135. Study on Crystallization Kinetics of Partially Melting Polyethylene Aiming to Improve Mechanical Properties
writer：HL Zheng, B Wang, GQ Zheng, ZG Wang, K Dai, CT Liu, CY Shen
keywords：聚乙烯，力學性能，部分熔融，結晶
source：期刊
specific source：Ind. Eng. Chem. Res., 2014, 53 (14), 6211–6220
Issue time：2014年
Partially melting high-density polyethylene (HDPE) is investigated by
differential scanning calorimetry and in situ Fourier transform infrared
spectroscopy (FTIR) measurements. The results show that some
incompletely molten crystals can be preserved in the partially melting
HDPE, thus accelerating subsequent crystallization. Moreover,
quantitative calculation of such incompletely molten crystals has been
done based on the FTIR results. Interestingly, the kinetically enhanced
crystallization results from the improved nucleation rate because of the
incompletely molten crystals. Furthermore, such interesting
self-nucleation originating from the partially melting HDPE has been
deliberately applied to practical polymer processing, i.e., extrusion,
aiming to investigate the influence of partially melting HDPE on the
microstructural development and the resultant mechanical properties of
the extruded products. Unexpectedly, an increment in tensile strength
has been achieved in the sheets extruded from partially melting HDPE
compared with that extruded from completely melted HDPE. Wide-angle
X-ray diffraction and small-angle X-ray scattering results show that the
crystallinity, long period, and lamellar thickness increase for the
sheets extruded from the partially melting HDPE. These increases are
considered to be responsible for the mechanical increment. This work
opens a new gateway for applying the self-nucleating effect of partially
melting polymer melt into practical processing with the purpose of
preparing high-performance polymer products.