Mechanics of particulate composites with glassy polymer binders in compression

Abstract

Whether used as structural components in design or matrix materials for composites, the mechanical properties of polymers are increasingly important. The compressive response of extruded polymethyl methacrylate (PMMA) rod with aligned polymer chains and Al–Ni–PMMA particulate composites are investigated across a range of strain rates and temperatures. The particulate composites were prepared using an injection-moulding technique resulting in highly anisotropic microstructures. The mechanics of these materials are discussed in the light of theories of deformation for glassy polymers. The experimental data from this study are compared with PMMA results from the literature as well as epoxy-based composites with identical particulates. The PMMA exhibited the expected strain rate and temperature dependence and brittle failure was observed at the highest strain rates and lowest temperatures. The Al–Ni–PMMA composites were found to have similar stress–strain response to the PMMA with reduced strain softening after yield. Increasing volume fraction of particulates in the composite resulted in decreased strength.

High Strain Rate Mechanics of Polymers: A Review

“…The percent crystallinity and Fig. 6 Peak stress vs. strain rate for a PMMA [16,95,125,[128][129][130][131][132], b PC [19], c PVC [138], and d epoxy [74] across a range of strain rates molecular conformation are highly dependent on the processing history.…”

“…The challenges associated True Strain Fig. 5 Representative compressive stress-strain curves for a PMMA [128], b PC [19], c PVC [138], and d epoxy [74] across a range of strain rates with these elastomers are similar to those experienced when characterizing many biological materials, giving further motivation to the development of suitable experimental techniques.…”

“…Careful studies like those conducted on PMMA [128], shown as the blue data points and fitted line in Fig. 6a, and epoxy [74] where experiments are conducted at every decade of strain rate using novel hydraulic loading devices capable of testing the intermediate rate regime reduced the uncertainty associated with the third reason described above.…”

“…There are several glassy polymers that have been extensively studied at high strain rate in the literature, including polymethylmethacrylate (PMMA) [16,95,100,[123][124][125][126][127][128][129][130][131][132], polycarbonate (PC) [15, 18-20, 100, 110, 124, 126, 127, 133-136], polyvinylchloride (PVC) [137,138] and varying classes of epoxy [23,74,[139][140][141]. The large number of studies on a ''single'' material indicates that it is critical to understand the pedigree of the polymer being tested, including processing history and storage.…”

Temperature and strain rate effects on the mechanical properties of a polymer-bonded explosive

“…[12][13][14][15][16][17][18][19][20][21][22][23][24]. The main conclusions of such research were: (i) the strain rate and temperature response are generally governed by the properties of the polymer binder [15,16]; (ii) the absolute value of the stress supported for a given strain rate and temperature is governed by the size of the explosive crystals [12,14].…”