Mineral filler content

It has been found that, for a fixed mineral filler content, the viscosity of PMF-based composites increases when the coat is made of polyethylene [164, 209, 293], poly(vinyl chloride) [316] and polypropylene [326, 327], The picture was different, however, for composites based on the ethylene/vinyl acetate copolymer to which kaolin with grafted poly (vinyl acetate) was added [336]. Addition of PMF with a minimum quantity of grafted polymer results in a sharp drop of flowability (rise of viscosity), in comparison to addition of unmodified filler but with a further increase of the quantity of grafted polymer the flow gradually increases and, depending on the kaolin content and quantity of grafted polymer, may even become higher than in specimens with unmodified filler, for equal concentrations. 

Resistance to environmental stress cracking - Measurement of the melt flow index -Carbon black and/or mineral filler content measurement in polyethy-lene by direct combustion - Measurement of carbon black content by thermogravimetric analysis (TGA) - Assessment of carbon black dispersion in polyethylene using a microscope... 

A typical application of TGA is its use in compositional analysis. For example, a particular polyethylene part contained carbon black and a mineral filler. The electrical properties were important in the use of this product and could be affected by the carbon black content. TGA was used to determine the carbon black content and mineral-filler content for various lots, which were considered either acceptable or unacceptable. The samples were heated in nitrogen to volatilize the PE, leaving carbon black and a mineral-filler residue. The carbon content was then determined by switching to an... 

The technique can also be used to determine mineral filler contents of certain products. In this case, a sample is heated gradually to a high temperature and maintained at this temperature for a period to ensure complete ashing. A typical thermogram obtained for a chipbonding product is shown in Figure 7. The sample was heated from room temperature to 600°C, and held at the final temperature for 30 min. The resultant stable baseline obtained after complete combustion is used in the calculation of filler content for the sample (13.7% w/w). 

If the amount of plasticizer varies from 42.5 to 57.5 parts while mineral filler content remains constant (Figure 5.77), virtually the same reduction in elongation at break is obtained for all DOP variations over the entire weathering period [683]. 

Mineral fillers are used for light-colored compounds. Talc has a small particle size and is a semireinforcing filler. It reduces air permeabihty and has htde effect on cure systems. Calcined clay is used for halobutyl stoppers in pharmaceutical appHcations. Nonreinforcing fillers, such as calcium carbonate and titanium dioxide, have large particle sizes and are added to reduce cost and viscosity. Hydrated siUcas give dry, stiff compounds, and their acidity reduces cure rate hence, their content should be minimized. 

Hydrolysis of polyamide-based formulations with 6 N HC1 followed by TLC allows differentiation between a-aminocaproic acid (ACA) and hexamethylenedi-amine (HMD) (hydrolysis products of PA6 and PA6.6, respectively), even at low levels. The monomer composition (PA6/PA6.6 ratio) can be derived after chromatographic determination of the adipic acid (AA) content. Extraction of the hydrolysate with ether and derivatisa-tion allow the quantitative determination of fatty acids (from lubricants) by means of GC (Figure 3.27). Further HC1/HF treatment of the hydrolysis residue, which is composed of mineral fillers, CB and nonhydrolysable polymers (e.g. impact modifiers) permits determination of total IM and CB contents CB is measured quantitatively by means of TGA [157]. Acid hydrolysis of flame retarded polyamides allows to determine the adipic acid content (indicative of PA6.6) by means of HPLC, HCN content (indicative of melamine cyanurate) and fatty acid (indicative of a stearate) by means of GC [640]. Determination of ethylene oxide-based antistatic agents... 

Increasing the mineral component content in the filler (cp = const) leads to the growth of the melt heat conductivity coefficient. As a result, L i decreases along with decreasing the C organic component content in the fiUer. Processing of experimental data showed that in this case Equation (28) will change to ... 

The traditional method of reducing the polymer content by the addition of mineral fillers will be less u%d in the future since this results in a considerable in-... 

The content of amorphous phase and the small size of spherulites lead to an improvement of the fracture toughness of Polypropylene [16]. In presence of mineral filler, the particle surface chemistry can induce some specific microstructural characteristics of the PP matrix parameters such as degree of crystallisation, spherulite size, and p phase content (a/p ratio) [16]. 

Thermal expansion-contraction of inorganic fillers is much lower compared with that of plastics. Therefore, the higher the filler content, the lower the coefficient of expansion-contraction of the composite material (see Chapter 10). Many inorganic nonmetallic fillers decrease thermal conductivity of the composite material. For example, compared with thermal conductivity of aluminum (204 W/deg Km) to that of talc is of 0.02, titanium dioxide of 0.065, glass fiber of 1, and calcium carbonate of 2-3. Therefore, nonmetallic mineral fillers are rather thermal insulators than thermal conductors. This property of the fillers effects flowability of filled plastics and plastic-based composite materials in the extruder. 

Impact resistance typically suffers progressively with an increased content of a mineral filler. For example, 40% of talc in polypropylene decreases unnotched impact... 

Now, let us see how a high content of a mineral filler may affect creep in some particular examples (Examples 3 and 4). 

The dimensions of a polymeric component are temperature, time and moisture content dependent. The extent of these dimensional instability effects, especially those related to temperature and moisture content is important if the physical properties of different engineering polymers are compared. The expansion due to moisture absorption of polyketone and that of a alternative system Minion 13T1 (Nylon 6.6 with 33 %wt. mineral filler) were measured in order to obtain such a comparison. 

Graphene-polymer nanocomposites share with other nanocomposites the characteristic of remarkable improvements in properties and percolation thresholds at very low filler contents. Although the majority of research has focused on polymer nanocomposites based on layered materials of natural origin, such as an MMT type of layered silicate compounds or synthetic clay (layered double hydroxide), the electrical and thermal conductivity of clay minerals are quite poor [177]. To overcome these shortcomings, carbon-based nanofillers, such as CB, carbon nanotubes, carbon nanofibers, and graphite have been introduced to the preparation of polymer nanocomposites. Among these, carbon nanotubes have proven to be very effective as conductive fillers. An important drawback of them as nanofillers is their high production costs, which... 

Dewatered pond fines have the potential for use as a mineral filler in hot mix asphalt paving, depending on the clay content of the pond fines... 

Mineral microfillers have been tested in a plasticized starch matrix [CAR 01]. For example, micrometric particles of kaolin have been incorporated by extrusion. Due to a significant compatibility between the matrix and the filler, we note an increase in the glass transition temperature, a reduction in water absorption and an increase in the rigidity of the material. However, with the corresponding filler contents, these composites no longer satisfy the standards of biodegradation (at least 90% of the material has to be degraded). 

PVC profile with high content of mineral filler. [Data from Bussels, R, Gabriels, J P, Spijkerman, World Patent W02010049532, May 6, 2010, Tessenderlo Chemie. 

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