Polymers high density

Second, in the early 1950s, Hogan and Bank at Phillips Petroleum Company, discovered (3,4) that ethylene could be catalyticaHy polymerized into a sohd plastic under more moderate conditions at a pressure of 3—4 MPa (435—580 psi) and temperature of 70—100°C, with a catalyst containing chromium oxide supported on siUca (Phillips catalysts). PE resins prepared with these catalysts are linear, highly crystalline polymers of a much higher density of 0.960—0.970 g/cnr (as opposed to 0.920—0.930 g/cnf for LDPE). These resins, or HDPE, are currentiy produced on a large scale, (see Olefin polymers, HIGH DENSITY POLYETHYLENE). 

These results at 20° C refer to low stress moulded parts made from Makrolon. The chemical resistance of this material may be affected by mechanical stresses and high temperatures. The polymer High Density 3... 

High density polyethylene, shown in Fig. 18.2 a), consists primarily of linear hydrocarbon chains of the type shown in Fig. 18.1. We commonly abbreviate its name to HDPE. As with all other polymers, high density polyethylenes contain a distribution of molecular weights. The molecules have few, if any, branches. 

Olefin polymers -high density polyethylene [OLEFIN POLYMERS - POLYETHYLENE - HIGH DENSITY POLYETHYLENE] (Vol 17) -m hydraulicfluids [HYDRAULIC FLUIDS] (Vol 13) -linear low density polyethylene [OLEFIN POLYMERS - POLYETHYLENE - LINEAR LOW DENSITY POLYETHYLENE] (Vol 17) -low density polyethylene [OLEFIN POLYMERS - POLYETHYLENE - LOW DENSITY POLYETHYLENE] (Vol 17) -polyethylene [OLEFIN POLYMERS - POLYETHYLENE - INTRODUCTION] (Vol 17) -polymers of higher olefins [OLEFIN POLYMERS - POLYMERS OF HIGHER OLEFINS] (Vol 17) -polypropylene [OLEFIN POLYMERS - POLYPROPYLENE] (Vol 17)... 

Yury V. Kissin, Mobil Chemical Company. Edison. NJ. htlp/Acwu. csxonmobilchcmical.com/. Polyethylene (under Olefin Polymers) High Density Polyethylene (under Olefin Polymers) Linear Low Density Polyethylene (under Olefin Polymers) and Polymers of Higher Olefins (under Olefin Polymers)... 

Thc ic results t 2I) C ctci to ow stress moiildct P ladc iVom Makrolon The clicmi al C of this nv 1 m V be affected b V mccha ical stresses and h eh tempera. I hc polymer High Density X... 

Figure 2.13 Examples of crystalline polymers high-density polyethylene (EIDPE), isotactic polypropylene (PP) and polyamide-6 (Nylon-6).

Figure 3-29. Effect of Glass Fiber Content on Deflection Temperature Under Load (DTUL) for Two Amorphous Polymers (Polycarbonate and Polystyrene) and Two Crystalline Polymers (High-Density Polyethylene and Nylon 6/6) (Typically, the optimum effect is reached at 20% glass fiber content, with the exception of nylons where 30% is the optimum.)...

Properties of semicrystalline thermoplastics are normally enhanced via reinforcing filler. However, the type and amount of such fillers would complicate any comparison. Hence, properties of various unfilled semicrystalline resins are compared shown in Tables 1.1-1.3. For comparison two commodity semicrystalline polymers, high density polyethylene (HDPE) and polypropylene (PP), are included in Table 1.1. Table 1.1 summarizes properties of HDPE, PP, POM, and polyesters. Table 1.2 contains properties of polyamides and SPS. Table 1.3 lists properties of the highly aromatic, semicrystalline polymers. Clearly, semicrystalline ETPs exhibit very broad performance enhancements over commodity semicrys-talhne polymers. 

HDPE [OLEFIN POLYMERS - POLYETHYLENE - HIGH DENSITY POLYETHYLENE] (Vol 17)... 

The protonated form of poly(vinyl amine) (PVAm—HCl) has two advantages over many cationic polymers high cationic charge densities are possible and the pendent primary amines have high reactivity. It has been appHed in water treatment, paper making, and textiles (qv). The protonated forms modified with low molecular weight aldehydes are usehil as fines and filler retention agents and are in use with recycled fibers. As with all new products, unexpected appHcations, such as in clear antiperspirants, have been found. It is usehil in many metal complexation appHcations (49). 

C. C. Shiflett, D. B. BuchhoF, and C. C. Faudskar, "High-Density Multilayer Hybrid Circuits Made with Polymer Insulating Layers (Polyhic s)," Society of Hybrid Microelectronics Proceedings, 1980, pp. 481—486. 

The problems of monomer recovery, reaction medium viscosity, and control of reaction heat are effectively dealt with by the process design of Montedison Fibre (53). This process produces polymer of exceptionally high density, so although the polymer is stiU swollen with monomer, the medium viscosity remains low because the amount of monomer absorbed in the porous areas of the polymer particles is greatly reduced. The process is carried out in a CSTR with a residence time, such that the product k jd x. Q is greater than or equal to 1. is the initiator decomposition rate constant. This condition controls the autocatalytic nature of the reaction because the catalyst and residence time combination assures that the catalyst is almost totally expended in the reactor. 

The most important stmctural variables are again polymer composition, density, and ceU size and shape. Stmctural foams have relatively high densities (typically >300 kg/m ) and ceU stmctures similar to those in Figure 2d which are primarily comprised of holes in contrast to a pentagonal dodecahedron type of ceU stmcture in low density plastic foams. Since stmctural foams are generally not uniform in ceU stmcture, they exhibit considerable variation in properties with particle geometry (103). 

The variation in total thermal conductivity with density has the same general nature for ah. cellular polymers (143,189). The increase in at low densities is owing to an increased radiant heat transfer the rise at high densities to an increasing contribution of k. ... 

The majority of spunbonded fabrics are based on isotactic polypropylene and polyester (Table 1). Small quantities are made from nylon-6,6 and a growing percentage from high density polyethylene. Table 3 illustrates the basic characteristics of fibers made from different base polymers. Although some interest has been seen in the use of linear low density polyethylene (LLDPE) as a base polymer, largely because of potential increases in the softness of the final fabric (9), economic factors continue to favor polypropylene (see OlefinPOLYMERS, POLYPROPYLENE). 

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