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This work deals with assessing the approach for preparation of cellulose nanoparticles (CNPs) to be acted as synergistic component in liquid crystal (LC) ethyl cellulose composite (EC‐CNPs). In this respect different structures of CNPs were prepared by acid and salt agents. These prepared CNPs were characterized by carboxyl content, IR, transmission electron microscope (TEM), and zeta potential, while their composites with EC were characterized by rheological measurements as a key factor for measuring the critical concentration of LC behavior. The results showed that, the crystallinity of CNPs obtained by ammonium persulfate exceeded that prepared by sulfuric acid hydrolysis. TEM images of stained CNPs showed both methods led to produce nanoparticles have rod like shape with aspect ratio (L/W) between 7.69 ± 3 and 31.3 ± 5. For the rheological measurements, it demonstrated the efficient of incorporating the CNPs to EC (EC‐CNPs composites) to decrease the critical concentration of EC from 40 wt% to approximately 34 wt%.

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Purpose -The purpose of this paper is to study the possibility of preparing high performance, agro-based composites from rice straw, using ecopolyalcohol polymers-based adhesive system. The utilization of rice straw (undesirable biowastes) for the production of high quality biocomposite products, will add economic value, help to reduce the environmental impact of waste disposal and, most importantly, provide a potentially inexpensive alternative to the existing commercial artificial wood-panels. Design/methodology/approach -Simple synthesizing and optimizing the polyalcohol polymers-based non-toxic adhesive system were carried out, by blending corn starch, as natural polyalcohol polymer with polyvinyl alcohol, as synthetic polyalcohol polymers-based adhesive (St/PV adhesive), at temperature , 758C. The percentages of adhesive components, type of starch, bonding temperature and time were optimized. Assessment of the synthesized adhesive was performed from its adhesion behavior (bond strength), in comparison with commercial thermosetting resin (ureaformaldehyde), as well as the properties (mechanical and physical properties) of the composites produced. The effects of amount and type of water resistance co-additives (paraffin wax and polyester), on mechanical properties of RS-based composite were also optimized. Findings -The promising adhesive system exhibits improved performance over a previously commercially HCHO-based adhesive (UF), and results bonding strength 9.8 N/mm2, as well as MOR, IB and TS of RS-based composites up to 31 N/mm2, 0.49 N/mm2 and 20%, respectively. Research limitations/implications -Through the studied eco-adhesive with relatively high natural polyalcohol polymer (starch) in presence of water-resistance additive (PE) provided a good bonding strength and comparative RS-based composite properties, with that produced from commercial UF. For the mechanical properties (MOR and IB) are complied the standard values; while water resistance is still higher. Further study is needed to solve this problem. Practical implications -The approach provided a HCHO-free adhesive with good bonding strength, comparative board strength and water resistance, reasonable working life, and without formaldehyde emission. Starch-based adhesive with low percentages of polyvinyl alcohol is considered a promising inexpensive alternate adhesive in wood industry based on rice straw wastes, which traditionally required expensive pMDI. Originality/value -The paper provides a potential way to utilise undesirable rice by-product (RS), corn starch as industrial raw material. This will benefit farmers significantly. Meanwhile, the modified starch adhesive with low percentage of PVA is promising to partly or completely replace urea formaldehyde resin and pMDI that are mainly used in wood industry, or pMDI in RS-based artificial wood, avoiding formaldehyde emission or toxic gases during exposed to burning, and reducing the dependence on petroleum products.

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The role of starch aerogel (St‐AG) and carboxymethyl cellulose (CMC) as biolgical active compounds, when they subjected for complexation with metal ions, is assessed in this work. The complexation is carried out with palladium(II) and copper(II) ions, in solid state. Different tools of analysis are carried out to characterize and elucidate the structures of these complexes, namely: elemental analysis, IR, thermal analysis, magnetic measurement and molar conductance techniques. All synthesized complexes are formed with 1:2 (metal:ligand) stoichiometry except the case of aerogel starch 1:1 (Pd:starch). All isolated complexes show a satisfactory cytotoxic effect results against colon cancer cell lines HCT11. Additionally, these complexes are screened for their antibacterial activities against two types of Gram positive and negative bacteria. Molecular docking investigation confirmed the cytotoxicity and antibacterial results. Proton–ligands association constants and their complex formation constants with some bivalent metal ions, using potentiometric method show that the complexes formed in solution have a stoichiometry of 1:1 [metal:ligand]. The effects of metal ion, ionic radius, electronegativity and nature of ligand on the formation constants are discussed. The formation constants of the complexes with 3D transition metals followed the order Mn2+ < Co2+ < Ni2+ < Cu2+ > Zn2+.