Filler modified by a sequential encapsulation and preflocculation method and its effect on paper properties

2020 ◽  
Vol 35 (1) ◽  
pp. 89-95
Author(s):  
Nannan Chen ◽  
Lijun Wang ◽  
Junchao Wen ◽  
Xianping Yao ◽  
Wenyan Zhao
Keyword(s):  
Filler Content ◽  
Strength Properties ◽  
Paper Strength ◽  
Cationic Starch ◽  
Paper Properties ◽  
Polyelectrolyte Complexes ◽  
New Methods ◽  
Charge Potential ◽  
Filler Retention ◽  
Anionic Polyacrylamide

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.

scholarly journals New Diatomite Filler for Improvement of Paper Strength Properties

2020 ◽  
Vol 71 (5) ◽  
pp. 479-490 ◽  
Author(s):  
Wei Shang ◽  
Haoran Han ◽  
Hunan Liang
Keyword(s):  
Particle Size ◽  
Strength Properties ◽  
Filler Loading ◽  
Sodium Hexametaphosphate ◽  
Paper Strength ◽  
Pulp Fibers ◽  
Cationic Starch ◽  
Coating Method ◽  
Filler Retention ◽  
Modified Diatomite

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.

Composite filler by pre-flocculation of fiber fines and PCC and its effect on paper properties

2020 ◽  
Vol 35 (2) ◽  
pp. 251-260
Author(s):  
Hyun Kang ◽  
Jong Myoung Won ◽  
Byoung-Uk Cho
Keyword(s):  
Strength Properties ◽  
Ash Content ◽  
Paper Strength ◽  
Precipitated Calcium Carbonate ◽  
Paper Properties ◽  
Loading Method ◽  
Retention Aids ◽  
Composite Filler ◽  
Filler Retention ◽  
Better Than

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.

Strengthening effect of polyelectrolyte multilayers on highly filled paper

2018 ◽  
Vol 33 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Jegon Lee ◽  
Hye Jung Youn
Keyword(s):  
Surface Modification ◽  
Bonding Strength ◽  
Filler Content ◽  
Breaking Strength ◽  
Polyelectrolyte Multilayers ◽  
Strengthening Effect ◽  
Paper Strength ◽  
Cationic Starch ◽  
Surface Modification Techniques ◽  
Anionic Polyacrylamide

AbstractPolyelectrolyte multilayering (PEM) treatment is regarded as one of the surface modification techniques to increase paper strength. In this study, the strengthening effect of PEM treatment of highly filled paper was investigated. PEM treatment was performed on both fiber and filler with cationic starch and anionic polyacrylamide systems. Both approaches provided an improvement in the strength of filled paper. However, the strengthening effect of PEM treatment on fibers became weaker as filler content increased, whilst the PEM treatment on fillers was more effective in improving the strength of the highly filled paper. This was because PEM treatment on fillers improved bonding strength between fiber and filler as well as bonding strength between fillers. This was confirmed by the evaluation of specific debonding factor between fiber and filler, and the measurement of the breaking strength of dense film composed of fillers.

A novel predictive method for filler coflocculation with cellulose microfibrils

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 653-664
Author(s):  
IGNACIO DE SAN PIO ◽  
KLAS G. JOHANSSON ◽  
PAUL KROCHAK
Keyword(s):  
Negative Impact ◽  
High Strength ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Paper Strength ◽  
Flow Loop ◽  
Cationic Starch ◽  
Reflectance Measurement ◽  
Drainage Rate ◽  
Complete Study

Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.

scholarly journals Use of Oxalic-Acid-Modified Stellerite for Improving the Filter Capability of PM2.5 of Paper Composed of Bamboo Residues

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Hua Chen ◽  
Jian Lou ◽  
Fei Yang ◽  
Jia-nan Zhou ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Oxalic Acid ◽  
Pore Formation ◽  
Strength Properties ◽  
Filtration Efficiency ◽  
Kraft Pulping ◽  
Paper Strength ◽  
Cationic Starch ◽  
Promising Technique ◽  
Cooking Temperature ◽  
Experimental Parameters

In this study, pulping conditions for kraft pulping of bamboo residues were investigated, predominantly focusing on cooking temperature and time during pulping. Oxalic acid and cationic starch were used for the modification of natural stellerite, and the use of modified stellerite for preparing filter paper for PM2.5 filtration was investigated. The optimal pulping technology of bamboo residues was established based on the following experimental parameters: liquor ratio of 1 : 5.5, cooking temperature of 160°C, and a holding time of 2 h. Modification by oxalic acid resulted in the promotion of pore formation at the stellerite surfaces and induced the microscopic changes. Nevertheless, paper strength remained practically unchanged after the addition of fillers, indicating that the cationic starch preblend method is a promising technique for papermaking because it enhances the strength properties of paper. With the variation in the addition of modified stellerite from 3 to 15%, while simultaneously maintaining the basis weight constant at 60 gm−2, the filtration efficiency of paper sheets first increased and then decreased later; thus the optimum stellerite content was found to be 9%. Filtration efficiency was suggested to be affected by gas flowing velocity.

scholarly journals Study of the mechanical behavior of recycled fibers. Applications to papers and paperboards.

2018 ◽  
Author(s):  
Imtiaz Ali
Keyword(s):  
Surface Friction ◽  
Strength Properties ◽  
Size Exclusion ◽  
Ultrastructural Changes ◽  
X Rays ◽  
Paper Strength ◽  
Electron Microscopic ◽  
Paper Properties ◽  
Recycled Pulp ◽  
Fibre Width

Incorporation of recycled fibres in high value paper products can reduce cost and environmental loads. Papermaking potential of cellulosic fibres decreases with recycling. The phenomenon of fibre hornification during pressing and drying is normally held responsible for the loss in strength. To study the impacts of recycling on pulp, fibre and paper properties some non conventional characterisation techniques like fibre saturation point, X-rays microtomography, environmental scanning electron microscopic observations, atomic forcemicroscope (PeakForce QNM mode) and inverse size exclusion chromatography(ISEC) were used. In order to achieve good reproducibility of ISEC measurements,a semi-automatic column fabrication pilot system was built. The techniques were first validated on refining process before being applied to the recycling process. In this study, it was found that fibre hornification alone cannot fully explain loss in strength during recycling. The loss in strength is much more complex and it is required to understand the morphological and ultrastructural changes associated with recycling. Fibre width, cell wall thickness,curl, kink, irregularities decreased during recycling. Fibre became hard and brittle in dry state. Number of weak points in the fibre wall were increased initially and in the later recyclings. The increase in wet breaking length indicates increased surface friction and capillary forces with recycling. Decrease in bonded area during first recycle may be caused by the loss of fines and fibre flexibility whereas the increase afterwards may be linked to the lumen collapse.The strength of fibres did not decrease with recycling as shown by zero-span breaking lengths therefore the quality of bond may be deteriorated. It was thought that the partially delaminated P/S1 layers may be responsible for the loss of paper strength. It is suggested since the significant change is associated with the pressing and drying of never dried pulp therefore the drying process needs to be revisited. The delaminated layer should be restored so as to increase the recyclability of the recovered fibres for high value paper. Influence of recycled pulp blends on physical properties of paper was also studied. It was revealed that small quantity of recycled pulp can be used without significantly affecting the mechanical strength properties.

Role of particle size and preflocculation of talc in improvement of paper properties

TAPPI Journal ◽  
2014 ◽  
Vol 13 (4) ◽  
pp. 17-26 ◽  
Author(s):  
VIPUL SINGH CHAUHAN ◽  
NISHI KANT BHARDWAJ
Keyword(s):  
Particle Size ◽  
Strength Loss ◽  
Filler Loading ◽  
Paper Strength ◽  
Paper Properties ◽  
Viable Solution ◽  
Filler Retention ◽  
Mineral Fillers ◽  
Different Doses

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.

Fractionation of epidermal cells from wheat straw pulp by flotation

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 229-235
Author(s):  
MIKKO KARJALAINEN ◽  
ARI ÄMMÄLÄ ◽  
PÄIVI ROUSU ◽  
JOUKO NIINIMÄKI
Keyword(s):  
Wheat Straw ◽  
Cell Types ◽  
Strength Properties ◽  
Epidermal Cells ◽  
Raw Material ◽  
Paper Strength ◽  
Paper Properties ◽  
Vessel Elements ◽  
Wide Availability ◽  
Wheat Straw Pulp

The wide availability of wheat straw makes it a promising raw material for various fiber products, but its heterogeneity makes it a challenging material to use. In addition to reducing paper properties, some cell types cause processing problems such as silicate deposition and poor dewatering. The aims of this work were to examine the fractionation tendency of wheat straw pulp cells in flotation and to determine the effect of fractionation on paper strength properties. A cell type categorization based on automatic optical fiber analysis was used to assess fractionation. The results showed that epidermal cells can be selectively enriched from unbleached wheat straw pulp by flotation and other short cells had a tendency to become enriched in the overflow fraction. The underflow fraction consisted mostly of fibrous material, as well as vessel elements and long parenchyma cells. Removal of the epidermal cells from pulp will reduce its silicate content and improve the strength properties of the paper.

scholarly journals Recycling of Waste MDF by Steam Refining: Evaluation of Fiber and Paper Strength Properties

2021 ◽  
Author(s):  
Sebastian Hagel ◽  
Jesan Joy ◽  
Gianluca Cicala ◽  
Bodo Saake
Keyword(s):  
Strength Properties ◽  
Steam Treatment ◽  
High Yield ◽  
Medium Density ◽  
Paper Strength ◽  
Fiber Morphology ◽  
Steam Refining ◽  
Paper Test ◽  
Paper Properties ◽  
Intimate Knowledge

AbstractCurrently, most of the collected waste medium-density fiberboards (MDF) is incinerated or landfilled, as economically viable recycling methods are yet to be developed. By steam refining waste medium-density fiberboards (MDF), it is possible to hydrolyze the incorporated resins and isolate a high yield fiber fraction. Further refining of the steam treated fibers might enable the fibers to be utilized in applications such as paper packaging, facilitating a cascading use of the waste material stream. To this end, intimate knowledge of the material is needed. In this study, the steam refined fibers of two waste MDF samples containing differing amounts of softwood and hardwood underwent refining and beating. The resulting fibers were characterized regarding their morphology and paper test sheets were produced to evaluate their strength (compression-, tensile- and tear-strength). Distinct differences in response to refining between the MDF samples were apparent. For the sample with the higher hardwood share an increase in strength properties with increasing steam treatment severities could be observed and it was possible to produce test sheets with comparable compression strength to recycled pulp for industrial corrugated paperboard. For the sample with a higher share of softwood, the steam treatment severity did not show any influence on fiber morphology or paper properties, and the resulting paper strength was low in comparison to the other steam refined waste MDF sample. Graphic Abstract

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