writer：Gai Jing-Gang*, Yuan Zuo.
keywords：optimum parameter range，ultrahigh molecular w eight polyethylene
source：期刊
specific source：J. Mol. Model., 2012, 18(6): 2501–2512
Issue time：2012年

Numerous studies suggest that two-phase morphology and thick interface

are separately beneficial to the viscosity reduction and mechanical property

maintainence of the matrix when normal molecular weight polymer (NMWP) is used

for modification of ultrahigh molecular weight polyethylene (UHMWPE).

Nevertheless, it is very difficult to obtain a UHMWPE/NMWP blend which may demonstrate

both two-phase morphology and thick interface. In this work, dissipative

particle dynamics simulations and Flory-Huggins theory are applied in

predicting the optimum NMWP and the corresponding conditions, wherein the melt

flowability of UHMWPE can be improved while its mechanical properties can also

be retained. As is indicated by dissipative particle dynamics simulations and phase

diagram calculated from Flory-Huggins theory, too small Flory-Huggins

interaction parameter (χ)

and molecular chain length of NMWP (NNMWP)

may lead to the formation of a homogeneous phase, whereas very large interfacial

tension and thin interfaces might also appear when parameters NNMWP

and

χ are

too large. When these parameters are located in the metastable region of the

phase diagram, however, two-phase morphology occurs and interfaces of the

blends are extremely thick. Therefore, metastable state is found to be

advisable for both the viscosity reduction and mechanical property improvement of

the UHMWPE/NMWP blends.