Polyolefin polymer suppliers

Table 4. Polyolefin Polymer Suppliers for Hot Melt Adhesive Applications.

In the 1970s, a number of polymer suppliers introduced a marketing policy which discontinued the supply of polyolefin compounds in favour of supplying natural materials. The discontinued compounds included black polyethylene for water pipe extrusion in which the pipe producers substituted the black compound fed to their extruders with pellet blends of natural polyethylene and carbon black masterbatch. 

Within that framework, the most effective constructions to meet existing requirements have been developed based on a variety of polymers including poly(vinyl chloride) (PVC), polyolefins, silicones, and fluoropolymers. Researchers are continually striving to develop more cost-effective compositions and cable constructions to enable replacement of more expensive materials with less expensive ones. In some cases, OEMs, cable manufacturers, and material suppliers are working to pass new standards that allow for substitution of new classes of materials or designs. 

For example, the examination of mixtures of polyamides and polyolefins is relatively easy because the polyamide component can be degraded by acid hydrolysis, and the resulting low molecular weight fragments can then be identified according to the procedure described in Section 6.2.10. The Table 1.3 lists some of the most important polymer blends together with their trade names and suppliers. 

MAJOR SUPPLIERS Equistar Chemicals LP, Dow Chemical Co., Chevron Chemical Co., Du Pont Co., Exxon Chemical Co., Eastman Chemical Co., Union Carbide Corp., Mobil Polymers, Montell Polyolefins, Solvay Polymers, Inc., Novacor Chemicals, Inc. 

There were also attempts to calibrate the SEC columns with help of broad molar mass dispersity poplymers but this is less lehable. The most common and well credible SEC cahbration standards are linear polystyrenes, PS, which are prepared by the anionic polymerizatioa As indicated in section 11.7, according to lUPAC, the molar mass values determined by means of SEC based on PS calibration standards are to be designated polystyrene equivalent molar masses . Other common SEC calibrants are poly(methyl methaciylate)s, which are important for eluents that do not dissolve polystyrenes, such as hexafluoroisopropanol, further poly(ethylene oxide)s, poly(vinyl acetate)s, polyolefins, dextrans, pullulans, some proteins and few others. The situation is much more complicated with complex polymers such as copolymers. For example, block copolymers often contain their parent homopolymers (see sections 11.8.3, 11.8.6 and 11.9). The latter are hardly detectable by SEC, which is often apphed for copolymer characterization by the suppliers (compare Figure 16). Therefore, it is hardly appropriate to consider them standards. Molecules of statistical copolymers of the same both molar mass and overall chemical composition may well differ in their blockiness and therefore their coils may assume distinct size in solution. In the case of complex polymers and complex polymer systems, the researchers often seek support in other characterization methods such as nuclear magnetic resonance, matrix assisted desorption ionization mass spectrometry and like. 

EPDM and EPR are used to modify polyolefins, primarily in the automotive industry. The largest volume is in automotive PP bumpers. This application is gradually being replaced by impact-resistant polymers produced by metallocene technology, providing better performance and economics. DuPont Dow and Exxon are leading producers in North America. When used with plastics such as nylon, PET, and PBT, the EPDM and EPR are often modified with a functionalized monomer to allow them to react with the plastic. Additionally, the shell of a core-shell modifier can also be modified to include a reactive group. Suppliers of fimctionalized modifiers include Rohm Haas, AtoFina, Shell, and Exxon. 

Polymers, composed of long molecules based on carbon-carbon links, are inherently combustible. Many, such as the polyolefins, have a much higher calorific value than coal. It is not surprising that the materials suppliers have invested enormous resources into improving the flammability resistance of plastics. There are many ways of assessing burning performance, e.g. ... 

Key processes, in use today, can be retrofitted with metallocenes to produce designed polymers. The catalyst can be used in solution or slurry processes. It can also be used in gas-phase processes. High catalyst productivity minimizes catalyst removal needs and attendant waste streams. Metallocene catalysts offer process optimization opportunities that benefit both the resin supplier and the convertor. In Table 14a, the demand for metallocene-catalyzed polyolefins, polystyrene, and copolymers has been projected up to the year 2010. 

Metallocene based polyolefins and polyolefin elastomeric compositions (POE) are often noted in supplier product literature to exhibit useful (and commercially viable) properties in blends with other polyolefins. Metallocene based polyethylene has also been noted to have the potential to replace the LLDPE/LDPE blends that are employed in a myriad of film applications [32 ]. PP/metaUocene ethylene-a-olefin copolymer blends for car interior applications have been noted [33 ]. MetaUocene-LLDPE blends with HDPE have been proposed for heavy-duty industrial grade bags as well as food packaging films [34]. Exxon-Mobil product literature notes the utility and ease of blending the metallocene LLDPE Exceed with other polyolefins. PP/POE blends showed similar mechanical properties and lower viscosity than the more conventional PP/EPDM blends [35]. Polyolefin plastomers (POP) imder the tradename Affinity GA were introduced by Dow as a polymer blend additive to improve the flow without loss of... 

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