparation of the PE/clay masterbatch and low melt index HDPE as "matrix PE" in the final HDPE-clay composite. The crosslinking which accompanies the graft polymerization of MAH onto PE also plays a significant role in the enhancement of the mechanical properties of the composite, ... 

The attainment of these characteristics and the properties resulting therefrom is shown in Table II, which describes 70/30 and 50/50 HDPE/clay composites prepared from 30/70 PE/clay masterbatches using 15 and 22 MI HDPE as coating PE and 0.7 MI HDPE as matrix PE . The properties of unfilled blends of the high and low melt index HDPE in the proportions used in the composites are shown for comparison. 

HDPE/CLAY COMPOSITES BASED ON HIGH MELT INDEX COATING HDPE" AND LOW MELT INDEX "MATRIX HDPE"... 

Plackett D, Siu A, Li Q et al (2011) High-temperature proton exchange membranes based on polybenzimidazole and clay composites for fuel cells. J Membr Sci 383 78-87... 

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