Cellulose Ether-Based Liquid Crystal Materials: Review Article

The development of liquid crystal materials via nanotechnology has become an interesting subject of research in optical material chemistry. One of the significant nanomaterials is cellulose-based nanoparticles. In this review article, we highlighted the classification of liquid crystal materials (LCs), and types of cellulose-NPs and their characterization as LCs materials. Finally, we present our promising data on the synergistic effect of cellulose-NPs on liquid crystal behavior of ethyl cellulose- and hydroxypropyl cellulose- nanocomposites

Role of pulping process as synergistic treatment on performance of agro-based activated carbons

Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.International audienceTo recommend the beneficial effect of the pulping process on enhancing agro-wastes as precursors for the production of high-performance activated carbons (ACs), different pulping methods (alkali, sulfite and neutral sulfite) were applied on two available Egyptian agriculture by-products (rice straw and sugar cane bagasse), using the one-step pyrolysis method and H3PO4 activating agent. The adsorption performance of the different prepared ACs was evaluated in terms of Iodine Numbers and their sorption properties for removing the methylene blue (MB) from aqueous solutions. The corresponding sorption processes were also analysed using Lagergren first order, pseudo-second order and intraparticle diffusion models. Data revealed that the applied pulping conditions were effective for removing the non-cellulosic constituents of agro-residues. This was demonstrated by the hydrogen/carbon and oxygen/carbon ratios, thermal stability and IR-measurements of the final pulps. These data were effective on the particular sorption properties of RS and SCB-based ACs. Interestingly, the pulping process is a profound modification of the SCB-based fibres, on which it induced a clear increase of the specific surface areas of the corresponding ACs even though they had an impact on the sorption of MB and iodine. These values are superior to the reported data on agro-based ACs with H3PO4 activators. Pulping processes therefore play a dual role in the sorption properties of ACs. The first important role is the impact on the specific surface areas and the second impact is a profound modification of the surface chemistry of the ACs. Therefore, SCB-based ACs can be seen as an economical breakthrough product, and an alternative to the high-cost commercial ACs for the purification of industrial wastewaters

Comparison of the benzene sorption properties of metal organic frameworks: influence of the textural properties

International audienceThe adsorption of benzene by CuBTC and MIL101(Cr) is investigated. The differences between both materials are discussed in terms of porous volume and affinities, determined by calculating Henry's constants and by measuring the adsorption enthalpies. If MIL101(Cr) adsorbs higher quantities of benzene, CuBTC develops stronger interaction, interesting for VOC remediation.Environmental significanceVolatile organic compounds are a key environmental issue as their release in the atmosphere is poorly controlled. Amongst these VOCs, benzene is classified as a known human carcinogen based on leukemia observed in epidemiological studies. Various strategies have been used for removing benzene from air and adsorption using metal organic frameworks appears very promising. This study compares two benchmark MOFs which differ by their porous structure for the adsorption of benzene. As many parameters influence the sorption properties of porous materials, we focused on the influence of the textural properties of materials having similar surface chemistry. These results may be utilized to better choose between sorption capacities and irreversibility of adsorption. In the frame of toxic chemicals, irreversibility must be favored

Upcycling polyethylene terephthalate wastes for enhancing the performance of polyester from rice straw polyol in HDPE-composites

Abstract Upscaling the utilization of polymer wastes together with the valorization of undesirable waste rice straw (RS) will minimize the environmental impact of waste disposal by traditional tools. This present work assesses the utilization of polyethylene terephthalate wastes in enhancing the production of polyester-(high density polyethylene) HDPE from Rice straw polyol composites. In this respect, the polyester from rice straw polyol in hybrid with glycolysis polyethylene terephthalate wastes (Gly-WPET) was assessed in comparison with that resulted from RS-polyol, using FTIR, non-isothermal analysis, and mechanical tests. The data showed the positive role of Gly-WPET in hybrid with RS-polyol in production polyester with high thermal stability and mechanical properties. It provided an increase in activation energy of degradation, elongation, Young's Modulus, and modulus of toughness from 184.5 to 1201 kJ/mole, from 4.7 to 9.8%, from 47.5 to 66.5 MPa, and from ~ 4.0 to 23 J/m3, respectively. This behavior was reflected in the properties of HDPE-polyester polyol (PEPO) composites, especially in improving elongation (from 55.4 to 72%). These promising data persuade us to recommend the influential role of Gly-WPET in using PEPO from liquefied RS as a plasticizer

ROLE OF SOME TREATMENTS ON ENHANCING THE ECO-FRIENDLY UTILIZATION OF LIGNOCELLULOSIC WASTES IN PRODUCTION OF CEMENT-FIBER BRICKS

Rice straw (RS) and sawdust (SD) were evaluated for the manufacturing of fiber-cement bricks. The utilization of these bio-wastes will contribute to the reduction of the environmental impact of waste disposal. Pre-treating the fiber wastes, mechanically and/or chemically, was carried out before mixing them with cement and the appropriate amount of water. This approach was done for trials to reduce the tendency of fibers to absorb water, and consequently overcome the side effects of exposing the fiber-bricks to humidity. Different chemical treating agents, based on organic and inorganic materials, were used, e.g., gelatin-hexamine mixture, sodium silicate, and linseed oil. The results obtained show that the investigated organic treatments, especially linseed oil, were effective to reduce the water retention value (WRV) of RS and SD by 60% and 65%, respectively. The treatment provided bricks with compressive strengths of 4.9 MPa and 5.4 MPa, respectively. According to the Engineering Encyclopedia of Building standards, these values are suitable for construction purposes. The bricks manufactured from linseed oil-treated fibers with cement and Nitobond AR may be suited for load-bearing walls, since the compressive strength reached is 7.8 to 8.6 MPa

Confinement-Induced Electronic Excitation Limitation of Anthracene: The Restriction of Intramolecular Vibrations

International audienceThe spectroscopic behavior of anthracene encapsulated in porous zeolitic zinc imidazolate framework ZIF-8 was studied. Nanoparticles of ZIF-8 with high crystallinity and large specific surface areas were prepared in one-pot synthesis. Monitoring single anthracene encapsulation in a ZIF-8 cell was done by careful control of the synthesis of the hybrid. The molecular electronic spectra of anthracene adsorbed on the external surface of ZIF-8 were compared with those of encapsulated anthracene. It was demonstrated that the encapsulation of anthracene induced unexpected confinement effects including the restriction of intramolecular vibrations in its absorption spectrum. It was shown that vibronic components in the high-energy part of the S0 → S1 absorption band totally collapse upon encapsulation. Our study highlights the mechanism of confinement-induced electronic excitation limitation related to the restriction of intramolecular vibrations, which evidences the role of host–guest interaction in infrared absorption and fluorescence emission properties

Evaluation of palm fiber components an alternative biomass wastes for medium density fiberboard manufacturing

This work deals with assessing the date palm component wastes as alternative lignocellulosic material for production of Medium density fiberboards, in order to establish economic and balance between production/consumer ratio at different provinces rather than Upper Egypt. Palm leafs and palm frond was used as Medium density fiberboards precursors. Different urea formaldehyde levels (10-14%/fiber) and pressing pressure (25-35 bar) were applied in this evaluation. The acceptable interaction of palm fibers component with urea formaldehyde was optimized by characterizing its differential scanning calorimetry and thermogravimetric analysis, in comparison with commercial used sugarcane bagasse fibers. The promising Medium density fiberboards Panel is obtained from palm frond fibers and its mechanical and water resistance properties fulfill the ANSI standard for high grade Medium density fiberboards wood products, especially on applying urea formaldehyde level 12-14%, and pressing pressure, 35 bar. It is interesting to note that, applying higher pressing pressure together with 12% urea formaldehyde level provided palm frond-based Medium density fiberboards with static bending properties, higher than commercial bagasse-based Medium density fiberboards. The insignificant effect of pressing pressure was noticed on water swelling property and free-HCHO of Medium density fiberboards panels.  Where, both type of fibers have the same water swelling property (reached ~ 10%), and free-HCHO (~ 27 mg/100g board)