Kloce Dongfang Li

Fatty foods are very susceptible to lipid oxidation caused by oxygen and light. To minimize this issue, active bioplastic materials are suitable for food packaging. In this work, the feasibility of blending locust bean milling derived dust (LBMD) with potato starch to develop heat-sealable bioplastic films for packaging sliced cheese and oat cookies was studied. Blending LBMD with starch allowed to obtain bioplastic films 2-fold more rigid (Young's modulus of ca. 48 MPa) and 1.3-fold more… Vis mer

Fatty foods are very susceptible to lipid oxidation caused by oxygen and light. To minimize this issue, active bioplastic materials are suitable for food packaging. In this work, the feasibility of blending locust bean milling derived dust (LBMD) with potato starch to develop heat-sealable bioplastic films for packaging sliced cheese and oat cookies was studied. Blending LBMD with starch allowed to obtain bioplastic films 2-fold more rigid (Young's modulus of ca. 48 MPa) and 1.3-fold more resistant to water (water contact angle of ca. 87°) than LBMD-based films (Young's modulus of ca. 12 MPa and water contact angle of ca. 47°), maintaining their UV protective capacity. LBMD/starch-based bioplastic films were used to pack cheese, with no molds or yeasts grown after 21 days, similar to petroleum-based plastic packages used as reference. Despite cheese dehydration (ca. 10% weight loss), its texture did not significantly change after the storage period. An increase (ca. 43%) in volatile compounds derived from cheese oxidation was observed after 7 days of storage. When used to pack oat cookies, LBMD/starch-based bioplastic films played an active role in decreasing oxidation-derived volatile compounds after 21 days of storage, maintaining their textural properties, when compared to oat cookies packaged with petroleum-based plastic. Therefore, blending LBMD with starch revealed to be a proper strategy to develop heat-sealable and active bioplastic films with water absorption, protection against UV radiation, volatile compounds scavenging capacity, and antioxidant activity suitable to preserve fatty foodstuffs while providing them new characteristics. Vis mindre

Nanocelluloses and cellulose nanomaterials derived from natural resources are a group of ideal platform materials for advanced applications. However, their synthesis through sustainable and facile processes to achieve the required properties are still challenging. Here, we prepare the nanocellulose oxalate (n-COX) from cotton with outstanding physicochemical properties by defining the optimal oxalic acid pretreatment conditions. Thus-obtained n-COX with unique 1D nanofiber shape as a platform… Vis mer

Nanocelluloses and cellulose nanomaterials derived from natural resources are a group of ideal platform materials for advanced applications. However, their synthesis through sustainable and facile processes to achieve the required properties are still challenging. Here, we prepare the nanocellulose oxalate (n-COX) from cotton with outstanding physicochemical properties by defining the optimal oxalic acid pretreatment conditions. Thus-obtained n-COX with unique 1D nanofiber shape as a platform material is further processed to various high-performance multidimensional bio-nanomaterials through several simple yet effective strategies. First, 2D n-COX films prepared through a casting-drying method show comparable or even better transparency and tensile strength than those made from other types of nanocelluloses. Second, 3D n-COX hydrogels/aerogels fabricated by a molding-crosslinking approach demonstrate good shape stability, well-preserved nanoporous networks, and qualified mechanical properties. Third, n-COX-derived bioinks display improved printability and fidelity, resulting in better size-preserving and shape-control of the 3D-bioprinted scaffolds. We expect this work could offer new insights on engineering natural cellulose and using n-COX as a platform material for further advanced fabrication, and thus, open up application potentials of this new nanocellulose. Vis mindre

It is common practice to use cellulose as reinforcement and fatty acid as compatibilizer in the preparation of polymeric composites. However, the used catalysts (e.g., pyridine) are usually toxic and should be avoided. In this study, a new type of microcellulose – cellulose oxalate (COX) was chosen as reinforcement to be reacted with oleic acid to prepare hydrophobic fillers in a catalyst-free esterification for different times. For comparison, microcrystalline cellulose (MCC) was also… Vis mer

It is common practice to use cellulose as reinforcement and fatty acid as compatibilizer in the preparation of polymeric composites. However, the used catalysts (e.g., pyridine) are usually toxic and should be avoided. In this study, a new type of microcellulose – cellulose oxalate (COX) was chosen as reinforcement to be reacted with oleic acid to prepare hydrophobic fillers in a catalyst-free esterification for different times. For comparison, microcrystalline cellulose (MCC) was also selected. The success of esterification of COX and oleic acid was confirmed but little esterification occurred when MCC was used. After reacting COX with oleic acid for 18 and 48 h, the products showed stable water contact angles of about 130°. Composites of polypropylene with COX or MCC were prepared. Tensile tests showed that for a given reaction time, the COX-based composites exhibited higher values of both Young’s modulus and tensile strength than those of MCC-based composites. Vis mindre

Micro-sized cellulosic materials are promising reinforcements for thermoplastic composites. In this study, a new type of microcellulose – cellulose oxalate (COX) was used as reinforcement for polypropylene-based composites and its reinforcing effect was evaluated. COX and microcrystalline cellulose (MCC), which was used for comparison, were subjected to ball milling process for different times to obtain milled cellulose powders. Ternary composites consisting of 60 wt% polypropylene (PP) as the… Vis mer

Micro-sized cellulosic materials are promising reinforcements for thermoplastic composites. In this study, a new type of microcellulose – cellulose oxalate (COX) was used as reinforcement for polypropylene-based composites and its reinforcing effect was evaluated. COX and microcrystalline cellulose (MCC), which was used for comparison, were subjected to ball milling process for different times to obtain milled cellulose powders. Ternary composites consisting of 60 wt% polypropylene (PP) as the matrix, 10 wt% maleic anhydride grafted polypropylene (MAPP) as the coupling agent and 30 wt% milled or non-milled cellulose powder as reinforcement were prepared by melt-extrusion and injection molding. Tensile test results showed that 1h milled COX-containing composite exhibited the best tensile properties (e.g., tensile strength and Young’s modulus are 16.1% and 106.0% respectively higher than those of neat PP) and MCC generally exhibited a poorer reinforcing effect than COX with same milling time. Vis mindre

To graft epoxy and ester functional groups onto cellulose nanofibrils (CNFs) and to overcome their poor hydrophobicity, we studied the modification of CNFs using graft copolymerization with glycidyl methacrylate (GMA) by a Fe2+–thiourea dioxide–H2O2 initiator system (Fe2+–TD–H2O2) in aqueous solution. The synthesized poly (GMA)-grafted CNF (CNF-g-PGMA) was characterized by FTIR, AFM, XRD, water contact angle, and TGA. GMA was successfully grafted onto the CNFs by Fe2+–TD–H2O2, the epoxy groups… Vis mer

To graft epoxy and ester functional groups onto cellulose nanofibrils (CNFs) and to overcome their poor hydrophobicity, we studied the modification of CNFs using graft copolymerization with glycidyl methacrylate (GMA) by a Fe2+–thiourea dioxide–H2O2 initiator system (Fe2+–TD–H2O2) in aqueous solution. The synthesized poly (GMA)-grafted CNF (CNF-g-PGMA) was characterized by FTIR, AFM, XRD, water contact angle, and TGA. GMA was successfully grafted onto the CNFs by Fe2+–TD–H2O2, the epoxy groups and ester groups of GMA were clearly present and intact in the CNF-g-PGMA, and TD is an important component of the initiator system under relatively mild graft conditions. CNF-g-PGMA may be an important intermediate because of its epoxy and ester functional groups. The main nanostructure of the CNFs was retained after graft copolymerization, and there were no obvious effects of graft copolymerization on the crystalline structure of the CNF backbone, although the crystalline index slightly decreased with the increased percentage of grafting. Graft copolymerization significantly modifies the CNF hydrophobicity. This strategy could extend the applications of CNFs into many areas. Vis mindre

Sustainable thermal insulating materials produced from cellulosic fibers provide a viable alternative to plastic insulation foams. Industrially available, abundant, and inexpensive mechanical pulp fiber and recycled textile fiber provide potential raw materials to produce thermal insulating materials. To improve the fire retardancy of low-density thermal insulating materials produced from recycled cotton denim and mechanical pulp fibers, bio-based fire retardants, such as sulfonated kraft… Vis mer

Sustainable thermal insulating materials produced from cellulosic fibers provide a viable alternative to plastic insulation foams. Industrially available, abundant, and inexpensive mechanical pulp fiber and recycled textile fiber provide potential raw materials to produce thermal insulating materials. To improve the fire retardancy of low-density thermal insulating materials produced from recycled cotton denim and mechanical pulp fibers, bio-based fire retardants, such as sulfonated kraft lignin, kraft lignin, and nanoclays, were coated onto sustainable insulating material surfaces to enhance their fire retardancy. Microfibrillated cellulose was used as a bio-based binder in the coating formula to disperse and bond the fire-retardant particles to the underlying thermal insulating materials. The flammability of the coated thermal insulating materials was tested using a single-flame source test and cone calorimetry. The results showed that sulfonated kraft lignin-coated cellulosic thermal insulating materials had a better fire retardancy compared with that for kraft lignin with a coating weight of 0.8 kg/m2. Nanoclay-coated samples had the best fire retardancy and did not ignite under a heat flux of 25 kW/m2, as shown by cone calorimetry and single-flame source tests, respectively. These cost-efficient and bio-based fire retardants have broad applications for improving fire retardancy of sustainable thermal insulating materials. Vis mindre

Nanocellulose prepared from cellulose oxalate has been discussed as an alternative to other methods to prepare cellulose nanofibrils or crystals. The current work describes the use of a bulk reaction between pulp and oxalic acid dihydrate to prepare cellulose oxalate followed by homogenization to produce nanocellulose. The prepared nanocellulose is on average 350 nm long and 3-4 nm wide, with particles of size and shape similar to both cellulose nanofibrils and cellulose nanocrystals. Films… Vis mer

Nanocellulose prepared from cellulose oxalate has been discussed as an alternative to other methods to prepare cellulose nanofibrils or crystals. The current work describes the use of a bulk reaction between pulp and oxalic acid dihydrate to prepare cellulose oxalate followed by homogenization to produce nanocellulose. The prepared nanocellulose is on average 350 nm long and 3-4 nm wide, with particles of size and shape similar to both cellulose nanofibrils and cellulose nanocrystals. Films prepared from this nanocellulose have a maximum tensile stress of 140-200 MPa, strain at break between 3 % and 5 %, and oxygen permeability in the range of 0.3-0.5 cm3 µm m-2 day-1 kPa-1 at 50 % relative humidity. The presented results illustrate that cellulose oxalates may be a low-cost method to prepare nanocellulose with properties reminiscent of those of both cellulose nanofibrils and cellulose nanocrystals, which may open up new application areas for cellulose nanomaterials. Vis mindre

Betulin, a natural compound extractable from the outer bark of birch, can be used to improve the properties of cellulosic textile fibres. Herein, oxidation was performed to prepare carboxyl-functionalized cellulose, which was subsequently covalently attached by betulin through esterification. The surface-modified cellulosic textile fibres showed a substantially improved hydrophobicity, as indicated by a water contact angle of 136°. Moreover, the material showed excellent antibacterial… Vis mer

Betulin, a natural compound extractable from the outer bark of birch, can be used to improve the properties of cellulosic textile fibres. Herein, oxidation was performed to prepare carboxyl-functionalized cellulose, which was subsequently covalently attached by betulin through esterification. The surface-modified cellulosic textile fibres showed a substantially improved hydrophobicity, as indicated by a water contact angle of 136°. Moreover, the material showed excellent antibacterial properties, as indicated by over 99% bacterial removal and growth inhibition, in both Gram-positive and Gram-negative bacterial assays. The method of surface-modification of the cellulosic materials adapted in this study is simple and, to the best of our knowledge, has not been carried out before. The results of this study prove that betulin, a side-stream product produced by forest industry, could be used in value-added applications, such as for preparing functional materials. Additionally, this modification route can be envisaged to be applied to other cellulose sources (e.g., microfibrillated cellulose) to achieve the goal of functionalization. Vis mindre

The mechanism and kinetics of thermal degradation of materials developed from cellulose fiber and synergetic fire retardant or expandable graphite have been investigated using thermogravimetric analysis. The model-free methods such as Kissinger–Akahira–Sunose (KAS), Friedman, and Flynn–Wall–Ozawa (FWO) were applied to measure apparent activation energy (Eα). The increased Eα indicated a greater thermal stability because of the formation of a thermally stable char, and the decreased Eα after the… Vis mer

The mechanism and kinetics of thermal degradation of materials developed from cellulose fiber and synergetic fire retardant or expandable graphite have been investigated using thermogravimetric analysis. The model-free methods such as Kissinger–Akahira–Sunose (KAS), Friedman, and Flynn–Wall–Ozawa (FWO) were applied to measure apparent activation energy (Eα). The increased Eα indicated a greater thermal stability because of the formation of a thermally stable char, and the decreased Eα after the increasing region related to the catalytic reaction of the fire retardants, which revealed that the pyrolysis of fire retardant-containing cellulosic materials through more complex and multi-step kinetics. The Friedman method can be considered as the best method to evaluate the Eα of fire-retarded cellulose thermal insulation compared with the KAS and FWO methods. A master-plots method such as the Criado method was used to determine the possible degradation mechanisms. The degradation of cellulose thermal insulation without a fire retardant is governed by a D3 diffusion process when the conversion value is below 0.6, but the materials containing synergetic fire retardant and expandable graphite fire retardant may have a complicated reaction mechanism that fits several proposed theoretical models in different conversion ranges. Gases released during the thermal degradation were identified by pyrolysis–gas chromatography/mass spectrometry. Fire retardants could catalyze the dehydration of cellulosic thermal insulating materials at a lower temperature and facilitate the generation of furfural and levoglucosenone, thus promoting the formation of char. These results provide useful information to understand the pyrolysis and fire retardancy mechanism of fire-retarded cellulose thermal insulation. Vis mindre

Betulin is a naturally abundant and hydrophobic compound in the outer bark of birch and can readily be obtained by solvent extraction. Here, solutions of betulin were used to treat cotton fabrics and improve their water repellency. Cotton fabric impregnated in a solution of betulin in ethanol showed a contact angle for water of approximately 153° and reached a water repellency score of 70 according to a standard water repellency test method. A betulin-terephthaloyl chloride (TPC) copolymer was… Vis mer

Betulin is a naturally abundant and hydrophobic compound in the outer bark of birch and can readily be obtained by solvent extraction. Here, solutions of betulin were used to treat cotton fabrics and improve their water repellency. Cotton fabric impregnated in a solution of betulin in ethanol showed a contact angle for water of approximately 153° and reached a water repellency score of 70 according to a standard water repellency test method. A betulin-terephthaloyl chloride (TPC) copolymer was synthesized. Both betulin and betulin-TPC copolymer were characterized by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The copolymer was characterized by size exclusion chromatography and differential scanning calorimetry. When impregnated with a solution of betulin-TPC copolymer in tetrahydrofuran, a cotton fabric showed a water contact angle of 151° and also reached a water repellency score of 70. Films based on betulin and betulin-TPC copolymer were prepared and coated onto the surface of the fabrics by compression molding. These coated fabrics showed water contact angles of 123° and 104° respectively and each reached a water repellency score of 80. Vis mindre

The development of thermal insulation materials from sustainable, natural fibrous materials is desirable. In the present study, cellulose fiber based insulation foams made of bleached chemi thermo mechanical pulp (CTMP) have been investigated. To improve water resistance, the foams were impregnated with hydrophobic extractives from the outer bark of birch (Betula verrucosa) and dried. The surface morphology of the foams and the distribution of the deposited particles from the extractives were… Vis mer

The development of thermal insulation materials from sustainable, natural fibrous materials is desirable. In the present study, cellulose fiber based insulation foams made of bleached chemi thermo mechanical pulp (CTMP) have been investigated. To improve water resistance, the foams were impregnated with hydrophobic extractives from the outer bark of birch (Betula verrucosa) and dried. The surface morphology of the foams and the distribution of the deposited particles from the extractives were observed by scanning electron microscopy (SEM). The modified foams showed improved water resistance, as they did not disintegrate after immersion in water for 7 days, whereas the unmodified foam did. Compared to the unmodified foam, the modified foams absorbed 50% less moisture within 24 h. The modification had no negative effects on the thermal insulation properties, fungal resistance or compressive strength of the foams. The proposed approach is simple and can be easily integrated into plants working based on the biorefinery concept. Vis mindre

The poor reaction-to-fire properties of cellulosic thermal insulation need to be improved to meet the safety regulations for building materials. In this study, cellulose-fiber-based insulation foams were prepared from formulations containing mechanical pulp and commercial fire retardants. Results of single-flame source tests showed that foams developed from the formulations with 20% expandable graphite (EG) or 25% synergetic (SY) fire retardants had substantially improved reaction-to-fire… Vis mer

The poor reaction-to-fire properties of cellulosic thermal insulation need to be improved to meet the safety regulations for building materials. In this study, cellulose-fiber-based insulation foams were prepared from formulations containing mechanical pulp and commercial fire retardants. Results of single-flame source tests showed that foams developed from the formulations with 20% expandable graphite (EG) or 25% synergetic (SY) fire retardants had substantially improved reaction-to-fire properties, and passed fire class E according to EN 13501-1. The results indicated that the foams could resist a small flame attack without serious flame spreading over a short period of time. Compared with the reference foam that contained no fire retardant, the peak heat release rate of the 20% EG and 25% SY foams decreased by 62% and 39% respectively when the samples were subjected to a radiance heat flux of 25 kW m-2 in a cone calorimeter, which suggested enhanced reaction-to-fire properties of these foams. Vis mindre

A one-pot esterification and hydrolysis of cellulose was carried out by treating cellulose fibres with molten oxalic acid dihydrate. Each cellulose oxalate had a free carboxyl content above 1.2 mmol g−1 and an average molecular weight of approximately 40 kDa. Aqueous suspensions of the oxalates were sonicated to prepare cellulose nanocrystals with a gravimetric yield of 80.6%.

A biorefinery of forest resources should be able to convert all components of trees, including the bark and other types of forest residues, into value-added products. Here, non-cellulosic polysaccharides (NCPs) isolated from Norway spruce bark and cellulose nanocrystals (CNCs) isolated from the logging residues of Norway spruce were mixed to prepare nanocomposites with competitive thermo-mechanical properties. Polyepoxy acid (PEA) derived from a monomer of suberin in birch bark was used as a… Vis mer

A biorefinery of forest resources should be able to convert all components of trees, including the bark and other types of forest residues, into value-added products. Here, non-cellulosic polysaccharides (NCPs) isolated from Norway spruce bark and cellulose nanocrystals (CNCs) isolated from the logging residues of Norway spruce were mixed to prepare nanocomposites with competitive thermo-mechanical properties. Polyepoxy acid (PEA) derived from a monomer of suberin in birch bark was used as a coating on the nanocomposites to develop functional materials entirely based on forest resources. All of the PEA-coated nanocomposites were hydrophobic. At 50% and 80% relative humidity, they showed high oxygen-barrier properties that were comparable to or even better than those of some renewable materials such as xylan-, galactoglucomannan- and nanofibrillated cellulose-based films and synthetic materials such as polyvinylidene chloride and polyamide. Vis mindre

Suberin is a natural hydrophobic material that could be used to improve the water repellency of cellulose surfaces. It is also abundant in the outer bark of birch (Betula verrucosa); birch bark is a side-stream product in Scandinavia from the forest industry, which is generally burned for energy production. A suberin monomer, cis-9,10-epoxy-18-hydroxyoctadecanoic acid, was isolated from birch outer bark and polymerized via lipase (immobilized Candida antarctica lipase B). The resulting… Vis mer

Suberin is a natural hydrophobic material that could be used to improve the water repellency of cellulose surfaces. It is also abundant in the outer bark of birch (Betula verrucosa); birch bark is a side-stream product in Scandinavia from the forest industry, which is generally burned for energy production. A suberin monomer, cis-9,10-epoxy-18-hydroxyoctadecanoic acid, was isolated from birch outer bark and polymerized via lipase (immobilized Candida antarctica lipase B). The resulting epoxy-activated polyester was characterized by nuclear magnetic resonance (NMR) imaging, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, and size exclusion chromatography. Then the polyester was cured with tartaric or oxalic acid, and the crosslinked polyesters were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry. Hydrophobic materials were prepared by compression molding of polyester-impregnated cellulose sheets, and the final products were characterized by FTIR, cross-polarization magic angle spinning 13C NMR, and field-emission scanning electron microscopy. The water contact angle was significantly increased from 0° for the original cellulose sheets to over 100° for the produced hydrophobic materials. Vis mindre

The biorefinery concept requires the development of value-added products, such as materials from biomass, including bark. Suberin is the most abundant component in birch (Betula verrucosa) outer bark and acts as a barrier against the penetration of water and external attacks from microorganisms. The aliphatic domain of suberin is rich in hydroxy fatty acids, such as cis-9,10-epoxy-18-hydroxyoctadecanoic acid. In this study, it was isolated from the outer bark of birch and polymerized to prepare… Vis mer

The biorefinery concept requires the development of value-added products, such as materials from biomass, including bark. Suberin is the most abundant component in birch (Betula verrucosa) outer bark and acts as a barrier against the penetration of water and external attacks from microorganisms. The aliphatic domain of suberin is rich in hydroxy fatty acids, such as cis-9,10-epoxy-18-hydroxyoctadecanoic acid. In this study, it was isolated from the outer bark of birch and polymerized to prepare polyepoxy acid (PEA), which was used to impregnate filter papers. After complete drying, PEA-loaded filter papers were placed under UV to crosslink the epoxides through cationic polymerization with a diaryliodonium salt as the photo-initiator. The crosslinking was evaluated using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The materials obtained after UV curing showed substantially increased hydrophobicity, decreased moisture absorption, increased tensile strength, and increased ductility. Field-emission scanning electron microscopy (FE-SEM) showed that the crosslinked PEA covered the surface of the cellulose fibers and filled the interstitial spaces. Vis mindre

Varje år bränns hundratusentals ton björkbark – en sidoström
och biprodukt i skogsindustrin. Barken innehåller dock flera
intressanta substanser och det finns stor potential att använda
barken i ett bioraffanderikoncept. På KTH har jag använt barkkomponenten suberin för att göra
cellulosa vattenavstötande.

Few Scandinavian pulp mills produce dissolving pulps; however, the demand on textile fibers is increasing. This study investigates the chemical interaction of dissolving pulp with ionic liquids (ILs), where softwood and hardwood industrial dissolving pulps were pretreated with ILs 1-butyl-3-methy-limidazolium acetate ([C4mim+]CH3COO-) and 1-butyl-3-methyl-imdazolium chloride ([C4mim+]Cl-). Time and temperature dependence of the dissolution process as well as the impact of the pretreatment on… Vis mer

Few Scandinavian pulp mills produce dissolving pulps; however, the demand on textile fibers is increasing. This study investigates the chemical interaction of dissolving pulp with ionic liquids (ILs), where softwood and hardwood industrial dissolving pulps were pretreated with ILs 1-butyl-3-methy-limidazolium acetate ([C4mim+]CH3COO-) and 1-butyl-3-methyl-imdazolium chloride ([C4mim+]Cl-). Time and temperature dependence of the dissolution process as well as the impact of the pretreatment on the molecular weight properties, thermal stability, morphology, and crystallinity of the cellulose were evaluated by means of size exclusion chromatography (SEC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and solid state nuclear magnetic resonance (NMR). It was shown that the dissolution of cellulosic material in ILs is a temperature-dependent process; however, the viscosity of ILs affected the efficiency of dissolution at a given temperature. Molecular weight properties were affected negatively by increased dissolution temperature, while the type of antisolvent for the regeneration had no major impact on the degree of polymerization of cellulose. Water was more efficient than ethanol for the regeneration of cellulose when performed at an elevated temperature. The pretreatment decreased the crystallinity of cellulosic material. This might lead to the increased accessibility and reactivity of cellulose. Vis mindre

A raw material with high cellulose content and low content of hemicelluloses, residual lignin, extractives and minerals is required for many important applications in the pharmaceutical, textile, food and paint industries i.e. cotton and dissolving grade pulp are used. However, the high costs for the production of dissolving grade pulps has triggered interest in upgrading paper-grade pulps into dissolving pulps by selective removal of hemicelluloses and subsequent activation of the pulps. This… Vis mer

A raw material with high cellulose content and low content of hemicelluloses, residual lignin, extractives and minerals is required for many important applications in the pharmaceutical, textile, food and paint industries i.e. cotton and dissolving grade pulp are used. However, the high costs for the production of dissolving grade pulps has triggered interest in upgrading paper-grade pulps into dissolving pulps by selective removal of hemicelluloses and subsequent activation of the pulps. This study reports the feasibility to produce dissolving grade pulps from different wood and non-wood paper-grade pulps employing enzymatic and chemical pre-treatments. The results were compared to those of commercial bleached dissolving pulps. Vis mindre