Plastics, of course, are used extensively now, with urethane, thermoplastic polyolefin and PVC making up skins on door and instrument panels, and polypropylene, ABS and other materials used in substrates that are sometimes visible.

Traditionally, though, interior plastics have been disguised as something else, with PVC or urethane given a grained texture to mimic leather, trim painted to look like chrome accents, or appliqués that give the impression of wood.

“If you look into product design, there is a move to use plastic that’s happy to be plastic,” said Dave Lyon, executive director of interior design for North America at General Motors Corp. (GM).

“Maybe it’s a generational bias that we don’t talk about it being plastic if we can fool you into thinking it’s something else, but maybe we’re looking at it in the wrong way,” Lyon said during a May 21 speech at Ward’s Auto Interiors Conference in Dearborn.

“I hate gloss on an instrument panel, for instance, but I love it on an iPhone,” he said.

Detroit, Michigan-based GM is already putting the high-gloss example to use in its planned Chevrolet Volt, the electric-powered car set to begin production in November 2010. The interior trim on the production version features a high-gloss white plastic, similar to that on an iPod digital media player, rather than the traditional chrome, leather or wood for an automotive look.

The industry also is looking in the opposite direction, with automakers and suppliers considering the potential for stripping the cover skins and veneers off of structural parts and showcasing substrate made with natural materials, such as hemp and kenaf mixed with thermoplastics.

Luxury sports car maker Lotus Group International Ltd. used a hemp and polyester blend on the seat for its Eco Elise concept. The move is part of a plan to reduce the car’s carbon footprint, using hemp grown near the factory. Nissan Motor Co. Ltd.’s Nuvu concept electric car has a wood-blend composite for its floor.

Interiors suppliers Johnson Controls Inc. and Faurecia SA have been showing automakers separate concept interiors that would expose a highly polished natural-fiber substrate.

“I have seen some work with design concepts that use [natural fiber] as a decorative element,” Lyon said. “They’re not hiding it behind vinyl.”

But while a lot of companies are experimenting with the look, there’s no guarantee that it will gain acceptance in the marketplace.

It is an intriguing experiment because consumers say they are interested in more environmentally friendly and green products, but those same buyers don’t necessarily agree on what those terms mean. Consumers could mean that they’re interested in purchasing cars that go further on a gallon of gas, according to Lyon, or that they want to know vehicles can be recycled easier or made using recycled materials.

Home appliance manufacturers are able to market their products’ environmental aspects using the Energy Star label. Builders can rely on standards from the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) program to certify a building as environmentally friendly.

The auto industry, however, lacks similar standards, said Sherry Sabbagh, principal materials designer for Johnson Controls’ Plymouth, Michigan-based auto interiors group.

“There’s no über-eco material,” she said. “We’re all looking for it.”

Low-weight materials that help tweak gas mileage could also be considered eco-friendly even if they have no recycled content or bio-based background, said Tim Greig, interior design manager for GM’s Volt.

Eventually, finding the breakthrough look for the future car interior may mean taking a chance, and believing that consumers will be ready when those cars appear.

“Social trends happen faster than we care to admit,” Lyons said. “That is a leap of faith we take, considering how long it takes us to develop new materials and processes.”