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  3. A fledgling firm. EcoLean, in Sweden, has developed a new packaging material. Unlike conventional substance, it takes very littl

A fledgling firm. EcoLean, in Sweden, has developed a new packaging material. Unlike conventional substance, it takes very littl

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问题     A fledgling firm. EcoLean, in Sweden, has developed a new packaging material. Unlike conventional substance, it takes very little energy to produce, is made up mostly of a natural material in abundant supply and, when exposed to sunlight, disappears in a matter of hours. It could go a long way toward easing the problems of a litter-strewn world. The brain behind EcoLean is chemist Ake Rosen.
    A monument to Rosen’s inspiration can be found in the forecourt of EcoLean s main plant in Helsingborg in southern Sweden. It is a giant egg. Eggshells, it happens, are 95 percent calcium carbonate. And when it comes to eggs, they are a perfect packaging material- though a little too brittle. Rosen, however, found a way to improve on nature’s formula. The other 5 percent of eggshells consists of a crucial "binding agent" that keeps the chalk from turning into dust and toughens the shells. Instead of using the natural protein as a binding agent, Rosen used polylefins(聚烯烃), a type of plastic derived from natural gas. After experimenting with the proportions, Rosen hit upon a Lean Material that consists of up to seventy percent chalk and thirty percent polylefins.
    Lean Material looks and feels like conventional plastic, but it isn’t. According to Rosen’s tests, EcoLean asserts that it can be as strong as glass or as pliable as rubber, and it could be a viable, and cheaper, substitute for plastic, cardboard or aluminum packaging. For conservationists, the material has numerous benefits. Even though it consists in part of plastic, which costs energy to produce, polyolefins are pretty low on the eco-hate list. They degrade into carbon and oxygen. Besides, less plastic means using less oil, the essential component in plastic and a nonrenewable resource. Chalk, the main ingredient, is abundant (and cheap) on every continent in the world.
    But Lean Material’s most remarkable charm is apparent only when it is ready for the garbage. Bottles, yogurt tubs or candy wrappers made of Lean Material would all he degradable. Leave them sitting on the picnic table and in a month or two sunlight will have reduced them to sand. Or, once in the incinerator the resulting ash will be rich in carbonates, good for making the soil less acidic. As a bonus, the material also has no "memory. " Stamp on a Lean Material bottle and it stays crushed, taking up less space in landfill. (399 words)
The function of polylefins is______.
选项 A、binding
B、toughening
C、softening
D、smoothening
答案A
解析 聚烯烃是起粘连作用的，故选A。
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