Hydroxypropylcellulose-based liquid crystal materials

Sustainable development of rice straw pulping liquor-based lignin nanoparticles in enhancing the performance of cellulose nanostructured suspension for UV shielding

This study aims to assess the role of lignin nano-particles (LNPs) from RS-pulping black liquor in motivating the application of cellulose nanocrystals (CNCs), as new ultraviolet (UV) biodegradable shielding composite in comparison with zinc oxide nanoparticles (ZnO-NPs) individually or in hybrid with lignin nano-particles (LNPs-ZnONPs). The prepared nanoparticles and their nanocomposites were characterized by Transmission electron microscope (TEM), Attenuated total reflectance- Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Polarizing Optical Microscopy (POM) and UV shielding property. The amount of LNPs or ZnO-NPs (1-5 wt%) incorporated to CNCs was optimized toward the optical behavior and UV-blocking percentage of the resulting composites. As a result, all the investigated nanocomposites achieved a complete UV shielding rate for ultraviolet radiation C (UVC). Applying the LNPs in nanocomposite with CNCs provided higher blocking for ultraviolet radiation B and A (UVB and UVA) than ZnO-NPs. Images from cross-polarized optical microscopy of the dried nanocomposite revealed varying degrees of CNC rod alignment following the inclusion of ZnO-NPs and LNPs. This promising feature could motivate the CNCs aqueous suspensions with LNPs or LNPs/ZnONPs to produce semi-transparent and homogeneous dried suspension, providing a simple and green approach in engineering UV-protection. Packaging, smart windows, and other exterior UV-sensitive material regions are prospective uses for UV-shielding.

Carbon quantum dots derived from rice straw doped with N and S and its nanocomposites with hydroxypropyl cellulose nanocomposite

As biomass, rice straw (RS) is often valorized as a precursor of green products. In this respect, the RS-based carbon quantum dots (CQDs) are synthesized doped with N and S during the preparation. Synergistic doping with lipoic acid and ethylenediamine can vastly increase the yield of CQD from rice straw from 6.14 % to 62.8 %, and sulfur doping plays a more important role on the surface functional groups of the quantum dots. Further assessment is achieved toward the performance of SN-CQDs-hydroxypropyl cellulose nanocomposites. The optical behavior of synthesized SN-CQDs, and the critical concentration of its liquid crystal behaviors, at which the anisotropic phase begins to emerge, is approximately 1 %. Incorporating it into HPC, especially at 5 %, provided nanocomposite films with effective liquid crystal, tensile strength, and thermal stability. This sample's texture reveals a planar structure with colors ranging from yellow to red. The synergistic effect of incorporating SN-CQDs is shown by improving the strength to ~282.1 %, and the activation energy increased from 583.6 kJ.mol-1 to 615.1 kJ/mol. HPC-SN-CQDs can be assembled into an LED device, emitting warm light, of which CIE coordinate is (0.34,0.43).