2022年3月3日雅思阅读真题+题目+答案：Nature works for Nature Work PLA

2022年3月3日雅思阅读真题+题目+答案：Nature works for Nature Work PLA

A

A dozen years ago, scientists at Cargill got the idea of converting lactic acid made from corn into plastic while examining possible new uses for materials produced from corn wet milling processes. In the past, several efforts had been made to develop plastics from lactic acid, but with limited success. Achieving this technological breakthrough didn’t come easily, but in time the efforts did succeed. A fermentation and distillation process using com was designed to create a polymer suitable for a broad variety of applications.

B

As an agricultural based firm, Cargill had taken this product as far as it could by 1997. The company needed a partner with access to plastics markets and polymerization capabilities, and began discussions with The Dow Chemical Company. The next step was the formation of the joint venture that created Cargill Dow LLC. Cargill Dow’s product is the world’s first commercially available plastic made from annually renewable resources such as com:

· Nature Works™ PLA is a family of packaging polymers (carbon-based molecules) made from non-petroleum based resources.

· Ingeo is a family of polymers for fibers made in a similar manner.

C

By applying their unique technology to the processing of natural plant sugars, Cargill Dow has created a more environmentally friendly material that reaches the consumer in clothes, cups, packaging and other products. While Cargill Dow is a stand-alone business, it continues to leverage the agricultural processing, manufacturing and polymer expertise of the two parent companies in order to bring the best possible products to market.

D

The basic raw materials for PLA are carbon dioxide and water. Growing plants, like com, take these building blocks from the atmosphere and the soil. They are combined in the plant to make carbohydrates (sucrose and starch) through a process driven by photosynthesis. The process for making Nature Works PLA begins when a renewable resource such as corn is milled, separating starch from the raw material. Unrefined dextrose, in turn, is processed from the starch.

E

Cargill Dow turns the unrefined dextrose into lactic acid using a fermentation process similar to that used by beer and wine producers. This is the same lactic acid that is used as a food additive and is found in muscle tissue in the human body. Through a special condensation process, a lactide is formed. This lactide is purified through vacuum distillation and becomes a polymer (the base for NatureWorks PLA) that is ready for use through a solvent-free melt process. Development of this new technology allows the company to “harvest” the carbon that living plants remove from the air through photosynthesis. Carbon is stored in plant starches, which can be broken down into natural plant sugars. The carbon and other elements in these natural sugars are then used to make NatureWorks PLA.

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Questions 1-4

Write the letters A-F in boxes 1-4 on your answer sheet.

1 scientists manage to

2 Cargill needs to have contacts with

3 Nature work is used for

4 Ingeo is used to

A make things like clothes

B produce plastic from plant

C selling plastic in market

D fermentation process

E drape fabrics

F wrapping products

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2022年3月3日雅思阅读真题+题目+答案：Nature works for Nature Work PLA，10元有偿下载完整版！