Enhanced thermal and mechanical properties of epoxy composites by addition of hyperbranched polyglycerol grown on cellulose fibers

Stimuli-responsive hydrogels composed of modified cellulose nanocrystal and gelatin with oriented channels for guiding axonal myelination

Myelination is modulated by neuron-glial communication, which is an essential physiological process during nerve regeneration. However, available scaffold for myelination of oriented axons is still challenging and lack of sufficient attention in neural tissue engineering. Here, we fabricate an extracellular matrix-mimic hydrogel (GB-SH), which was composed of cellulose nanocrystal grafted with sulfated hyperbranched polyglycerols (SHC) and 3-aminophenylboronic acid modified GelMA (GMPB) for stimuli-responsive release of sodium Danshensu (DSS). SHC with a "lubricative coating" maintained the crystalline core with a uniform size and 17.27 % of sulfation degree. GMPB having a grafting ratio of 14.94 % displayed a glucose-responsive release of dye. GB-SH hydrogels displaying oriented microchannels with controllable pore sizes were constructed by combining directional freeze-casting and photo-crosslinking strategies, which performed improved strengths, high water contents and slow degradation. It also exhibited stimulus (glucose, pH, H2O2) triggered release of DSS. In vitro studies revealed that DSS loaded GB-SH enhanced the cellular viability, proliferation and orientation on fibroblast and oligodendrocyte precursor cells (OPCs). This scaffold induced OPCs differentiated into matured oligodendrocytes, which myelinated the extensive axons of hippocampal neurons successfully. The multi-functional hydrogel is a promising platform for studying myelination in vitro and a potential neural transplant in treating traumatic nerve injury.

Recent studies on modified cellulose/nanocellulose epoxy composites: A systematic review

Cellulose and its derivatives are widely explored for films and thickening of pharmaceutical solutions, in paints, as reinforcement in composites, among others. This versatility is due to advantages such as renewability, low cost, and environmental friendliness. When used in polymer composites, due to the hydrophilic character of the cellulose, surface chemical modification is highly recommended to improve its compatibility with the polymeric matrix. Hence, this paper presents a systematic review of chemically modified cellulose/epoxy resin composites focusing on the last five years. The investigation followed the PRISMA protocol that delivers a meticulous summary of all available primary research in response to a research question. After including/excluding steps, thirty-six studies were included in the review. The results were presented focusing on thermal, mechanical and dynamic-mechanical properties of the composites. In brief, this methodology helped identifying the main gaps in knowledge in that field.

Shaddock peels-based activated carbon as cost-saving adsorbents for efficient removal of Cr (VI) and methyl orange

A simple and economical method was proposed to synthesize the shaddock peels-based activated carbon (SPAC) for their application as efficient sorbents to eliminate Cr (VI) and methyl orange (MO) from one-component and two-component systems. The synthesis was conducted via activation of phosphoric acid and high-temperature carbonization. The as-prepared SPAC was characterized by Brunauer-Emmett-Teller, scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy, among other techniques. The adsorption experiment, which used five types of fruit peel (shaddock peels, orange peels, apple peels, banana peels, and tangerine peels), indicated that shaddock peels were the optimal precursors, with the high removal efficiencies for Cr (VI) (21.2%) and MO (54.25%). The effects of various factors (e.g., initial concentration, sorbent dosage, pH values, and contact time) were systematically evaluated. For the one-component system, the maximum adsorption capacities of Cr (VI) (9.95 mg/g) and MO (94.59 mg/g) reached pH levels 2 and 3, respectively. Kinetic modeling demonstrated that the pseudo-second-order kinetic model was adopted for the one-component and two-component systems. Isotherm studies suggested that Cr (VI) and MO sorption processes in the one-component explained well the Langmuir and Freundlich models, respectively. The extended Freundlich multicomponent isotherm model was more compatible for explaining competitive adsorption in the binary component system. The adsorbed amount of Cr (VI) was markedly suppressed by MO, whereas MO adsorption was not significantly influenced owing to the existence of Cr (VI). The higher adsorption capacity of MO could be mainly attributed to the strong force acting between MO and SPAC. The findings of this study confirmed that SPAC provided a sustainable choice for cycling solid waste shaddock peels to remove hazardous contaminants.