Effects of PEI as ATC on the Retention and Drainage of APMP

2011 ◽  
Vol 233-235 ◽  
pp. 1587-1591
Author(s):  
Fu Shan Chen ◽  
Huan Fei Xu ◽  
Xiu Ying Jiang ◽  
Song Lin Wang
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Charge Density ◽  
Retention Rate ◽  
Alkaline Hydrogen Peroxide ◽  
Mechanical Pulp ◽  
The Impact ◽  
Retention And Drainage

The impact of highly cationic density polymers such as modified poly-ethyleneimine(PEI), as anionic trash catcher(ATC) on the drainage and retention properties of aspen alkaline hydrogen peroxide mechanical pulp(APMP) in different CPAM(/bentonite) systems was studied. The results showed that Modified PEI could improve the retention and drainage properties of CPAM/ bentonite systems; when adding 0.02% dosage of PEI, the drainage and retention rate were increased by 16.0% and 1.9% respectively as compared to control with 0.03% dosage of the CPAM with 1.55 meq/g cationic charge density and 4.9 million molecular weight, which denoted by CPAM(W/W); the drainage and retention rate were increased by 28.6% and 3.0% respectively as compared to the control with 0.03% dosage of CPAM(W/W) and 0.3% dosage of bentonite. The CPAM with more cationic charge density and higher molecular weight than the CPAM(W/W) is denoted by CPAM(W/O) in this paper. The microparticle system which consisted with PEI and the CPAM(W/O)(/bentonite) was slightly superior to the PEI/CPAM(W/W)/bentonite system. When 0.02% dosage of PEI and 0.03% dosage of CPAM were added respectively, PEI/CPAM(W/O) made the drainage and retention rate increased by 9.5% and 1.9% respectively as compared with PEI/CPAM(W/W).

The behavior of chromophoric structures in softwood mechanical pulp on bleaching with alkaline hydrogen peroxide

2006 ◽  
Vol 21 (3) ◽  
pp. 359-364 ◽  
Author(s):  
Eva Svensson Rundlöf ◽  
Eric Zhang ◽  
Liming Zhang ◽  
Göran Gellerstedt
Keyword(s):  
Hydrogen Peroxide ◽  
Alkaline Hydrogen Peroxide ◽  
Mechanical Pulp

Effects of lignin content and acid concentration on the preparation of lignin containing nanofibers from alkaline hydrogen peroxide mechanical pulp

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Lulu Zhu ◽  
Shiwen Xue ◽  
Hao Ren ◽  
Jin Zhao ◽  
Huamin Zhai ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Acid Concentration ◽  
Lignin Content ◽  
Raw Material ◽  
Sodium Chlorite ◽  
Fiber Morphology ◽  
Alkaline Hydrogen Peroxide ◽  
Mechanical Pulp ◽  
Chemical Pulp ◽  
Nano Cellulose

AbstractThe poplar alkaline hydrogen peroxide mechanical pulp (APMP) with the lignin content of 24.63 % was used as raw material, which with lignin content of 10.04 %, 6.33 %, 3.82 %, and 1.14 % were obtained by the acid sodium chlorite method for 1–4 hours respectively. Then, different lignin content APMP were micro-nano processing treated with acidolysis (6.5 M, 9.8 M) or ultra-granular grinding respectively. Afterwards, poplar bleached chemical pulp (BCP) was prepared micro-nano cellulose under the same conditions as the APMP. Then, compared the data of the particle size, specific surface area, fiber morphology and zeta potential of suspensions between micro-nano cellulose products. The results show that the presence of a small amount of lignin (1–4 %) in APMP does not affect the preparation of different scales nano cellulose under different acid concentration conditions. When the lignin content is reduced to below 2 %, the acidolysis is more uniform, stable, and well-dispersed compared to BCP products; when the APMP is processed by the ultra-granular grinding, the higher lignin content, the more obvious cutting effect in the fiber length direction. The characteristics and feasibility of the preparation of micro-nano cellulose by the acidolysis and ultra-granular grinding using APMP with varying degrees of delignification are compared.

scholarly journals Staged alkali and hydrogen peroxide treatment of poplar chemi-mechanical pulp

BioResources ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 1062-1073
Author(s):  
Yuqian Guo ◽  
Zhongjian Tian ◽  
Xingxiang Ji ◽  
Gaojin Lyu ◽  
Jiachuan Chen ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Physical Properties ◽  
Treatment Method ◽  
Alkaline Hydrogen Peroxide ◽  
Mechanical Pulp ◽  
Treatment Methods ◽  
Peroxide Bleaching ◽  
Hydrogen Peroxide Treatment ◽  
Tear Index ◽  
Peroxide Method

In order to improve the physical properties and brightness of poplar chemi-mechanical pulp, a new staged alkali and hydrogen peroxide treatment method was proposed and applied. Wood chips were impregnated and swelled with an alkali solution and then treated with a hydrogen peroxide bleaching liquor. A thorough evaluation and comparison of the physical properties and brightness of the pulps that underwent different treatment methods was conducted. The results showed that when the pulp was treated with an alkali and hydrogen peroxide treatment method with an alkali dosage of 6% and a hydrogen peroxide dosage of 6%, the tear index was 3.64 mN‧m2/g, the tensile strength was 3.61 kN/m, and the pulp brightness was 67.1% (ISO). The obtained physical properties and brightness of the alkali and hydrogen peroxide method treated pulp were greater than the traditional alkaline hydrogen peroxide method values, as well as the values of any other single treatment methods.

Understanding the risks and rewards of using 50% vs. 10% strength peroxide in pulp bleach plants

TAPPI Journal ◽  
2018 ◽  
Vol 17 (11) ◽  
pp. 601-607
Author(s):  
Alan Rudie ◽  
Peter Hart
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Rate ◽  
The Other ◽  
Mechanical Pulp ◽  
Engineering Controls ◽  
Point Of Use ◽  
Process Failure

The use of 50% concentration and 10% concentration hydrogen peroxide were evaluated for chemical and mechanical pulp bleach plants at storage and at point of use. Several dangerous occurrences have been documented when the supply of 50% peroxide going into the pulping process was not stopped during a process failure. Startup conditions and leaking block valves during maintenance outages have also contributed to explosions. Although hazardous events have occurred, 50% peroxide can be stored safely with proper precautions and engineering controls. For point of use in a chemical bleach plant, it is recommended to dilute the peroxide to 10% prior to application, because risk does not outweigh the benefit. For point of use in a mechanical bleach plant, it is recommended to use 50% peroxide going into a bleach liquor mixing system that includes the other chemicals used to maintain the brightening reaction rate. When 50% peroxide is used, it is critical that proper engineering controls are used to mitigate any risks.

scholarly journals Mechanical Behavior of Hydroxyapatite-Chitosan Composite: Effect of Processing Parameters

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 213
Author(s):  
Hamid Ait Said ◽  
Hassan Noukrati ◽  
Hicham Ben Youcef ◽  
Ayoub Bayoussef ◽  
Hassane Oudadesse ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Bone Repair ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Composite Effect ◽  
Solid Liquid ◽  
The Impact

Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field.

scholarly journals Improving Rheological and Mechanical Properties of Various Virgin and Recycled Polypropylenes by Blending with Long-Chain Branched Polypropylene

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1137
Author(s):  
Sascha Stanic ◽  
Thomas Koch ◽  
Klaus Schmid ◽  
Simone Knaus ◽  
Vasiliki-Maria Archodoulaki
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Test ◽  
Reactive Extrusion ◽  
Original Material ◽  
Melt Flow Rate ◽  
Single Screw Extruder ◽  
Pp Blends ◽  
The Impact ◽  
Long Chain

Blends of two long-chain branched polypropylenes (LCB-PP) and five linear polypropylenes (L-PP) were prepared in a single screw extruder at 240 °C. The two LCB-PPs were self-created via reactive extrusion at 180 °C by using dimyristyl peroxydicarbonate (PODIC C126) and dilauroyl peroxide (LP) as peroxides. For blending two virgin and three recycled PPs like coffee caps, yoghurt cups and buckets with different melt flow rate (MFR) values were used. The influence of using blends was assessed by investigating the rheological (dynamic and extensional rheology) and mechanical properties (tensile test and impact tensile test). The dynamic rheology indicated that the molecular weight as well as the molecular weight distribution could be increased or broadened. Also the melt strength behavior could be improved by using the two peroxide modified LCB-PP blends on the basis of PODIC C126 or PEROXAN LP (dilauroyl peroxide). In addition, the mechanical properties were consistently enhanced or at least kept constant compared to the original material. In particular, the impact tensile strength but also the elongation at break could be increased considerably. This study showed that the blending of LCB-PP can increase the investigated properties and represents a promising option, especially when using recycled PP, which demonstrates a real “up-cycling” process.

scholarly journals Gravitational polarization of the quantum vacuum caused by two point-like bodies

2021 ◽  
Vol 503 (4) ◽  
pp. 5091-5099
Author(s):  
Dragan Slavkov Hajdukovic ◽  
Sergej Walter
Keyword(s):  
Dark Matter ◽  
Solar System ◽  
Charge Density ◽  
Numerical Method ◽  
Quantum Vacuum ◽  
Body System ◽  
Complex Fluid ◽  
The Impact ◽  
The Universe ◽  
Gravitational Charge

ABSTRACT In a recent paper, quantum vacuum was considered as a source of gravity, and the simplest, phenomenon, the gravitational polarization of the quantum vacuum by an immersed point-like body, was studied. In this paper, we have derived the effective gravitational charge density of the quantum vacuum, caused by two immersed point-like bodies. Among others, the obtained result proves that quantum vacuum can have regions with a negative effective gravitational charge density. Hence, quantum vacuum, the ‘ocean’ in which all matter of the Universe is immersed, acts as a complex fluid with a very variable gravitational charge density that might include both positive and negative densities; a crucial prediction that can be tested within the Solar system. In the general case of ${N \ge {\rm{3}}}$ point-like bodies, immersed in the quantum vacuum, the analytical solutions are not possible, and the use of numerical methods is inevitable. The key point is that an appropriate numerical method, for the calculation of the effective gravitational charge density of the quantum vacuum induced by N immersed bodies, might be crucial in description of galaxies, without the involvement of dark matter or a modification of gravity. The development of such a valuable numerical method, is not possible, without a previous (and in this study achieved) understanding of the impact of a two-body system.

scholarly journals POS0642 THE IMPACT OF AGE ON DISCONTINUATION OF BIOLOGIC DMARDs IN PATIENTS WITH RHEUMATOID ARTHRITIS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 559.2-560
Author(s):  
V. Rivera Teran ◽  
S. Sicsik ◽  
D. Vega-Morales ◽  
F. Irazoque-Palazuelos ◽  
D. Miranda ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Adverse Effects ◽  
Adverse Events ◽  
Cox Regression ◽  
Retention Rate ◽  
Drug Discontinuation ◽  
Discontinuation Rate ◽  
Biologic Dmards ◽  
Conventional Dmards ◽  
The Impact

Background:Rheumatoid arthritis (RA) is the most common autoimmune disease. Older patients treated with biologic DMARDs (bDMARDs) are at a significantly greater risk of adverse effects (AEs) [1]. However, the rate of drug discontinuation because of adverse effects caused by bDMARDs has not differed in elderly compared to younger patients in different registries.Objectives:Determine if drug discontinuation of bDMARDs differs by age in patients with rheumatoid arthritis in the Mexican Adverse Events Registry (BIOBADAMEX).Methods:BIOBADAMEX is a Mexican ongoing cohort of patients using bDMARDs since 2016. In this analysis we included all patients with diagnosis of RA with at least two assessments. Survival on bDMARDs was estimated using Kaplan-Meier analysis. Predictors of discontinuation, including age older than median age in the sample were investigated by Cox regression analyses.Results:Among 743 patients in the registry, 497 had RA diagnosis, from which, 214 had at least two assessments. At baseline, patients had a median (IQR) age of 53.4 (45-61) years old, median disease duration of 10.7 (6-17) months and median DAS28 of 4.7 (3-6). Conventional DMARDS were used by 185 (87%) patients and 94 (44%) patients used corticosteroids. Comorbidities were present in 194 (91%). The most common bDMARDs received at baseline were abatacept 59 (27%), tocilizumab 45(21%), adalimumab 31 (15%) and certolizumab 30 (14%). At the time of analysis, the median bDMARDs treatment duration was 21.0(13-34) months, 128 (59%) had discontinued treatment, 66 for inefficacy, 32 for adverse events and 30 for others. Fig 1 shows discontinuation rate curves in patients younger and older than median age. Cox proportional-hazards demonstrated no significant differences regarding age older than median age (HR 1.1, 95% CI 0.8-1.4, p=0.7), female sex (HR 1.2, 95% CI 0.7-1.9, p=0.44), use of corticosteroids (HR 1.2, 95% CI 0.9-1.6, p=0.20), comorbidities (HR 0.9, 95% 0.6-1.5, p=0.78), DAS28 (HR 0.9, 95% 0.9-1.1, p=0.93) or other factors.Figure 1.Discontinuation rate curves in patients younger and older than median age (< 53.4 and >=53.4 years old)Conclusion:This analysis did not show a role of age on discontinuation of bDMARDs in Mexican RA patients. Further longitudinal analyses will be performed including more patients to assess retention rate of bDMARDs and identify predictive variables of discontinuation in Mexican population.References:[1]Akter R, et al. Can Geriatr J. 2020 May 1;23(2):184-189.[2]Ikari Y, et al. Medicine (Baltimore). 2020 Dec 24;99(52):e23861.Disclosure of Interests:None declared

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