例如 ，对于半结晶聚合物 ，为何只有聚丙烯才有此独特结构 ?此外有关聚丙烯熔体在应?。

There was more c axis orientation crystallization when the melt was treated under high stress. The formation mechanism of such unique structures was also discussed.

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结晶度：聚合物可以是晶体状的或非结晶质的，但它们通常是晶体状和非结晶质结构的结合物(半晶体)。

Crystallinity. Polymers can be crystalline or amorphous, but they usually have a combination of crystalline and amorphous structures (semi-crystalline).

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