(181bb) Multi-Scale Modeling of Fiber-Matrix Interphase
AIChE Annual Meeting
2019
2019 AIChE Annual Meeting
Poster Sessions
Poster Session: In Recognition of the 50th Anniversary of ExxonMobil Corporate Strategic Research
Tuesday, November 12, 2019 - 3:30pm to 5:00pm
Applications of fiber reinforced polymers (FRP) have grown so rapidly that
developing well-bonded and durable interfaces between the fibers and polymer
matrix has often become an important bottleneck in the their developmment.
To tailor composites with desirable properties to be used in a a variety of applications,
it is necessary to know the mechanisms of the polymer-fibre adhesive
contact formation and their behavior under mechanical loading. Since the 1970s
[1], the concept of interphase, a finite interlayer with a blend of physico-chemical
properties between the fiber and matrix, has become a major focus of research
into new practical applications [1, 2]. Nevertheless, most research activities are
mainly confined to experimental works, while only a relatively small number
of theoretical studies have been dedicated to the issue. Specifically, molecular
dynamics (MD) studies of interphase are rare, despite the fact that MD is a tool
that can complement experiments by giving capturing the molecular and atomistic
configurations characteristic of interface failure. In this work, all-atom
MD simulations are used to describe the effects of tunable contributors to interphase
formation in the context of particular silica surface chemistry, such as
pH and surface morphology. The results show that the epoxy based polymers
have a higher affinity to the glass-fiber surface and forming an interphase in
acidic conditions with pH around 3:5 whereas they would form a stable droplet
far apart from the glass-fiber surface by increasing the pH. Then, to assess
the adhesive strength of the formed intephase models, they are subjected to
mechanical loading in different directions to derive cohesive traction laws [3, 4].
developing well-bonded and durable interfaces between the fibers and polymer
matrix has often become an important bottleneck in the their developmment.
To tailor composites with desirable properties to be used in a a variety of applications,
it is necessary to know the mechanisms of the polymer-fibre adhesive
contact formation and their behavior under mechanical loading. Since the 1970s
[1], the concept of interphase, a finite interlayer with a blend of physico-chemical
properties between the fiber and matrix, has become a major focus of research
into new practical applications [1, 2]. Nevertheless, most research activities are
mainly confined to experimental works, while only a relatively small number
of theoretical studies have been dedicated to the issue. Specifically, molecular
dynamics (MD) studies of interphase are rare, despite the fact that MD is a tool
that can complement experiments by giving capturing the molecular and atomistic
configurations characteristic of interface failure. In this work, all-atom
MD simulations are used to describe the effects of tunable contributors to interphase
formation in the context of particular silica surface chemistry, such as
pH and surface morphology. The results show that the epoxy based polymers
have a higher affinity to the glass-fiber surface and forming an interphase in
acidic conditions with pH around 3:5 whereas they would form a stable droplet
far apart from the glass-fiber surface by increasing the pH. Then, to assess
the adhesive strength of the formed intephase models, they are subjected to
mechanical loading in different directions to derive cohesive traction laws [3, 4].
References
[1] Papanicolaou G.C., Paipetis S.A., Theocaris P.S. The concept of boundary
interphase in composite mechanics, Colloid Polym Sci, 1978, 256, 7: 625–630.
[2] Peterson A.M., Jensen R.E., Palmese G.R. Thermoreversible and remendable
glasszpolymer interface for fiber-reinforced composites, Compos Sci Technol,
2011, 71, 5: 586–592.
[3] Barenblatt G.I. The Mathematical Theory of Equilibrium Cracks in Brittle
Fracture, Adv Appl Mech, 1962, 7: 55–129.
[4] Dugdale D.S. Yielding of steel sheets containing slits, J Mech Phys Solids,
1960, 8, 2: 100–104.