Rigid poly(vinyl chloride)-organosolv lignin blends for applications in building

Research and application progress of lignin-based composite membrane

In view of the serious environmental pollution, which is the greatest problem the world is facing, and the continuous consumption of raw materials, it is imminent to search for green and sustainable resources. Lignin is an organic polymer that exists widely in nature, and if it can be transformed from traditional low-value waste product with low range of applications to functional materials with high application prospects, it can be of great significance to alleviate environmental pollution and shortage of fossil resources. One of the functional applications of lignin involves its use to fabricate composite with other polymeric materials, which can then be used to prepare membrane materials. This review summarizes the recent research and application progress of combining lignin with polypropylene, polyvinyl alcohol, starch, cellulose, chitosan, and other polymeric materials to prepare composite membranes; and summarizes the future development direction of lignin-based composite membranes. We hope this review may provide a new perspective to the understanding of lignin-based composite membranes and a useful reference for future research.

Revisiting lignin: a tour through its structural features, characterization methods and applications

A pedagogical overview of the main extraction procedures and structural features, characterization methods and state-of-the-art applications.

The Rheological and Mechanical Properties of PVC-Lignin Blends

The rheological and mechanical properties of PVC-lignin blends were studied, and their alterations were investigated after lignin was treated with poly(ethyl acrylate-co-maleic anhydride). The addition of lignin changes the early rheological properties of the blend comparing with PVC control because the rigidity of lignin particles leads to more intensive shearing in the system, but has little effect on its rheology during the equilibrium period. The processing stability slightly decreases with the increase of lignin content in the blend. The mechanical properties of the blends are worse than that of PVC control. The rheological properties of the blends are little influenced after lignin is treated with polyacrylate, but the mechanical properties, especially toughness, are improved, and the maximum impact strength is 37.7% higher than that of PVC control.

The Effect of Silane Treated Hybrid Filler on the Mechanical and Thermal Performance of Carboxylated Nitrile Butadiene Rubber (XNBR) Composites

Carboxylated Nitrile Butadiene Rubber (XNBR) was reinforced with untreated and silane treated hybrid filler. The hybrid filler was composed of organic layered nanosilicates (NLS) and agro polymer based olive husk powder (OHP). The fabricated composites were inspected with regard to their mechanical and thermal properties. It was found that the silane treated hybrid filler was able to improve the tensile strength at break and the tensile modulus as compared to the control. The overall degree of interaction between the matrix and both the untreated and treated hybrid filler was improved. This was evidenced by the increased degree of curing which is the torque difference (τmax–τmin) derived from the moving die rheometer (MDR) and the decreased swelling index data. Dynamic mechanical analysis (DMA) revealed that the apparent was the highest in case of the silane treated hybrid filler. The thermogravimetric analysis (TGA) revealed that the thermal stability of the composites improved with the incorporation of the hybrid filler. The attenuated total reflectance (ATR-IR) revealed that dipole-dipole interactions between the various reactive functional groups namely the carboxylic of the XNBR, the hydroxyl group of the agro-polymer and the silanol of the silane agent occurred during the fabrication stage of the composites. Scanning electron microscopy (SEM) showed that the fracture surface of the samples differ after the incorporation of the treated hybrid filler.

Molecular mobility and relaxation process of isolated lignin studied by multifrequency calorimetric experiments

The glass transition of lignin has been studied by multifrequency calorimetric measurements in order to highlight the morphological changes and the dynamic aspects associated to this relaxation process. Influences of water sorption and thermal annealing on molecular mobility have been considered. Additional investigations by thermogravimetry, infra-red spectroscopy and rheometry have been performed to corroborate the claims. The relaxation process of annealed lignin shows a different behaviour as the consequence of micro-structural modifications of lignin. These are explained by redistribution of secondary bonds as well as formation of new interunit linkages. Concerning the dynamic aspects, apparent activation energy, E, and sizes of cooperatively rearranging region, V(crr), have been evaluated respectively from the frequency dependence and heat capacity measurements of the glass transition. Compared to dried lignin, both E and V(crr) significantly decrease in a water-sorbed matrix indicating that the three-dimensional structure presents a higher mobility and is less confined.

Biomimetic synthesis of a water soluble conducting molecular complex of polyaniline and lignosulfonate

A new biomimetic route for the synthesis of a conducting molecular complex of polyaniline (Pani) and a natural polyelectrolyte, lignosulfonate (LGS) is presented. A poly(ethylene glycol) modified hematin (PEG-hematin) was used to catalyze the polymerization of aniline in the presence of LGS to form a Pani/LGS complex. UV-vis, FTIR, conductivity and TGA studies for the LGS-polyaniline complex indicate the presence of a thermally stable and electrically conductive form of polyaniline. Also the presence of LGS in this complex, an inexpensive byproduct from pulp processing, provides a unique combination of properties such as electronic conductivity, processability and biodegradability. The use of this conductive complex for corrosion protection is also proposed.