Scholarly article on topic 'Termite Resistance of Medium Density Fibreboard Produced from Renewable Biomass of Agricultural Fibre'

Termite Resistance of Medium Density Fibreboard Produced from Renewable Biomass of Agricultural Fibre Academic research paper on "Biological sciences"

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{"Pineapple leaf fibre" / MDF / "PF resin" / "Termite resistance"}

Abstract of research paper on Biological sciences, author of scientific article — Yuliati Indrayani, Dina Setyawati, Tsuyoshi Yoshimura, Kenji Umemura

Abstract The development of Medium Density Fibreboard (MDF) made from renewable biomass of pineapple (Ananas comosus) leaf fibre and their suitability as a construction material has been investigated. Two different types of board with a target density of 0.8 gr/cm3 were manufactured. The board was prepared in three layers of about 1:1:1 weight ratio in unidirectional and cross-oriented board using low molecular weight (LM) PF resin type PL-3725 and high molecular weight (HM) PF resin type PL-2818 for impregnation and adhesive purposes. For comparison, boards with the same structure were prepared using high molecular weight PF resin only. The biological properties of the boards have been examined as their termite resistance against subterranean termite attack. The results indicate that there was a significant effect of impregnation with low molecular weight PF resin on the susceptibility of the MDF board specimens. The results also show that fiber orientation had no significant effect on the termite resistance of the specimens against Coptotermes formosanus Shiraki. The Type PF resins were significant for termite mortalities of the tested property. The total resin content of 20% of the board type prohibits the degradation by termites.

Academic research paper on topic "Termite Resistance of Medium Density Fibreboard Produced from Renewable Biomass of Agricultural Fibre"

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Procedia Environmental Sciences 20 (2014) 767 - 771

4th International Conference on Sustainable Future for Human Security, SustaiN 2013

Termite Resistance of Medium Density Fibreboard Produced from Renewable Biomass of Agricultural Fibre

Yuliati Indrayania*, Dina Setyawatia, Tsuyoshi Yoshimurab, Kenji Umemurab

aFaculty of Forestry, Tanjungpura University, Jl. Imam Bonjol, Pontianak 78124, Indonesia bResearch Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan

Abstract

The development of Medium Density Fibreboard (MDF) made from renewable biomass of pineapple (Ananas comosus) leaf fibre and their suitability as a construction material has been investigated. Two different types of board with a target density of 0.8 gr/cm3 were manufactured. The board was prepared in three layers of about 1:1:1 weight ratio in unidirectional and cross-oriented board using low molecular weight (LM) PF resin type PL-3725 and high molecular weight (HM) PF resin type PL-2818 for impregnation and adhesive purposes. For comparison, boards with the same structure were prepared using high molecular weight PF resin only. The biological properties of the boards have been examined as their termite resistance against subterranean termite attack. The results indicate that there was a significant effect of impregnation with low molecular weight PF resin on the susceptibility of the MDF board specimens. The results also show that fiber orientation had no significant effect on the termite resistance of the specimens against Coptotermes formosanus Shiraki. The Type PF resins were significant for termite mortalities of the tested property. The total resin content of 20% of the board type prohibits the degradation by termites.

© 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/3.0/).

Selectionandpeer-reviewunder responsibility of the SustaiN conference committee and supported by Kyoto University; (RISH), (OPIR), (GCOE-ARS) and (GSS) as co-hosts

Keywords: Pineapple leaf fibre; MDF; PF resin; Termite resistance

* Corresponding author. Tel.: +62-561-767673; fax: +62-561-767673. E-mail address: mandaupermai@yahoo.com.

1878-0296 © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Selection and peer-review under responsibility of the SustaiN conference committee and supported by Kyoto University; (RISH), (OPIR),

(GCOE-ARS) and (GSS) as co-hosts

doi:10.1016/j.proenv.2014.03.092

1. Introduction

In recent years it has been difficult to obtain solid woods and this causes some problems for wood-based industry. To meet the standard requirements for a high-class residential environment, substitute wood-based materials including natural materials are required as construction materials. In addition, such systems contribute to the recycling of agricultural wastes. Nowadays, attention has been paid to non-woody fibre which has gained high importance as a sustainable plant fibre resource for composite products. The use of agricultural fibre for panel composite materials is commonplace in many parts of the world.

There are vast supplies of agricultural fibre residues in Indonesia. Pineapple is one of important economic fruits for Indonesia with a strong domestic and export demand. However, there has been a lack of successful harvesting for this fruit, which could be attributed to residues from their leaves. Manufacturing composite materials using pineapple leaf fibres is an option for sustainable utilization in areas where this material is abundant. Due to its large production of pineapple, Indonesia is an ideal place for development of the composite materials.

Production of composite products has increased dramatically. One of them is Medium density fibreboard (MDF). MDF is a wood-based panel that is composed of wood fibres bonded together with resin under heat and pressure. MDF has a wide application for both structural and non-structural uses. In order to recycle natural resources to meet the demands caused by the decrease in supplies of solid wood and wood-based materials, several researchers have succeeded to substitute wood fibre, using lignocellulosic fibres. Composites made from agro-fibres have been investigated [1, 2, 3].

On the other hand, wood-based composite boards were susceptible to termite attack [4, 5]. One of the most important termite species in the world is subterranean termite. Subterranean termites can cause extensive damage to wood and non-woody composites produced from non-durable material resources. The adhesive has an important influence on termite resistance of agro-based composites. Wood-based boards depend on adhesive bonds for their integrity and susceptibility to biological degradation [6, 7]. This research is sure to contribute in developing novel production processes of agro-waste pineapple leaf fibre for construction materials and to determine their resistance to termite attack in laboratory conditions.

2. Material and Methods

2.1. Material

Pineapple (Ananas comosus (L.) Merr.) leaves were used as raw material. Two types of PF resins were chosen for impregnation and adhesive purposes; low molecular weight (LM) PF resin type PL-3725 and high molecular weight (HM) PF resin type PL-2818 (Gunei Chemical Industry Co., Ltd., Head Office: 700 Shukuorui-machi. Takasaki-Shi, Gunma 370-0032, Japan). Methanol (Nacalai Tesque, Inc., Kyoto, Japan) and water were also used as the solvent.

2.2. Fibre preparation

The fibre was taken out from pineapple leaves by decortications. The fibres were cut to 35 cm in length and manually combed and finally were sorted by length. The main purposes of this procedure were to homogenize the fibres in length and to obtain straight fibres. The fibres were then oven-dried to moisture content of about 5%.

2.3. Resin solution preparation

Both resins were mixed and an impregnation solution of the resins was prepared by adding methanol and water to decrease the viscosity. The weight ratio of LM:HM:methanol:water was 0.5 : 0.5 : 1 : 1. Whereas the usage of HM PF resins type - 2818 only was also manufactured to compare the effects of its impregnation toward the mechanical and physical properties.

2.4. Board preparation

MDF boards at a target density of 0.8 gr/cm3 were manufactured measuring 35 cm x 35 cm x 0.4 cm. The fibres were dipped into the PF resin solutions. Excess impregnation PF resin was squeezed out by passing the fibre through a pair of rollers. The impregnated fibres were dried at room temperature for 24 hours to get a resin content of 20% (dry weight) of the fibres.

Two sets of boards were produced using both PF resins. Uni-oriented (UB) board as Type I was created with all layers oriented in the longitudinal direction. While the rest, cross-oriented (CB) as Type II, consisted of a plywood-type board with an orientation of 0°-90°-0° as a form of loosely packed mats. The MDF was prepared in three layers of about 1:1:1 weight ratio. The mats were consolidated in a laboratory hot press with a specific pressure of 4.5 MPa and at a pressing temperature of 160°C for 10 min to completely cure the PF resin. Afterward, all boards were conditioned at 20°C and 65% relative humidity for seven days before the test.

2.5. Termite bioassay

MDF specimens measuring 20 x 20 x 10 mm were obtained from MDF boards and exposed to the subterranean termites Coptotermes formosanus Shiraki in accordance with Japan Wood Preserving Association (JWPA) standard. An acrylic cylinder (80mm in diameter, 60 mm in height) which is sealed by a 5mm thick of hard dental plaster (New Plastone, GC Corp) was used as a test container. A test specimen was placed at the centre of the plaster bottom of the container. A total of 150 worker termites and 15 soldiers collected from a laboratory termite colony at RISH, Kyoto University, were placed into each test container. Three specimens for each MDF were exposed against termites. Small wood blocks of Sugi (Cryptomeria japonica) were also employed for control purposes. The assembled containers were set on wet cotton pads to maintain the humidity and were kept in an unlighted controlled-temperature room at 28°C and 85% RH for 3 weeks. At the end of the experiment, the specimens were removed from the containers, carefully cleaned the debris from termite attack, oven-dried and reweighed to determine the percentage of weight losses and to record survival rates of termite.

3. Results and Discussion

The average of weight losses and percentage mortality of termites of MDF during the termite bioassays are shown in Figs.1 and 2. As shown in Fig. 1, the lower mean weight loss values were observed in MDF board specimens containing mix PF resin, however, no statistically significant difference was observed between mix PF resin and high molecular weight PF resin (Tukey's test: P < 0,05). Fiber orientation had no statistically significant difference on the termite resistance of the MDF board specimens against Coptotermes formosanus Shiraki (Tukey's test: P < 0,05).

All specimens were found almost intact after 3-weeks termite exposure for both mixed and high molecular-PF resin (Fig. 1). It was observed that types of resin have no statistically significant effect on average weight loss of the specimens (Tukey's test: P < 0,05) as describe above. However, a slight decrease was found for the weight loss of the MDF board specimens containing the mix of high and low molecular weight-PF resin (Fig. 1).

Fig. 1 shows that average weight loss of the MDF control was obtained at 15.8%, however average weight loss of the MDF specimens containing high molecular PF-resin was approximately 1.7%, while the Mix PF resin was approximately 1.5%. The results suggest that the chemicals derived from the PF resin may show inhibitory properties against termite as stated by Curling and Murphy [5]. Moreover, this finding supported the previous observation by Walther et al. [8] that PF resin used in this study is a fast-acting chemical that kills termites when they ingest the fibers.

The outcome as shown in Fig. 2 illustrates that average mortalities of termites of control was obtained at 14.4%. In contrast, the average mortalities of termites of the MDF specimens containing high molecular PF resin was around 23%, while the Mix PF resin reached to 100% at the end of the tests (Fig. 2). As shown in Fig. 2, no significant difference was observed between termite mortalities in uni-oriented (UB) and in cross-oriented (CB) boards (Tukey's test: P < 0,05). This is indicated that fiber orientation had no effect on termite mortality.

18 16 — 14 $ 12 10 8 6 4 2 0

□ High molecular PF resin ■ Mix PF resin_

Board Type

Control

Fig.1 Weight loss in MDF specimens after 3 weeks exposure to termite Coptotermes formosanus Shiraki. UB, uni-oriented; CB, cross-oriented.

This observation highlighted that MDF specimen without low molecular weight PF-resin impregnation gave lower worker termite mortalities than those impregnated with low molecular weight PF-resin (Fig. 2). It can be said that the PF resin used in this study is a fast-acting chemical that kills termites when they ingest the fibres as stated by Walther et al [8]. In addition, Nzokou et al [9], state that the increase in termite resistance of laminated veneer lumber products was attributed to the density and the phenolic resin.

In general, termite mortalities were confirmed to the weight loss in the specimens. In contrast to the MDF fibre, small wood blocks of Sugi (Cryptomeria japonica) show lower termite mortalities (Fig. 2) and higher weight loss

(Fig.1).

4. Conclusions

The utilization of pineapple leaf fibre and PF resin is effective in prohibiting the degradation by termites. Termite resistance test revealed that the PF resin impregnated to pineapple leaf fibre MDF seem to be suitable for building construction materials purposes and promising for the development of a durable construction material. It is not only useful as a renewable and environmentally friendly construction material for regions with a low available of wood product but also is a promising alternative to the declining of wood supply. As the next step, the use of adhesives made from renewable resources that provide termite resistance will be a challenge for the near future in bio-based materials research.

ss 100 -

t 80-ra t

° 60 -

« 4°-

□ High molecular PF resin ■ Mix PF resin

Board Type

Control

Fig. 2 Termite mortality during the-3 weeks exposure of MDF to termite Coptotermes formosanus Shiraki. UB, uni-oriented; CB, cross-oriented.

Acknowledgements

The authors gratefully acknowledges the Directorate General of Higher Education of Indonesia for financial support in Fiscal Year 2012 under the Program "International Research Collaboration and Scientific Publication"

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