Chemical Pulp Research Articles

Removal of hazardous trace elements from green liquor dregs by mechanical separation methods

Abstract Green liquor dregs represent the most important inorganic residue of chemical pulp mills. The dregs are usually settled in thickeners, washed and deliquored with lime mud precoat filters, and transported to the landfill. The utilization of dregs is challenging, due to the high concentration of hazardous trace elements (HTE) in their solid phase. There are basically two potential strategies for the reduction of the HTE content of dregs: mechanical classification according to differences in the size and density of particles, and removal of HTE by various chemical treatments. The objective of this study was to evaluate the applicability of straightforward mechanical separation methods for the purification of dregs from HTE. The evaluated separation methods included particle size–based classification by sieving, and classification on the basis of differences in the settling properties of particles in gravitational and centrifugal separation. It can be concluded that all the evaluated separation methods could be used to reduce the HTE content of dregs, although the separation efficiency was not very high in most cases. Centrifugation had clearly the best performance of the investigated techniques. The fractions consisting of large particles contained consistently lower concentrations of HTE, compared to fractions containing a lot of fines.

Enzymatic hydrolysis of ionic liquid-extracted chitin

Chitin, one of Nature’s most abundant biopolymers, can be obtained by either traditional chemical pulping or by extraction using the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate. The IL extraction and coagulation process provides access to a unique chitin, with an open hydrated gel-like structure. Here, enzymatic hydrolysis of this chitin hydrogel, dried shrimp shell, chitin extracted from shrimp shells using IL and then dried, and commercial chitin was carried out using chitinase from Streptomyces griseus. The enzymatic hydrolysis of shrimp shells resulted only in the monomer N-acetylglucosamine, while much higher amounts of the dimer (N,N′-diacetylchitobiose) compared to the monomer were detected when using all forms of ‘pure’ chitin. Interestingly, small amounts of the trimer (N,N′,N′′-triacetylchitotriose) were also detected when the IL-chitin hydrogel was used as substrate. Altogether, our findings indicate that the product distribution and yield are highly dependent on the substrate selected for the reaction and its hydrated state.

Energy efficiency and environmental assessment of papermaking from chemical pulp - A Finland case study

Abstract Pulp and paper manufacturing sector constitutes one of the largest industry segments in the world in terms of water and energy usage as well as of significant use and release of chemicals and combustion products. Since its chief feedstock –wood fiber– is renewable, this industry can play an important role in sustainable development, becoming an example of how a resource can be managed to provide a sustained supply to meet society's current and future needs. This calls for a thorough assessment of environmental costs and impacts associated to pulp and paper operations, including both direct and indirect inputs supporting the whole papermaking process as well as the main outputs, co-products and by-products. By means of Life Cycle Assessment (LCA) methodology, this paper aims at assessing the environmental sustainability of the pulp and paper production so as to identify those phases across the whole supply chain that entail the highest environmental loads, thus requiring improvements. To determine the environmental impacts as accurately as possible, the manufacturing stages performed in the pulp and paper mill complex of Stora Enso Oyj Veitsiluoto Mills at Kemi, Northern Finland, were taken as a model and assessed by means of the SimaPro 8 LCA software, utilizing ReCiPe Midpoint (H) method for the impact assessment. As expected, most of the resulting impacts are caused by the industrial production phase. The production processes of pulp and paper jointly affect all the investigated impact categories with the highest shares, ranging from 50% of generated impacts on water depletion up to 88% on freshwater eutrophication. Generally, the main contributions to environmental loads come from the electricity and heat requirements and, only at a minor extent, from the use of chemicals such as the sodium hydroxide and sodium chlorate. In particular, pulp production process generates the main loads on global warming (46% of the total impacts), ozone depletion (39%), freshwater eutrophication (55%), human toxicity (46%), metal depletion (42%) and fossil depletion (46%). In the remaining investigated impact categories, namely terrestrial acidification, photochemical oxidant formation and terrestrial ecotoxicity, most of impacts derive from the use of optical brighteners and fillers in the final steps of paper production and from the intensive consumption of water in the recycling step of end-of-life affecting water depletion. Moreover, the implementation of measures for material and energy efficiency in the assessed system, such as the use of renewable energy generated in situ from black liquor and residual biomass to support the requirements of the integrated pulp and paper mills and the waste paper recycling, resulted to be crucial in lowering the environmental burdens. In particular, the partial fulfillment of electricity and heat requirements by means of a circular use of residues within the system leads to a noteworthy reduction of impacts in all the investigated impact categories, up to more than 70% in global warming and fossil depletion potentials, thus contributing to higher process sustainability compared with other averaged European systems for paper production. The obtained research results are a valuable source of management information for the decision makers, at both company and national levels, with the aim to improve the environmental performance of pulp and paper industry.

Concerning operational aspects in supercritical water gasification of kraft black liquor

Abstract Kraft Black Liquor (KBL) is an aqueous solution of lignin residues, hemicelluloses and inorganic chemicals produced during the pulping process. It is sometimes classified as waste even if this definition is wrong in most of the cases where the BL is reutilized (recovered) by using it as fuel in recovery boilers. In this process, the pulping chemicals are recovered and sent again to the cooking process of wood. BL has more than half of the energy content of the inlet wood. KBL is generally used as an energy source although recovery boilers are still quite thermally inefficient compared to coal or gas fired power producing ones. Among the various solutions, supercritical water gasification (SCWG) enables bio-fuels and value products to be obtained from KBL. The present study deals with the KBL SCWG by using a plug-flow reactor operating continuously at 250 bar pressure and variable temperatures in the range 500–700 °C. The objective was to identify the experimental conditions that lead to the development of operational problems and to document them accurately. In this study, real time visualization of online measurements has been conducted by means of the LabView software. In order to highlight the differences in behavior, tests were conducted on two different substrates, the sucrose and KBL. Results highlight how tests were carried out without problems at 500 °C resulting in a total gas yield of 18.31 g-mol/kgfeed, consisting mainly of H2 (7.87 g-mol/kgfeed), CO2 (5.84 g-mol/kgfeed), H2S (2.29 g-mol/kgfeed) and CH4 (1.96 g-mol/kgfeed). On the contrary, in the case of KBL SCWG the test was interrupted at 600 °C because of salt deposits and consequent clogging in the entrance of the reactor. The LabView software showed particularly rapid pressure drops which were not addressed to technical problems in the layout. However, the recording of the pressure drop was only the final symptom of this occurrence. The saline content in the investigated inlet KBL also suggested the need of a pre-treatment for the removal of the inlet salts in the case where a non-catalytic reactor would be used.

Effect of chemical pretreatment on pulp and paper characteristics of bamboo gigantochloa scorthechinii kraft fibers

In chemical pulping process, lignin is targeted to be dissolved and eliminated as much as possible in order to obtain better fiber separation. A primary study was carried out to investigate the effect of sodium hydroxide pretreatment prior to bamboo chemical pulping. The selected bamboo species was Gigantochloa scortechinii which is a well-known bamboo in Malaysia. The bamboo chips were soaked in 2 % sodium hydroxide solution for 6 hours at 60 °C. These treated chips were cooked at 14 % and 18 % of alkali active via kraft pulping process. The unbleached pulp was obtained and made into paper. The pulp and paper were tested according to pulp yield, pulp freeness, paper optical, paper physical and paper mechanical properties. The results exhibited that by using treated bamboo chips, the value of pulp yield, freeness and paper brightness increasing. Slight decrement was observed for mechanical paper properties such as tensile, tear and burst strength. Chemical pretreatment prior to pulping process was investigated to offer significant effects to the pulp and paper properties of bamboo Gigantochloa scortechinii. Hence, mild kraft pulping can be carried out to produce bamboo unbleached pulps. In addition, dependency on bleaching sequences can also be declined.

The use of a pilot-scale continuous paper process for fire retardant cellulose-kaolinite nanocomposites

Nanostructured materials are difficult to prepare rapidly and at large scale. Melt-processed polymer-clay nanocomposites are an exception, but the clay content is typically below 5 wt%. An approach for manufacturing of microfibrillated cellulose (MFC)/kaolinite nanocomposites is here demonstrated in pilot-scale by continuous production of hybrid nanopaper structures with thickness of around 100 μm. The colloidal nature of MFC suspensions disintegrated from chemical wood fiber pulp offers the possibility to add kaolinite clay platelet particles of nanoscale thickness. For initial lab scale optimization purposes, nanocomposite processing (dewatering, small particle retention etc) and characterization (mechanical properties, density etc) were investigated using a sheet former (Rapid Köthen). This was followed by a continuous fabrication of composite paper structures using a pilot-scale web former. Nanocomposite morphology was assessed by scanning electron microscopy (SEM). Mechanical properties were measured in uniaxial tension. The fire retardancy was evaluated by cone calorimetry. Inorganic hybrid composites with high content of in-plane oriented nanocellulose, nanoclay and wood fibers were successfully produced at pilot scale. Potential applications include fire retardant paperboard for semi structural applications and as reinforcement mats in molded thermoset biocomposites.

THE PAPER CHARACTERISTICS FROM COMBINATION OF RICE HUSKS AND EMPTY FRUIT BUNCHES

Abstract- Rice husk and empty fruit bunches are agricultural and plantation wastes which have fiber cellulose and hemicellulose, it can be converted to pulp and paper. This research aims to study the effect of NaOH concentration (2, 4, 6 and 8% w/v) and raw material composition to pulp yield and to study characteristics of the paper combination of rice husk and empty fruit bunches using soda process based on SEM and XRD analysis. This research using soda process because it is suitable for non-wood raw materials, low cost operations and not use sulfur compounds. Dry raw materials are mixed with NaOH and digesting using autoclave (100°C, 1 atm) for 60 minutes. NaOH concentration optimum used in the pulping process a combination rice husk and empty fruit bunches (1:3, 1:2, 1:1, 2:1 and 3:1) and then cooled for 30 minutes. Pulp is bleached with NaClO 5.25% (v / v), then formed and dried as paper. The lowest pulp yield obtained in a ratio of 2: 1 is 27.6%. Based on the observation of SEM known the fiber of rice husk and empty fruit bunches is 5.88 to 9.8 μm and 8.82 to 14.71 μm, while based on XRD observations, chemical treatment can improve the characteristic of peak intensity on paper combination. The highest advances of peak intensity in the 1:3 ratio is 71.28% (cellulose I) dan 83.33% (cellulose II). Keywords: rice husk, empty fruit bunches, chemical pulping, soda process

Understanding the Effect of Machine Technology and Cellulosic Fibers on Tissue Properties – A Review

Hygiene tissue paper properties are a function of fiber type, chemical additives, and machine technology. This review presents a comprehensive and systematic discussion about the effects of the type of fiber and machine technology on tissue properties. Advanced technologies, such as through-air drying, produce tissue with high bulk, softness, and absorbency. Conventional technologies, where wet pressing is used to partially dewater the paper web, produces tissue with higher density, lower absorbency, and softness. Different fiber types coming from various pulping and recycling processes are used for tissue manufacturing. Softwoods are mainly used as a source of reinforcement, while hardwoods provide softness and a velvet type surface feel. Non-wood biomass may have properties similar to hardwoods and/or softwoods, depending on the species. Mechanical pulps having stiffer fibers result in bulkier papers. Chemical pulps have flexible fibers resulting in better bonding ability and softness. Virgin fibers are more flexible and produce stronger and softer tissue. Recycled fibers are stiffer with lower bonding ability, yielding products that are weaker and less soft. Mild mechanical refining is used to improve limitations found in recycled fibers and to develop properties in virgin fibers. At the same time that refining increases strength, it also decreases bulk and water absorbency.

Key mechanisms controlling internal curing performance of natural fibers

Since the physical and chemical characteristics of wood pulps are complex, their behaviors in a cementitious matrix are difficult to capture by conventional techniques. Here, in situ NMR/MRI along with isothermal calorimetry and surface characterization methods are used to obtain new insights into the internal curing mechanisms of hardwood pulp-cement composites. It found that eucalyptus pulps release free water in their lumen structure within 25 h of hydration. Beyond 25 h, mostly free water in small cell wall pores and bound water in the cell wall are responsible for mitigation of the ongoing self-desiccation during continued cement hydration. Sorption results suggest that chemical wood pulps behave like a semi-permeable membrane, in which the greatest binding occurs for the most abundant cation. Surface analysis reveals discrete precipitates on the pulp surface, suggesting that it may facilitate nucleation of hydration products.

Mechanical properties of gamma‐irradiated EPDM/Waste newsprint microfibers composites treated using acrylic styrene emulsion as a coupling agent

This study investigated the effect of gamma radiation and acrylic styrene emulsion as a coupling agent on mechanical properties of the ethylene propylene diene monomer (EPDM)/newsprint microfibers composite. The recycled newsprint paper was subjected to chemical pulping and the resulted micro fibers treated by using a different ratio of acrylic styrene emulsion (5, 10, and 15 wt% to the microfibers) before mixing with EPDM rubber matrix. The effect of the treated microfibers concentration, namely, 5 up to 50 phr (part per hundred part of rubber) and the effect of different doses of gamma radiation on the mechanical properties of the EPDM/newsprint microfibers composites was investigated. The newsprint microfibers structure and EPDM/treated microfibers composite were investigated using X‐ray diffraction and FTIR analysis. The results indicated that bonding had occurred between the treated microfibers and EPDM polymer matrix. EPDM/untreated newsprint microfibers composites have achieved higher mechanical properties than EPDM matrix up to 10 phr microfibers concentration and up to 60 kGy. Meanwhile, treatment of the newsprint microfibers by using acrylic styrene emulsion leads to improve mechanical properties of EPDM/treated microfibers composites higher than that of the EPDM/untreated fibers composites. Newsprint microfibers treated using 10% acrylic styrene and gamma irradiated at 60 kGy, was found to maintain a higher tensile strength, modulus of 100% strain and toughness. POLYM. COMPOS., 40:1209–1227, 2019. © 2018 Society of Plastics Engineers

APPLICATION OF TITANYL SULPHATE FOR MANUFACTURING PAPER CONTAINING TIO2 FILLER

The aim of research was first, to study the interactions between components for finding out how pH effects on ζ-potential, dewatering rate and retention of TiO2/MCC mixtures with/without titanyl sulphate in order to find a way to titanyl sulphate hydrolysis in a papermaking process. The maximum heterocoagulation interactions between TiO2, MCC and TiOSO4 were revealed in the pH range 4.4–5.6. Second, handsheets made from refined chemical pulp, titanyl sulphate and TiO2 at pH 4.4 were investigated. The handsheets were formed and studied conventionally and with scanning electron microscopy (SEM). It was shown that titanyl sulphate hydrolysis leads to formation of translucent polymer film covering the fibres and TiO2 particles. The maximum first-pass ash retention reached is lower than its values usually obtained with an organic polymer. Addition of titanyl sulphate led to higher strength, but lowered opacity and brightness compared to a reference sample. The use of low dosage of titanyl sulphate together with a filler improved air permeability. As there exist certain advantages/disadvantages of titanyl sulphate application, extended research is needed to find suitable conditions for its applying to mass paper and board grades production.

A comparable study on the hot-water treatment of wheat straw and okra stalk prior to delignification

Wheat straw and okra stalk were studied to evaluate their potential use for integrated lignocellulosic biorefining. Besides chemical pulp, a wide spectrum of value-added by-products were prepared by hot-water extraction of the feedstocks under varying conditions (140 °C for 60 and 240 min and 150 °C for 25 and 100 min) prior to sulfur-free soda-anthraquinone (AQ) pulping (NaOH charge 15 and 20% by weight on o.d. feedstock for wheat straw and okra stalk, respectively, with an AQ charge of 0.05% by weight on o.d. for both feedstocks). During the hot-water pre-treatment, the most significant mass removal, respectively, 12% (w/w) and 23% (w/w) of the initial wheat straw and okra stalk was obtained at 150 °C with a treatment time of 100 min. The hydrolysates were characterized in terms of pH and the content of carbohydrates (6–20% (w/w) of the initial amount), volatile acids (acetic and formic acids), and furans. The pre-treatment stage also facilitated the delignification stage, and, for example, the pulp yields (w/w), 57% (145 °C, 15 min, and kappa number 18) and 41% (165 °C, 180 min, and kappa number 32) were obtained for the pre-treated (150 °C, P200) wheat straw and okra stalk, respectively. Results clearly indicated that both non-wood materials were suitable for this kind of biorefining approach.

Impact of thermal pretreatment and MSW origin on composition and hydrolysability in a sugar platform biorefinery

Municipal solid waste (MSW) is a widely available large volume source of lignocellulosic material containing a waste paper/cardboard mixture which can be converted into fermentable sugars via cellulolytic enzyme hydrolysis in a sugar platform biorefinery. Thermal pretreatments are generally applied to MSW to facilitate the extraction of the lignocellulosic material from recyclable materials (plastics, metals etc.) and improve the paper pulp conversion to sugars. Applying high temperature might enhance food waste solubilisation but may collapse cellulose fibre decreasing its hydrolysability. Low temperature pre-treatment will reduce the energy demand but might result in highly contaminated pulp. Preliminary results showed that the enzymatic hydrolysis performances were dependent on the MSW origins. Using 8 different samples, the impact of thermal pretreatment and MSW origin on pulp composition and hydrolysability was assessed in this work. Low pre-treatment temperature produced pulp which contained less lignocellulosic material but which hydrolysed to a higher degree than MSW treated at high temperatures. High temperature pre-treatment could have exposed more of the inhibiting lignin to cellulase. This information would have a significant economic impact on a commercial plant as expensive autoclave could be advantageously replaced by a cheaper process. Glucan conversions were also found to vary depending on the region, the recycling rate possibly because of the lower recycling rate resulting in the use of less paper additive in the material or the difference in paper production technology (chemical VS mechanical pulping). This could also be explained by the differences in paper composition.

Production and Characterization of Cellulose Nanofibrils from Different Chemical and Mechanical Pulps

In this study, mechanical fibrillation for the production of cellulose nanofibrils (CNF) from chemical and mechanical pulps with different chemical compositions was studied. To investigate the effect of nanofibrillation on wood pulps by the grinder, the nanofibrils obtained from grinded pulp were characterized with morphology, particle size distribution, apparent viscosity in aqueous solution, degree of crystallinity, and water retention capacity. The results showed that the low lignin-containing unbleached kraft pulp (UKP) exhibited good performance for fibrillation, resulting in CNF with high viscosity, high water retention value, and small particle size. However, the fibrillation of high lignin-containing chemi-thermomechanical pulp was the most inefficient which resulted in heterogeneous materials with relatively low viscosity, low water retention value, and large particle size compared to chemical pulps. Furthermore, bleached softwood pulp from radiata pine was found to be much faster and for easier fibrillation compared to the bleached hardwood pulp from acacia due to the more rigid structure of hardwood fibers.

Effect of wet storage on alkali-oxygen pulping of bagasse

Carbohydrate degradation is a serious problem in alkali-oxygen pulping due to the inherently oxidative reaction conditions. Hemicellulose and short-chain cellulose are particularly susceptible to degradation by oxidation, and thus have a great effect on the pulping yield, as well as the viscosity and crystallinity of resultant pulp in alkali-oxygen pulping. Removal of the low molecular weight substances by wet storage prior to alkali-oxygen pulping may increase the pulping yield and improve pulp properties, in addition to savings in pulping chemicals and energy. This paper investigated alkali-oxygen pulping of bagasse pretreated by wet storage, and results show that wet storage of bagasse had a significant effect on its alkali-oxygen pulping, in terms of pulping yield, pulp viscosity and crystallinity. The pH and time were found to be the two most important factors in wet storage on bagasse. Pulp crystallinity increased from 31.78% to 42.06% when the wet storage of bagasse was performed at pH 6.0 for 16 days. In addition, the screened pulp yield increased from 58 to 60%, and pulp viscosity increased from 650 to 700 mL/g. The improved pulping performance was attributed to increased pore volumes in bagasse due to dissolution of low molecular weight lignin and carbohydrates during wet storage, which in turn improved the selectivity of delignification in the alkali-oxygen pulping process.

Effect of retention rate of fluorescent cellulose nanofibrils on paper properties and structure

In this work, we report a new characterization method using fluorescent cellulose nanofibrils to analyze retention and loss rates in the papermaking process. Cellulose nanofibrils (CNF) were isolated from chemical pulp by enzymatic pretreatment and used as a strengthening additive in sheet forming. The aim of this paper was to investigate its effects on flocculation, retention and loss rate and the physical and mechanical properties. CNF was subjected to fluorescent labeling with RBITC (Rhodamine B isothiocyanate), and the retention of fluorescent cellulose nanofibrils (FCNF) was analyzed by elemental analysis and fluorescence intensity. The retention and loss rate of the FCNF decreased with increasing the addition of FCNF. Laser Confocal Scanning Microscopy (LCSM) and Scanning Electron Microscope (SEM) images confirmed that FCNF can be evenly distributed in the paper. A thorough investigation of the relation between the retention rate and papersheet performance was conducted.

Potential of all‐cellulose composites in corrugated board applications: Comparison of chemical pulp raw materials

All‐cellulose composites (ACCs) were produced using various commercially available chemical pulps by partial dissolution method using an aqueous zinc chloride (ZnCl2) solvent. Characterization methods used for defining material performance, keeping especially corrugated board products in mind, were as follows: scanning electron microscopy, tensile strength, 2‐point bending stiffness, concora medium test, and short‐span crush test. Hardwood (bleached eucalyptus), softwood (bleached spruce, bleached and unbleached pine), speciality softwood pulps (sulphite dissolving with 530 and 398 mL/g intrinsic viscosities), and annual plant pulp (bleached abaca) were investigated to give a broad overview of the potential for making ACCs. Softwood pulps, especially bleached, showed highest increase in mechanical properties across the board. Hardwood pulp showed relatively good results, and the selected annual plant pulp (abaca) responded partially negatively to treatment. Comparing unbleached and bleached softwood ACCs, it seems that bleaching is beneficial for tensile properties. However, when material comes under compressive or bending loads, unbleached pulp performs very well. Comparing sulphite dissolved pulps, it could be proven that pulps with higher intrinsic viscosities, thus higher polymerization grade, respond better to partial dissolution. It was proven that a wide set of pulps, also of lesser cellulose purity, used in the paper industry are viable for ACC production. Furthermore, results from short‐span crush test and concora medium tests show high potential of ACCs for corrugated board applications.

Competitividade das exportações dos principais produtos do agronegócio no nordeste brasileiro.

This study evaluates the export value competitiveness of chemical wood, soda or sulphate pulp (other than non-coniferous dissolving, semi-bleached or bleached pulp); broken or unbroken soybean (other than for sowing); other sugarcane sugars; cotton; bagasse and other solid residues from soybean oil extraction as well as hides from Northeastern Brazil from 2002 to 2016. We used the following indicators: Balassa’s revealed comparative advantage index, Vollrath’s symmetric index of revealed competitiveness and the normalized revealed comparative advantage index. Data were extracted from the Brazilian foreign trade (COMEX STAT) database of the Ministry of Development, Industry and Foreign Trade (MDIC). The results indicated that the six analyzed commodities exported by Brazil’s Northeastern region —mainly by the states of Ceará, Rio Grande do Norte, Pernambuco and Bahia — had a comparative advantage over the other states of Brazil, with the exception of bagasse and other solid residues, and the best performance was by chemical wood pulp and cotton.

ENVIRONMENTALLY FRIENDLY CELLULOSIC FIBERS FROM CORN STALKS

One of the main causes of global climate change is deforestation. Wood is largely used in construction, furniture, and pulp and paper industries, which consume hundred of millions of cubic meter of wood year by year. Forest surfaces decrease rapidly at global level and this reality is of crucial importance for world global ecological footprint. Shortage of pulpwood for paper industry became a great challenge and, for this reason, other raw materials must be taken into consideration. Recovered paper is the most important raw material for paper industry, but low paper grades can be produced only. Collection rate of recovered paper is high in most countries and there are no additional quantities to assure the large requirements of the paper industry. Today, nonwood plants are considered more and more important raw material for this industry. Wheat and rice straws are used for decades to produce chemical pulp in many Asian and European countries. This paper investigates the possibility of replacing pulpwood with corn stalks as raw material in producing chemical pulp for paper. Corn stalks are abundant agricultural waste in Romania, since more than 12 million tones of stalks were generated in 2017. It was found that corn stalks contain less lignin than wood and can be delignified using less chemicals, at lower temperatures and in shorter time. Moreover, corn stalks can be processed using ordinary reagents like sodium hydroxide, and pulps with different yields and lignin content can result. Natron pulping of corn stalks offers pulps with reasonable strength properties which can replace wood pulp in obtaining papers for corrugated board.

A Microscopic Study of Paper Decayed by Trichoderma harzianum and Paecilomyces variotii

The current study is interested in evaluating the decay of cotton, Whatman and chemical pulp caused by Trichoderma harzianum and Paecilomyces variotii. The structural changes of the paper were evaluated by Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). The SEM results show differences in hyphae colonization and paper decay patterns between studied species under the current study; P. variotii caused an eroded structure in the cotton (cavity forming), whereas the initial T. harzianum colonization produced rupture and erosion (soft-rot decay type II) for the three types of paper ,the gaps were elongated with sharp pointed ends, which consisted either of individual cavities or in chains. Moreover, FTIR results confirmed that there a relationship could be observed between fungal decay and crystalline cellulose content because the intensity of peaks at 1335 and 1111 cm−1 significantly decreased due to the fungal decay. Furthermore, the intensity of O–H stretching absorption slightly decreased, and this may be attributed to hydrolysis of cellulose molecules.