Mechanical Properties of Paper Thermosetting Resin ...

MECHANICAL PROPERTIES OF PAPER THERMOSETTING RESIN COMPOSITES BY

VARIOUS PAPER MATERIALS

Takanori Kitamura Kyoto Institute of Technology

Matsugasaki, Sakyo-ku, Kyoto, Japan Daiwa Itagami Co., Ltd.

5-32, Kawaharacho, Kashiwara-city, Osaka, Japan,

Qianjin Zhang College of Textiles, Donghua University, Songjiang District,Shanghai, P.R. China

Kanta Ito Daiwa Itagami Co., Ltd.


Suguru Teramura Daiwa Itagami Co., Ltd.


Zhiyuan Zhang Daiwa Itagami Co., Ltd.

5-32, Kawaharacho, Kashiwara-city, Osaka, Japan

Yuqiu Yang * College of Textiles, Donghua University, Songjiang District,Shanghai, P.R. China

Key Laboratory of Textile Science &Technology, Ministry of Education, China

[email protected]

Hiroyuki Hamada Kyoto Institute of Technology

Matsugasaki, Sakyo-ku, Kyoto, Japan

ABSTRACT

Recycling and reusing is a noticeable method for environment protecting. Recycled paper is one of the most successful cases as it contributes to energy saving, low cost, low wood consumption and environmental protection. During paper recycling process, many different kinds of raw materials can be used. Paperboards made of different raw materials showed different properties. In this study, three kinds of raw materials were selected to fabricate paperboards respectively combining with thermosetting resin, paperboards reinforced plastic composite was laminated by hand layup method. Detailed observation were carried out to analysis the molding stations including the tensile property which was investigated on both unnotched and notched specimens, besides, to investigate the anisotropy, tensile test was conducted on the

specimens both in machine rolling direction and transverse direction. SEM was also employed to observe the materials and fracture area respectively.

INTRODUCTION

The recycle and reuse of waste paper has increased around the word in the past decades, and the trend will continue. It was reported that the use of recovered paper had increased from 117 million tons in 1995 to 206 million tons in 2007[1]. The recycling paper are widely used in many aspects, such as making art works, packing products, housing products and so on. Paper and paperboards are fibrous materials made from pulp such as wood and plant straw. However, paperboard’s low mechanical property limits its applications.

Proceedings of the ASME 2014 International Mechanical Engineering Congress and Exposition IMECE2014

November 14-20, 2014, Montreal, Quebec, Canada

IMECE2014-37798

1 Copyright © 2014 by ASME

Many researchers had paid attention to paperboard materials. In the study of Preston et al, it was pointed that Recyclable paper and composite materials were excellent choices for the construction of temporary structures for both exhibition spaces or for rapid-recovery shelters in emergency operations [2]. In the study of Eshraghi et al. The mechanical property of single layer particleboards made with various ratios of waste paperboard fibers to wood particles was evaluated. Urea formaldehyde resin in different amounts of 9% and 10% were applied in this study. The results indicated that applying waste paperboard fibers satisfied the minimum modulus of rupture and modulus of elasticity requirements for load-bearing boards for use in humid and dry conditions respectively. The internal bonding values of all panel types decreased with the addition of waste paperboard fiber [3]. In the study of Kitamura et al. It was found that the paperboard which was made by the combination of paperboard and thermosetting resin can reinforce the mechanical property of paperboard [4].

The structure in machine rolling direction is different from that in transverse direction. As a result, the properties of paperboard express obviously anisotropy. The machine rolling direction was generally defined as MD and the cross or transverse direction was defined as TD [5-6]. This anisotropic property was investigated by many researchers. In the study of Xia et al. Several material models had been investigated to describe the mechanical behavior of paperboard. A three-dimensional constitutive model of the anisotropic elastic-plastic behavior of paper and paperboard was proposed [5]. In the study of Ayrilmis et al. Physical and mechanical properties of cardboard panels made from used beverage carton with veneer overlay were researched [7]. Water resistance and mechanical properties of biopolymer (alginate and soy protein) coated paperboards were researched in the study of Rhim [8]. Experimental and numerical studies of creasing of paperboard were done by Nygårds et al [9].

In this study, the thermosetting resin and paperboards from different kinds of raw materials were used to fabricate composites by hand lay-up method. The resin can help not only to improve the resistance to water but also to enhance the mechanical property. The mechanical property of paperboard and paperboard composites was investigated respectively. Tensile test was conducted on both unnotched specimens and notched specimens. The tensile test was conducted both in TD and MD to investigate the anisotropy property. SEM was also employed to observe the materials and fracture area respectively.

MATERIALS AND EXPERIENCE

Paperboard There were three kinds of recycled paperboards (DAIWA

ITAGAMI CO. LTD.) were used in this study. Among these paperboard materials, a type paperboard was made of recycle newspaper and magazine; b type of paperboard was made of recycled Kraft, c type of paperboard was made of package paper of milk and wine.

Matrix and fabrication

Unsaturated polyester resin (150HRBQNTNW, produced by Showa Highpolymer Co.Ltd) was used as matrix in this study. (Polymer was mixed with the hardener MEKPO (PERMEK N; NOF Corporation) in a ratio of 100:0.7). The composite plate was fabricated by hand lay-up method. The special steps were as follows: first, did the preparation and mixed the resin and hardener in the ratio of 100:0.7, then put a piece of plastic paper on the iron plate; second, put some resin on the plastic paper then put the paperboard above the resin and make the resin impregnate the paperboard with a small roller, after that ,resin was put on the paperboard and went on making the resin impregnate the paperboard, after finishing that, cover the paperboard composite with another piece of plastic paper. After fabrication, the materials were disposed on steel moulds in 24 hours for cure. Post cure was followed in the condition of 100 ℃ maintained 2 hours. The paperboard fiber reinforced plastics (FRP) was fabricated with the paperboard in MD and TD respectively. The information of 150HR is shown in Table 1. The information of paperboard is shown in Table.2.

Table 1. The information of 150HR

Resin Density/g/cm3

Strength/ MPa

Modulus/ GPa

Elongation%

150HR 1.19 42.00 3.20 2.18

Table 2. The information of three type of paperboard

Paperboard Composition Grammage

g/m2 Thickness

mm

A recycle newspaper

and magazine 213 0.285

B recycled Kraft 214 0.286

C package paper of

milk and wine 245 0.305

Tensile test Tensile test was conducted on both notched and

unnotched specimens in this research. The composites were cut into the design size according to Japanese Industrial Standards (JIS K7113 and JIS K7085). Tensile test was performed by using an Instron universal testing machine under a speed of 1 mm/min. An extensometer was used to measure the strain during tensile process. Both MD and TD was tested and the results were compared between different raw materials. To make notched specimens, 10 mm hole were drilled in the geometric center of the specimens with drills from H.A.M. PRECISION TOOLS (Type: 342) at the speed of 2300 rad/min. The dimension of the unnotched specimens was 200×20 mm, the dimension of the notched specimens was 200 ×30 mm, and the span of each specimen was 100 mm.


RESULTS AND DISCUSSION

Tensile test of paperboards The stress-strain curve of paperboard materials is shown

in Figure 1. From the figure, it was found that all these three type paperboards showed obvious anisotropy. The break elongation in TD of all types specimens were longer compared to corresponding specimens in MD. This result mainly attributed to the fabrication process of paperboards. The fibers were stretched in MD which made the fibers distributed in MD during paperboard fabricating process.

Figure 1. Stress-strain curve of three types of paperboard in

MD and TD

The modulus and strength of paperboard materials were

also compared to each other and is shown with the histogram in Figure 2.

A. Young’s modulus of paperboard

B. Tensile strength of paperboard

Figure 2. Tensile results of paperboard

The c type of paperboard had highest strength in both MD

and TD which was considered the higher density of c type specimen contributed to higher mechanical property. The decreasing ratio of Young’s modulus and tensile strength in TD from MD were calculated. It was found that all of the decreasing ratio was more than 60%, the b type specimens expressed the highest decreasing ratio of young’s modulus compared with other specimens while a type express the highest decreasing ratio of tensile strength. Overall, the paperboard showed obviously anisotropy.

Tensile test of paperboard composites The tensile test was conducted on paperboard composite

specimens. The stress-strain curve of paperboard composite was shown in figure 3. From the figure, it could be found that the anisotropic property was obvious from MD to TD for that both modulus and strength of paperboard composites in MD was much higher than that in TD. Besides, it also could be found that the break elongation in MD is longer than that in TD after combining with 150HR resin while the paperboard showed the contrast result.

Figure 3. Stress-strain curve of 3 types of paperboard

composites in MD and TD

The modulus and strength of each type of composite is shown with the histogram in figure 4. The tensile results showed that B type of paperboard composite had the highest strength in both MD and TD. Compared to the results of paperboard, the C type specimen become the lowest in the 3 types on both modulus and strength which was considered that the high density of paperboard has compact arrangement of fibers which prevent the impregnation of resin during fabrication process.

A. Young’s modulus of paperboard FRP


B. Tensile strength of paperboard FRP

Figure 4. Tensile result of paperboard composites

The reinforced factor to paperboard and reinforced factor to resin was also calculated to show the increasing situation from paperboard materials to paperboard FRPs and increasing situation from matrix to paperboard FRPs respectively:

; (1)

(2)

A .Reinforced factor to paperboard

B. Reinforced factor to matrix

Figure 5. The reinforced factor of paperboard composites

The results are shown with the histogram in figure.5. It could be found from the figure.5 (A) that the reinforced factor of three type paperboard FRPs to paperboard was more than 1, the highest reinforced factor to paperboard is A type both in MD and TD, it reached 1.87 and 2.51 respectively. But it showed the different situation in figure.5 (B) which described the reinforced factor to matrix. From the figure.5 (B) it could be seen that the reinforced factor to matrix in TD was less than 1, in other words, the strength of paperboard FRPs in TD is less than the strength of thermosetting resin 150HR which was considered that most of the fibers were orientated in MD and the interfaces between resin and fibers play an important role in determining mechanical property in TD. As a result, the strength of paperboard composite in TD was less than the strength of resin due to the weakness of interfaces property. In the contrast, the reinforced factor to matrix in MD was more than 1.5, especially B type which reinforced factor to matrix in MD was 1.99. It was easy to conclude that it was an efficient way to improve the mechanical property of paperboard in by combining with thermosetting resin 150HR.

Tensile test of notched paperboard composites The tensile test was also conducted on notched

paperboard composites which were drilled a 10mm hole in their geometric center, the size of these specimens was 200×30 mm. The notch stress-displacement curve of notched paperboard composites is shown in figure.6. The elongation was lower in notched specimens compared to unnotched specimens. The fracture photo of unnotched and notched specimens are shown in figure 7.

Figure 6. The stress-displacement curve

The result of tensile test was shown with the histogram in

figure.8. It could be found that A type paperboard composites had the highest notch stress in MD which reached to 45.4MPa. The tensile strength of each type of paperboard was decreased after being notched, especially the B type whose decreasing ratio reached 43.36%.


Figure 7. Fracture of unnotched and notched specimens

Figure 8. The tensile strength of notched specimens and

paperboard FRPs in MD

Calculation of characteristic distance The characteristic distance was obtained according the

point stress criterion (whitney and Nuismer, 1974) [10]. In the point-stress failure criteria, the characteristic distance (d0) is the length from the hole edge to the point where the stress equals to unnotched strength when the notched specimen carries maximum load. It could be used to evaluate sensitivity of materials to circular hole. In this research, the stress

distribution was calculated by finite element method (MSC.Marc). The calculation results is shown in Figure 9. The results revealed that the A type specimens had the best performance to resist the hole effect.

Figure 9. Calculation result of characteristic distance

SEM observation The SEM observation results are shown in figure 10.

From the low magnification it was found that the fracture can be divided into near-hole area and far-hole area. The fracture in near-hole area was relative smooth, however the fracture in far-hole area was uneven.

The higher magnification showed more fiber pulled out can be found in far-hole area compared to near-hole area. It was considered the high stress concentration in near-hole area cut the fibers in near-hole area. However in far-hole area, due to the stress concentration was released it became difficult to cut the fibers in this area.

Figure 10. SEM observation of notched specimen

Optical observation


The optical observation between 3 types of paperboard FRP is shown in figure 11. This figure showed that the A type and B type specimen had better impregnation compared to C type specimens. It was considered that this situation has close relation with paperboard density.

According to the paperboard information, the C type specimens had the highest density which make it difficult to absorb the resin during hand layup process. That is why the C type paperboard has highest mechanical property but the paperboard FRP of C type has the lowest mechanical property.

Figure 11. Optical observation of 3 type specimens

CONCLUSION

Short fiber mat is widely used as reinforcement due to its advantage on production and cost. Many kinds of fibers can be used in this form such as carbon fiber, glass fiber, and nature fibers. Paper materials consist of nature fibers and can be treated as mat fabrics. This study is one of our researches on mat reinforced composite. In this paper, mechanical property and SEM observation was conducted on three types of paperboards and paperboard composites. The following conclusion was obtained.

1. The mechanical property of each type of paperboard and paperboard composite showed obvious anisotropy, the modulus and tensile strength of each type of paperboard and paperboard composite in TD was less than that in MD.

2. The mechanical property of each type of paperboard was increased after combining with 150HR resin, the reinforced factor to paperboard of each type of paperboard composite was more than 1.

3. The tensile strength of each type of paperboard was decreased after being notched, the break elongation was also decreased after being notched. 4. From the SEM observation, it was found that the fracture in notched specimens has different characters, which was defined as near-hole area and far-hole area. Different fracture on fibers was distinguished.

REFERENCES

[1] Miranda R, Blanco A. Environmental awareness and paper recycling [J]. Cellulose Chemistry & Technology, 2010, 44(10): 431. [2] Preston S J, Bank L C. Portals to an Architecture: Design of a temporary structure with paper tube arches [J]. Construction and Building Materials, 2012, 30: 657-666.

[3] ESHRAGHI A, KHADEMIESLAM H. WASTE PAPERBOARD IN COMPOSITION PANELS [J]. [4]Kitamura T, Ito T, Teramura T, et al. MECHANICAL PROPERTY OF PAPER-THERMOSETTING RESIN COMPOSITE [J]. [5] Xia Q S, Boyce M C, Parks D M. A constitutive model for the anisotropic elastic–plastic deformation of paper and paperboard [J]. International journal of solids and structures, 2002, 39(15): 4053-4071. [6] Ramasubramanian M K, Wang Y. A computational micromechanics constitutive model for the unloading behavior of paper [J]. International Journal of Solids and Structures, 2007, 44(22): 7615-7632. [7] Allaoui S, Aboura Z, Benzeggagh M L. Effects of the environmental conditions on the mechanical behaviour of the corrugated cardboard [J]. Composites Science and Technology, 2009, 69(1): 104-110. [8] Rhim J W, Lee J H, Hong S I. Water resistance and mechanical properties of biopolymer (alginate and soy protein) coated paperboards [J]. LWT-Food Science and Technology, 2006, 39(7): 806-813. [9] Nygårds M, Just M, Tryding J. Experimental and numerical studies of creasing of paperboard [J]. International Journal of Solids and Structures, 2009, 46(11): 2493-2505. [10] J.M. Whitney and R.J. Nuismer. Stress Fracture Criteria for Laminated Composites Containing Stress Concentrations [J]. Journal of Composite Materials, 1974, 8: 253-265


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