東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Influence of Mechanical Properties o...

Hashemi Najafi, Seyyed Mohammad.

FindBook

Google Book

Amazon

博客來

Influence of Mechanical Properties of Paper Coating on the Crack at the Fold Problem.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Influence of Mechanical Properties of Paper Coating on the Crack at the Fold Problem./
作者:	Hashemi Najafi, Seyyed Mohammad.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
面頁冊數:	78 p.
附註:	Source: Dissertations Abstracts International, Volume: 80-09, Section: B.
Contained By:	Dissertations Abstracts International80-09B.
標題:	Agricultural engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=13870441

Influence of Mechanical Properties of Paper Coating on the Crack at the Fold Problem.
Hashemi Najafi, Seyyed Mohammad.

Influence of Mechanical Properties of Paper Coating on the Crack at the Fold Problem. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 78 p.

Source: Dissertations Abstracts International, Volume: 80-09, Section: B.

Thesis (Ph.D.)--The University of Maine, 2019.

This item must not be sold to any third party vendors.

Paper coating layers are subject to various stresses and deformations in many converting processes such as calendering, printing, slitting, and folding of the paper. In some cases, products may crack during folding to generate a defect called cracking at the fold (CAF). The parameters that influence these defects are not well understood. The overall goal of this thesis is to better understand the CAF behavior as related to material properties of the coating layer. A method was developed to produce free-standing pigmented coating layers thick enough to be tested in bending as well as tension. The mechanical properties of these coating layers were characterized for mixtures of latex and starch for two different pigment volume concentrations (PVC). Three different types of paper were coated with these formulations and their failure during printing was evaluated through a standard ink picking test. These same coating formulations were also applied on two paper grades as single and double coating layers. The cracking propensity of these samples were characterized for a range of latex and starch content. Samples of calcium carbonate marbles with binder films between them were tested in tensile tests: the results were compared with the tensile properties of the pure binder films. The failed surfaces were analyzed using Raman spectroscopy and scanning electron microscopy (SEM). Tensile and flexural moduli of the coating layers were found to be similar and were a function of the binder content and the latex to starch ratio of the binder. However, the stress and strain at failure were higher in flexural tests compared to those in tensile tests. Papers with different basis weights and porosities were found to have different picking resistance values. The picking resistance did not correlate with the elastic modulus of the coating, but did better with the strain at failure behavior. This result indicates that the stiffness of the coating layer is not as critical during printing as compared to its flexibility. In the folding tests, as the PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content as the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. Crack area decreased to a low level if the top layer was composed of a latex only system. Increasing the starch ratio in the binder increased the tensile modulus and decreased the strain at failure. All marble rock samples failed at lower maximum stress and strain at failure values compared to pure films: this result indicates the dominance of adhesive failure. While Raman results did not indicate any residual latex or starch on the adhesively failed surfaces, SEM confirmed that at least part of the failure was still cohesive. The results indicate that if better adhesion between the pigment and the binder could be obtained, the coating layers should have improved mechanical properties and potentially better CAF resistance.Subjects--Topical Terms:

3168406
Agricultural engineering.

Influence of Mechanical Properties of Paper Coating on the Crack at the Fold Problem.
LDR:04158nmm a2200325 4500 001 2205886
005 20190828140042.5
008 201008s2019 ||||||||||||||||| ||eng d
035 $a (MiAaPQ)AAI13870441
035 $a (MiAaPQ)U_Maine4019
035 $a AAI13870441
040 $a MiAaPQ $c MiAaPQ
100 1 $a Hashemi Najafi, Seyyed Mohammad. $3 3432764
245 1 0 $a Influence of Mechanical Properties of Paper Coating on the Crack at the Fold Problem.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2019
300 $a 78 p.
500 $a Source: Dissertations Abstracts International, Volume: 80-09, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Tajvidi, Mehdi.
502 $a Thesis (Ph.D.)--The University of Maine, 2019.
506 $a This item must not be sold to any third party vendors.
520 $a Paper coating layers are subject to various stresses and deformations in many converting processes such as calendering, printing, slitting, and folding of the paper. In some cases, products may crack during folding to generate a defect called cracking at the fold (CAF). The parameters that influence these defects are not well understood. The overall goal of this thesis is to better understand the CAF behavior as related to material properties of the coating layer. A method was developed to produce free-standing pigmented coating layers thick enough to be tested in bending as well as tension. The mechanical properties of these coating layers were characterized for mixtures of latex and starch for two different pigment volume concentrations (PVC). Three different types of paper were coated with these formulations and their failure during printing was evaluated through a standard ink picking test. These same coating formulations were also applied on two paper grades as single and double coating layers. The cracking propensity of these samples were characterized for a range of latex and starch content. Samples of calcium carbonate marbles with binder films between them were tested in tensile tests: the results were compared with the tensile properties of the pure binder films. The failed surfaces were analyzed using Raman spectroscopy and scanning electron microscopy (SEM). Tensile and flexural moduli of the coating layers were found to be similar and were a function of the binder content and the latex to starch ratio of the binder. However, the stress and strain at failure were higher in flexural tests compared to those in tensile tests. Papers with different basis weights and porosities were found to have different picking resistance values. The picking resistance did not correlate with the elastic modulus of the coating, but did better with the strain at failure behavior. This result indicates that the stiffness of the coating layer is not as critical during printing as compared to its flexibility. In the folding tests, as the PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content as the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. Crack area decreased to a low level if the top layer was composed of a latex only system. Increasing the starch ratio in the binder increased the tensile modulus and decreased the strain at failure. All marble rock samples failed at lower maximum stress and strain at failure values compared to pure films: this result indicates the dominance of adhesive failure. While Raman results did not indicate any residual latex or starch on the adhesively failed surfaces, SEM confirmed that at least part of the failure was still cohesive. The results indicate that if better adhesion between the pigment and the binder could be obtained, the coating layers should have improved mechanical properties and potentially better CAF resistance.
590 $a School code: 0113.
650 4 $a Agricultural engineering. $3 3168406
650 4 $a Mechanical engineering. $3 649730
650 4 $a Wood sciences. $3 3168288
690 $a 0539
690 $a 0548
690 $a 0746
710 2 $a The University of Maine. $3 1029373
773 0 $t Dissertations Abstracts International $g 80-09B.
790 $a 0113
791 $a Ph.D.
792 $a 2019
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=13870441