Cogon Plant as an Alternative for Paper Production PDF

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The Use of Cogon Grass as an Alternative in Paper Production

I.

Introduction Although with the rise of technologies, going completely paperless is still impossible.

Transactions, businesses, and activities that require paper cannot be helped. In fact, according to Huxley (2016),

paper consumption has increased by 400% in the past four decades. It is

known that approximately 93% of paper comes from trees where in a total of 10,000 trees are cut down every year in order to make paper. Furthermore, when it comes to the detailed contents of the production, a ton of standard printing paper requires a total of 24 trees with the combination of both softwood and hardwood, 40 feet in length, and a 6-8 inches diameter. In 2011, the Philippine Congress released a study stating that about 123,000 hectares of the country’s forest are lost every year and that by 2036, without the plans for reforestation there would be no more forest left (Tacio, 2013). A capstone project by chemistry students currently taking organic chemistry as a related course in utilizing other resources available in the country as an alternative for timber based papers in order to not only decrease the amount of trees being cut down but also to lessen carbon footprints and promote biodegradable or recyclable products. One of said alternatives is Imperata cylindrica, also known as Cogon grass, is a type of perennial rhizomatous grass species that is native in tropical and subtropical countries, such as China, Philippines, and Japan (Bonnia et al., 2018). It is considered as an invasive weed that causes crop, economic and environmental damage. Cogon grass contains long, abundant, smooth and straight fibres which provide durability (Kassim et al., 2016). Thus, making it a good potential fibre source for paper production. This capstone project centers on determining whether Cogon or Imperata cylindrica have properties that could be used as an alternative material in producing papers. It also focuses on the structure of its fibers and determining the kind of chemical process it undergoes to prove its capability to be one of the sources in the production of paper through tensile strength or “tear capacity”. The use of cogon grass as an alternative use from paper made of timber in order to significantly decrease the number of trees being cut down and slowly solve deforestation. The use of cogon grass will not only be better for the environment but will also give farmers an opportunity for a source of income due to cogon or Imperata cylindrica’s availability being planted and sourced everywhere.This study will be performed through online library research due to the inaccessibility of materials and the restriction of performing it in real life due to the COVID19 pandemic. Other factors that Cogon or Imperata cylindrica have will not be taken into account if

it's not related to the data needed for the study. Parameters like paper quality, such as the smoothness of the paper, will not be analyzed due to pandemic restriction. II.

Review of Related Literature

Cogon Plant According to MacDonald (2004), cogongrass, also known with the scientific name of Imperata cylindrica, is a rhizomatous, perennial grass species commonly found in tropical and subtropical countries. Imperata is a genus of the Poaceae (grass family) with nine different species, including the I. cylindrica. Cogongrass is distinguished from the other Imperata species by the presence of two anthers or stamens. The leaves of this plant can grow up to 1.5 meters in height depending on the moisture and fertility of the environment. The I. cylindrica produces 3000 seeds per plant. It produces a short branched, compacted, and dense seedhead, with cylindrical and spike-like appearance.

As to the Weed Risk Assessment for Imperata cylindrica (Cogongrass) by the United States Department of Agriculture in 2018, cogongrass has a species name of Imperata cylindrica (L.) P. Beauv, and it belongs to the family of Poaceae. The leaves grow in bunches up to 1-4 feet directly from the ground. The plant can grow up to 0.15 to 1.2 meters tall. Cogongrass is the most widespread species in the Imperata genus. It is also highly variable with five varieties of three different ploidy levels (i.e. 2n=20,40,60).

In the Philippines, open and drylands formed extensive cogon grassland that is called cogonales. It is propagated through the stoloniferous rhizome and considered a damaging noxious weed or disruptive perineal grass in Indonesia (Stuart, 2020). Invasiveness of Cogon Plant According to the United States Department of Agriculture’s Animal and Plant Health Inspection Service (2020), cogon grass is an invasive exotic grass that grows rapidly, reducing the forest productivity as well as harming the wildlife. It is found both in public and private properties, roadways and farmland also have this noxious weed. The rhizomes of cogon plants are white and tough with shortened internodes. These rhizomes contain a band of sclerenchyma fibers, below the epidermis, with each vascular bundle enclosed by sclerotic tissue (MacDonald, 2004). In some studies, these rhizomes had shown

allelopathy in cogongrass that suppresses the growth of crops. In a mentioned study in this article, the crude water extracts of cogongrass rhizomes inhibited the germination of a fungus and reduced the fusarium wilt of glasshouse grown tomato plants. Another factor that causes the invasiveness of cogon plants is the hard, sharp points of cogongrass rhizomes which causes infection as it penetrates the bulbs, tubers and roots of the surrounding plants. In Asia, cogon plants are considered as a primary weed species in tea, rubber, coconut, and in other perennial plantation crops. In Africa, it causes great damage in agronomic production. In other areas, cogongrass infests natural habitats and destroys native plant ecosystems. This plant competes with the crops for water, light and soil nutrients, causing growth suppression to the crops. Chemical Processes and Treatments Involved in Processing Cogon Plant In the research of Kassim et al. (2016), the samples of I. cylindrica were collected, washed, air-dried and cut to 2-5 centimeters long prior to analysing the samples. The cogon plant samples were, then, grounded and stored in an airtight container for chemical analyses. The I. cylindrica sample was processed by soxhlet extraction for six hours. The cellulose, holocellulose, lignin hot water solubility, 1% NaOH solubility and ash contents of the cogongrass sample was determined through the use of Technical Association of the Pulp and Paper Industry (TAPPI) standard methods. Pulp properties were tested by drying the cogongrass using an oven, and pulping it with 15% active alkaline solution. The pulp was then screened using a fractionator vibratory flat screen with 0.25 mm slits, concentrated by a centrifuge, and homogenized using a Hobart mixer. The screened pulp was dried to constant weight to determine the pulp yield. For morphological properties, the fibre length of cogon plant was measured under a profile projector microscope at 100x magnification, and by applying the Franklin method. For surface morphology, the sample was coated with a thin layer of gold, and was observed using a scanning electron microscopy at different magnifications. Common Raw Materials for Paper Production Paper is commonly produced by using fibrous raw materials, which consist of primary and secondary fibres (Blechschmidt et al., 2012). Primary fibres are obtained from raw materials such as woody plants and non-woody plants. On the other hand, secondary fibres are obtained from recovered papers. Wood is the 90% raw source for paper production. Mechanical pulp, which involves mechanical defibration of wood, yields up to 80% to 95% of pulp for paper production.

There are an approximate of 25,000 varieties of plants with a woody stem that are used differently for the production of paper (Sappi, n.d.). Conifers are greatly preferred as they have long fibres, which forms firmer fibrous web, thus, a firmer paper. Conifers that are mainly used are spruce, fir and pine. Deciduous trees, such as beech, birch, poplar and eucalyptus, are also used in paper production but are less preferred than conifers. Tree trunks, having different cells which transport the nutrients and the saps, can be used for paper pulp production. However, the bark part of the tree trunk cannot be utilized for the pulp production, so it must be removed (debarked). Chemical Processes Involved in Paper Production According to Blechschmidt et al. (2012), there are two processes involved in obtaining pulp from raw materials: chemical pulping and mechanical pulping. Chemical pulping produces chemical pulp from vegetable raw materials such as hardwood, softwood, cereals, bagasse, reed, or esparto grass, and from other annual non-wood plants. In this process, most of the lignin is removed from the raw material, making the pulp yield only 45% to 55%. Two main industrial processes used in chemical pulping are sulfate process and sulfite process. About 80% of the pulp production uses the sulfate process or also known as the kraft pulping process. It creates fibers that form paper that has good durability. Furthermore, the process it undergoes allows the recovery of the used chemical raw materials. The sulfite process is a chemical digestion that uses an aqueous solution of sulfur dioxide and alkalis. The products obtained using this process are usually more light but have lower strength capability compared to the sulfate process (PCC Group, 2018). For mechanical pulping, mechanical pulp is produced by mechanical defibration. Wood is commonly used in this process. In mechanical pulping, the lignin is plasticized and remains in the pulp. Thus, the pulp yield, which is about 80% to 95%, is higher than the pulp yield of chemical pulping.

III.

Methodology

This chapter discusses the materials, methods and data analysis that were used in the study of different chemical compositions, morphological properties, and capabilities of Cogon grass (Imperata cylindrica) as an alternative source for paper production.

Figure 1. Schematic diagram for the Preparation of Materials

Cogon grass (Imperata cylindrica) was collected and cut into 1-2 inch long pieces. The chopped cogon grass was then washed to remove dirt and possible source of contaminants for the experiment. The small pieces of cogon grass were dried ensuring that no excess water was present in the sample and preparing them for the next process.

Figure 2. Schematic diagram for the Production of Cogon Pulp

Dried cogon pieces were placed in a pot with water and baking soda to soften them and to make the fibers appear. It was cooked for 3 hours or until it became tender. The cogon grass

was then pounded into pulp for better binding property and washed 3-4 times to remove unnecessary impurities. Chlorine was added to bleach and to remove the natural color of the cogon grass and to further soften the cogon pulp. Lastly, excess water was drained.

Figure 3. Schematic diagram of the Process for Cogon Paper Making

A mixture of water, starch, alum or tawas, and insenso was prepared as the binding agent to produce cogon paper. The cogon pulp was put in a molder and was placed in the binding agent mixture. It was spread evenly and was removed from the mixture using a dry cloth to discard the excess liquid in the wet cogon paper. Then, a rolling pin was used to flatten the surface of the paper. Lastly, the cogon paper was removed from the molder and was set to dry. The process from figure 1-3 is based on the video uploaded by City of Koronadal (2015) about the Cogon Paper Making.

Figure 4. Schematic diagram for the Study of Cogon Grass as an Alternative Source of Paper

Cogon grass (Imperata cylindrica) as an alternative source of paper was studied using journals that discussed its chemical properties, pulping properties, and capabilities. Chemical properties of cogon grass are first gathered from Kassim et al. (2015) to know its lignin and ash content as well as the hot water and 1% NaOH solubility. This is to determine whether cogon grass (Imperata cylindrica) is preferable compared to other wood and non-wood fibres. The amount of cellulose and hemicellulose was also observed to measure the amount of its fiber and determine its quality. It is followed by the study of pulping properties from Kassim et al. (2016). This study concentrated on the pulp yield and the degradation capability of cellulose in cogon grass. It is to determine if cogon grass (Imperata cylindrica) has sufficient pulp quantity in producing paper compared to other possible sources. Then, the capabilities of cogon grass (Imperata cylindrica) were studied by Sharma et al. (2018) that focused on the fibre length, fibre diameter, fibre lumen diameter, and the fibre wall thickness of cogon grass. This is to determine if cogon grass (Imperata cylindrica) is a flexible and suitable material for paper production. Lastly, the data gathered is analyzed quantitatively, qualitatively, and comparatively to other paper sources. IV.

Results and Discussion There were three journals, used in this discussion, that studied the capabilities of Imperata

cylindrica, also known as cogon plant or cogongrass, as an alternative source for pulp and paper production. In the study of Sharma et al. (2018), grass species, including Imperata cylindrica, were tested for their capacities as an alternative for paper and pulp production. These grass species were also compared to Bambusa tulda, a bamboo species in India for pulp and paper

making. In the study of Kassim et al. (2015), the chemical properties and surface morphological properties of Imperata cylindrica were analyzed and compared to other non-wood plants. Lastly, in the study of Kassim et al., (2016), chemical compositions, pulping and pulping properties, morphological characteristics, and surface morphology of I. cylindrica were analyzed and tested.

A thick walled epidermis and scattered vascular bundles in ground tissue were found in cogon grass (Sharma et al., 2018). The vascular bundles were small in the periphery and large in the center. Each was surrounded by a fibrous sclerenchymatous sheath. A ring of fibrous sheath and cortical cavities were also present in I. cylindrica.

Cogon grass had 5.67% lignin content (low), 8.24% ash (high), and 3.83% hot water solubility (low) (Kassim et al., 2016). For the holocellulose, cellulose and 1% NaOH solubility, I. cylindrica had acceptable values of 64.9%, 37.1% and 19.6% respectively. The same results were also measured in the study of Kassim et al. (2015). Low lignin amount is preferable for paper and pulp production as lignin is an undesired polymer that should be removed since it affects the pulping process and bleaching process of the material. Moreover, lignin affects the quality of the paper and it causes yellowing of the paper products. The ash content in cogon grass makes it unsuitable for grazing animals since it can cause a problem in refining and recovery of cooking liquor. For hot water solubility, cogon grass had a low value. A high value of hot water solubility indicates that the material contains a high content of tannins, gums, sugar, colouring and starch that could affect the quality of the pulp and paper product. For 1% NaOH solubility, cogon grass had a low value percentage. This means that a low amount of fibre will be disintegrated in the pulping process that will result in high pulp yield. Holocellulose and cellulose determine whether a material is suitable for paper production. The ideal holocellulose percentage for an alternative fibre should be 65% to 75% of the plant dry weight. With the results, which is 64.9%, cogongrass can be an alternative fibre (Kassim et al., 2015). For cellulose, cogongrass has a high content which indicates that it can be an alternative fibre for pulp and paper production (Kassim et al., 2015). High content of cellulose produces a high quality and strong paper product. Table 1 and Table 2 shows the results of cogongrass in the study of Kassim et al. (2016) and Kassim et al. (2015), respectively.

Table 1. Comparison of chemical compositions of I. cylindrica with published non-woods.

Source: Kassim, A., Aripin, A., Ishak, N., Hairom, N., Fauzi, N., Razali, N., & Zainulabidin, M. (2016). POTENTIAL OF COGON GRASS (IMPERATA CYLINDRICA) AS AN ALTERNATIVE FIBRE IN PAPER-BASED INDUSTRY. ARPN Journal of Engineering and Applied Sciences, 11(1), 2681-2686.

Table 2. The chemical compositions of cogon grass and other published non-wood and wood fibres

Source: Kassim, A., Aripin, A., Ishak, N., & Zainulabidin, M. (2015). Cogon Grass As an Alternative Fibre for Pulp and Paper-Based Industry: On Chemical and Surface Morphological Properties. Applied Mechanics and Materials, 773-774, 1242-1245.

In the study of Kassim et al. (2016), the pulp yield of I. cylindrica was 38.2%, which was the highest yield among the other samples. High pulp yield shows that there was a low degradation of cellulose during the pulping process (Dutt and Tyagi, 2011). This was also affected by the low lignin content in the material.

Table 3. Comparison of pulp and mechanical properties of I. cylindrica hand sheets with other non-wood.

Source: Kassim, A., Aripin, A., Ishak, N., Hairom, N., Fauzi, N., Razali, N., & Zainulabidin, M. (2016). POTENTIAL OF COGON GRASS (IMPERATA CYLINDRICA) AS AN ALTERNATIVE FIBRE IN PAPER-BASED INDUSTRY. ARPN Journal of Engineering and Applied Sciences, 11(1), 2681-2686.

Table 4. Comparison of fibre dimensions of the I. cylindrica with other non-wood fibre

Source: Kassim, A., Aripin, A., Ishak, N., Hairom, N., Fauzi, N., Razali, N., & Zainulabidin, M. (2016). POTENTIAL OF COGON GRASS (IMPERATA CYLINDRICA) AS AN ALTERNATIVE FIBRE IN PAPER-BASED INDUSTRY. ARPN Journal of Engineering and Applied Sciences, 11(1), 2681-2686.

Table 5. Dimensions of fibrous and non-fibrous cells of selected grass species

Source: Sharma, M., Gogoi, B.R. & Pangging, G. (2018). Anatomical Characteristics and Fibre Dimensions of Some Grass Species of Arunachal Pradesh and their Potential for Pulp and Paper. Journal of Bioresources, 5(1), 41-48

Fibre length, fibre diameter, fibre lumen diameter and fibre wall thickness accounts the quality of a material in tearing resistance, pulp beating, bursting, tensile strength and folding endurance (Sharma et al., 2018). Table 4 and 5 shows that I. cylindrica had a high fibre length

which makes it suitable for pulp and paper production as it resulted in the highest tensile index and burst index in Table 3. For surface morphological properties, it can be seen in Figure x and Figure x that there was an abundance of long fibres and rough surface in cogongrass.

Source: Kassim, A., Aripin, A., Ishak, N., & Zainulabidin, M. (2015). Cogon Grass As an Alternative Fibre for Pulp and Paper-Based Industry: On Chemical and Surface Morphological Properties. Applied Mechanics and Materials, 773-774, 1242-1245.

Figure 5. SEM images of cogon grass on magnification level at: (a) 100x, (b) 200x and (c) 800x

Source: Kassim, A., Aripin, A., Ishak, N., Hairom, N., Fauzi, N., Razali, N., & Zainulabidin, M. (2016). POTENTIAL OF COGON GRASS (IMPERATA CYLINDRICA) AS AN ALTERNATIVE FIBRE IN PAPER-BASED INDUSTRY. ARPN Journal of Engineering and Applied Sciences, 11(1), 2681-2686.

Figure 6. SEM images of I. cylindrica hand sheet at magnifications of: (a) 500x and (b) 1000x. Runkel ratio is the ratio of the fibre wall thickness to the fibre lumen diameter. For I. cylindrica, the Runkel ratio was between 0.5 to 0.95 (Sharma et al., 2018). A value of less than 1 is suitable for pulp and paper production.

The ratio of fibre lumen diameter to fibre diameter determines the flexibility of the material. Cogongras...