Ethylene content

The quantity of coproduct acetylene produced is sensitive to both the feedstock and the severity of the cracking process. Naphtha, for example, is cracked at the most severe conditions and thus produces appreciable acetylene up to 2.5 wt % of the ethylene content. On the other hand, gas oil must be processed at lower temperature to limit coking and thus produces less acetylene. Two industry trends are resulting in increased acetylene output (/) the ethylene plant capacity has more than doubled, and (2) furnace operating conditions of higher temperature and shorter residence times have increased the cracking severity. 

Vinyl Acetate—Ethylene Copolymers. In these random copolymers, the ratio of ethylene to vinyl acetate (EVA) is varied from 30—60%. As the vinyl acetate content increases, the oil and heat resistance increases. With higher ethylene content the physical strength, tensile, and tear increases. The polymers are cured with peroxide. The main properties of these elastomers include heat resistance, moderate oil and solvent resistance, low compression set, good weather resistance, high damping, exceUent o2one resistance, and they can be easily colored (see Vinyl polymers, poly(VINYL acetate)). 

Ethylene content Diene type Diene content distribution classification... 

Manufacturer Trade Type Grade name elastomer designation Oil content (phr) Mooney viscosity (T + 8 ) at 127 C Ethylene content Diene type Diene content Molecular weight distribution classification... 

Bowmer and Tonelli [161] have also observed that the magnitude of the glass transition (ACp) increases with the ethylene content of the copolymer, goes through a maximum at about 30 mol%, and then continually decreases until no glass transition is observed at more than 80 mol% of ethylene. This may constitute further evidence in favor of the explanations put forward by Naqvi for the thermal stability behavior of similar copolymers reported by Braun et al. [159]. Initially, with increasing content of nonpolar ethylene units in the co-... 

FIGURE 6.1 A set of consistent stress-strain data for P-plastomers with ethylene content between 8.2 wt% (highest) and 16.0 wt% (lowest). The data for P-plastomers with intermediate composition is intermediate within these extremes. 

The Tg of P-plastomers changes as a function of ethylene content. The Tg decreases with increasing ethylene content, primarily due to an increase in chain flexibility and loss of pendant methyl residues due to incorporation of ethylene units in the backbone. It is well known that PP has a Tg of 0°C, and polyethylene a Tg< —65°C. The addition of ethylene to a propylene polymer would therefore be expected to decrease the Tg, as is observed here. A secondary effect would be the reduction in the level of crystallinity associated with increasing ethylene content, which is expected to reduce the constraints placed upon the amorphous regions in proximity to the crystallites. Thus, an increase in ethylene content will result in a lower T as well as an increase in magnitude and a decrease in breadth of the glass transition. 

The cross-hnking efhciency of EP copolymer has been investigated by some workers [368,371] and the yield is found to increase with increasing ethylene content. The value lies closer to PP homopolymer. The amounts of cross-hnking as well as scission have been observed to increase with increasing diene content, the labile point. Cross-linking enhancers like chlorobenzene, nitrous oxide, allylacrylate, and A-phenylmaleimide are reported to promote cross-linking [85,370,371]. 

GP 2] ]R 3a] Studies were performed at constant ethylene content and residence time and by varying the oxygen content by exchange versus methane. An increase... 

Composition of the terpolymers as expressed in mole%, of course, must be kept in the range that yields good elastomeric properties. E-E polymers of higher ethylene content naturally result in higher tensile strength as a consequnece of formation of partial crystallinity due to short ethylene blocks (f ). of EEDMs studied in this work all abide by the usual EEDM requirements. ... 

This patent is a reissue (RE 34607). The composition described, capable of forming foams with excellent mechanical properties and heat resistance, is made of (a) 14-80 wt.% of a propylene-ethylene random copolymer having an ethylene content of 1.5-6 wt.%, (b) 10-60 wt.% of a propylene-ethylene random copolymer having an ethylene content of 0.2-1.0 wt.%, (c) 10-60 wt.% of a linear low-density polyethylene, and (d) 1-30 pbw, per 100 pbw of the above resin composition, of a foaming agent. JAPAN... 

VAM is used to produce a homopolymer and, together with a wide array of different monomers, a number of copolymers. Copolymers with ethylene are one of the most important classes of copolymers known and, depending on the ratio of ethylene and vinyl acetate, are abbreviated as EVA (high ethylene and low vinyl acetate content) or VAE (high vinyl acetate and low ethylene content) [18] polymers. 

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