Compatibilizers commercial examples

PA s are excellent candidates for blending with PPE — each ingredient compensates for deficiency of the other. Since the resins are immiscible and brittle, they must be compatibilized and toughened. In consequence, PA/PPE blends comprise minimum four polymeric components PA, PPE, a styrenic modifier and an acidic com-patibilizer. Usually PA is the matrix in which PPE/styrenic resin domains are dispersed. As time progresses, these blends are getting more complex — examples are shown in Table 1.57. Commercial blends are Artley, Dimension , Luranyl , Lynex A and Xyron , Noryl GT, Remarry , Ultranyl , Vestoblend , etc. 

It is also not the purpose of this chapter to summarize examples of compatible polymer blends formed in a solution step involving dissolution of the polymer components. In some cases such blends are only pseudo-stable , since they may not have been processed above the Tg of one or both of the components. Also, mixing in solution followed by devolatilization is rarely economical for practice in industry, particularly since many commercially important compatibilized polymer blends comprise at least one semicrystalline component e.g., PA) which is poorly soluble in common solvents. There are included in the Tables a small number of examples of solution blended polymer blends when these complement similar examples prepared by melt processing. 

Furthermore, glycerol is not added to the mixture. This reduces the water absorbency of the final product (13). An example of a grafting compound is maleic anhydride (MA). An example of a good compatibilizer is poly(ethylene) (PE) containing approximately 5% MA which is commercially available and only slightly more expensive than pure poly (ethylene). 

Multiphase polymer blends are of major economic importance in the polymer industry. The most common examples involve the impact modification of a thermoplastic by the microdispersion of a rubber into a brittle polymer matrix. Most commercial blends consist of two polymers combined with small amounts of a third, compatibilizing polymer, typically a block or graft copolymer. 

In these blends, ABS s role is to improve flowabihty and reduce cost, while that of PSF is to improve the shape retention at high temperatures. ABS/PSF blends are compatibilized either by phenoxy, EVAc-GMA, or SMA copolymers. They have good processability, high notched Izod impact strength, plateability, hydrolytic stability, and economy. However, they may show poor surface and weld-line strength. Arylon and Mindel A are examples of the commercial ABS/PSF alloys, while Ucardel is an example of PSF blends with SAN. Evolution of ABS/PSF blends technology is summarized in Table 1.19. 

Blending PPE with either PEST or PC poses similar problems - the polymers are immiscible and brittle, hence require compatibilization and toughening. The PEST/ PPE blends are multicomponent systems, with > 5 components PEST, PPE, styrenic copolymer, compatibilizer, and impact modifier. Examples of commercial blends are Dialoy X, Gemax , or lupi-ace . For improved modulus and dimensional stability, they are usually reinforced with GF. These alloys are known for excellent processability, high solvent resistance, and dimensional stability. Evolution of these systems is outlined in Table 1.64. 

In this section, we discuss a specific example of a compatibilized recycled PP-HDPE system. An extrusion-compounding process that is representative of a typical commercial operation was used for blending. Detailed process and economic analyses are presented. 

Besides copoljmiers synthesized specially for compatibilization of immiscible poljmiers, commercial products (typically used as impact modifiers) are utilized as compatibilizers in research as well as in practice. Typical examples are styrene-butadiene block copolymers and their styrene-hydrogenated butadiene analogues used for compatibilization of styrene pol5miers (PS, HIPS, SAN, ABS), with polyolefins (49), or ethylene-propylene copol5miers for compatibilization of various polyolefins (50). 

Polymer alloys are a commercial polymer blend with improvement in property balance with the use of compatibilizers. They exhibit an interface and show varied physical characteristics. Sometimes they have excellent physical properties in one area but possess poor physical properties in others. For example, silicone rubber has poor oil and abrasion resistance but possess excellent heat resistance. A product solution in this regard would be to obtain a polymer blend with constituents possessing physical properties that complement each other such that the resultant polymer blend would exhibit superior physical properties compared with the components of the blend. 

Monomeric liquid plasticizers are closely analogous to monomeric solvents. If two polymers are immiscible, but are both miscible with the same plasticizer, adding this plasticizer to the polymer blend may improve its compatibility. For example, blends of CPE with polyvinyl chloride were compatibilized by addition of 50% of dioctyl phthalate plasticizer [67]. In commercial practice, polyvinyl chloride -I- polyurethane are sometimes compatibilized in a similar way. 

Current commercial practice is still quite new and secretive. Most commercial blends name the polymers in the blend, but rarely the technique or additives used to compatibilize them. From the public literature and informal discussions, it would appear that the most common technique is peroxide-initiated grafting of maleic anhydride onto an active hydrogen or a vinyl group in the backbone of polymer A, to attract or react it with a more polar group in polymer B. Most common examples of polymer A are polyethylene. 

Reactive compatibilization dominates, in some fashion or another, commercial blending practices today, and is the main theme of this volume. The chapters that follow look at the fundamentals that enable this approach to material design, and will cover the important practical examples of implementation. 

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