Examples of Commercial Blends

Examples of Commercial Blends. In this subsection we will review some of the commercial activity in polymer blends. We find it interesting and informative to categorize examples into specific areas that relate to both technical issues associated with these mixtures, such as miscibility or crystallinity, and the intended commercial applications, such as rubbers or fibers. Other schemes of classification could be used, and the present one is not intended to be exhaustive. Likewise, there is no intent to mention all of the commercially interesting polymer blends, but rather, the present purpose is to illustrate some of the possibilities. Information about the examples used here was obtained from product literature supplied by the companies who sell these blends and from various literature references that have attempted to review commercial developments in polymer blends (70-76). 

Since most of the applications of the PMMA type acrylic resins are based on their high degree of transparency and UV resistance characteristics, there has been little commercial interest or motivation in developing acrylic blends. This is understandable because unless there is complete, molecular level miscibility between the components, it is not possible to maintain a high degree clarity in the blends. Nevertheless, several examples of commercial blends of acrylic resins are known. These will be discussed under separate headings. 

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. 

The processability of the final material may also be improved, included here the resistance to chemical decomposition during processing, among other features. Examples of commercial blends are modified starch + PEAT (e. g., Novamont - MaterBi Com Products/Basf - Ecobras) for films, thermoformed and injection moulded parts PEAT + PLA (e. g., BASF - Ecovio) for films, thermoformed and extmded parts PLA + starch (e. g., Cereplast - Cereplast Compostables) for bags and packaging, injection moulded and extmded articles for food, pens, etc. 

Examples of commercial PVC/acrylics blends are Acrylivin , Decoloy , Enplex , Hostalit , Kane-ace , Kydene Metabulen or Vinidur . The blends have been used for industrial, commercial, and consumer goods, in medical, electrical, and chemical engineering equipment, for food... 

The oldest and most common method of POM toughening is by incorporation of TPU. Delrin POM/TPU blends were commercialized in 1960. The others followed, e.g., Celcon , Duraloy , Formaldafil , Fulton KL, Hostaform , RTP 800, TC, or Ultraform . These alloys have high impact strength and elastic recovery that depend on composition, morphology, as well as on the compounding and processing methods. Examples of these blends are listed in Table 1.66. 

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. 

Blends of butadiene-acrylonitrile copolymer rubber (nitrile rubber or NBR) and PVC are among the oldest known examples of commercial elastomer/ thermoplastic blends. The shortage of natural rubber during World War II stimulated research in the USA on the compounding and modification of synthetic polymers to produce rubber-like materials. An outcome of this research was the commercial introduction of NBR/PVC blends by B.F. Goodrich in 1947 under the trade name of Geon Polyblends [Pittenger and Cohan, 1947]. The blend showed improved ozone resistance and melt processability compared to the nitrile rubber (Table 15.12). 

Some of the methods (a) i) are used for the production of commercial blends, but others have so far been used mainly on an experimental scale. An example of the latter is (a), because the production of small quantities of the specific graft or block copolymer is very expensive. 

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. 

---