▎ 摘　　要

In polymer processes, nucleating agents are often usedto controlthe kinetics of crystallization, but their application remains largelya matter of trial and error. Thermodynamically, the efficiency ofa nucleating agent can be quantified by the difference in substrate/crystal,crystal/melt, and substrate/melt interfacial energies, Delta sigma.In this work, the efficiency of graphene nanoplatelets (GNP) as nucleatingagents for high-density polyethylene (HDPE) is investigated. HDPEnucleates and crystallizes rapidly, so Delta sigma can be especiallydifficult to measure experimentally. To overcome this difficulty,blends of HDPE+GNP are confined to microdomains so that crystallizationbecomes nucleation limited. Two methods of microdomain formation areemployed. In the first, HDPE+GNP is melt-blended with an immisciblematrix of polystyrene (PS), and crystallization is characterized usingdifferential scanning calorimetry (DSC); in the second, dispersionsof HDPE+GNP in toluene are sprayed onto PS substrates, and crystallizationis characterized with polarized optical microscopy (POM). Heterogeneousnucleation rates at several crystallization temperatures and for severalGNP loadings were measured by these two methods and found to giveexcellent agreement across GNP loadings. The value of Delta sigma for HDPE+GNP is calculated to be 0.83 +/- 0.18 erg/cm(2). This value is only 2.8 times larger than that reported for HDPEnucleated heterogeneously on a HDPE fiber, a nearly ideal nucleatingagent for HDPE, and much smaller than many of the best nucleatingagents reported for other polymers. We conclude that GNP is an efficientnucleating agent for HDPE.