Filler phase dispersion

The altered free-volume state of the multicomponent system (polyblend or filled polymer) could be denoted by f(T, < )2), where dispersed polymer phase in case of polyblend and the dispersed filler phase in the case of filled polymer. The melt fiow index of the multicomponent system is denoted as MFI(r, ( >2) and Eq. (8.81) would show the relationship between melt fiow index and the altered free volume. 

As SR decreases, 1 must be decreased too (and thereby also the inlet pressure loss/total pressure ratio is decreased). This is what is really observed when dispersed fillers are added to polymer [182,190,193,194], The rubber phase in heat resistant polystyrene behaves much like a dispersed filler it also diminishes the inlet correction [195]. For polystyrene with different fillers the following relationship was found to be valid [196] ... 

Closed-form expressions from composite theory are also useful in correlating and predicting the transport properties (dielectric constant, electrical conductivity, magnetic susceptibility, thermal conductivity, gas diffusivity and gas permeability) of multiphase materials. The models lor these properties often utilize mathematical treatments [54,55] which are similar to those used for the thermoelastic properties, once the appropriate mathematical analogies [56,57] are made. Such analogies and the resulting composite models have been pursued quite extensively for both particulate-reinforced and fiber-reinforced composites where the filler phase consists of discrete entities dispersed within a continuous polymeric matrix. 

Generic RTV Silicones. Our major purpose in the study of the RtV silicone by TGA is to optimize the thermal stability of the formulation. The TGA curve reveals not only the thermal stability of RTV silicone material but also the degree of dispersion of polymer-filler and/or filler-filler incorporation. With the aid of derivative thermogravimetry (DTG) curve we are able to detect any decomposition of the polymer. A wel 1-dispersed filler-filled silicone material will result in one distinct derivative TGA curve (see Figure 8). However, poor dispersion of the polymer and flller(s) or poor polymer resin often reveals more than one derivative from the DTG curve. The phase separation between polymer-filler and/or filler-filler may be the cause of the multiple DTG cure. Even very close decompositions peaks which are hard to distinguish from the TGA curve will also be easily distinguished by the derivative curve. 

The commercial LCP/PPS blend is designed for injection molding complex electronic parts, chip carriers, sockets and cod bobbins. It is very likely that due to its low melt viscosity, LCP still forms the continuous phase, while PPS may simply be present as a dispersed filler along with the glass fibers. Very httle information about this blend has been pubhshed. 

Polypropylene (PP500P, SABIC) has melt flow rate of 3.1 (2.16 kg at 230 °C) and density of 905 kg/m3 was used as matrix resin. Nano-sized synthetic ultrafine surface treated precipitated calcium carbonate (Socal 312, Solvay, France) with mean particle diameter of 70 nm used as filler phase. PP-g-MAH compatibiliser (Priex 20097, Solvay, France) with a maleic anhydride content of 0.05 wt % and MFI of 15 (2.16 kg at 230 °C) was employed to promote the interfacial interaction between nano-CaC03 and PP, and to extend the dispersion of nanoparticles in polymer matrix. Compounds used as processing materials are listed in the table 1. 

Figure 1.13 Schematic representation of composite material and its various phases viz. continuous phase (or matrix), discontinuous (dispersed/discrete) phase (or filler fiberlike phase), and inter-phase/interfacial region (glowing outer region of filler s surface).

Nanocomposite technology using small amounts of silicate layers can lead to improved properties of thermoplastic elastomers with or without conventional fillers such as carbon black, talc, etc. Mallick et al. [305] investigated the effect of EPR-g-M A, nanoclay and a combination of the two on phase morphology and the properties of (70/30w/w) nylon 6/EPR blends prepared by the melt-processing technique. They found that the number average domain diameter (Dn) of the dispersed EPR phase in the blend decreased in the presence of EPR-g-MA and clay. This observation indicated that nanoclay could be used as an effective compatibilizer in nylon 6/EPR blend. X-ray diffraction study and TEM analysis of the blend/clay nanocomposites revealed the delaminated clay morphology and preferential location of the exfoliated clay platelets in nylon 6 phase. 

Control of Filler Phase Dispersion in Bio-Based Nanocomposites by In-situ Reactive Polymerization... 

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