Polyolefins electrical applications

Example 15.2 PVC has an advantage over other thermoplastic polyolefins in applications such as insulation for electrical circuitry in household electronic appliances. Explain. 

Keywords automotive, automotive application, car components, automotive requirements, substitution of metals and polymers, interior parts, exterior parts, electrical applications, filled PP, elastomer-modified PP, thermoplastic polyolefins (TPO), GMT-PP, long-fiber reinforced PP, composites, market trends, glass fiber (GF) reinforcement. 

The low concentrations of ozone normally present in the atmosphere are sufficient to cause severe oxidation and cracking in polyolefins (2-13) and many other polymers such as polystyrene (6,11,12,14.15). poly(vinyl chloride) ( y, J 2,J 6) and rubbers (11,12,17-20). Where the ozone concentration is increased by air pollution, higher altitudes or the present of electrical machinery, the rate of degradation considerably increases.The prevention of such degradation represents a matter of considerable economic interest since it can greatly improve service life of polymers and plastics. An additional application of this research is to apprise the suitability of polymers for upper atmosphere application (Space Shutle flights) where a plentitude of ozone and atomic oxygen prevails. 

Nonwoven materials such as cellulosic fibers have never been successfully used in lithium batteries. This lack of interest is related to the hygroscopic nature of cellulosic papers and films, their tendency to degrade in contact with lithium metal, and their susceptibility to pinhole formation at thickness of less than 100 fjim. For future applications, such as electric vehicles and load leveling systems at electric power plants, cellulosic separators may find a place because of their stability at higher temperatures when compared to polyolefins. They may be laminated with polyolefin separators to provide high-temperature melt integrity. 

Besides their two main uses as reinforcing fillers and pigments, small amounts of carbon blacks are used by the electrical industry to manufacture dry cells, electrodes, and carbon brushes. Special blacks are used to give plastics antistatic or electrical conduction properties. Another application is the UV stabilization of polyolefins [4.31]. 

Polyolefin transportation, industrial, electrical and electronic, construction generally for low cost applications can be easily tailored for specific applications. 

Solution Though polar, PVC-like nonpolar thermoplastics can be used as insulation for electrical wires in low-frequency applications. Prolonged use of hotrsehold electronic appliances has a tendency to generate heat. Therefore, these appliances can be a potential sotrrce of fire hazard. Unlike other thermoplastic polyolefins, PVC has inherent (built-in) fire retardancy because of its 57% chlorine content. This reduces the susceptibility to fire outbreak arising from prolonged use of household electronic apphances. 

The electrical properties of polymers that are of general interest are those related to the behavior of the polymer as an electrical insulating material. It is, however, true that such properties may be important in assessing the behavior and suitability of a material in applications that may not be electrical in nature (for example the dissipation factor may be useful to detect the presence of an unwanted contaminant in a polyolefine). 

Polyolefins are now being used increasingly in underground electricity transmission. Although not normally called geosynthetics in this application, the same durability characteristics are essential here. One of... 

MAJOR APPLICATIONS Blow molded bottles. Extruded film and sheets for food packaging, including blend, multilayer, and laminate with nylon 6, PET, and polyolefins. Monofilament for bristle and filter cloth. Glass fiber reinforced injection molding materials used to make parts for the automotive, machine, electrical/electronic, civil engineering, sports, and other industries as a metal substitute. 

MAJOR APPLICATIONS Automotive, business machine, and electrical/electronics industries. PPO is mainly used to manufacture blends with high-impact polystyrene (HIPS). PPO/nylon, PPO/PBT, and PPO/polyolefin blends are also available on the mcuket. PPO based materials rank first in terms of total consumption among blends based on engineering resins such as nylon, polycarbonate (PC), polyacetal, and reinforced terephthalate polyesters (PET and PBT).( ... 

Addition of micro- or nanofiUers or additives to the polyolefins can improve their properties for different modem applications such as in the automotive, furniture, medical, packaging, electrical, transportation, constmction, textile, and agriculture industries. These industries have been increasing over the last few decades. Additives can include diflerent shapes such as flakes, fibers, and particulate types. It can be of natural or synthetic nature. The additives can improve the performance of the new composites or nanocomposites of the polyolefins. 

Another commercially produced polyolefin is isotactic poly(4-methyl pentene-1). The polymer carries a trade name of TPX. This material is known for high transparency, good electrical properties, and heat resistance. PoIy(4-methyI pentene-1) has a density of 0.83 g/cm. This polyolefin exhibits poor load-bearing properties and is susceptible to UV degradation. It is also a poor barrier to moisture and gases and scratches readily. This limits its use in many applications. 

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