Summary: In this work is discussed an alternative approach to the toughening of epoxy networks by the addition of acrylic block copolymers, composed of rigid and rubbery blocks. Once the reaction is completed, the initial self‐assembly of block copolymers in epoxy thermoset precursors produces rubbery domains: depending on the block copolymer structure and composition, these domains are of the micrometer or the nanometer size. Nanostructures are obtained when the rigid block is a random copolymer of methylmethacrylate and N,N‐dimethylacrylamide. The rubbery domains prevent rapid crack propagation and the highest toughness is obtained with filament‐like microparticles or wormlike micelles.

We present and review optical and rheological data on a number of sheared thermotropic liquid crystal polymers LCPs. Optical observations were carried out by using a shearing apparatus that was designed for these and additional in situ X-ray measurements. X-ray data on sheared LCPs are also presented together with orientation relaxation measurements made on the cessation of flow. To reconcile the optical, X-ray and rheological data, a numerical scheme is constructed that can qualitatively, and in some cases quantitatively predict observed behaviour. Essential elements of the model are concerned with a local molecular anisotropy, a molecular correlation coefficient, and a local defect structure. The model shows, among other predictions, that stress relaxation is essentially decoupled from both orientation and optical relaxation. In addition the presence of a defect texture influences orientation aspects more than the rheology.

The effect of initial fiber orientation and welding conditions on the mechanical properties and microstructure of 30 wt% glass-fiber-reinforced polyamide 66 was systematically evaluated. For all conditions studied no significant change in the polymer matrix was evidenced. However, fibers in the welded zone were reoriented toward the squeeze and vibration flows and this reorientation is related to the appearance of cavities, as evidenced by high-resolution synchrotron-based X-ray microtomography. It is shown that stress at break values of the welded samples increase with the thickness of the weld zone together with the minimum value of the fiber orientation tensor component in the tensile direction. A drop of strain at break is also related to an increase in the fibers' concentration in the weld. The maximum void volume fraction being measured on samples which have the thickest welded zones, counterintuitively it does not induce lower stress at break.

A review of good weatherability requirements for PVC profiles is presented. Analytical tools to assess these requirements are recalled and justified. Detailed analysis of the various parameters that may affect PVC weatherability show that except for a few additives, the key point is the level of thermal degradation undergone by PVC during its processing.

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