TY - THES ID - 136440670 TI - Curing and nanostructure development in epoxy/block copolymer blends AU - Bogaerts, Kevin AU - Goderis, Bart AU - Nies, Eric AU - KU Leuven. Faculty of science. Department of chemistry PY - 2022 PB - Leuven KU Leuven. Faculty of Science DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:136440670 AB - Throughout the last decades, material research has increasingly been exploring the potential of ordered nanostructures to enhance mechanical, electrical, optical or other properties. Nanostructuring most elegantly happens through processes of self-assembly, being the spontaneous association of molecules, through non covalent bonds.When amphiphilic molecules, such as surfactants or block copolymers are introduced in a liquid matrix with which only one of the chemical moieties is compatible, nanostructuring is readily realized. When using rather high amphiphile concentrations, progressed molecular stacking may lead to structuring from nanometer to micrometer length scales.From the perspective of structural materials, solid rather than liquid state structures are required. During material processing challenges arise to transfer the liquid state ordering to the solid state via vitrification or crystallization. Solidification via crystallization in particular may affect structure formation and in fact provides extra means to gain control over the materials' morphology and properties.Besides purposely synthesized organic molecules, also nanoparticles can be considered to induce nanostructuring. In that case, properties may benefit from the establishment of ordered patterns in their topology, which vastly differ from disordered clusters or homogeneous dispersions within a given matrix. For instance theoretical work in the literature has demonstrated that certain patterns in the location of reinforcing nanoparticles may be very advantageous to the overall material toughness. This toughness increase may furthermore be related to the establishment of structural hierarchy, i.e. the presence of structural elements at different length scales. A second application of ordered nanoparticles can be found in nano-electronics, in which the conductivity of ordered nano-dispersions can be exploited for wearables or implantable technology applications. Generating ordered patterns in nanoparticle distributions is challenging and calls for innovative methodologies.This work aimed at providing new pathways and recipes to generate ordered, nanostructured, solid materials. More specifically, in this dissertation nanostructure formation relied on the assembly of amphiphilic block copolymers when added to an epoxy matrix. Solidification was realized through vitrification of the curing epoxy matrix as well as block copolymer crystallization. The selected diblock copolymer was stearyl-block-poly(ethylene oxide20), which is rather unique as both the aliphatic and the poly(ethylene oxide) block are crystallizable. The study included systems from very low to very high block copolymer concentrations.viAt first the epoxy curing kinetics in the presence of the block copolymer was addressed. In a next stage the nanostructuring potential of the system was explored over the entire compositional range during isothermal epoxy curing and during cooling/heating cycles in the uncured and cured state. Using synchrotron small angle X-ray scattering and wide angle X-ray diffraction in conjunction with transmission electron microscopy, we were able to construct morphology maps involving micelles, vesicles and wormlike structures at low block copolymer fractions and stacked lamellar morphologies at high fractions. Intermediate block copolymer concentrations also exhibited hexagonally packed cylindrical micelles and showed complex transitions between different structures as function of the temperature. These transitions occasionally were triggered by the crystallization of the interconnected block copolymer moieties.In the last part of this manuscript it was investigated to what extent the studied amphiphilic block copolymers may affect the dispersion and topology of carbon nanotube (CNT) reinforcements when added to a curing epoxy matrix. Unfortunately, it turned out that the block copolymer was not able to affect the CNT dispersion and patterning to any degree. Gaining control over the structural patterning of nanoparticles therefore remains a huge challenge. ER -