Polyolefins, uses

The stabili2ation of polyolefins used to insulate copper conductors requires the use of a long-term antioxidant plus a copper deactivator. Both A[,Ar-bis(3,5-di-/ A-butyl-4-hydroxycinnamoyl)hydra2ine (29) and 2,2 -oxamidobisethyl(3,5-di-/ A-butyl-4-hydroxycinnamate) (30) are bifimctional. They are persistent antioxidants that have built-in metal deactivators. Oxalyl bis(ben2yhdenehydra2ide) (28) is an effective copper deactivator when part of an additive package that includes an antioxidant. 

Polyolefins. The most common polyolefin used to prepare composites is polypropylene [9003-07-0] a commodity polymer that has been in commercial production for almost 40 years following its controlled polymerisation by Natta in 1954 (5). Natta used a Ziegler catalyst (6) consisting of titanium tetrachloride and an aluminum alkyl to produce isotactic polypropylene directly from propylene ... 

Polybutylene It is a polyolefin used for cold and hot water piping. As a blown film it is used for food packaging. 

Oligomeric additives with broad MWD tend to be a problem in conventional HPLC conditions. In cases where no interest exists in the oligomer distribution it is common practice to solve the problem by creating a uniform structural unit useful for analysis. For example, isocratic (or gradient) LC-UV was used for the determination of the polymeric light stabiliser Tinuvin 622 in polyolefins using dissolution (toluene)/derivatisation (TBAH)-precipitation (alcohol) the diol formed was quantitatively determined by NPLC [653]. 

These three polymeric HALS stabilisers can be detected and positively identified in extracts from polyolefins using an Agilent Ion-trap instrument with positive APCI. Figure 34 shows a chromatogram for a 5-ppm standard of Tinuvin 622 in tetrahydrofuran (THF) and the peak mass spectrum (Figure 35). Similar data for Chimassorb 944 in THF are shown in Figures 36 and 37, respectively. A Waters Xterra C8 150 x 2.00 mm 3 pm 125A column at 60°C with the mobile phase of isopropanol +700 pl/1 hexylamine was employed. 

More recently, Yang et al. [123] have examined a new approach in which a reactive functional group was introduced into polyolefins using methylenecyclopropane (Scheme 27). Thus, ethylene (1.0 atm) was copolymerized with methylenecyclopropane (0.25-2.5 ml) using [LnH(C5Me5)2]2 (Ln = Sm, Lu) in toluene at 25 °C. It was shown that 10-65 units of exo-methylenes were incorporated per 1000-CH2- units and the resulting polymer had an Mw of 66-92 x 103, yet its Mw/Mn was > 4. 

Hivalloy A process for grafting styrenic polymers on to polyolefines, using a Ziegler-Natta catalyst. The products combine the physical properties of both polymer types. Developed by Montell and commercialized in the United States in 1997. See also Catalloy. Oxley, D. F., Chem. Ind. (London), 1998, (8), 307. 

The radical initiated copolymerization of C2H4 and CO in the presence of a polyolefin has been reported to result in the grafting of the C2H —CO copolymer onto the polyolefin backbone31). Polyolefins used included polyethylene, ethylene-propylene copolymer and polyisobutylene. 

Symyx-Dow A process for making polyolefins using a hafnium-based metallocene catalyst that had been identified by the Symyx combinatorial method. Not commercialized in 2003. 

The photosensitizing action of Ti02 pigments in isopropanol depends on their crystal structure and the presence of any surface modifications. The Ti02-ZnO-photocatalysed oxidation of hexane is a good model for polyolefins. Using e.s.r. and luminescence spectroscopy, Ti centres have been... 

Since the early 1990s there has been considerable interest in metallocene-based polyolefines using catalysts incorporating anilines, in which the nitrogen is a preferred heteroatom for ligand attachment139. 

XX 10, 07, 03, 02 - designed for polyolefins used in automotive and apphance S.E.T., S.A., Leon, Spain Specialty Minerals, Easton, PA, USA PolyTalc AG Series AG... 

Recently Waymouth and Coates have demonstrated that it is also possible to produce an optically active polyolefin using a chiral non-racemic metallocene catalyst of the Brintzinger type. [7] Although optically active oligomers can be obtained in the presence of a resolved metallocene complex according to the above mentioned procedure... 

For polyolefins used under aggressive conditions (e.g. polypropylene fibres subject to dry-cleaning or detergent action) solvent-resistant TMP systems have been developed by covalent chemical attachment of UV stabilisers to the polymer. Two synthetic routes have been developed to do this. The first involves the modification of the polymer e.g. polypropylene) by copolymerisation with maleic anhydride to give an anhydride group in the polymer chain. This can be subsequently reacted with an alcohol or amine group in the light absorber ... 

Poly[3-hydroxybutyrate] was the first PHA to be produced on an industrial scale, but its brittle nature, its poor mechanical properties and its high production cost limited its application potential. In the early 1990s, Imperial Chemical Industries [ICI] started the production of poly[3-hydroxybutyrate-co-3-hydroxyvalerate] [P3HB3HV] under the trade name Biopol . This material showed lower degrees of crystallinity and superior mechanical properties. Later on, the production of Biopol was continued by Monsanto and subsequently followed up by Metabolix. PHAs were originally intended as bio-based alternatives for polyolefins used in plastic containers, films and bottles. Despite the large interest in PHAs, their application remains, however, limited due to their narrow processing window [84, 85]. 

Cong et al (2012) Determination of the microstructure of polyolefins using thermal gradient interaction chromatography and its hyphenated techniques. In Proceedings 4th international conference on polyolefin characterization, Houston, October 2012... 

Recent research and development (R D) work used metallocene-catalyzed PP to make submicron diameter MB fibers [16]. The polyolefin used in this work had a narrow molecular weight distribution and an MFR greater than 1000 g/10 min, a typical range for MB non woven polymers. 

Fig. 13.6 Effect of sample concentration on the % recovery of polymer from model polyolefins using xylene/n-hexane at 140 °C...

Chem. Descrip. Chlorinated polyolefin Uses Primer tor polyethylene coatings ingred. 

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