Blended polymers, additive coloring effects

None of this of course is new information. But it can be forgotten. The purpose of this paper is to present information that unequivocally shows that color should not be an afterthought in the development cycle. Discussion will be focused on describing adverse effects on colorability attributed to the base polymer itself, other blended polymers, modifiers, additives and stabilizers. [Note since this paper is written by a colorist, information will be presented in the spirit of the pure colorant being adulterated by the polymer system and all of its additives ]... 

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

Thus, the thermal stabilization of PVC which resulted from the heterogeneous grafting of as little as 3-5% cis-1,4-polybutadiene was more than a simple additive effect and indicates a synergistic interaction. This was demonstrated further by dissolving up to 10% cis-1,4-polybuta-diene in a chlorobenzene suspension or solution of PVC and isolating the polymer blend by precipitation with methanol. Films pressed from the polymer blend were generally deeply colored and contained incompatible, probably gelled or crosslinked, areas. 

The above discussion deals with the base polymer only. One can see that if the additive system imparts light scattering similar to these examples above, the effect on coloring the total resin system can be dramatic. We begin our discussion of additives by looking at polymer blends, where the secondary polymer can be considered an additive to the continuous base polymer. 

So is the case in polymers and blends. As will be shown, some polymer systems can impart so much light scattering that certain colors can no longer be achieved. Or if they can be achieved, other properties may be adversely affected such as impact strength and cost. In either case, the practical color gamut or palette that is obtainable with this particular resin system is reduced. The discussion below presents the effects that the polymer and its additives can have on colorability. 

A wide variety of additives and modifiers are incorporated into polymers and polymer blends to tailor specific properties. Unfortunately, these additives can also impact the colorability to the total resin system. Listed below are some common additives and modifiers used in polymers and a short discussion of their typical effect on colorability. 

The effects of BPA-PC molecular weight dominate the properties of blends that contain this material. Modifications are also made by blending with other polymers and the use of additives to achieve specific effects. These additives may be UV stabilizers, thermal stabilizers, flame retardants, mold release agents, fillers, colorants, impact modifiers, etc. Blends are made with... 

Commercial plastics are invariably mixtures of one or more polymers blended with a variety of additives such as colorants, flame-retardants, biocides, etc., all tailored to achieve cost-effective performance for specific applications or processibility requirements. For example, flexible PVC for wire insulation contains one or more plasticizers, and poly (2,6-dimethyl-1,4-phenylene oxide) (PPO), an engineering plastic, is marketed in several grades which may contain varying amounts of lubricants, stabilizers, fillers etc., in addition to the high-impact PS (HIPS) which is added to PPO to modify impact properties and melt viscosity. 

The applications of the soluble polythiophene derivatives to the PLED are advantageous in that their polymer blends or composites can be easily formed [147]. Berggren et al. [126] have recently reported that these polymer blends (e.g. a mixture of different kinds of polythiophene derivatives) exhibit voltage controlled colors in electroluminescence. This effect was explained by the assumption that a number of nano-PLEDs of 50-200 nm in size yielded by micro phase separation are coupled parallel and operate in a specific voltage range depending upon the polymer species [126,130,131]. In addition, these nano-PLEDs dispersed in an insulator matrix such as poly(methyl methacrylate) display white hght emission with quantum efficiency ofO.4-0.6% [133]. 

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