Under the current situation of the

Under the current situation of the exhausting non-renewable
resources such as coal, oil and natural gas, many efforts have been
directed at extending the utilization of renewable resources for new
energy and new materials [1,2]. Cellulose, natural polymer from the
cell wall of green plants with the formula of (C6H10O5)n, is the most
abundant renewable resources on earth [3,4]. It exists not only in
various plants, but also in some organisms such as bacteria and
animals. The unique chemical and physical properties of cellulose
make it being a biomass resource for many decades, and will still be
an indispensable raw material for papermaking, food, and additives
in optical and pharmaceutical industries [5].
Cellulose molecular chains are biosynthesized and selfassembled
into microfibrils, which are composed of orderly
crystalline domains and disordered amorphous domains. Cellulose
keeps the supramolecular structures and the fiber morphology by
hydrogen bonding within molecular area and van der Waals force
between cellulose chains [6]. The amorphous domains are susceptible
to acid attack because cellulose chains in these regions are
randomly oriented and with a lower density. Nanocrystalline cellulose
(NCC) extracted from natural fibers by acid is in the size of nano-scale, which demonstrates not only the features of nanoparticles,
but also unique strength and optical properties. It was
reported that the rod-like cellulose particles acquired from different
sources through acid hydrolysis are basically with a diameter
from 5 to 20 nm, and a length from 100 nm to several micrometers
[7,8]. Recent researches showed that NCC had wide application
prospects in nanocomposite field [6,9–11], while its application in
pulp and paper has seldom been reported.
In the pulp and paper industry, many efforts have recently
been made to increase the utilization of recycled pulp in producing
paper and paperboard products in order to protect the
environment, save energy and lower production cost [12,13]. However,
with the increase of the ratio of recycled pulp, the strength
and quality of paper and paperboard decreases. Paper strengthening
agents can give the required dry strength to paper and
paperboard even when they are made with a large amount of
recycled pulp. Drainage and retention are also very important
parameters for the deinked pulp in the papermaking process,
because they limit the production efficiency of a paper machine
[14]. As the paper and paperboard industry continues to increase
the speed and output of paper machines, the demands on retention
and drainage aids are increasing greatly. Increased water
system closure and increased water temperatures are also altering
the environment within which the retention and drainage
aid has to function, requiring an alternative approach in many
cases.
The importance of “green” characteristics such as biodegradability,
biocompatibility and favorable CO2 balance grows with the awareness of consumers and engineers [15,16]. To meet the environmental
requirements, so as to make the pulp and papermaking
industry sustainable, it is desirable to develop bio-based papermaking
chemicals [17]. Approaches of effective utilization of renewable
lignocellulosic resources to produce chemicals and materials are
attracting the interest of scientific and industrial committee all
over the world. By applying mechanical, chemical, physical or
biological methods, cellulosic fibers can be disintegrated into cellulose
substructures with micro- or nano-size dimensions, which
have the advantages of bio-based materials such as being lightweight,
bio-degradable, bio-compatible, and renewable. However,
these methods tend to be energy-demanding and/or chemicaldemanding.
A common method of obtaining cellulose nano-fibers
involves conventional refining procedures, in which large quantities
of energy are required [18]. Acid hydrolysis is the main process
used to produce nanocrystalline cellulose, in which H2SO4, HCl or
H3PO4 are usually used [19]. When sulfuric acid is used as hydrolyzing
agent, it interacts with the surface hydroxyl groups of cellulose
to yield charged surface sulfate groups, which can promote the
dispersibilty of nano whiskers in water [7].
It was reported that the nano fibrillation cellulose (NFC) can
be used for improving the physical properties of papers and cellulosic
films [20]. Henriksson et al. [2] and Zimmermann et al. [21]
reported that microfibrillated cellulose (MFC) could be formed into
sheets with high strength properties. Similar results for enhancing
paper strength are obtained when MFC was added into the pulp
suspension [21,22]. In papermaking process, it is important that
the papermakers are able to effectively retain mineral fillers and
fiber fines while simultaneously improving dewatering rate [23].
NCC provides a very high water retention capacity due to their
large surface area and high aspect ratio. However, the strong water
retention property may deteriorate the drainage rate of the pulp.
In this study, NCC was isolated from bleached aspen kraft pulp
by acid hydrolysis, and characterized by particle charge detector,
X-ray diffraction, and atomic force microscopy, respectively. Then,
NCC was used as an additive in the deinked pulp, and the retention
of fines and improvement of paper strength were evaluated and
discussed. In addition, its influence on the drainage rate of the pulp
when applied together with cationic polyacrylamide and cationic
starch was also investigated.

ผลลัพธ์ (ไทย) 3:

ภายใต้สถานการณ์ปัจจุบันของการหลบหนีไม่หมุนเวียน
ทรัพยากร เช่น ถ่านหิน น้ำมัน และก๊าซธรรมชาติ ความพยายามหลาย
กำกับที่ขยายการใช้ทรัพยากรพลังงานหมุนเวียนพลังงานใหม่และวัสดุใหม่
[ 1 , 2 ] เซลลูโลส พอลิเมอร์ธรรมชาติจากผนังเซลล์ของพืช
สีเขียวกับสูตร ( c6h10o5 ) N เป็นส่วนใหญ่
มากมายทดแทนทรัพยากรบนโลก [ 3 , 4 ]