Pulp and paper
Hossein Jalali Torshizi; Abdollah Aabedi Bafraajerd; Reza Shidpour
Abstract
DOR:98.1000/1735-0913.1398.34.1.66.1.1578.32 Providing some paradox properties of paper products at the same is of utmost challenging issues of papermakers, e.g., attaining proper strength together with high water absorbency in hygienic papers. Because higher bonding resulted in lesser accessibility ...
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DOR:98.1000/1735-0913.1398.34.1.66.1.1578.32 Providing some paradox properties of paper products at the same is of utmost challenging issues of papermakers, e.g., attaining proper strength together with high water absorbency in hygienic papers. Because higher bonding resulted in lesser accessibility to the hydrophilic functional group. Therefore, hydrogel as an ever-increasing material in bulk cellulosic diapers were surficial coated on paper and compared with distillated water saturated papers. The prepared chitosan-acrylic acid (AA) hydrogel converted into nanoparticles by ultrasonic homogenizer and the nano scaled particles approved by Dynamic Light scattering (DLS). SEM images and paper caliper revealed the nanohydrogel coating layer. All papers water uptake coated with 1, 1.5 and 2% nanohydrogel increased significantly up to 50% compared to the untreated sample. Burst and dry tensile strengths along with water uptake improved, with no toleration in tear strength. Increased fiber bonding due to plenty of carboxylic acid in AA together with hydroxyl and amine groups in chitosan, along with nanohydrogel film formation as a complementary assembly and constituent with the cellulosic substrate of paper were resulted in strength improvement. Wet tensile strength of paper revealed remarkable increment at 2% coating application, only; without enhancing effects at the lower dosages. Paper opacity, brightness and whiteness stayed almost stable, but due to chitosan yellowish nature, the paper yellowness increased. The coated paper stiffness enhanced compared to untreated paper, but revealed lesser stiffness than water saturated papers. Water treated papers revealed caliper, tensile and burst indices reduction and stiffness rising.
Pulp and paper
Zohreh Taheri; Hamidreza Rodi; Hossein Jalali-Torshizi; Reza Shidpour
Abstract
DOR:98.1000/1735-0913.1398.34.112.66.1.1578.1610 Nowadays, the barrier property against water take up of different packaging papers which mostly prepared from recycled fibers is of highly significance for paper manufacturers. In current study, the effect of AKD sizing agent has been examined on the properties ...
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DOR:98.1000/1735-0913.1398.34.112.66.1.1578.1610 Nowadays, the barrier property against water take up of different packaging papers which mostly prepared from recycled fibers is of highly significance for paper manufacturers. In current study, the effect of AKD sizing agent has been examined on the properties of papers made from recycled fibers of Atrak pulp and paper industries. Sizing of pulp suspension using AKD was conducted at levels of 0, 0.5, 1 and 1.5 % based on oven dry (OD) pulp in neutral pH (7), according to the TAPPI standard methods. Then, by preparation of handsheets with basis weight of about 60±3 g/m2, their Cobb test (60 second) and different characteristics were evaluated. According to the statistical analysis of the results, up to 1 % AKD consumption amount based on OD pulp exhibited for optimum level in internal sizing of these recycled fibers. In such AKD level, water take up of size-free papers revealed 174±7.4 g/m2, decreased to the value of about 24±1.7 g/m2 in AKD-treated papers. Further, contact angle of water droplet with the paper surface increased from 35.2º to 109.1º. Applying 1 % of AKD, paper tensile index increased to 33.2±1.01 N.m/g by 2.4 unit compared to the base paper. Apparently, such phenomena can be attributed to the AKD potential in creating hydrogen bonds which concurrent to the development of paper water repellency, resulted in improving bonding-ability of paper network. Additionally, AKD treatment led to in meaningful increase of paper opacity. This can also be attributed to the increase in filler retention in fibers network, which influences the development of light scattering from the paper surface.