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一、关于塑料薄膜使用年限问题 作为水利工程防渗的塑料薄膜,国内外多用聚乙烯和聚氯乙烯两种。根据地区温差和薄膜特性,一般在温差小的地区多用聚氯乙烯薄膜;温差大的严寒地区用聚乙烯薄膜为宜。但也不是绝对的。其所以有差异,是由于塑料薄膜是一种化学组成物,而聚氯乙烯薄膜因所加成分较多,相对稳定性较聚乙烯稍差些,遇冷变脆,易老化,其分子式为-[CH_2-CHCl~-]_n~-,
First, the use of plastic film on the issue of life As a seepage of water conservancy plastic film, both at home and abroad with polyethylene and polyvinyl chloride two. According to the regional temperature difference and the film characteristic, generally uses the polyvinyl chloride film in the area where the temperature difference is small; The polyethylene film is suitable in the cold area where the temperature difference is big. But not absolute. Therefore, the difference is due to the plastic film is a chemical composition, and polyvinyl chloride film due to the addition of more components, the relative stability of polyethylene slightly less than some, if cold brittle, easy to aging, the formula - [CH_2-CHCl ~ -] _ n ~ -,