Sclair resins

Additive-free film samples of isotactic polypropylene (iPP, 30pm Himont Profax resin) and polyethylenes (LLDPE, 120ym, linear low density DuPont Sclair resin, and UHMW-PE, 120wm, ultra high molecular weight, high density Himont LSR 5641-1B resin) were oxidized by exposure in air to y-radiation (AECL Gamma Cell 220, 1.0... 

It appears that in these Sclair resins the increased crystallinity is the result of fewer, larger crystallites rather than more of the same size. These larger crystallites have a lower total surface area. The tortuosity is then relatively unaffected, but the chain immobilization factor defined by Equation 2 is reduced significantly, resulting in a larger diffusion coefficient in the denser, more crystalline materials. 

The Sclair resins under study here were of similar melt index and were manufactured under similar conditions. They are a uniform series of polyethylenes differing only in density. Microscopic observation under polarized light confirmed the hypothesis that the higher crystallinity in... 

Sclair resins results from fewer, larger crystallites. These results are given in Table II along with estimates of the specific surface area to which p is assumed proportional. Thus even in relatively well defined systems, diflFusion measurements provide new information on polymer structure. 

The first ELDPE (Sclaire resins) was produced by DuPont Canada Ltd. in a solution process using Z-N vanadium (V) catalyst 0 0-n butyl)2 Cl, and A1 (Et)i li.5. The comonomer was C4-20. with the Al/V ratio increasing with comonomer MW from 5 1 to 12 1... 

Polyethylene. The effect of crystallinity on the diffusion coefficient of iso-octane at 54°C in PE was determined in a sorption experiment. Films of Sclair PE (DuPont Chemical Co., Kingston, Ontario) were compression-molded in a hot platens press at 170°C and were allowed to cool in the press. All films were 200 /xm thick. The properties of the resins are given in Table II. 

Novapol LF-0717-A Sclair 69A resin, gloss overlacquers Pliolite VTAC... 

A Petrothene NA 220-000 Sclair 69A resin, thermopiastic chem.-resistance... 

Schulink, Crosslinkable polyethylene rotational molding compound, Schulman, A., Inc. SCLAIR, Polyethylene resins, NOVA Chemicals Ltd. 

Sanoprene. TP elastomer. Monsanto Co. Saran. PVDC resin. Dow Chemical Co. ScLAiR. Linear PE resin. Du Pont. 

DuPont s Sclair process was extremely important technology which was introduced in the 1960s, as it offered commercial ethylene copolymers at densities as low as 0.916 g/cc with improved physical properties over comparable polyethylene resins produced with the high-pressure process. In addition, DuPont scientists also developed improved catalysts for the Sclair process based on vanadium compounds that produced homogeneous branching distribution of the short-chain branches introduced along the polymer backbone by incorporation of a comonomer such as 1-butene into the polymer structure. 

The first commercial process for making LLDPE was the Sclair technology developed by Dupont Canada and now implemented by NOVA Chemicals. This process involves high-temperature solution polymerization. Much LLDPE is now made in gas-phase reactors with butene or hexene as the co-monomer. The constrained-geometry catalyst (CGC) is a metallocene catalyst developed by Dow Chemical for the manufacture of linear, very-low density polyethylene resins by solution polymerization with octene as the comonomer. For a given co-monomer content, the solid-state density is lower for octene than for lower a-olefins. 

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