Cellulose acetates (CA) with different degrees of substitution (DS) and different distribution of substituents within the anhydroglucose unit (AGU) have been synthesized in conventional (acetic acid/water) and unconventional (toluene or benzene/acetic acid /water) media, and their susceptibility to enzymatic attack has been investigated using a purified cellulase from Trichoderma reesei. The degradation experiments have been carried out in heterogeneous (water suspension) or homogeneous (water solution) conditions, in dependence of the DS of the derivatives. The behaviour of CAs to enzymatic attack has been correlated with their structural characteristics which are dependent on the procedure used for their synthesis. CA Samples with DS above 1.3 have been treated with enzyme in water suspension for 14 days. It has been observed that the decrease of the reduced viscosities of these acetates solutions in adequate solvents after the enzymatic treatment depends on the procedure and conditions employed for their synthesis. Gel permeation chromatograms show some associations of macromolecules for polymers with DS higher than 1.3. These fractions of apparent high degree of polymerization seem to be preferentially degraded by the enzyme. Water-soluble Cellulose acetates undergo similar degradation, irrespective of the reaction medium used for their synthesis.

This study aimed to enhance probiotics thermal stability and viability in the digestive tract through encapsulation using hybrid fibers of Cellulose acetate and polyvinyl alcohol with single-jet electrospinning. This study used Lactiplantibacillus plantarum NIMBB003 as an encapsulated probiotic strain in engineered sandwich nanofibers (Cellulose acetate/polyvinyl alcohol and Lactiplantibacillus plantarum/Cellulose acetate). Regarding nanostructure, polyvinyl alcohol and Cellulose acetate nanofibers were spun independently; when these layers were set on top of each other, they could act as an integrated system. Results of scanning electron microscope images and Fourier transform infrared spectrometry have verified the micro/nanoencapsulation structure of probiotics. The layered structure demonstrated increased protection against environmental factors, particularly heat and acidity. Thermogravimetric analysis verified that Cellulose acetate-polyvinyl alcohol and probiotic-Cellulose acetate nanofibers maintained the structural stability up to 530 °C, while encapsulated probiotics showed 89.8% encapsulation efficiency or 9% improvement, compared to single-layer polyvinyl alcohol and probiotic fibers. Moreover, probiotic survival under simulated gastrointestinal conditions (75 °C and stomach acid exposure) was extended to 8 min, whereas unencapsulated probiotics were entirely destroyed within 5 min. Scanning electron microscopy and Fourier transform infrared spectroscopy validated the formation of nanofiber encapsulation and probiotic integration. This engineered nanofiber sandwich structure offers enhanced probiotic protection, making it a promising candidate for food and pharmaceutical uses.

Fe3O4 nanoparticles were synthesized via a simple chemical reaction between FeCl2.4H2O and Fe (NO3)3.9H2O under nitrogen atmosphere at room temperature, and then nanoparticles were added to Cellulose acetate (CA) polyme r. The influence of nanoparticles on the thermal properties of CA polymeric matrix was studied using thermogravimetric analysis (TGA). Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The magnetic properties of the samples were also investigated using an alternating gradient force magnetometer (AGFM). We found that the Fe3O4 nanoparticles exhibit a ferromagnetic behavior with a saturation magnetization of 59 emu/g and a coercivity of 105 Oe at room temperature.

Background and Objectives To avoid laboratory errors in the detection of hemoglobinopathies, a control sample containing hemoglobin (Hb) A,F,S or C should run with each set of samples.The aim of this project was to prepare a lyophilized heme control for the Cellulose acetate electrophoresis.Materials and MethodsAfter lysing the red blood cells, the hemolysate was centrifuged at 25000 rpm. The clear red supernatant was diluted with drabkin reagent to 20-30 gr/L and Hb was converted to cyanomethemoglobin. After adding sucrose and preservatives, the hemolysate was passed through milipore filter (0.45 µm) and then aliqouted and lyophilized.ResultsIn this project three heme control samples were prepared. The first sample contains Hbs A,F,D or G ,the second one contains Hbs A,S, and the third contains Hb A,F. Although the amount of potassium cyanide used is 10 times less than other methods , the stability is more than 6 months at 4oC; moreover, and the electrophoretic patterns have good resolution and the obtained CV and SD show good reproducibility.ConclusionsThe preparation method in this project is simple, reliable, cost effective and in comparison with other methods has less amount of potassium cyanide; therefore, it is safe for the laboratory staff.

silk fibroin (SF) /Cellulose acetate (CA) blend nanofibres were prepared by electrospinning with 98% formic acid as a spinning solvent, and their structure and thermal properties were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The electro-spinnability of SF solution was remarkably improved with a small quantity of CA (not more than 10%), and the blend fibres were fine and uniform with the fibre diameters ranging from 50 nm to 300 nm.While adding 10% (by weight) CA into SF, the blends showed excellent spinnability without any beads or droplets in the surface of the electrospun mats under observation in large area, and the average diameter reached 142.1 nm. However, the spinnability of SF/CA deteriorated seriously when the content of CA was more than 30% (by weight), as the electrospun production of SF/CA blends were discontinuous and tacky with beads and dendritic structures. The results from FTIR, XRD and DSC showed that adding a small quantity of CA (not more than 10%) could induce the conformation transition of SF molecules from random coil toβ-sheet. Accordingly, the thermal and mechanical properties were improved. Especially, the mechanical properties of the blend mats were greatly improved with the increasing of CA content from 5-10% (by weight). The blend nanofibre mats with 10% (by weight) CA content showed excellent mechanical properties, as the tensile stress and elongation-at-break reached 88.9 cN/mm2 and 12.77%, respectively. Nevertheless, the phase separation was observed between SF and CA in blend nanofibres when the content of CA was more than 30% (by weight).

A study of the phthaloylation of Cellulose acetate in two reaction media consisting of acetic acid and acetone is performed respectively by using a statistical experimental design. Two kinds of Cellulose acetate having degrees of acetylation of 1.62 and 1.93 are used as starting materials respectively. Two mathematical models are obtained for describing the correlation between the degree of phthaloylation of the synthesized Cellulose acetate phthalates and the principal reaction parameters involved: the molar ratios of catalyst/Cellulose acetate and phthaloylation agent/Cellulose acetate. It is concluded that the degree of phthaloylation of the products is mainly influenced by the amount of phthaloylation agent in the case of acetic acid and by the amount of catalyst in the case of acetone used as organic solvent.