Effect of plastic additives

Conventional plasticizers may be used in formulated products. Phthlate esters are the preferred plasticizers. They exhibit little tendency to migrate and have good compatibility with both resins and hardeners. Addition rates are typically 5 to 20%. Chlorinated plasticizers may be used to reduce flammability, especially in conjunction with antimony trioxide. The effect of plasticizer additions is generally to degrade most physical properties, although at low additions the effect is usually small. The effect of plasticizer additions on various important properties is as follows ... 

Positron annihilation spectroscopy was employed to study the effect of plasticizer addition on free volrrme. The positrorrium atoms may form in amorphous regions of the polymer. In these regiorts, free volrrme exists if orthopositrorrirrm may live for several nanoseconds. The lifetime of the longest hved component, T3, is attributed to the pick-... 

Figures 12.1 and 12.2 show the effect of plasticizer addition on glass transition temperatures of component polymers. ...

At the same time, the addition of these low molecular weight components dilutes the entanglements of the polymer and reduces the plateau modulus. The net result for the addition of a tackifier to an elastomer is shown in Fig. 16. The effect of plasticizer addition is shown in Fig. 17. Note that the combination of the shift in... 

The effects of release additives on bulk properties must also be carefully considered, particularly with integral additives to plastics. Eor example, partial solubiHty usually confers some plastici2ing effect. This may improve impact strength but could reduce the heat distortion temperature. Some release additives such as metallic soaps have secondary antioxidant and heat-stabiH2er benefits. Such effects are exploited in multipurpose formulations. 

The effect of plasticizers and temperature on the permeabiUty of small molecules in a typical vinyUdene chloride copolymer has been studied thoroughly. The oxygen permeabiUty doubles with the addition of about 1.7 parts per hundred resin (phr) of common plasticizers, or a temperature increase of 8°C (91). The effects of temperature and plasticizer on the permeabiUty are shown in Figure 4. The moisture (water) vapor transmission rate (MVTR or WVTR) doubles with the addition of about 3.5 phr of common plasticizers (92). The dependence of the WVTR on temperature is a Htde more comphcated. WVTR is commonly reported at a constant difference in relative humidity and not at a constant partial pressure difference. WVTR is a mixed term that increases with increasing temperature because both the fundamental permeabiUty and the fundamental partial pressure at constant relative humidity increase. Carbon dioxide permeabiUty doubles with the addition of about 1.8 phr of common plasticizers, or a temperature increase of 7°C (93). 

The role of plastics in municipal solid waste combustion is discussed, and in particular, their fuel characteristics. Details are given of a state-of-art municipal solid waste combustor and the effects of plastics on the different combustion stages. In addition, the contribution of plastics to the total output spread over the various emission paths of solids, liquids and gases, is also assessed. 

However, the results do not necessarily reflect the fastness to overlacquering in actual application, because overprint varnishes may contain other solvents as well. Besides, a series of additional factors such as the effect of plasticizers, uneven flow of the pigmented lacquer, etc., play a role in pigment performance. The fastness to overlacquering is therefore most realistically determined in actual application. 

In the search for substitutes, other considerations than just sulfide stability have to be considered. These include the possible interference of the newly introduced element with other steel porperties, the plasticity of the new sulfides, the physical alloyability of the additive and, of course, the cost effectiveness of the additive. Zirconium and titanium interfere with other properties of the steel because of the excessive stability of their nitrides. Figure 9, and carbides. Figure 10. Although considerable usage of these two elements has played a part in sulfide substitution — over 500 metric tons of nuclear zircalloy scrap were used in — it appears that their role will progressively fade away primarily because of poor low temperature impact properties of steels treated with Zr and Ti. 

While not mandatory from regulatory guidehnes, much research has been carried out to investigate the extractability of plastic additives in contact with a variety of pharmaceutical formulations, mainly those for parenteral use. The research concentrates on the extractability of plasticizer phthalates, mainly di-2-ethylhexylphthalate (DEHP) from polyvinyl chloride (PVC) into the blood, blood components, and infusion solutions. The purpose for these studies lies in its, up to now, controversial hazardous effects on humans. The amount of additive necessary to turn rigid PVC into a flexible material (40% m/m) and the absence of chemical bonds between the polymer and the plasticizer make it a potentially extractable species. 

In Fig. II the effect of plasticizer is shown for the system poly(vinyl chloride)/tricresyl phosphate. Water also affects the conductivity considerably but its precise function is by no means clear particularly at low moisture contents (135). The presence of ionic impurities causes increased conductivity but the effect of organic impurities is less apparent. For instance, the addition of plasticizers of differing purity to poly-... 

The effects of plasticizers has also been studied by PAL [64, 65]. The addition of a plasticizer to polymers generally has the effect of lowering the Tg, however in some cases an anti-plasticization can occur. Borek et al [65] have shown that the fraction of free volume in PVC polymers could be fit with a fourth order polynomial as a function of plasticizer concentration. The decrease in th Tg with increasing amount of plasticizer is attributed to this increase in the free volume of the polymers. 

Consistency. Lecithins are available in both fluid and plastic (solid) forms. Fluid lecithins generally follow Newtonian flow characteristics. The viscosity profile of lecithins is a complex function of acetone-insoluble content, moisture, mineral content, acid value, and the combined effects of assorted additives such as vegetable oils and surfactants. Generally, higher AI and/or moisture content yields higher viscosity, whereas an increased AV often decreases viscosity. Certain divalent minerals, such as calcium and others, can also adjust the viscosity level. 

The effect of plasticizer on the conversion level at the deviation point was very apparent (Table V, Figure 8). At 10% of plasticizer addition, the conversion level at deviation point increased twice (Table V, elastomers A and C). 

The concept of modern multilayer packaging means that there is a minimum use of plastic material, because various characteristics can be combined into one thin packaging film. The most widely used plastic for combination is PE. The PA-PE combination processed by coextrusion has a good gas resistance. It can be deep drawn, and its fat resistance and IlexibiUty are suitable, too. These combinations are very widely used for vacuum packages. In addition, the PET-PE combination is heat resistant, and the PE-PP is sterilizable. As an illustration of the effectiveness of plastic composites, WilUams presents multilayer plastic... 

If one could conclusively show that there is an effect of plasticizers on reaction rate that is independent of moisture content or a , then this would demonstrate the significance of matrix properties for governing reaction rate. Labuza et al. (1977) studied the Maillard reaction and measured the effects of several parameters. These included temperature, reactant concentration, pH, buffers, and the addition of humectants. The formulation consisted of glucose and casein as reactants within a carrier matrix of microcrystalline cellulose and an inert lipid. Reaction rate was measured both as glucose loss, lysine loss, and pigment production (A42o). 

Role of partially water soluble additive solvents. There have been published many studies on the membrane formation mechanism and the effects of solvents, additives (swelling agents or poreformers) and precipitants. Membrane performance and morphology are well correlated to polymer precipitation rate in nascent membrane (. Low precipitation rate generally produces membranes of finely pored sponge substrate structure with low solute permeation. Remarks on solvent-precipitant interaction by Frommer et al. (3) is helpful to speculation on membrane formation. In the following paragraphs is discussed the role of partially water soluble solvent as a plasticizer of nascent membrane matrix. 

Figure 6-5 shows the burning rate characteristics as a function of (N02). The burning rate increases linearly as pressure increases in In p versus In r plots and also increases as (N02) increases. The effect of the addition of the plasticizer, DEP, on the burning rate is evident, i.e., the burning rate decreases as the energy content... 

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