Polyethylene technologies

Polyethylene. Traditional melt spun methods have not utilized polyethylene as the base polymer because the physical properties obtained have been lower compared to those obtained with polypropylene. Advances in polyethylene technology may result in the commercialization of new spunbonded stmctures having characteristics not attainable with polypropylene. Although fiber-grade polyethylene resin was announced in late 1986 (11,12), it has seen limited acceptance because of higher costs and continuing improvements in polypropylene resin technology (see Olefin POLYMERS, POLYETHYLENE). 

Knuuttila, H., Lehtinen, A. and Nummila-Pakarinen, A. Advanced Polyethylene Technologies - Controlled Material Properties. Vol. 169, pp. 13-27. 

DE, http //www.dupunt.com/ag/, Information Retrieval Lloyd W. Pebsworth, Polyethylene Technology. Morris. IL Low Density Polyethylene (under Olefin Polymers)... 

Advanced Polyethylene Technologies— Controlled Material Properties... 

The big revolutionary improvements in polyethylene technology have occurred in steps of 20 years (Fig. 1) [2]. In each new development step, catalyst and process innovations have gone hand-in-hand and the control over the polymer structure and the ability to tailor material properties have increased. Today ethylene can be polymerised under various conditions to yield polyethylenes having markedly different chain structures and physical... 

Fig. 1 Polyethylene technology S curve (modified from S curve by ChemSystem)...

Synthesis. The early PP plants used a slurry process adopted from polyethylene technology. An inert liquid hydrocarbon diluent, such as hexane, was stirred in an autoclave at temperatures and pressures sufficient to keep 10-20 percent of the propylene monomer concentrated in the liquid phase. The traditional catalyst system was the crystalline, violet form ofTiCl3 and A1C1(C2H5)2. Isotactic polymer particles that were formed remained in suspension and were removed as a 20-40 percent solid slurry while the atactic portion remained as a solution in the liquid hydrocarbon. The catalyst was deactivated and solubilized by adding HC1 and alcohol. The iPP was removed by centrifuging, filtration, or aqueous extraction, and the atactic portion was recovered by evaporation of the solvent. The first plants were inefficient because of low catalyst productivity and low crystalline yields. With some modifications to the catalyst system, basically the same process is in use today. 

Definitions of abbreviations, acronyms and terms are in context of polyethylene technology may be different in other contexts... 

Meola, C. Nele, L. Giuliani, M. Suriano, P. Chemical and irradiation crosslinking of polyethylene. Technological performance over costs. Polym. Plast. Technol. Eng. 2004, 43 (3), 629-646. 

Folie B., and Radosz, M., 1995. Phase equilibria in high pressure polyethylene technology. Ind. Eng. Chem. Res., 34 1501-1516. 

Eor polymer systems, most applications are related to the high-pressnre polyethylene technology. Typical results are shown in Fignres 16.8 through 16.13. 

In 1961, the first plant using Standard Oil of Indiana polyethylene technology only went on stream in Japan [2]. Unfortunately, the early Standard Oil of Indiana discovery had little impact on the developing linear PE industry, and within a few years the process was dead. 

One of the concerns in commercial wire and cable application of crossllnked polyethylene technologies is the type and amounts of peroxide decomposition products (Figures 3 and 4) and their relationship to the polymer s dielectric strength performance capabilities. Peroxide decomposition products such as acetophenone have been shown to Increase the breakdown voltage limits of chemically crossllnked polyethylene materials (Figure 5). (2)... 

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