Mechanical Properties and Fracture Behaviors of Epoxy Composites With Phase-Separation Formed Liquid Rubber and Preformed Powdered Rubber Nanoparticles: A Comparative Study
作者：Li-Zhi Guan, Li-Xiu Gong, Long-Cheng Tang, Lian-Bin Wu, Jian-Xiong Jiang, Guo-Qiao Lai
關鍵字：Epoxy, rubber, toughening mechanisms
論文來源：期刊
具體來源：POLYMER COMPOSITES
發表時間：2015年
Epoxy composites filled with phase-separation formed
submicron liquid rubber (LR) and preformed nanoscale
powdered rubber (PR) particles were prepared at differ-
ent filler loading levels. The effect of filler loading and
type on the rheological properties of liquid epoxy resin
suspensions and the thermal and mechanical properties
of the cured composites as well as the relative fracture
behaviors are systematically investigated. Almost
unchanged tensile yield strength of the cured epoxy/PR
composites is observed in the tensile test compared
with that of the neat epoxy; while the strength of the
cured epoxy/LR composites shows a maximum value at
??4.5 wt% and significantly decreases with increasing
LR content. The glass transition temperature (Tg) of the
cured PR/epoxy has shifted to the higher temperature in
the dynamic mechanical thermal analysis compared
with that of the cured pure epoxy and epoxy/LR compo-
sites. Furthermore, the presence of LR results in highly
improved critical stress intensity factor (KIC) of epoxy
resin compared with the corresponding PR nanopar-
ticles. In particular, the PR and LR particles at 9.2 wt%
loading produce about 69 and 118% improvement in KIC
of the epoxy composites, respectively. The fracture sur-
face and damage zone analysis demonstrate that these
two types of rubber particles induce different degrees of
local plastic deformation of matrix initiated by their
debonding/cavitation, which was also quantified and
correlated with the fracture toughness of the two
epoxy/rubber systems.