Fillers identifying inorganic

Simple tests can only indicate which polymer type the plastic contains. To identify materials more precisely, it is necessary to use instrumental analytical methods. Each technique provides specific information either about which polymers or which additives are present, so it is usually necessary to use several in combination. For example, gas chromatography-mass spectrometry (GC-MS) is a destructive technique which allows identification of the polymer, plasticizer and other organic components. X-Ray Fluorescence (XRF) spectroscopy is an effective, non-destructive surface technique for identifying inorganic fillers, pigments and metal components, but carmot be used to identify polymers. 

Analysis of the solvent extract obtained to prepare the plastic sample for an IR technique can be used to identify the plasticiser present in a compound. IR analysis of an ash of the compound obtained by heating at 550 °C can help to identify inorganic fillers. IR can also be used to identify specialist additives such as fire retardants. 

This technique is very useful for obtaining semi-quantitative elemental data from plastic compoimds and their ashes. Among other things, it helps to identify inorganic fillers and pigments in samples. The technique is usually used in conjunction with IR. 

Coupling agents are ehemieals that are used to treat the surface of fillers. These ehemieals normally have two parts one that combines with the surface ehemieaUy and another that is eompatible with the polymer. One example is the treatment of ealeium earbonate filler with stearic acid. The acid group of the latter reacts with the surface, whereas the ahphatic chain sticks out of the surface and is eompatible with the polymer matrix. In the same way, if carbon black is to be used as a filler, it is first mixed with benzoyl peroxide in alcohol at 45°C for at least 50 h and subsequently dried in vacuum at 11°C [5]. This activated carbon has been identified as having C—OH bonds, which can lead to polymerization of vinyl monomers. The polymer thus formed is chemically bound to the filler and would thus promote the compatibihzation of the filler with the polymer matrix. Most of the fillers are inorganic in nature, and the surface area per unit volume increases with size reduction. The number of sites where polymer chains can be bound increases, and, consequently, compatibility improves for small particles. 

Inorganic fillers in plastics compositions are usually in a very finely divided form and, as such, are ideal for powder XRD study. A sample size of a few mg gives a good pattern in 1 or 2 h. Crystalline mineral fillers can usually be observed directly in the complete polymeric formulation, in concentrations exceeding about 1 %. Combined XRD/XRF studies are favoured [326]. A mineral filler is easy to identify in a compound in the absence of other fillers. 

Analysis of inorganic fillers in plastics and rubber materials is normally accomplished by ashing material in a muffle furnace at a temperature of 550°C. An IR spectrum of the resulting ash, sometimes as a paraffin oil mull is then obtained to identify the filler type. Examination of the ash by XRF and/or X-ray diffraction can also provide useful information to help identify complex systems. 

Phenolic resins are made from phenol or phenol derivatives and formaldehyde. In many cases they also contain inorganic or organic fillers. After curing, the resins are insoluble in all the usual solvents, but they dissolve with decomposition in benzylamine. Phenolic resins may be identified in... 

The aminoplastics are condensation products of formaldehyde and urea, thiourea, melamine, or aniline. They are often filled with finely ground wood, stone, or other inorganic fillers and are used mainly as molded parts or laminates. All aminoplastics contain nitrogen and bound formaldehyde, which can be identified using chromotropic acid (see Section 6.1.4). 

Inorganic ash from burning polymers to separate the organic polymer from fillers can be identified by infrared spectroscopy. The technique of infrared spectroscopy has been described previously in this chapter. The bands characteristic to inorganic fillers are shown in Table 5.9. 

In general, infrared spectroscopy can be used to investigate the chemical bonds of the NR matrix and the chemical links of the inorganic filled added to the matrix. For infrared spectrum of composites and nanocomposites based on NR, it is possible to identify all of the vibration band characteristics of the poly(cw-l,4-isoprene) structure being principally two main sets of bonds. The first set around 3000 cm and the second set around 1500 cm For the inorganic filler, it is expected to identify bands mainly between 800 and 200 cm that it can be attributed mainly to the metal-oxygen bonds. 

Before moving further, let us first present a brief review of polymer blends filled with micron-sized particles to gain more insight into filled polymer blends. Indeed, the majority of the fundamental issues, such as selective filler dispersion, filler exclusion due to high viscosity, and changes in droplet size and shape in the presence of inorganic particles, had been first identified in blend composites filled with micron-size particles. 

In recent decades, various inorganic materials have been investigated and identified as potential fillers for hybrid membrane preparation. The required features for the choice of the embedded phase are typically chemical adaptation for the dispersion in the polymeric matrix, particle shape and morphology, and suitable effects on the overall transport properties. 

The fillers can be isolated by ashing a quantity of polyurethane to yield the desired quantity of ash for spectroscopic (or wet chemical method) analysis. Often the filler can be identified by infrared without any elemental analyses. Usable spectra of inorganic compounds may be obtained by grinding with a mortar and pestle to a powder, spreading uniformly between two salt plates, and gently moving one plate over the other until good contact between plates and sample is achieved. A demountable cell is normally required to centre the plates in the spectrophotometer beam. 

X-ray diffraction Identifies crystalline phases Identification of inorganic fillers and crystalline organic pigments 48... 

Machalkova [643] has described analysis of polymer composites and rubber blends with emphasis on separation of low-MW additives by instrumental methods. Examples refer to analysis of inorganic filler- or synthetic fibre-reinforced plastics and laminated plastic Aims using PyGC and IR. The versatility of PyGC has further been exemplified by Jones [633] as a thermovolatilisation technique for direct determination of occluded volatiles and low-MW additives in lube oil, novolac resins and HDPE, of plasticisers and vinylchloride in PVC, and of solvent residues in paints and bitumens, etc. Dicumylperoxide (DCP) in LDPE was identified through detection of three main by-products of reaction, acetophenone, a-methylstyrene and 2-phenylpropan-2-ol [633]. 

Commercial pyrolyzers are available for the controlled thermal degradation of materials which are difficult to prepare for transmission spectroscopy because of toughness, surface texture, or composition, including certain polymers and rubbers.Carbon-filled rubbers are best identified by this technique. The condensate from the destructive distillation process can be collected on a plate and run by transmission or internal reflection techniques or the gas formed in the chamber can be run directly. The condensate spectra from pyrolysis should be compared with a library of pyrolyzates since they may differ somewhat from that of the starting material. Polymer pyrolyzates, for example, may show new monomer bands whereas any inorganic fillers originally present will be missing. 

Lattimer et al have very successfully applied mass spectrometry to the determination and identification of organic additives (antioxidants and antiozonants) in rubber vulcanizates (Method 42). A wide variety of components are involved - polymers, fillers, solvents and organic and inorganic additives. Field desorption/ionization (FD/FI) is the most efficient for identifying typical organic additives in rubber vulcanizates. 

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