托福阅读考试，涉及历史，政治，科技，生物等等，非常广泛的话题，在托福阅读考试紧张的时间里，如果对文章背景不熟悉，轻则影响考生心情重则影响理解和考分。因此小编就托福阅读中的常考背景解释总结了系列文章供大家参考。
polymer gels一种聚合凝胶
The following information was part of our display for the SET96 and SET98 Scientific Power to the People Exhibition, The Galleries, Bristol, 20th and 21st March 1998.
A POLYMER is a very long molecule rather like a very long piece of string.
The borax joins two molecules together to make a large network - rather like a flexible scaffolding. This is cross-linking.
This turns the fluid dissolved polymer into a GEL.
In oilwells water is pushed down to push oil up. If this breaks through to the production well bore, the well will just produce water. A solution is to block the rock pores with polymer gel to make the well produce oil again. These gels can be made from naturally occurring sugar-based polymers such as Guar and they can be cross-linked with Cobalt or Chromium.
Other everyday examples of polymer gels are to be found in non-drip emulsion paints, foods, car tyres and agrochemicals.
The polymer that we are using is POLYVINYL ALCOHOL and we are joining the strands together with BORAX. This gel, when coloured, is sold in toyshops as SLIME.
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新托福阅读背景知识系列(60)
托福阅读考试，涉及历史，政治，科技，生物等等，非常广泛的话题，在托福阅读考试紧张的时间里，如果对文章背景不熟悉，轻则影响考生心情重则影响理解和考分。因此小编就托福阅读中的常考背景解释总结了系列文章供大家参考。
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