Improved enzymatic hydrolysis of waste paper by ozone pretreatment

Waste paper samples made from newsprint, copier paper, and magazine paper, as well as samples of kraft pulp and thermomechanical pulp, were pretreated with ozone to improve enzymatic hydrolysis. The ozone treatment of pulps of newsprint and of magazine paper increased the specific surface areas and total pore volumes while decreasing the lignin content so that these values became similar to those of thermomechanical pulps. These morphological and chemical changes in the pulps resulted in the increased access of cellulase to the pulp fiber surface and increased enzymatic hydrolysis. For copier paper, in which the lignin content was very low, additives on the pulp fiber surface were oxidized and removed by ozone treatment and extraction, and this allowed improved enzymatic hydrolysis. In contrast, surface areas and total pore volumes of kraft pulp and bleached kraft pulp were decreased by the ozone treatment, resulting in morphological changes in the pulps that decreased enzymatic hydrolysis.     

Cellulose–Polymer Based Green Composite Fibers by Electrospinning

Green composite fibers (339?C612?nm in diameter) have been developed from wood pulp, acetylated wood pulp and polyethylene oxide under various concentrations by electrospinning process. A polymer solution concentration of 7 wt% with 5 wt% wood pulp have been found to produce uniform composite fibers. Scanning electron microscopy micro-images demonstrated that composite fibers diameter and morphology depended on the processing parameters, such as solution concentration and molecular weight of polymer. Transmission electron microscopy and laser confocal microscopy observations indicated that the acetylated wood was well dispersed and oriented along the length of composite fibers axis. X-ray diffraction studies revealed that the structure of electrospun composite fibers became more non-crystalline.     

Effect of some environmentally degradable materials on the pyrolysis of plastics II: influence of cellulose and lignin on the pyrolysis of complex mixtures

Pyrolysis of polymer mixtures with a composition similar to that of municipal plastic waste containing polyvinyl chloride (PVC) and of municipal plastic waste free of PVC was performed in the presence of components of biomass, namely lignin, cellulose, or both. The pyrolysis products were characterized by standard methods utilized in the petrochemical industry, i.e., paraffins-isoparaffinsolefins-naphthenes-aromatics analysis, proton nuclear magnetic resonance and infrared spectroscopy, and gas chromatography-mass spectrometry. Up to 3 wt% lignin, cellulose, or both in mixed polymers changed the material balance of pyrolysis by decreasing the amount of waxy products. The presence of both PVC and biomass components significantly changed the material balance by decreasing the waxy product yield and increasing the gas and coke yield. The composition of all pyrolysis products was also modified with the addition of PVC, components of biomass, or both.     

Graft Copolymerization of Methyl Acrylate onto Cellulosic Biofibers: Synthesis,Characterization and Applications

Graft copolymerization of cellulosic biopolymers with synthetic polymers is of enormous interest because of its application in biofiltration, biosorption, biomedical, biocomposites and various other eco-friendly materials. Synthesis of graft copolymers of methyl acrylate onto mercerized Grewia optiva biofibers using ferrous ammonium sulfate–potassium per sulfate as redox initiator in air was carried out. Different reaction parameters such as amount of solvent, monomer concentration, initiator molar ratio, reaction time and reaction temperature were optimized to get the maximum percentage of grafting. The graft copolymers thus formed were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential thermal analysis and differential thermogravimetric techniques. A plausible mechanism for explanation of the graft copolymerization reactions pattern shown is offered. The effect of grafting percentage on the physico–chemical properties of raw as well as grafted Grewia optiva biofibers has also been investigated. The graft copolymers have been found to be more moisture resistant and also showed better chemical and thermal resistance. Green polymer composites were also successfully prepared through compression molding technique by using grafted Grewia optiva biofibers as reinforcement.     

Thermal cracking of oils from waste plastics

Thermal cracking of decomposed waste plastic oil produces a good yield of olefins. The solvent extraction of such waste plastic oil seems to be efficient for increasing gas yields and recycling monomers. To assess the potential of monomer recovery from municipal waste plastics, the oils were cracked using a laboratory-scale quartz-tube reactor. The waste plastic oils were provided by two commercial plants of the Sapporo Plastic Recycle Co. and the Dohoh Recycle Center Co. in Japan. A model waste plastic oil made in a laboratory was also examined. Yields of ethene, propene, and other products were measured at different temperatures. Two-step pyrolysis reduces coking compared with the direct thermal degradation of plastics. The raffinates from waste plastic oils extracted by sulfolane were also cracked. The primary products were almost the same as those from nontreated oils. The maximum total gas yield was 78wt%–85wt% at 750°C, an increase of about 20wt% compared with that of nonextracted oil. Solvent extraction removes stable aromatic hydrocarbons such as styrene, which is more coked than cracked.     

Qualitative and Quantitative Analysis of Lignin Produced from Beech Wood by Different Conditions of the Organosolv Process

Lignins in general have been extensively studied, while beech wood lignin in particular is rarely researched. In the present work, Organosolv isolated lignin from beech wood (OBL) has been characterized. The isolation was done by two methods: (a) by using sulfuric acid at 170 °C and a reaction time of 120 min and (b) at a temperature of 180 °C for 240 min. A range of analytical methods were applied including elemental analysis, FT-IR, UV–Vis, ³¹P NMR, SEC, Pyrolysis-GC/MS and HPLC to gain information about establish the purity, structure, molecular weight, thermal behavior and to determine carbohydrate residues according to the NREL protocol. FT-IR and UV–Vis spectra of OBL revealed expected typical absorptions for lignins. NREL analysis presented a carbohydrate-free lignin fraction which has not been achieved to date. TGA and DSC are used to study the thermal behavior of the isolated lignins and showed a relatively low glass transition temperatures (T_g: 123 °C) and decomposition temperatures of 348 and 381 °C. The pyrograms generated from the pyrolysis–GC/MS at 550 °C consisted mainly of fragments of syringyl, guaiacyl and hydroxyphenyl units, thereby confirming the results of the NMR analysis. Our findings support Organolsolv as an efficient method to isolate pure lignin fractions from beech wood with practical value in industry.     

改性蚁酸木质素的制备与应用

采用加拿大一枝黄花茎杆为原料提取蚁酸木质素，通过氧化或接枝复合的方法对蚁酸木质素进行改性，对改性产物进行了FTIR和SEM表征。实验结果表明：接枝复合改性产物中存在-CONH的接枝复合链，氧化改性产物基本保持了蚁酸木质素原来的吸收峰；采用接枝复合改性产物处理初始质量浓度为50 mg/L的亚甲基蓝废水，在废水pH 7、吸附时间4 h、改性产物加入量22 mg/mL的条件下，亚甲基蓝去除率为90.94%；采用氧化改性产物处理相同亚甲基蓝废水，在废水pH 10、吸附时间12 h、改性产物加入量22 mg/mL的条件下，亚甲基蓝去除率为81.93%。     

Performance and efficiency of old newspaper deinking by combining cellulase/hemicellulase with laccase-violuric acid system

Performance and efficiency of old newspaper (ONP) deinking by combining cellulase/hemicellulase with laccase-violuric acid system (LVS) were investigated in this study. Brightness, effective residual ink concentration (ERIC) and physical properties were evaluated for the deinked pulp. Fiber length, coarseness, specific surface area and specific volume were also tested. The changes of dissolved lignin during the deinking processes were measured with UV spectroscopy. The fiber morphology was observed with environmental scanning electronic microscopy (ESEM). Experimental results showed that, compared to the pulp deinked with each individual enzyme, ERIC was lower for the cellulase/hemicellulase-LVS-deinked pulp. This indicated that a synergy existed in ONP deinking using a combination of enzymes. After being bleached by H₂O₂, enzyme-combining deinked pulp gave higher brightness and better strength properties. Compared with individual enzyme deinked pulp, average fiber length and coarseness decreased a little for the enzyme-combining deinked pulps. A higher specific surface area and specific volume of the pulp fibers were achieved. UV analysis proved that more lignin was released during the enzyme-combining deinking process. ESEM images showed that more fibrillation was observed on the fiber surface due to synergistic treatment.     

A Study on Benzoylation and Graft Copolymerization of Lignocellulosic Cannabis indica Fiber

Present work deals with the surface modification of Cannabis indica fiber through benzoylation and graft copolymerization of acrylonitrile (AN) onto C. indica fibers under the influence of microwave radiations. The Benzoylation of C. indica fiber was carried out by treating raw fiber with varying concentrations of benzoyl chloride solution. Different reaction parameters for graft copolymerization, such as reaction time, initiator concentration, nitric acid concentration, pH and monomer concentration were optimized to get the maximum percentage of grafting (25.54%). A suitable mechanism to explain benzoylation and graft copolymerization has been also proposed. Raw C. indica fiber, graft copolymerized and benzoylated fibers were subjected to evaluation of some of their properties like swelling behavior, moisture absorbance and resistance towards chemicals. Cannabis indica fibers treated with 5% benzoyl chloride solution and AN graft copolymerized fibers have been found to show more resistant towards moisture, water and chemicals when compared with that of untreated fibers. Morphological, structural changes, thermal stability and crystallanity of raw, graft copolymerized and benzoylated fibers have also been studied by SEM, FTIR, TGA and XRD techniques. It has been observed that the crystallinity of fiber decreases but thermal stability increases on surface modification.     

Thermal decomposition of expanded polystyrene in a pebble bed reactor to get higher liquid fraction yield at low temperatures

Expanded polystyrene is one of the polymers produced in large quantities due to its versatile application in different fields. This polymer is one of the most intractable components in municipal solid waste. Disposal of polymeric material by pyrolysis or catalytic cracking yields valuable hydrocarbon fuels or monomers. Literature reports different types of reactors and arrangements that have uniform temperatures during pyrolysis and catalytic cracking. The present study focuses on reducing the temperature to maximize the quantity of styrene monomer in the liquid product. A bench scale reactor has been developed to recover the styrene monomer and other valuable chemicals. Experiments were carried under partial oxidation and vacuum conditions in the temperature range of 300-500 degrees C. In the pyrolysis optimization studies, the best atmospheric condition was determined to be vacuum, the pyrolysis temperature should be 500 degrees C, yield of liquid product obtained was 91.7% and yield of styrene obtained was 85.5%. In the characterization studies, distillation and IR spectroscopy experiments were carried out. The remaining of the liquid product comprises of benzene, ethyl benzene, and styrene dimers and trimers.     

乙二醇降解聚2,6-萘二甲酸乙二醇酯

采用乙二醇对聚2,6-萘二甲酸乙二醇酯（PEN）进行降解,表征了醇解产物,探讨了醇解原理。结果表明：醇解后PEN中的酯键断裂,PEN分子内的蟄合羟基变成2,6-萘二甲酸乙二醇酯（BHEN）上分子间缔合羟基和游离羟基;醇解后产物的O与C的原子比由醇解前的0.28增至0.38,醇解产物中C=O和C—O两种O结构的质量比为1∶2.18,C—C、C—O和O—C=O三种C结构的质量比为5.38∶2.22∶1,产物的平均分子量降为200左右;醇解产物主要为BHEN及其低聚物,BHEN单体纯度在90%以上,收率为25.95%。该醇解反应是酯基断裂又聚合,PEN长链变短的过程。     

Novel Environmentally Friendly Copolymers Carboxymethyl Starch Grafted Poly(Lactic Acid)

Modified natural polymers have been gaining increasing scientific interest for many years. In this study carboxymethyl starch (CMS) was grafted with L(+)-lactic acid (LA) in different molar ratios CMS/LA (1/36, 1/22 and 1/12), resulting carboxymethyl starch-g-poly(lactic acid) (CMS-g-PLA) copolymers. The grafting reaction was carried out by solution polycondensation procedure in toluene and stannous 2-ethyl hexanoate Sn(Oct)₂ as catalyst was utilized. Poly(lactic acid) (PLA) was synthesized in the same conditions with the copolymers for comparative analyses of the physico-chemical and thermal properties. The copolymers and PLA were structurally and morphologically characterized by FT-IR, ¹H-NMR spectroscopy, WAXD and SEM analyses, taking CMS as reference. The molecular weight of the copolymers, CMS and PLA were determined, using a dynamic light scattering technique. The thermal behavior of the products was studied by DSC and TG-DTG analyses. The CMS-g-PLA graft copolymers exhibited lower Tg and thermal stability than pure CMS.     

Lignin Functionalized by Thermally Curable Propargyl Groups as Heat-Resistant Polymeric Material

Lignin was chemically functionalized via Williamson etherification reaction with propargyl bromide to prepare a thermosetting bio-resin, propargyllignin. The optimum reaction conditions were found at 70?°C for 4?h under the catalysis of sodium hydroxide in the ethanol solution. The propargllignin resin had highly improved processing capability, evidenced by good solubility, low melting point (<100?°C) and thermal curability. Upon heating, propargyllignin resin solidified with an exotherm around 180?C280?°C peaking at 240?°C, implying its thermal cure reaction via ethynyl polymerization. Compared with lignin feedstock, the propargyllignin resin showed much higher thermal properties: an onset decomposition temperature of 410?°C and a residue yield of 58?% at 800?°C (for lignin, onset decomposition temperature of 250?°C and residue yield of 34?%). Different from the lignin feedstock, propargyllignin was readily applied as curable thermosetting resin for composite matrix, and exhibited high mechanical and thermal properties.     

Laccase-Assisted Grafting of Acrylic Acid onto Lignin for its Recovery from Wastewater

The acrylic acid (AA) in the wastewater from paint manufacturing could be recovered by grafting to lignosulfonate in the presence of laccase and tert-butyl hydroperoxide (t-BHP). The low concentration of t-BHP did not inhibit the laccase activity, but improved the radical formation on lignin by laccase reaction, then initiated AA polymerization on lignin. The results showed laccase took a significant role for AA grafting to lignin. 94 % of AA could be polymerized on lignin by laccase/t-BHP, while only 32 % of AA was grafted on lignin with the same condition without laccase. The ratio of lignin to acrylic acid also affected AA recovery, and higher concentration of acrylic acid led to high recovery rate of AA. In this reaction system, the suitable range of temperature was 30–40 °C for the chemo-enzymatic reaction. The AA grafted on lignin could be precipitated by calcium ion and recovered.     

Microwave-Assisted Solvent-Free or Aqueous-Based Synthesis of Biodegradable Polymers

Microwave radiation was used as the energy source for various types of chemical derivatizations of polysaccharides and for the synthesis of biodegradable polyesters in solvent-free or aqueous-based reaction systems. A medium to high degree of substitution was obtained for starch acetates, starch succinates, carboxymethyl konjac, aminated starch, and aminated chitosan. Ring-opening polymerization of lactide and -caprolactone proceeded rapidly even at low power output in the presence of tin octanoate catalyst. Complete monomer conversion and high molecular weight were achieved in less than 6 minutes under nonisothermal conditions. The yield rapidly increased with increasing power output and showed no significant change in a wide range of batch sizes. Polycaprolactone was successfully grafted from starch and konjac acetate in 3 minutes, yielding as high as 24% grafting efficiency and 25% grafting degree.     

Recovery of Kraft Lignin from OPEFB and Using for Lignin–Agarose Hydrogel

Lignins from the spent pulping liquor were normally acquired as waste product of pulp and paper mills. The possibilities of utilizing kraft lignin have yet been developed for commercial innovation. The objectives of this research are to recovery and utilization of lignin from black liquor of oil palm empty fruit bunches (OPEFBs). Kraft lignins from the OPEFBs black liquor were recovered by acidification procedure. They were precipitated at pH 4, 3, and 2 in order that determine the optimum pH for isolation. It can be clearly seen that the best condition of lignin precipitation was at pH 3. It offered the highest yield and purity. The kraft lignin and agarose were utilized as the crude material for the production of lignin–agarose hydrogel. Lignin–agarose hydrogel could be prepared by using epichlorohydrin as the cross-linking agent. The cross-linking occurrence was recognized by FTIR. Physical and chemical properties of hydrogel were investigated. Gel strength of lignin–agarose hydrogel was characterized by texture personal analysis. The results demonstrated that the gel strength increased with increasing of lignin and epichlorohydrin (ECH) in agarose solutions. 5% lignin, 5% agarose and 10 mL ECH contributed the best gel formation and the great mechanical properties. The effect of cross-linking condition on the gel properties, for example, gel hardness and fracturability, was examined.     

Investigation of Synthesis of Copolymers from the Waste Products of Industrial Oil Refinement having Adhesion Properties and Strength to the Thermal Destruction

In this study, the waste products of industrial vegetable oil refinement were transformed into the glycidyl ester for preventing the effects of them to the environment, the ways for evaluating them in polymer chemistry were investigated, copolymers having high adhesion property and strength to the thermal destruction were synthesized and the area of their usage was determined. For this reason, the waste product of sunflower oil refination as a vegetable oil in the industry; soap stock (SS) was converted to the unsaturated glycidyl esters by the interaction with epichlorohidrine in the alkaline medium. After that the copolymerization of synthesized unsaturated glycidyl esters and the other waste product of oil refinement fatty acid (FA) with styrene in the radicalic initiator medium were investigated and copolymers that have high strength to the thermal destruction and adhesion property were synthesized. From the results of TGA and DTA analysis, it was determined that synthesized copolymers have low loss of weight at high temperature. The structures of copolymers were fixed by spectral and chemical analysis methods.     

Synthesis and Characterization of Biodegradable Starch-Polyacrylamide Graft Copolymers Using Starches with Different Microstructures

The effects of starch structures, in particular amylose content, on grafting reactions were investigated using thermal gravimetric analysis (TGA), nuclear magnetic resonance, X-ray diffraction (XRD). As a model system, corn starches with different amylose contents (0, 26, 50 and 80 %) were grafted onto acrylamide to produce superabsorbent polymers (SAPs). The weight loss measured by TGA at different temperature was used to analyze the grafting ratio in quantity. In general, the grafting ratio increased (about 10 %) with increasing starch amylose content, and graft chain segment lengths were much lower for the amylopectin-rich (waxy) starch. The high molecular weight and branched structure of the amylopectin reduced the mobility of the polymer chains and increased viscosity, which resulted in resistance to chain growth. The water absorption capability was increased with increasing amylose content for the starch-based SAPs. XRD detection showed that the crystalline structure of all starches was destroyed after grafting reactions. The thermal stability of the polyacrylamide grafted onto the starches increased by about 10 °C, which could be explained by the strong bonding between the grafted polymer chains and the starch matrices.     

Synthesis and Properties of <Emphasis Type="Italic">N</Emphasis>-Maleyl Chitosan-Cross-Linked Poly(Acrylic Acid-co-Acrylamide) Superabsorbents

A high-swelling superabsorbent was synthesized with biodegradable N-maleyl chitosan as cross-linker, acrylic acid (AA) and acrylamide (AM) as the monomers, ammonium peroxodisulfate–sodium bisulfite (NaHSO₃) as redox initiation system, by means of aqueous solution polymerization. The best reaction condition was based on the orthogonal experiment design. The optimal conditions on distilled water absorbency and on 0.9 wt% NaCl solution absorbency were monomer concentration 20 wt%, mole ratio of AA to (AA + AM) 60%, the neutralization degree of AA 40%, cross-linker concentration 2% and monomer concentration 25 wt%, mole ratio of AA to (AA + AM) 60%, neutralization degree of AA 50% and cross-linker concentration 1%, respectively. Factors influencing the water absorbency of superabsorbent also were investigated, by single factor experiment method. The absorbency of superabsorbents in distilled water and 0.9 wt% NaCl solution increased and then decreased with the increasing of monomer concentration, mole ratio of AA to (AA + AM) and degree of neutralization of AA. With the increasing of cross-linker concentration, the absorbency in distilled water increased and then decreased, but it decreased all the time in 0.9 wt% NaCl solution. In enzymatic degradation tests, the weight loss of superabsorbent was related to the content of cross-linker.     

Synthesis and Characterization of Chitosan-Grafted-Poly(2-Hydroxyaniline) Microstructures for Water Decontamination

Chitosan as a biopolymer, biodegradable, safe, non-toxic and widely abundant in nature was grafted with poly(2-hydroxyaniline) (P2-HA) through aqueous chemical oxidative copolymerization using ammonium persulphate in acetic acid medium. The grafting conditions were studied by varying grafting parameters. The effect of oxidant, 2-hydroxyaniline (2-HA) and acetic acid concentrations on the rate of copolymerization was studied. The synthesized graft characterized using UV–Vis, FTIR, TGA, XRD, and scanning electron microscope and compared with chitosan and P2-HA. The grafting enhances the thermal properties of chitosan. The effect of temperature on the rate of grafting copolymerization reaction was studied. The apparent activation energy (Ea) of the copolymerization reaction found to be 21.1116 kJ/mol. Also, ΔH^* and ΔS^*, were calculated and found to 22.8630 kJ/mol and ?109.4290 J/mol K respectively. The mechanism of the grafting copolymerization reaction discussed. Chitosan, P2-HA and chitosan-graft-P2-HA used for the removal of Cr, Fe, Mn, Cu and Zn divalent ions from a contaminated water samples. The adsorption isotherm parameters are given.