Expandable polyethylene-copolymer

Expandable polyethylene- copolymers Arcel Nova Innovene, CFI 18-35 Up to 80 Energy absorbing molded parts, transport packaging for multiple use 0.1-0.15 120-127... 

Foams (cellular structures) made by expanding a material by growing bubbles in it [11]. A foam has at least two components. At a macroscopic scale, there are the solid and liquid phases. The solid phase can be a polymer, ceramic or metal. The fluid phase is a gas in most synthetic foams, and a liquid in most natural foams. At a microscopic scale, the solid phase may itself consist of several components. For example, the solid phase of an amorphous polystyrene foam has only one component. On the other hand, the solid phase of a polyethylene foam or a flexible polyurethane foam typically has two components. These components are the crystalline and amorphous phases in polyethylene foams, and the hard and soft phases formed by the phase separation of the hard and soft segment blocks in flexible polyurethane foams. The solid phase of a polyurethane foam may, in fact, have even more than two components, since additional reinforcing components such as styrene-acrylonitrile copolymer or polyurea particles are often incorporated [12,13]. The solid is always a continuous phase in a foam. Foams can generally be classified as follows, based on whether the fluid phase is co-continuous with the solid phase ... 

Polyolefin foams are somewhat higher in cost than PS foams. They are also more flexible and better able to provide protection from multiple impacts. Typical densities are 16 to 32 kg/m (1 to 2 Ib/ft ). Polypropylene foams have somewhat greater rigidity than polyethylene foams. Polyolefin foams, like PS foams, are available in two varieties expanded (generally termed moldable) and extruded. PE/PS copolymer foams are also available, with characteristics generally intermediate between PS and PE foams, but with outstanding toughness. 

Xincure ITX-2. See 2-Isopropyl thioxanthone Xincure MBP. See 4-Methoxybenzophenone Xincure MBZ. See 4-Methylbenzophenone Xincure PBZ. See p-Phenylbenzophenone Xincure TMBZ. See 2,4,6-T ri methyl benzophenone Xinsorb BP-4. See Benzophenone-4 Xinsorb UV-1. See Ethoxycarbonylphenyl)-N -methyl-N -phenylformamidine Xinsorb UV-9. See Benzophenone-3 Xinsorb UV-A. See Acetanisole Xinsorb UV-P. See Drometrizole X-Link 2833, X-Link 2893, X-Link 5627. See Vinyl acrylic copolymer XLPE. See Polyethylene, crosslinked XO White. See Calcium monocarbonate XP-36P. See Sodium hexametaphosphate X-Pand R . See Food starch, modified XPE. See Polyethylene, crosslinked XPS. See Polystyrene, expandable XSA 80, XSA 90, XSA 95, XSA. See Xylene sulfonic acid... 

The metallocene-ATRP route has been expanded by Matsugi etal. [164], to produce polyethylene-b-poly(methyl methacrylate). In the first step, hydroxyl-functionalized polyethylene was successfully prepared through the copolymerization of ethylene with aluminum-capped allyl alcohol, using a specific zirconium metaUocene/methylaluminoxane catalyst system. In the next step, the terminal alcohol was converted to hahde by 2-bromoisobutyryl bromide to obtain bromide-functionalized polyethylene, which could initiate the ATRP of MMA (Scheme 11.40). The block copolymers obtained exhibited unique morphological features that depended on the content of PMMA segment. Moreover, the block copolymers effectively compatibiUzed the corresponding homopolymer blend at the nanometer level. 

Temperature-resolved X-ray experiments on cooling are presented in Fig. 7.36. The first scans show only an amorphous halo. The copolymer is melted. At 321 K, the 110 and 200 orthorhombic crystal interferences appear. The peaks are shifted to lower values compared to the polyethylene homopolymer. The calculated lattice constant a of 0.766 nm is expanded, as discussed with Fig. 7.32. At slightly lower temperatures, the shape of the amorphous halo changes abruptly and acquires a... 

Phenylene oxide-based resins (Noryl ) epoxy, polyisocyanate, polyvinyl butyral, nitrile rubber, neoprene rubber, polyurethane rubber, polyvinyUdene chloride, and acrylic. Polyethylene-nitrile rubber, polyisobutylene rubber, flexible epoxy, nitrile-phenolic, and water-based (emulsion) adhesives. Polystyrene for these foams (expanded polystyrene (EPS)), aromatic solvent adhesives (e.g., toluol) can cause collapse of the foam cell walls. For this reason, it is advisable to use either 100% solids adhesives or water-based adhesives based on SBR or polyvinyl acetate. Specific adhesives recommended include urea-formaldehyde, epoxy, polyester-isocyanate, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, and reclaim rubber. Polystyrene foam can be bonded satisfactorily with any of the following general adhesive types ... 

The next decade, until the beginning of World War II, was devoted to systematic studies of such synthetic polymers as polystyrene, polyisobutylene, polyvinyl and polyacrylic derivatives, a series of copolymers and of polyelectrolytes. At the same time the work on polyo methylenes and on polyethylene oxide was continued and expanded. It was an amazing broad front along which Staudinger, together with an ever increasing number of able and devoted associates, invaded and conquered the newly created field of macromolecular science. 

Roofing PVC, chlorinated polyethylene (CPE), polyvinylidene chloride (PVDC), GRP, PC, ethylene-propylene-diene monomer (EPDM), expanded polystyrene (EPS) (sheet), reinforced styrene-butadiene-styrene (SBS) copolymer... 

Though Af-oxyl-immobilized silica gel 3c is easily prepared and used repeatedly [8], mechanical strength of the silica gel is not enough for practical use [9]. This method can be, however, easily expanded to polymer chemistry. A -Oxyl-modified polymers (partially carboxylated polyethylene (Fig. 5), polyethylene-polyacrylic acid copolymer (Fig. 6), or poly(p-phenylene-co-benzobisthiazole) (PBZT, Fig. 7), etc.) can be used as an absorbent [10, 11]. These polymer particles are tough enough and N-oxyl moiety is not lost by hydrolysis. 

Because of their lesser ability to control shrinkage, the non-polar polymers such as polystyrene and polyethylene are often classified as low shrink rather than low profile additives. Usually, low profile additives are supplied as 30-40% polymer solutions in styrene monomer. Polyester resin manufacturers also package the low profile additives dissolved in their resins. These are referred to as one pack systems. As the industry has expanded, other thermoplastics have been identified which have shrinkage control properties. These are also now used commercially in a variety of applications. Examples of these other polyers are saturated polyesters, polyurethanes, stryene-butadiene copolymers and polycapro-lactones. Polyfvinyl acetate) based materials are probably still the most used low profile additives, being useful with the broadest range of unsaturated polyester resin structures. Relative proportions of the organics used in most formulations are 30-50% polyester alkyd, 10-20% thermoplastic and 40-50% styrene. 

The introduction of single-site catalyst technology has expanded the polyethylene product space to densities as low as about 0.86 g/cc with traditional comonomers such as 1-butene, 1-hexene and 1-octene. In addition, single-site catalysts have provided new ethylene-based copolymers with comonomers based on styrene and cyclic olefins such as norbomene. 

To extend the use of polyethylene, it is desirable to enhance polyethylene s polarity, toughness, adhesion and compatibility with other materials. One approach is by incorporating polyethylene in block copolymer structures (Hong et al, 2002). Polyethylene block copolymers can maintain some of the superior properties of polyethylene while introducing the desired new properties from the other copolymer segments. In this way, the utility of polyethylene can be expanded to higher value areas, especially in polymer blends or composites, the preparation of micelles and the fabrication of nanoporous membranes (Wang and Hillmyer, 2001 Chen et al, 2009 Uehara et al, 2006 Uehara et al, 2009). 

Figure 2.6 MALDI-FTI-CR-MS spectrum of polyethylene oxide - polypropylene oxide. For this measurement, the trapping delay was optimised to be 900 ps for the centre of the molecular weight distribution, the spectra from 250 laser shots were summed. The series of polyoxypropylene homopolymers is indicated (the first number refers to n °, the second to n °). In the expanded mass scale, the composition of all monoisotopic copolymers is indicated. Reproduced with permission from G.J. van Rooij, M.C. Duursma, C.G. de Koster, R.M.A. Heeren, J.J. Boon, RJ.W. Schuyl, E.R.E. van der Hage, Analytical Chemistry, 1998, 70,...

The relatively open active sites of metallocene catalysts permit the copolymerization of nontraditional cyclic comonomers, snch as styrene and norbomene, with ethylene. Although such resins are not cormnercially available at present, they have the potential for exhibiting novel physical characteristics, possibly expanding the use of polyethylene into new markets. Metallocene technology has also been developed for the production of isotactic and syndiotactic polypropylene, copolymers of propylene with other olefins, and syndiotaetie polystyrene. 

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