(PDF) Study of thermodynamic properties of various ...
Thermodynamic characteristics of cellulose samples having different crystallinity (X) and type of crystalline allomorph (CI to CIV) have been studied. Using methods of combustion calorimetry and DSC, the accurate values of standard enthalpy,
Research and Reviews: Journal of Chemistry
same sample [different values of CrI from 0.57 to 0.93 can be obtained 23, 24]. Crystallinity index of chitosan samples calculated by different methods can also vary within a wide range from 0.4 to 0.8 [20, 25-27]. Thus, results about the crystallinity of chitin and chitosan samples based on estimation of CrI are doubtful.
A multitechnique approach to assess the effect of ball ...
we present the effect induced by a ball milling process on cellulose. the cellulose amorphization and the mean size reduction of the crystallite domains were quantified. ball milled cellulose shows increased water absorption and reduced thermal stability. the disappearance of the fibrous structure is evidenced as a consequence of the ball …
1, 1 á 1 ó - MDPI
under these milling conditions. This result is in agreement with Boldyrev and Tkácovˇá [44] who reported that the high energy ball milling can lead to lattice deformation and material amorphization. Figure 1. (a) X-ray di raction (XRD) patterns of silicon (Alfa Aesar), graphite, and ball milled samples (s-BMW and s-BMD). The asterisk ...
Amorphization by ball milling. A review - ScienceDirect
A third type of amorphization reaction is found by Weeber et al. [24] for the MA of Ni-Zr using a different milling equipment, namely a planetary ball-mill Fritsch Pulverisette 7. Steel cylindrical vials containing twelve hardened steel balls, each with a diameter of 1 cm, were moun- ted on the planetary ball-mill.
Effect of ball-milling on crystallinity index, degree of ...
63 0.53 to 0.15, but are not sufficient to achieve total amorphization. Schenzel and co-workers 64 (Schenzel et al., 2005) obtained a totally amorphous cellulose after 30 hours of milling, and 65 mixed amorphous and un-milled cellulose to obtain samples at …
Myint et al., J Bioprocess Biotech 2015, 5:11 Journal of ...
focused on amorphization of the cellulose crystalline component and particle size reduction by milling to improve the dissolution rate. Ogura et al. revealed that ball milling converts rice straw containing cellulose from crystalline to amorphous material and results in physical changes [3]. Prolonged ball milling technique not only induces
Structural changes and enhanced accessibility of natural ...
A kind of natural cellulose, bleached pine pulp (BPP), was pretreated by mechanical activation (MA) using a self-designed stirring ball milling. The effect of MA pretreatment on the dissolving capacity and molecular chain structure of BPP were investigated by the determination of alkaline solubility (Sa) and degree of polymerization (DP). In addition, …
The Influence of Milling on the Dissolution Performance of ...
Drug samples (600 mg) were placed in 25 mL stainless steel jars and milled using an oscillatory ball mill (Mixer Mill MM301, Retsch and Co., Germany) at 4 °C. Processing times (5-60 min), milling frequency (5-25 Hz) and number of stainless steel balls (3-60 with a diameter of 4 mm) were selected using a central composite face centered ...
nano synthasis high energy ball milling machines
The amorphization process during ball milling can be seen from the images of transmission electron microscopy (TEM) in Fig. 2a, which were taken from samples milled for different lengths of time. The TEM images show that the size and number of NiZr crystals decrease with increasing milling time, and a full amorphization is achieved after ...
BJOC - Mechanochemical amorphization of chitin: impact of ...
Figure 1: CrI% for chitin samples, before and after milling in a jar with one ball made of SS, ZrO 2, Cu, Al, brass, WC, PMMA, PTFE. One series has ball mass = 2 g (blue) and one ball diameter = 9.5 mm (in orange). Experimental conditions: 200 mg of chitin, milling time: 30 min, milling frequency 29.5 Hz.
European Journal of Pharmaceutics and Biopharmaceutics
2.2.1.2. Preparation of tadalafil solid dispersion using ball milling. The Td/PVP-VA (1:1, w/w) solid dispersion was obtained by milling in a planetary ball mill PM 100 (Retsch, Germany) at 3 C. The effective grinding time was 5 h at 600 rpm with 10-min breaks every 0.5 h.
Improvement of enzymatic digestibility of wood by a ...
AbstractA three-stage wood milling process was investigated leading to coarse, fine and amorphization of milled wood (MW) as a pretreatment for enzymatic wood hydrolysis. An eccentric vibratory tube mill (EVTM) and a spring suspended vibratory tube mill (SSVTM) were found to be suitable for wood cellulose amorphization. Both methods gave rise to …
High-energy ball milling technique for ZnO nanoparticles ...
TEM images for the ZnO samples before and after milling (Figure 5A2–E2) were also obtained.These images display similar trends to those observed by SEM images (Figure 3 A1–E1).The sample milled for 50 hours (Figure 5E2) contains ultrafine particles of sizes in the range 20–30 nm, which are close to those observed by SEM (Figure 3E1).These sizes are …
Rapid mechanochemical synthesis of amorphous alloys: AIP ...
Phase formation during high energy ball milling may be driven by thermodynamics, if the resulting phase is an equilibrium phase of lower energy than the starting materials. However, it is also possible to create non-equilibrium, or metastable, phases by milling. In these cases the driving force for metastable phase formation comes from …
Effects of Crystallinity on Dilute Acid Hydrolysis of ...
The dilute acid (0.05 M H2SO4) hydrolysis at 175 °C of samples comprised of varying fractions of crystalline (α-form) and amorphous cellulose was studied. The amorphous content, based on XRD and CP/MAS NMR, and the product (glucose) yield, based on HPLC, increased by as much as a factor of 3 upon ball milling. These results are interpreted in terms …
Ball mill versus vertyical mill - Manufacturer Of High-end ...
Amorphization of different cellulose samples by b. ball mill 1200x2100 gujaratgenomicsin amorphization of different cellulose samples by ball milling; thyssenkrupp design closed circuit ball mill;, ball mill 1200x2100, ball mill in pellet plants ball mill in pellet plants Chinese Manufacturer of Wood Pellet Mills and Complete Pellet Plants AKG BiofuelTech is a leading …
Ternary Solid Dispersion Strategy for Solubility ...
Amorphization of βCD by milling at room temperature is predictable, as milling is carried out at a temperature sufficiently below the Tg of βCD (Tg ≈ 292°C) . The enlargement of the Bragg peaks is explained by the reduction in the size of the crystallites and slight distortions of the crystal lattice generated by ball milling.
Ball Milling Pretreatment of Corn Stover for Enhancing the ...
12%The morphology of corn stover cellulose powder of different milling treatment was observed under a S-3400 scanning electron microscope imaging system. The samples were selected as unmilled, milled in water, and milled in 1% NaOH. Definitions of Yields for Glucose and Xylose The final glucose and xylose yields are defined as …
"Investigation of phase composition and nanoscale ...
The ball milling technique has been successfully applied to the synthesis of various materials such as equilibrium intermetallic phases, amorphous compounds, nanocrystalline materials, or metastable crystalline phases. However, how the phase composition and nanoscale microstructure evolute during ball milling in various materials is still controversial due to the …
Modification of microcrystalline cellulose structural ...
Abstract This study investigated the characteristics of cellulose Avicel PH-101 (NPA) and Avicel samples treated by either ball milling (BMA) or ionic liquid 1-ethyl-3-methylimidazolium acetate (ILA), which alter cellulose structural properties specifically and, consequently, affect the enzymatic hydrolysis of these materials differently. All materials were …
Mechanochemical Preparation of a H3PO4-Based Solid ...
Microcrystalline cellulose (0.5 g) and appropriate amounts of pure water and the sample prepared by ball-milling were put into a 250 mL Erlenmeyer flask on a magnetic stirring water bath. Parameters of hydrolysis time, hydrolysis temperature, rotation speed, and solid–liquid ratio reaction conditions were examined for hydrolysis experiments.
Role of polymers in the physical and chemical stability of ...
A new 2/1 carbamazepine (CBZ)/malonic acid (MA) cocrystal polymorph form C was formed using a vibrational rod mill, whereas the known cocrystal polymorph form A was prepared using a …
An X-Ray Diffraction Study of the Crystalline to Amorphous ...
Curve c belongs to the sample holder. Fig. 2 X-ray diffractograms of MC-cellulose samples after ball milling (curves b, to bg). Explanations see Table 1. Curve d belongs to tungsten carbide. N. Stubicar et al: Amorphization of Cellulose by High-Energy Ball Milling o.o ·0.5 -1.0 ·2.5 100 200 300 400 time, t/sec Fig. 3 Plots of In wc resp.
A multitechnique approach to assess the effect of ball ...
This paper presents a detailed analysis of effect induced by a dry ball milling process on cellulose structure, morphology and properties. The partial amorphization of cellulose was qualitatively estimated by ATR-FTIR analysis. Through WAXD analysis the crystallinity index and the mean size of the cellulose crystallite domains were calculated ...
Ball milling: a green technology for the preparation and ...
Further research on the effects of milling conditions (i.e. ball-to-cellulose mass ratio, milling time, ball size and alkaline pre-treatment) on the morphology of the prepared nano-cellulose derivatives was undertaken by the group of Wang.22,23 More in detail, they found out that the size of the milling balls
(PDF) Silicon-Carbon composite anodes from industrial ...
The samples ball milled 20 and 180 minutes, show a lower discharge capacity of 3692 and 3287, respectively, with initial Coulombic efficiencies of 82 and 83%. The discharge curves show a clear difference where BM5 and BM20 rapidly reach a well-defined plateau at ~0.1 V, while the BM180 has a longer slope between 0.3–0.1 V.
GB2066145A - Microfibrillated cellulose - Google Patents
Microfibrillated cellulose is produced by passing a liquid suspension of cellulose through a small diameter orifice in which the suspension is subjected to a pressure drop of at least 3000 psig and a high velocity shearing action followed by a high velocity decelerating impact, and repeating the passage of said suspension through the orifice until the cellulose suspension becomes a ...
WO1994002177A1 - Method of preparation of inclusion ...
A method for the preparation of inclusion compounds of nimesulide with cyclodextrins, which consists in subjecting a solid mixture, an aqueous solution or a homogeneous slurry of nimesulide and water-soluble cyclodextrins to co-milling, to spray …
Amorphization of different cellulose samples by ball milling
Cellulose samples with initially different crystal structures (cellulose I and II) have been found to yield virtually the same amorphous X-ray scattering …