Polyisobutylene polyethylene

Dimercapto-l,3,4-thiadiazole derivatives, accelerated by amines, are used to cross-link chlorinated polyethylene. Polyisobutylene containing brominated i ra-methylstyrene cure functionahty can be cross-linked in polymer blends with dimercapto-1,3,4-thiadiazole derivatives accelerated with thiuram disulfides. Trithiocyanuric acid is suggested for use in polyacrylates containing a chlorine cure site and in epichlorohydrin mbbers. 

Until the mid-1950s the only polyolefins (polyalkenes) of commercial importance were polyethylene, polyisobutylene and isobutylene-isoprene copolymers (butyl rubber). Attempts to produce polymers from other olefins had, at best, resulted only in the preparation of low molecular weight material of no apparent commercial value. 

Cationic Polyethylene Polyisobutylene Polystyrene Vinyl esters... 

According to the statistical-mechanical theory of rubber elasticity, it is possible to obtain the temperature coefficient of the unperturbed dimensions, d InsjdT, from measurements of elastic moduli as a function of temperature for lightly cross-linked amorphous networks [Volken-stein and Ptitsyn (258 ) Flory, Hoeve and Ciferri (103a)]. This possibility, which rests on the reasonable assumption that the chains in undiluted amorphous polymer have essentially their unperturbed mean dimensions [see Flory (5)j, has been realized experimentally for polyethylene, polyisobutylene, natural rubber and poly(dimethylsiloxane) [Ciferri, Hoeve and Flory (66") and Ciferri (66 )] and the results have been confirmed by observations of intrinsic viscosities in athermal (but not theta ) solvents for polyethylene and poly(dimethylsiloxane). In all these cases, the derivative d In sjdT is no greater than about 10-3 per degree, and is actually positive for natural rubber and for the siloxane polymer. 

Beret, S. Prausnitz, J. M., "Densities of Liquid Polymers at High Pressure. Pressure-Volume-Temperature Measurementsfor Polyethylene, Polyisobutylene, Poly(vinyl acetate), and Poly(dimethylsiloxane) to 1 kbar," Macromolecules, 8, 536 (1975). 

Newman, R. D. Prausnitz, J. M., "Thermodynamics of Concentrated Polymer Solutions Containing Polyethylene, Polyisobutylene, and Copolymers of Ethylene with Vinyl Acetate and Propylene," AlChE J., 19, 704 (1973a). 

Discovery of High-Pressure (Low-Density) Polyethylene Polyisobutylene... 

Blending within the family of PO has, however, been more common [Plochocki, 1978]. Although they are usually immiscible with each other, there exists some degree of mutual compatibihty between them. The similarity of their hydrocarbon backbones and the closeness of their solubility parameters, although not adequate for miscibility, accounts for a relatively low degree of interfacial tension. Eor example, the solubility parameters of polyethylene, polyisobutylene, ethylene-propylene rubber and polypropylene are estimated to be 16.0, 15.4,... 

PEIPIB (Polyethylene Polyisobutylene). It is used in sheet and film for barrier properties. 

Wu, S., Surface and interfacial tensions of polymer melts I. Polyethylene, polyisobutylene, and polyvinyl acetate, J. Colloid Interface ScL, 31, 153 (1969). 

Paxon Polyethylene/polyisobutylene, PE/PIB, blends Allied-Signal Corp./ Paxon... 

Polyolefins, Polyethylenes, Polyisobutylenes, Poly(Methyl Methacrylates), and Poly(Styrene Sulfonates), In addition to polyurethane foams, polyethylene and polypropylene fibers can be manufactured as alternative polymeric sorbents. However, based on sorbent capacity, cost, and availability, these materials would be considered inferior to polyurethane. 

Graft Polymerization. The most effective method for graft polymerization of VF is radiation polymerization (80). VF has been grafted to low density polyethylene, polyisobutylene, and polyamides (85-87). The density of the graft copolymers is higher than that of the starting homopolymer. Typically, VF is brought in contact with the polymer simultaneously with irradiation. 

Cross-linked polyethylene Polyisobutylene Styrene-ethylene-styrene PS... 

Low density polyethylene Polyisobutylene Poly(ethylene-co-vinyl acetate)... 

Molecular dynamics studies of penetrant diffusion have so far been performed for polyethylene, polyisobutylene and polydimethylsiloxane. Calculated diffusion coefficients have not been in particularly good agreement with experiment. In the case of polyethylene, modeled using the united atom approximation, diffusion coefficients were much higher than expected and the activation energies too small although much better results have been obtained using PE IV. Reliable comparisons with experimental data are made difficult by uncertainties as to the true diffusion coefficients... 

This has been done for polyethylene, polyisobutylene and polypropylene models, for instance, by prescribing spheres of a chosen diameter around each interaction site, or by using Voronoi polyhedra to define the unoccupied space. The free volume fraction,can be defined by... 

TPEs have also been prepared by grafting from linear maaoinitiators prepared by non-ATRP procedures including polyethylene, polyisobutylene, poly(epichlorohydtine-co-ethylene oxide) elastomer or natural rubber and/or a synthetic diene mbber backbones. 

Fig. 8. Reduced surface tension versus reduced temperature of polymers. Solid line is Poser Sanchez theory with ic = 0.55 O branched polyethylene linear polyethylene polyisobutylene polystyrene A poly(vinylacetate) A poly(dimethyl siloxane). From Ref. 21.

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