Development and application of triglyceride‐based polymers and composites

Abstract

Micromechanical deformation processes responsible for toughening mechanisms in ultrafine monospherical inorganic particle-filled polyethylene were investigated in situ by a field-emission gun-environmental scanning electron microscope (FEG-ESEM) with low-voltage techniques. In general, the ultimate properties of polymer composites are largely dependent on the degree of dispersion of filler particles into the matrix. Very often, the agglomeration is one of inevitable occurrences in polymer composites, mixed with ultrafine filler particles. In the present work, the effects of agglomerates, consisting of ultrafine monospherical filler particles, were reexamined in polymer composites on the toughening mechanism. The results show that the dominant micromechanical deformation processes are the multiple debonding processes inside agglomerates, in which the ratio of the matrix strand and the size of agglomerate plays a great role of matrix yielding. In the specimen, where the agglomerates are isolated in the matrix, deformation begins at the equatorial region of agglomerates and propagates through them. However, in the case of closely placed agglomerates, deformation occurs homogeneously within the whole area inside the agglomerates. In both cases, in conjunction with the multiple debonding processes, the major part of energy during the deformation dissipates through the shear-flow processes of the matrix material. In particular, the micromechanical deformation processes observed in this work confirm that the agglomerates do not always have negative effects on the mechanical properties-at least, in the shear deformable semicrystalline polymer matrices. The agglomerates may be effectively used for the improvement of toughness. Furthermore, the FEG-ESEM with low-voltage techniques offers an extremely promising and efficient alternative method to study the morphology as well as in situ micromechanical deformation processes in nonconducting polymer systems.

High‐strength composites based on tung oil polyurethane and wood flour: Effect of the filler concentration on the mechanical properties

“…The value of r m ¼ 1.24 g/ cm 3 was experimentally determined, and r f was taken as the density value of the wood flour cell walls, 1.53 g/cm 3 [17], because the particles are compressed in the composite and the resin is filling the cell lumens [18]. From the predicted densities (Eq.…”

“…The main relaxation of the polymeric matrix (a transition related to the peak of tan d) is quite broad due to the large number of different relaxation modes that can derive from the complex chemical structure of these oil-based polymers [3]. The storage modulus presents a direct functionality with the WF content in the whole range of temperatures (Fig.…”

“…In general, the polyurethane industrial production is carried out with materials derived from the petroleum industry [2]. In the recent decades, there have been several works, which indicate that vegetable oils can be used as the polyol component in polyurethane materials after being modified by the introduction of hydroxyl groups in their structure [3,4]. Thus, the rather inexpensive and widely available natural oils become interesting raw materials.…”

“…These oils can be functionalized by hydroxylation of the carbon-carbon double bonds with a peroxy acid and/or by alcoholysis with a triol like glycerol or triethanolamine to reach a hydroxyl value useful for elastomeric or rigid polyurethane production [3][4][5].…”

New environmentally friendly composite laminates with epoxidized linseed oil (ELO) and slate fiber fabrics

“…The most common vegetable oils are composed of fatty acids with 14-22 carbon atoms and each fatty acid typically can content between 0 and 3 carbon-carbon double bonds. In particular, linseed oil (LO) is one of the vegetable oils with more carbon-carbon double bonds per triglyceride with an average value of 6.6 which can be selectively functionalized due to their reactivity [26]; for this reason, linseed oil is one of the best candidates for bio-based thermosetting resins synthesis.…”