Morphology and elastic modulus of novel poly[oligo(ethylene glycol) diacrylate]‐montmorillonite nanocomposites

Abstract

Novel thermosetting poly[oligo(ethylene glycol) diacrylate]-sodium montmorillonite nanocomposites containing a range of clay volume fractions were prepared by an in situ polymerization method. X-ray diffraction showed that the basal plane spacing of the clay was increased to approximately 1.7 nm regardless of clay volume fraction. Transmission electron microscopy confirmed the basal spacing and intercalated structure. The elastic moduli of the composites were measured using ultrasonic pulse-echo equipment. The results show that the Young's modulus and shear modulus increase with nominal clay volume fraction up to 0.22, and are in good agreement with the well-established Christensen method and derived Hashin-Shtrikman bounds for conventional composites provided that the true volume fraction of clay reinforcement filler is calculated. At low clay volume fractions, the composites were transparent. When the nominal clay volume fraction was further increased, cracks and porous surfaces appeared, as observed by scanning electron microscopy. These defects decreased the elastic modulus, indicating an upper limit for clay additions in this preparation route.

A critical appraisal of polymer–clay nanocomposites

“…There are three main methods for preparing polymer-clay nanocomposites. They are in situ polymerisation, 92,93 solution methods 94 and melt-processing methods. 6,7 A wide range of polymers is known to form clay nanocomposites: thermoplastic and thermoset, water soluble and organic solvent soluble.…”

Impact strength of polymer-clay nanocomposites

“…Impact strength is often the major parameter that interests the plastics industry and can provide a dominant criterion for materials selection. It is well known that incorporation of clay filler often provides an increase in stiffness of polymers 3,[7][8][9] but whether it retains or enhances toughness is uncertain and academic authorities sometimes fail to assess impact strength directly or Dr Biqiong Chen has a BSc in Polymer Science and Engineering, and an MSc and a PhD in Materials Science. She started her research in polymer-clay nanocomposites in 2001 under the supervision of Prof. J.R.G.…”

Influence of compatibilizer on notched impact strength and fractography of HDPE–organoclay composites

“…Perhaps the organoclay platelets in our system were not randomly oriented as in Ref. 32 but had a certain degree of orientation due to the injection moulding process. 32 …”

“…32 Our data are too limited for a modeling of the modulus of the composites. However, if we take our best sample, PE08OM7CP14, and assume that the degree of dispersion in our system is comparable to that in, 32 the enhancement in the modulus, in terms of composite modulus (E c ) to polymer modulus (E p ) ratio in our system, is greater than that found in 32 (E c /E p % 1.44 as compared with 1.2). Perhaps the organoclay platelets in our system were not randomly oriented as in Ref.…”