Polymeric materials polyolefins

CAS 6683-19-8 EINECS/ELINCS 229-722-6 Uses Antioxidant, heat stabilizer for org. and polymeric materials, polyolefin, elastomer, acetal, acrylic, PET, PU, PMMA, PVC, food-contact adhesives/coatings/paper/polymers, petrol, prods., coatings Features Nondiscoloring, nonstaining U.S. patents3,285,855 and 3,644, 482... 

Polyolefins are one of the most important synthetic polymeric materials in all spheres of human activities ranging from packaging and construction to computer science and medicine. Similar to other polymeric materials, polyolefins are distributed in their molecular properties and in-depth analysis of these properties is required using the most sophisticated analytical methods. This helps to establish structure-property relationships and broadens the application of polyolefins in science and technology. In this review we have discussed recent developments in different analytical techniques for polyolefin analysis. 

F. Molesky in Recent Advances in Flame Retardamy of Polymeric Materials, Stamford, Coim., 1990 F. Molesky, "The Use of Magnesium Hydroxide for Flame Retarded Low Smoke Polypropylene," Polyolefins IHInternational Conference, Feb. 24,1991, Houston, Tex. 

Hindered Amines. Hiadered amines are extremely effective ia protecting polyolefins and other polymeric materials against photodegradation. They usually are classified as light stabilizers rather than antioxidants. 

Polyolefins represent one of the main types of synthetic polymeric materials. World production of polyolefins in 1980 amounted to 23 million tons, and since then the tendency to further growth has been prevailing [1]. The grave defect of polyolefins is low thermal and heat resistance, which is detrimental to the processing efficiency and limits their useability (Table 1). 

The synthesis of new polymeric materials having complex properties has recently become of great practical importance to polymer chemistry and technology. The synthesis of new materials can be prepared by either their monomers or modification of used polymers in industry. Today, polystyrene (PS), which is widely used in industrial applications as polyolefins and polyvinylchlorides, is also used for the production of plastic materials, which are used instead of metals in technology. For this reason, it is important to synthesize different PS plastic materials. Among the modification of PS, two methods can be considered, viz. physical and chemical modifications. These methods are extensively used to increase physico-mechanical properties, such as resistance to strike, air, or temperature for the synthesizing of new PS plastic materials. 

Poly(hydrosilane)s have been successfully applied as processing stabilizers for organic polymeric materials subject to oxidative degradation. The degradation of polyolefins during processing takes place by a widely accepted... 

Billions of pounds of polyolefins are produced annually in the world [1], Through simple insertion reactions, inexpensive and abundant olefins are transformed into polymeric materials for a wide range of applications including plastics, fibers, and elastomers. Despite its long history, the polyolefin industry continues to grow steadily and remains technologically driven because of continuous discovery of... 

Generally, a distinction can be made between membrane bioreactors based on cells performing a desired conversion and processes based on enzymes. In ceU-based processes, bacteria, plant and mammalian cells are used for the production of (fine) chemicals, pharmaceuticals and food additives or for the treatment of waste streams. Enzyme-based membrane bioreactors are typically used for the degradation of natural polymeric materials Hke starch, cellulose or proteins or for the resolution of optically active components in the pharmaceutical, agrochemical, food and chemical industry [50, 51]. In general, only ultrafiltration (UF) or microfiltration (MF)-based processes have been reported and little is known on the application of reverse osmosis (RO) or nanofiltration (NF) in membrane bioreactors. Additionally, membrane contactor systems have been developed, based on micro-porous polyolefin or teflon membranes [52-55]. 

Plastics are by far the largest group of polymeric materials being processed by electron beam irradiation. Cross-linking of polyolefins, PVC, polyesters, polyurethanes, fluoropolymers, and fiber-reinforced composites is a common practice. 

In terms of tonnage, polyolefins are by far the most important polymeric materials for structural applications, and there is consequently enormous interest in optimising their fracture properties. A rational approach to this requires detailed understanding of the relationships between macroscopic fracture and molecular parameters such as the molar mass, M, and external variables such as temperature, T, and test speed, v. Considerable effort is therefore also devoted to characterising the irreversible processes (crazing and shear deformation) that accompany crack initiation and propagation in these polymers, some examples of which will given. 

The second article by Kawahara and his coworkers focuses on polyolefin (PO)-based hybrid materials (POH), in view of their synthesis, structures, and properties. POs are currently the most widely and conveniently used polymeric materials as recognized by the production amount of over one hundred million tons annually in the world, due to the cheap price yet good properties. They are basically hydrocarbon polymers, and hence hydrophobic and less polar. These basic properties are to be modified by introducing a polar function for a wider use in practical applications. Preparation of POHs is one of the best ways to... 

Metal hydroxides in combination with various silicon-containing compounds have been used to reduce the amount of additive required to achieve a required level of flame retardancy in a variety of polymeric materials, including polyolefins.62-63 Systems that have been used contain a combination of reactive silicone polymers, a linear silicone fluid or gum, and a silicone resin, which is soluble in the fluid, in addition to a metal soap, in particular magnesium stearate. However, there is little insight given into how these formulations work. 

Green, J., The flame retardation of polyolefins, in Flame-Retardant Polymeric Materials, Volume 3, Lewin, M., Atlas, S.M., and Pearce, E.M. (Eds.), Plenum Press, New York, 1982, Chapter 1, pp. 1-37. 

The development of commercially useful polymers in the early 20th century ushered in an era where mass-produced, organo-polymeric materials have become a ubiquitous part of daily life. " Sixty years after the Nobel prize-winning discovery by Ziegler and Natta, " the scale of worldwide polyolefin production is massive. The current estimated aimual global production of polyolefins is over 150 million metric tons. However, the inherent chemical inertness of these substances causes them to persist in the environment centuries after they have been discarded. The detrimental environmental impact of a man-made waste problem of this scale has generated an interest in commercially viable, biodegradable alternatives. ... 

---