Plasticizers efficiency

Oatley and a succession of brilliant students, collaborating with others at the Cavendish Laboratory, by degrees developed an effective instrument a key component was an efficient plastic scintillation counter for the image-forming... 

Ultrafast photoinduced electron transfer in semiconducting polymers mixed with controlled amounts of acceptors this phenomenon has opened the way to a variety of applications including high-sensitivity plastic photodiodes, and efficient plastic solar cells ... 

New impact modifier offers cost and performance efficiencies, Plastics, Additives and Compounding, 11(2) 6, March-April 2009. 

Table IX shows the effect of two chemically very different organic liquids on the glass temperature of polystyrene (2). Ethylbenzene, with a chemical structure very similar to that of the polystyrene monomer unit, greatly lowers Tg and therefore, is a much more efficient plasticizer for polystyrene than paraffin oil, with its completely aliphatic structure.

Results The data in Table II offer the opportunity to compare phthalates of four different eight-carbon alcohols. The performance differences are perhaps greater than would be expected from such simple variations in skeletal makeup. The most notable differences are in volatility and low temperature properties, but other minor differences also exist. Greater linearity leads to increased efficiency (as measured by the 100% modulus), lower volatility, better flexibility at low temperatures, and better resistance to soapy water. In most circumstances, the linear alcohol phthalates are quite similar to straight chain phthalates. This is to be expected in view of the close similarity of structures. (The true value of a plasticizer system must, of course, consider not only oerformance but price. Thus, high efficiency can sometimes be a disadvantage when costs on a pound volume basis are calculated. In other words, a less efficient plasticizer often gives the lowest compound pound volume cost.)... 

The Solid—Gel Transition Temperature. This temperature, T, is a measure of plasticizer activity and is the temperature at which a single grain of PVC dissolves in excess plasticizer. The more efficient plasticizers show lower values of Im as a result of their higher solvating power. This can be correlated with the ease of processing of a given plasticizer, but all measurements should be conducted with a control PVC resin since clearly the choice of resin has an effect here also. 

A systematic study on the effect of plasticization on the PR properties is reported by Bolink et al. [58], It is shown that ECZ can be used as an efficient plasticizer, leading to a large increase in the gain coefficient and the diffraction efficiency, which arises solely due to an improvement in the orientational mobility of the dispersed NLO molecules. 

The importance of comparing plasticizers at equal efficiency levels (equal hardness or 100% modulus) rather than equal phr cannot be overemphasized. This is shown in Table III for a typical plastisol compound. It can be seen that use of a less efficient plasticizer, such as DIDP, even though it costs one half cent per pound more than DOP, results in a pound volume cost savings of 0.7c. 

Diisononyl adipate is a highly efficient plasticizer that imparts low temperature flexibility and impact resistance to the base resin. Widely used in shrinkwrap, electrical wire jackets and films. Also used in sausage casings. 

Very recently, the self-assembly of poly(y-benzyl-i,-glulamalc)-fo-poly(i,-lysine) rod-coil copolypeptide via ionic complexation was reported by Ikkala, Hadjichristidis and coworkers [65]. Complexation between the anionic surfactants dodecyl benzenesulfonic acid and the cationic poly(L-lysine) chains occurs via proton transfer from the acid group to the base, resulting in electrostatically bonded comb-like structures, and fluid-like liquid crystalline structures at room temperature due to efficient plasticization of dodecyl benzenesulfonic acid. 

The past 25 years have seen a tremendous improvement in the extrusion process (19). Productivity has increased 250-300% in this time. The process has evolved from an art to a science. The increased output is attributed to improvements in screw design and haul off equipment for increased cost effectiveness (70-80% lower than in the fifties). Processing costs have decreased due to energy efficiency. Plastic processing energy efficiency has increased 300-... 

Polymers have unique properties important for processing, viz., low thermal diffusivity, high viscosity and viscoelasticity. Because of the low thermal conductivity, efficient plastication cannot be based on thermal diffusivity alone. Polymer melting requires generating heat dissipation through intensive deformation of the highly viscous melts, leading to thin films. 

The level of plasticizer required to achieve the desired changes in properties is a measure of plasticizer efficiency. Plasticizer efficiency may also be measured on the basis of the magnitude of change induced in a number of physical properties of the polymer such as tensile strength, modulus, or hardness. For example, the actual reduction in Tg of the polymer per unit weight of plasticizer added is also known as the plasticizer efficiency. 

Plasticizers (see also Chapter 1) are essentially nonvolatile solvents for PVC. At the processing temperature of about 150°C, molecular mixing occurs in a short period of time to give products of greater flexibility. Phthalates prepared from alcohols with about eight carbon atoms are by far the most important class and constitute more than 70% of plasticizers used. For economic reasons, diisooctyl phthalate (DIOP), di-2-ethylhexyl phthalate (DEHP or DOP), and the phthalate ester of the C7-C9 0x0-alcohol, often known as dialphanyl phthalate (DAP) because of the ICI trade name Alphanol-79 for the C7-C9 alcohols, are used. DIOP has somewhat less odor, whereas DAP has the greatest heat stability. Dibutyl phthalate and diisobutyl phthalate are also efficient plasticizers and continue to be used in PVC (except in thin sheets) despite their high volatility and water extractabihty. 

Water acts as a plasticizer for many of the early plastics. A sheet of casein, 4 mm thick, absorbs 5-7 per cent of its own weight in 24 hours and 30 per cent in 28 days under normal room conditions (Brydson, 1999). Polyamides, such as nylon, are the most hygroscopic polymers in common use today, containing up to 3 per cent moisture by weight under ambient conditions. In the same environment, cellulose acetate contains 0.8 per cent and poly (methyl methacrylate) and polystyrene 0.1 per cent. Plasticized PVC swells and appears opaque if stored at high relative humidity (RH) (Figure 6.6). Water vapour is an efficient plasticizer for the PVC polymer but is incompatible with commercial ester plasticizers, which are hydrophobic. As a result, the more plasticized the PVC, the less water it absorbs. Because water is only weakly bonded to the PVC polymer, it rapidly evaporates again. 

If the incineration is efficient, plastics are claimed to produce no more serious emissions than incineration of any other material. For example, dioxins can be produced by inefficient incineration of many different materials, and there is no evidence that combustion of PVC makes any significant addition to acidic emissions. Modern computer-controlled furnaces ensure steady operating temperatures above 850C (I560F), giving high levels of total combustion. Studies show that at least two... 

In general, polyols have good plasticizing properties, especially when it comes to plasticizing carbohydrate-based products such as TPS. They have a dual action as primary plasticizers, altering the interaction between adjacent polysaccharide chains, and secondary plasticizers ensuring the presence of water -the most efficient plasticizer for carbohydrates. 

Martelli, V., Calculating Extruder Energy Efficiency, Plastics Compounding, Apr./May 1980. 

Lao.9oCeo.ioP04 nanocrystals were surface modified with mixed surfactants a mixture of DDA and BEHP or a mixture of OA and BEHP. The surface modified nanocrystals were dispersed at SO wt % in polystyrene, forming translucent thick films on quartz discs. Pulse height spectra from alpha particle detection (Source Am) of nanocrystal samples superimposed with the result from a highly efficient plastic scintillator, BC-400 are presented in Figure 3. 

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