Addition polymers polyolefins

A few approaches followed the tack of modifying the very inexpensive commodity addition polymers, polyolefins, to control and increase the rate of oxidation and hence hydropilicity of the polymer which enhanced degradation and biodegradation rates. 

A series of compounded flame retardants, based on finely divided insoluble ammonium polyphosphate together with char-forming nitrogenous resins, has been developed for thermoplastics (52—58). These compounds are particularly useful as iatumescent flame-retardant additives for polyolefins, ethylene—vinyl acetate, and urethane elastomers (qv). The char-forming resin can be, for example, an ethyleneurea—formaldehyde condensation polymer, a hydroxyethylisocyanurate, or a piperazine—triazine resin. 

The polymer/additive system in combination with the proposed extraction technique determines the preferred solvent. In ASE the solvent must swell but not dissolve the polymer, whereas MAE requires a high dielectric solvent or solvent component. This makes solvent selection for MAE more problematical than for ASE . Therefore, MAE may be the preferred method for a plant laboratory analysing large numbers of similar samples (e.g. nonpolar or polar additives in polyolefins [210]). At variance to ASE , in MAE dissolution of the polymer will not block any transfer lines. Complete dissolution of the sample leads to rapid extractions, the polymer precipitating when the solvent cools. However, partial dissolution and softening of the polymer will result in agglomeration of particles and a reduction in extraction rate. 

If the focus is on a wide variety of additives in polyolefins only the OSM/TSM procedure of Marcato and Vianello [210] appears to be far reaching, despite the fact that this total design approach must have required considerable effort in terms of method development. On the other hand, in comparison considerably more method development and optimisation appears to be necessary for SFE of a single polymer/additive matrix, but even then still without the demonstrated benefit of a total approach [322]. Where analyte integrity is of greater concern recourse should be taken to less... 

The additive analysis reported has been largely confined to conventional polymers (polyolefins, polycondensates, PS, PVC, etc.) Very little work, if any, has been reported on advanced engineering plastics. Similarly, also relatively little research activity has focused on additives in acrylics or blends. 

In addition to the above-mentioned polymers, other addition polymers such as polyolefin, polystyrene, polyvinylethers, polychloral, polyisocyanides, polyacetylene, and polyethers were synthesized and evaluated as the precursors for the preparation of CSPs. Some of them were coated or chemically bonded to silica gel and tested for the chiral resolution of different racemic compounds. 

Most commonly used separator materials for alkaline Zn/Mn02 batteries are nonwoven polymers, such as cellulose, vinyl polymers, polyolefin, and others. The separator materials must be chemically stable in concentrated KOH solutions and electrochemically stable under both oxidizing and reducing conditions in the cell. In addition to its good electronic insulation, physical strength, and porous structure, good wettability to concentrated KOH solutions is especially crucial to provide a good ionic pathway for the battery operation. 

The analysis of antioxidants is based on their non-volatile nature, their modest molecular weight and the fact that they absorb light due to their chro-mophore groups. In works concerning the separation of additives from polyolefins the main difficulty is generally to achieve the extraction and recovery in a reasonable time. Differences in shape, size or thickness of a polymer film or the presence of other additives may significantly affect the result of the extraction and analysis of the antioxidant content in a polymer. Consequently, method development has to be performed to find standardized methods. 

Choice of Solvent. The most appropriate solvent for NMR studies of polymers would allow a range of polymer concentrations to be investigated, be free of overlap problems and hopefully provide a signal for internal lock. Not all of these conditions can usually be met as many high molecular weight polymers pose solubility problems and can be examined in only a limited number of solvents. Deuterium resonance is the typical choice for an internal lock signal on most modern NMR spectrometers. Unfortunately, the majority of available deuterated solvents are poor solvents for many addition polymers such as the polyolefins while it is generally possible to find a number of appropriate deuterated solvents for many of the condensation polymers. The... 

Thermal processes are mainly used for the feedstock recycling of addition polymers whereas, as stated in Chapter 2, condensation polymers are preferably depolymerized by reaction with certain chemical agents. The present chapter will deal with the thermal decomposition of polyethylene, polypropylene, polystyrene and polyvinyl chloride, which are the main components of the plastic waste stream (see Chapter 1). Nevertheless, the thermal degradation of some condensation polymers will also be mentioned, because they can appear mixed with polyolefins and other addition polymers in the plastic waste stream. Both the thermal decomposition of individual plastics and of plastic mixtures will be discussed. Likewise, the thermal coprocessing of plastic wastes with other materials (e.g. coal and biomass) will be considered in this chapter. Finally, the thermal degradation of rubber wastes will also be reviewed because in recent years much research effort has been devoted to the recovery of valuable products by the pyrolysis of used tyres. 

All vinyl polymers are addition polymers. To differentiate the, the homopolymers have been classified by the substituents attached to one carbon atom of the double bone. If the substituent is hydrogen, alkyl or aryl, the homopolymers are listed under polyolefins. Olefin homopolymers with other substituents are described under polyvinyl compounds, except where the substituent is a nitrile, a carboxylic acid, or a carboxylic acid ester or amide. The monomers in the latter cases being derivatives of acrylic acid, the derived polymers are listed under acrylics. Under olefin copolymers are listed products which are produced by copolymerization of two or more monomers. 

Addition polymers, such as vinyls, acrylics, fluoroplastics, and polyolefins, can hardly be reprocessed except that, if they are sorted, they maybe converted into powder by grinding operation and mixed with respective virgin resins for remolding into finished goods or, in some cases, blended with other resins using suitable compatibilizers to make useful end-products of commercial value. 

Italmatch introduces low-halogen flame retardant for polyolefins. Addit Polym [trade journal—Elsevier] Febmary 2007. 

Chem. Descrip. y-Methacryloxypropyltrimethoxysilane CAS 2530-85-0 EINECS/ELINCS 219-785-8 Uses Adhesion promoter for adhesives and coatings coupling agent for glass-reinforced and min.-filled thermosetting resins blend additive in resin systems (polyester, acrylic), and filled or reinforced thermoplastic polymers (polyolefins, polyurethanes)... 

Polymers prepared from alkenes (olefins), regardless of whether they are homopolymers or copolymers, are known as polyolefins and are the most familiar addition polymers. 

Not all addition polymers are polyolefins. Formaldehyde, for example, polymerizes to give an addition polymer that retains all of the atoms of the monomer. 

Polyolefin An addition polymer prepared from alkene monomers. 

Hindered amine stabilizers (HAS) are the most common class of the curative additives and their application is the state-of-the-art in photoprotection of carbon-chain polymers, polyolefins in particular. HAS shape future polymer development, promote their consumption in new areas and expand material performance by increasing its lifetime. Application of HAS is based on a long-term effective development and is connected with commercial benefits for polymers. An optimized technical application of HAS required explanation of their chemistry and activity mechanisms in different phases of the oxidative degradation of polyolefins [14-17]. 

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