Melt compounding/intercalation

The morphology of rubber-based nanocomposites also seems to change in the presence of compounding ingredients [89, 90]. HNBR, when melt-compounded with organo-modified sodium montmorillonite clays (o-MMTs) prior to sulfur curing, resulted in the formation of nanocomposites with exfoliated or intercalated structures. In stark contrast, under similar conditions HNBR compounded with unmodified sodium montmorillonite clays (NA) formed microcomposites [90]. This was traced to its reactivity with the sulfur in the presence of amine-type organomodifiers. 

Melting point determination. If compounds intercalate with DNA, then the melting point is shifted to higher temperatures.21,25 70 pM Sinapis DNA was incubated in TE-buffer (pH 7.4) with 70 pM alkaloids for 30 min at 22°C. Then the temperature was increased by 1°C/min to 90 °C and the absorption was continuously... 

As outlined in the introduction, polymer melts can intercalate layered inorganic compounds unassisted by shear or solvents. This is a rather surprising result as it implies that polymer chains can undergo large center of mass displacement in almost two dimensional interstices as the distances between the confining sur-... 

Intercalated and partially exfoliated PVC-clay nanocomposites were produced by melt blending in the presence and absence of DOP and characterised by X-ray diffraction and transmission electron microscopy. The effects of various factors, including volume fraction of clay, plasticiser content, melt compounding time and annealing, on nanocomposite structure and the thermal and mechanical properties of the nanocomposites were also examined. It was found that the best mechanical properties were achieved at 2% clay loading and 5 to 10% DOP loading. 18 refs. 

The intercalation of a polymer chain between the host clay galleries can be achieved by conventional techniques such as melt compounding, polymerization in the presence... 

Poly(butylene terephthalate) (PBT) was melt compounded at 230°C with ClOA (MMT preintercalated with dimethyl benzyl hydrogenated tallow ammonium) [Wu et al., 2005a]. The clay concentration was 0 to 8 wt% and dooi = 3.4 to 3.7 nm thus, CPNC was only intercalated. The linear viscoelastic region was observed for y < 0.01... 

Pluta [49] studied the structure and properties of PLA/MMT nanocomposites and showed an effective enhancement of MMT dispersion with prolongation of the blending time (from 6 to 30 min). They stressed that this was possible due to strong interaction between PLA-MMT and shearing forces during melt compounding. The nanostructure was induced by the intercalation followed by tactoids formation and exfoliation of MMT, as confirmed by TEM analysis and XRD. The studies performed also clearly revealed the influence of MMT s dispersion in the PLA matrix on the physical properties of the nanocomposites formed as the improved MMT s dispersion (at their constant concentration) had increased the thermal stability of the nanocomposites under oxidative and nonoxidative conditions was improved with MMT s dispersion. Besides that, the crystallization ability of PLA also improved with incorporation of MMT. 

As the hydrophilic clay is incompatible with polypropylene, compatibilization between the clay and PP is necessary to form stable PP nanocomposites. There are two ways to compatibilize the clay and PP. In the first approach, the enthalpy of the interaction between the surfactant and the clay is reduced. In the second approach, a compatibilizer, such as maleic anhydride grafted PP (PPgMA) can be used( Manias et al.,2001). The clay is melt compounded with the more polar compatibilizer to form an intercalated master batch. The master batch is then compounded with the neat PP to form the PP nanocomposite. 

Polymer nanocomposites are generally prepared by three methods solution intercalation, in-situ polymerisation or melt compounding. 

Figure 1.15 Schematic representation of formation of polymer-based CMP systems viz. (a) conventional bulk CMP (tactoid), (b) intercalated NCs, and(c) exfoliated NCs, via physical mixing (dry/solution phase mixing or melt compounding) and in-situ polymerization routes.

TEM analyses showed that melt-compounded EAA/M2(HT)2 composites have homogeneous dispersion of thin intercalated tactoids with several individual silicate platelets... 

Scheme of the structural changes occurring in EAA/15A mixtures during melt compounding, solution blending, solvent de-intercalation, and static annealing. 

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