Laurent Clerc

Incorporation of elastomer into poly(ether ether ketone) an attempt to improve the damping factor

The incorporation of an elastomer phase into a poly(ether ether ketone) (PEEK) matrix was carried out using two different processing methods (melt blending (MB) and dry blending) to improve the damping factor (tan δ) of the composite with a minimal change in the PEEK stiffness. A cross-linked fluoroelastomer (CFE) was carefully chosen according to its high glass transition temperature (T α), high thermal stability and high modulus. The blends were characterized by scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), modified Oberst test, flexural test and pyrolysis combustion flow calorimeter. According to SEM micrographs, an original well-dispersed PEEK-elastomer composite was obtained. The tan δ of the materials was evaluated using DMTA and modified Oberst test. Both techniques indicate that the incorporation of 5–20 wt% of CFE fine powders only slightly increased the tan δ of the material. Moreover, a decrease in flexural modulus and thermal stability of the blends was detected when there was an increase in the CFE content. Even if the properties are not yet significantly improved, it was well ascribed that the MB method was suitable to mix elastomer particles within a PEEK matrix. Poor interfacial adhesion has been identified as the main key parameter, which should be improved in further work.

Pneumatic selection of fly ash: selection methods — influence of the operating parameters

This work concerns the use of a pneumatic classifier in the valorization of fly ash. This classifier is characterized by a rotor positioned vertically. Firstly, a study in laboratory was carried out. Three parameters were retained: the rotation speed of the rotor, the air flow and the ash feeding rate. The main parameter is the rotation speed of the rotor. There is a relation between the cut diameter and the speed rotation: d50=K/V with V as the speed and K as a factor in function of the process. The increase of the air flow and the ash feeding rate favours the extraction of the fine particles. After that, we realized a study of the industrial feasibility of the selection. We observe the same relation as those obtained during the laboratory study. We have found a set of operating parameters so as to obtain four granulometric fractions (<10, <30, <50 and <80 μm).

Two Typical Plant Aggregates for Bio-Based Concretes

Many by-products of plant origin have been incorporated in mineral binders. However, it is important to distinguish plant fibers used as reinforcement in cement composite materials from plant-derived aggregates used for the manufacturing of lightweight insulating concretes (bio-based concretes).

Lime-Based Binders

Unlike Portland cement, the use of lime goes back much further in time. During the Greco-Roman period, walls were built of lime-based mortars blended with fine sand and pozzolanic additives (volcanic ash).

Conclusion and Outlooks

The results reported in this document first contribute to the development of an innovative plant-based concrete using raw rice husk. This crop residue is available throughout the year at low cost and its use to manufacture bio-based concretes for green building provides a new recovery sector for a local by-product coming from rice farming in France.

Lime and Hemp or Rice Husk Concretes for the Building Envelope: Applications and General Properties

Hemp concrete is obtained from the mix of hemp shiv, water and a mineral binder (which can be itself a mixture of different binders).