New alloy marries PP and PPENew alloy marries PP and PPE

Pittsfield, MA -The latest material from GE Plastics bears out the idea that thermoplastic alloys should add up to more than the sum of their ingredients. Called Noryl PPX, this new alloy of polyphenylene ether (PPE) and polypropylene (PP) offers the best all-around property balance of any material the company makes, according to Noryl manager Keith DuPont. "There's nothing like it in the GE portfolio," he says.

GE brings these two formerly incompatible thermoplastics together with patent-pending alloying technology that uses a proprietary "compatibilizer" to incorporate PPE particles in a matrix of PP.

By varying the amount of the alloy constituents, the company can tailor formulations to different application requirements, DuPont reports. For now, the initial PPX line-up consists of two unfilled grades as well as 30% and 40% glass-filled grades.

The material offers what DuPont describes as a "unique balance" of stiffness, impact strength, temperature resistance, elongation, and a low specific gravity (see properties below).

Thanks to its polypropylene base, the alloy also resists chemicals, absorbs almost no moisture, and has a high flow rate "more like polypropylene than Noryl," DuPont says. With mold shrinkage values around 0.010 inch/inch and creep resistance closer to an engineering thermoplastic, the alloys exhibits better overall dimensional stability than either of its two ingredients, he adds.

The new PPX alloys target a variety of applications, including power tool and fluid-engineering components. But the material may see its maximum use on automobiles. Front-end modules made from reinforced grades and bumper fascias made from unfilled grades represent the first likely uses for the new material. And DuPont cites instrument panels, seat backs, load decks, and underhood components as other potential fits for PPX.

"The new alloys are aimed primarily at an automotive segment looking for system cost reduction," says John Carrington, Noryl's commercial director. He attributes the potential for savings to the alloy's high flow, mechanical properties, and relatively low processing temperatures-which together enable thinner-walled, faster-cooling parts. DuPont estimates that a PPX bumper fascia, for example, can be 20-25% thinner than a comparable TPO fascia while still meeting the same end-use requirements.

Finally, PPX advances the automotive industry's burgeoning plastic recycling efforts. DuPont explains that the material can be reground and reused both alone and mixed with other olefinic components-such as the PP foams and TPO skins that could round out a recyclable instrument panel.

For more information about engineering thermoplastics from GE Plastics:Enter 535