LDPE树脂正己烷提取物检测研究

STUDY ON DETERMINATION OF N-HEXANE EXTRACTIVES IN LDPE RESINS

在检测中发现低密度聚乙烯(LDPE)树脂正己烷提取物含量数值往往较高,分析了LDPE树脂正己烷提取物主要成分、正己烷提取物含量与熔体流动速率(MFR)、分子质量分布的相互关系等以探究其产生原由。认为LDPE树脂分子质量分布较宽,低分子质量成分相对较多而易被正己烷溶出,故检测结果往往较大。MFR是树脂原料品质的一个重要常测指标,它是相对分子质量的间接反映,这样在检测或生产过程中可以通过MFR间接粗略判断LDPE树脂正已烷提取物含量是否超过国家标准。

In daily test, the results were usually higher than that of the other kinds of polyethylene（PE） resins by determining the content of the n-hexane extractive in low-density polyethylene（LDPE） resins. The main component of the n-hexane extractive was measured by IR methods and the relationship such as melt flow rate（MFR）, molecular weight distribution were discussed in this article. It shows that LDPE had wide molecular weight distribution and therefore contained a certain amount of LDPE film with low molecular weight dissolved in n-hexane easily. On the other hand, there exited a close dependence between MFR and molecular weight distribution, So whether the content of the n-hexane extractive in LDPE resins exceeded national standard or not could be approximately evaluated with MFR data in experiment or production.