scholarly journals A comprehensive study on nanocelluloses in papermaking: the influence of common additives on filler retention and paper strength

Cellulose ◽  
2020 ◽  
Vol 27 (9) ◽  
pp. 5297-5309
Author(s):  
Ana F. Lourenço ◽  
José A. F. Gamelas ◽  
Pedro Sarmento ◽  
Paulo J. T. Ferreira
TAPPI Journal ◽  
2014 ◽  
Vol 13 (4) ◽  
pp. 17-26 ◽  
Author(s):  
VIPUL SINGH CHAUHAN ◽  
NISHI KANT BHARDWAJ

Mineral fillers are added during papermaking to improve the optical and printing properties of paper and decrease energy costs. Filler loading using conventional approaches has some disadvantages, such as reduction in paper strength. The finer filler, the more the strength loss. Several methods and materials have been reported to overcome or alleviate the same, but with higher costs. Our approach provides an economically viable solution to the problem, using conventional papermaking materials. Talc filler of different particle sizes, preflocculated using different doses of cooked amphoteric starch, were used for papermaking. Relatively higher filler retention, paper strength, and hydrophobicity of paper were obtained with preflocculated talc compared to native talc. The optical properties of paper were unchanged on the loading of similar talc after preflocculation. The preflocculated talc of finer particle size provided higher opacity at similar ash, as well as paper strength, than the native talc of coarser size.


2020 ◽  
Vol 71 (5) ◽  
pp. 479-490 ◽  
Author(s):  
Wei Shang ◽  
Haoran Han ◽  
Hunan Liang

In this work, diatomite particles were modified to improve the bondability of diatomite particles with pulp fibers and filler retention via a complex of cationic starch-sodium hexametaphosphate coating method. The particle size, FTIR spectroscopy characteristic and morphology of the resulting modified diatomite were studied to confirm the successful modification. The SEM results illustrated that the surface of modified diatomite particles was covered by the complex coatings. The coating efficiency of the complex of cationic starch-sodium hexametaphosphate on diatomite surface was up to 98%. Compared with the handsheet filled unmodified diatomite, the handsheet filled with modified diatomite had higher strength properties and lower bulk. When cationic starch dosage was 7%, and filler dosage was 25% , the resulting tensile strength of filled modified diatomite handsheet was 22.1% higher than the handsheet filled unmodified diatomite. Furthermore, with the filler loading of 30%, compared with that of unmodified diatomite, filler retention of modified diatomite was increased by 20.4%. The larger particle size and higher zeta potential of modified diatomite were benefitial to increase retention of modified diatomite filler.


2020 ◽  
Vol 35 (2) ◽  
pp. 251-260
Author(s):  
Hyun Kang ◽  
Jong Myoung Won ◽  
Byoung-Uk Cho

AbstractA composite filler was developed by pre-flocculation of fiber fines and precipitated calcium carbonate (PCC) particles with flocculants such as cationic polyacrylamide (cPAM) and bentonite. The composite filler was compared with a conventional loading method in terms of physical properties of handsheet and filler retention. The handsheets using the composite filler showed higher strength properties than that using a conventional loading at a similar paper ash content level, implying that paper ash content can be increased maintaining same level of paper strength. Optical properties such as opacity and brightness of the paper with the composite were quite similar with the paper with the conventional loading. Filler retention of the composite filler was slightly higher than that of the conventional loading even though retention aids were not used for the composite filler. Paper formation of the composite filler was better than the case of the conventional loading. However, the sheet with the composite filler showed lower bulk than that with the conventional loading. Conclusively, the composite filler technology by pre-flocculation of fines and filler has a potential to be utilized to produce a high loaded paper.


2020 ◽  
Vol 35 (1) ◽  
pp. 89-95
Author(s):  
Nannan Chen ◽  
Lijun Wang ◽  
Junchao Wen ◽  
Xianping Yao ◽  
Wenyan Zhao

AbstractIncreasing the filler content of sheet tends to decrease filler retention and paper strength properties. To overcome this problem and make better use of fillers, development of new methods on filler modification has never been stopped. In this study, filler modification was carried out by sequentially adding an anionic polyacrylamide, a cationic starch and a cationic polyacrylamide. It is believed that in this process, multiple polyelectrolyte complexes are formed which can not only encapsulate filler particles but also preflocculate the particles. The results showed that, compared to the single preflocculation treatment, the sequential encapsulation and preflocculation (SEP) treatment brought significantly larger particle size and higher surface charge potential of the filler, thus higher filler retention was achieved. When the modified fillers were used for papermaking and paper ash contents were controlled at the same level, the SEP modification was better in improving the tensile index, internal bond strength and tearing index of paper than the single preflocculation method, in addition, it maintained better paper formation, caused insignificant change on opacity of paper. It is believed that this newly developed SEP method is worthy of being applied to industrial scales in making various grades of filled paper.


2017 ◽  
Vol 7 (01) ◽  
pp. 17
Author(s):  
Ike Rostika ◽  
Nina Elyani ◽  
Evi Oktavia ◽  
Rina Masriani

Ground Calcium Carbonate (GCC) as the filler required in paper making that is intended to reduce production costs thus providing a profit opportunity for the paper industry. However the usage of GCC affected decreasing of paper strength and effectiveness of sizing process. In order to reduce the negative effect, this research has been conducted through the modification of filler using Tamarind Kernel Powder (TKP) which is a natural polymer obtained from local tamarind seeds. The results of high performance liquid chromatography (HPLC) analysis, showed that TKP contained 64-68%   xylose, glucose, maltose and arabinose. Filler modification was conducted with mixing the TKP into CaCO3 and addition of cationic polyacrylamide and sodium polyphosphate dispersant at composition ratio of 100: 0.4 : 0.1: 1.0. Filler application with added the retention aid of cationic polyacrylamide 0.1%, resulted the filler retention value on sheet of 26.9 %. The modified filler shows an increase in filler stability and is easy to form emulsions when compared to commercial fillers. Modification of GCC filler with higher number of TKP usage gives increased filler retention value on sheets, improved sheet formation properties and optical properties.ABSTRAKGround Calcium Carbonat (GCC) sebagai bahan pengisi (filler) dalam pembuatan kertas untuk mengurangi biaya produksi sehingga memberikan peluang keuntungan bagi industri kertas, namun peningkatan jumlah GCC dapat berpengaruh pada menurunnya kekuatan kertas dan efektivitas proses pendarihan. Untuk mengurangi pengaruh negatif telah dilakukan penelitian modifikasi filler menggunakan Tamarind Kernel Powder (TKP) yang merupakan polimer alami dari bahan lokal biji asam jawa. Hasil analisis kromatografi cair kinerja tinggi (KCKT) menunjukkan bahwa TKP mengandung silosa 64-68 %, glukosa, maltosa, dan arabinosa. Modifikasi filler dilakukan  dengan  mencampurkan TKP ke dalam  CaCO3 dengan  penambahan  poliakrilamida kationik dan dispersan natrium polifosfat pada komposisi 100 : 0,4 : 0,1 : 1,0. Aplikasi filler dengan penambahan zat peretensi 0,1 % poliakrilamida kationik diperoleh nilai retensi filler pada lembaran 26,9 %. Filler yang termodifikasi menunjukkan peningkatan stabilitas filler dan mudah membentuk emulsi jika dibandingkan dengan filler komersial. Modifikasi filler GCC dengan jumlah TKP yang lebih tinggi memberikan peningkatan nilai retensi filler pada lembaran, peningkatan formasi dan sifat optik lembaran.


Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.


Author(s):  
A. Singh ◽  
A. Dykeman ◽  
J. Jarrelf ◽  
D. C. Villeneuve

Hexachlorobenzene (HCB), a persistent and mobile organochlorine pesticide, occurs in environment. HCB has been shown to be present in human follicular fluid. An objective of the present report, which is part of a comprehensive study on reproductive toxicity of HCB, was to determine the cytologic effects of the compound on ovarian follicles in a primate model.Materials and Methods. Eight Cynomolgus monkeys were housed under controlled conditions at Animal facility of Health and Welfare, Ottawa. Animals were orally administered gelatin capsules containing HCB mixed with glucose in daily dosages of 0.0 or 10 mg/kg b.w. for 90 days; the former was the control group. On the menstrual period following completion of dosing, the monkeys underwent an induction cycle of superovulation. At necropsy, one-half of an ovary from each animal was diced into ca. 2- to 3-mm cubed specimens that were fixed by immersion in 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.3). Subsequent procedures followed to obtain thin sections that were examined in a Hitachi H-7000 electron microscope have been described earlier.


Author(s):  
D. L. Rohr ◽  
S. S. Hecker

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.


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