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Agriculture generates non-recyclable mixed waste streams, such as plastic (netting, twine, and film) and lignocellulosic residues (bluegrass straw/chaff), which are currently disposed of by burning or landfilling. Thermochemical conversion technologies of agricultural mixed waste (AMW) are an option to upcycle this waste into transportation fuel. In this work, AMW was homogenized by compounding in a twin-screw extruder and the material was characterized by chemical and thermal analyses. The homogenized AMW was thermally and catalytically pyrolyzed (500–600 °C) in a tube batch reactor, and the products, including gas, liquid, and char, were characterized using a combination of FTIR, GC-MS, and ESI-MS. Thermal pyrolysis wax products were mainly a mixture of straight-chain hydrocarbons C7 to C44 and oxygenated compounds. Catalytic pyrolysis using zeolite Y afforded liquid products comprised of short-chain hydrocarbons and aromatics C6 to C23. The results showed a high degree of similarity between the chemical profiles of catalytic pyrolysis products and gasoline. [ABSTRACT FROM AUTHOR]

Natural fiber plastic composites were made from Nigerian grown bamboo (Bambusa vulgaris) and high density polyethylene by extrusion and evaluated for strength, sorption and thermal properties. Composites were manufactured using two different screened bamboo particle size fractions (<2 mm and < 0,5 mm). The composites were tested for flexural properties, water sorption, melt flow and thermal properties. The melt viscosities at 190oC were 22,3 ± 0,91 kPa·s (<2 mm) and 27,4 ± 1,2 kPa·s (<0,5 mm). The results obtained indicated that the composites made with the smaller particle size fraction had higher flexural strength (37,4 ± 1,0 MPa) and modulus of elasticity (2,0 ± 0,2 GPa) than those made with the larger particle size fraction (29,9 ± 1,1 MPa and 1,7 ± 0,1 GPa). Dynamic mechanical analysis also showed higher dynamic storage modulus for the <0,5 mm particle-based composites than those made from the <2 mm particle size fraction due to higher density and better interfacial interaction between the fiber and matrix. Also, the composites made with the smaller particles and were more dimensionally stable (water absorption of 5,4% versus 18,5% at 61 d). The bamboo composites had thermal stability range of 265 - 279oC (onset degradation temperature). The composites made with the smaller bamboo particles possessed the better properties in comparison with those made from the <2 mm. Particle size and density significantly affected the mechanical, physical, thermal and rheological properties of the composites evaluated. [ABSTRACT FROM AUTHOR]

Volatility is an important property in fuels research because it can significantly affect performance and because it is highly sensitive to changes in the composition of a mixture. In the laboratory, volatility is measured as a distillation curve. Difficulty arises when the fluid to be measured is non-homogeneous; that is, it has more than one liquid phase. Using the advanced distillation curve (ADC) method, we analyzed two such fluids, crude pyrolysis oils containing significant water that formed an aqueous phase separate from the organic phase. In this communication, we present a data analysis method that compensates for non-homogeneity in these samples and enables us to compare the organic phase to the experience base of previously measured petroleum and pyrolysis oils. [ABSTRACT FROM AUTHOR]

A recent increase in the use of biofibers as low-cost and renewable reinforcement for the polymer biocomposites has been seen globally. Biofibers are classified into: lignocellulosic fibers (i.e., cellulose, wood and natural fibers), nanocellulose (i.e., cellulose nanocrystals and cellulose nanofibrils), and bacterial cellulose, while polymer matrix materials can be petroleum based or bio-based. Green biocomposites can be produced using both biobased fibers and polymers. Incompatibility between the hydrophilic biofibers and hydrophobic polymer matrix can cause performance failure of resulting biocomposites. Diverse efforts have focused on the modification of biofibers in order to improve the performances of biocomposites. "Grafting" copolymerization strategy can render the advantages of biofiber and impart polymer properties onto it and the performance of biocomposites can be tuned through changing grafting parameters. This review presents a short overview of various "grafting" methods which can be directly or potentially employed to enhance the interaction between biofibers and a polymer matrix for biocomposites. Major grafting techniques, including ring opening polymerization, grafting via coupling agent and free radical induced grafting, have been discussed. Improved properties such as mechanical, thermal, and water resistance have provided grafted biocomposites with new opportunities for applications in specific industries. [ABSTRACT FROM AUTHOR]

The effect of accelerated weathering exposure time on the bioplastic, poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) was studied. The chemical structure and thermophysical property changes of solvent cast PHBV films were examined by a combination of optical microscopy, size exclusion chromatography, FTIR and 1 H NMR spectroscopies, tensile testing, and differential scanning calorimetry (DSC). The exposed PHBV surfaces experienced surface crazing upon weathering. The molar mass of weathered PHBV was shown to decrease due to chain scission which was dominant over the crosslinking reaction mechanism, and compositional analysis showed the polymer degradation was non-random between the hydroxybutyrate-hydroxyvalerate units. The degree of crystallinity for PHBV was shown to increase significantly (by about 20%) upon weathering. Tensile tests showed that the weathered PHBV exhibited reduced ultimate strength and elongation to break, while the Young's modulus increased ascribing to an increase in crystallinity. Different degradation mechanisms (Norrish I/II, radical initiation, crosslinking, and hydrolysis) of PHBV are proposed and confirmed based on the experimental findings. This study provides degradation insight for PHBV exposed to both UV radiation and moisture. [ABSTRACT FROM AUTHOR]

This study investigated the feasibility of anaerobic digestion (AD) of potato peel waste (PPW) and its lactic acid fermentation residue (PPW-FR) for methane (CH 4 ) production. The experimental results showed that about 60–70% CH 4 content was obtained. The digester using PPW-FR as feedstock exhibited better performance and produced a highest cumulative CH 4 production of 273 L/kg VS fed , followed by 239 L/kg VS fed using PPW under the same conditions. However, with increasing solid loadings of PPW-FR feedstock from 6.4% to 9.1%, the CH 4 production was inhibited. The generation, accumulation, and degradation of volatile fatty acids (VFAs) in digesters were also investigated in this research. [ABSTRACT FROM AUTHOR]

Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8 L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L −1 , solids retention time of 2–4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g −1 PPW and highest productivity of 125 mg g −1 d −1 were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L −1 solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g −1 PPW and a productivity of 138 mg g −1 d −1 were achieved with a 1 d SRT. [ABSTRACT FROM AUTHOR]

This study investigated the efficacy of lauric arginate (LAE) as a potential preservative against wood deteriorating fungi. First, the antifungal properties of LAE against two brown rot fungi, Gloeophyllum trabeum (G.t.) and Rhodonia placenta (R.p.), and two white rot fungi, Trametes versicolor (T.v.) and Irpex lacteus (I.l.) were examined using malt-agar media as substrate. Then the biological resistance of LAE-treated wood specimens (10, 20, and 25 % LAE solutions) was tested following American Wood Protection Association (AWPA) E10 soil-block test procedures. The in vitro study showed LAE actively inhibited the growth of all the fungi tested compared to growth in control plates but there were no considerable changes observed in the morphology of fungi hyphae. Wood impregnated with LAE showed increased weight percent gain as a function of treatment concentration. Characterization of LAE-treated wood on a thermogravimetric analyzer showed LAE shifted the thermal degradation temperatures to lower stages but did not significantly improve the thermal stability of the treated specimen. LAE in wood significantly suppressed fungus growth, leading to decreased mass loss but it also leached out from wood specimens during fungi exposure. [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB) was grafted onto cellulose fiber by dicumyl peroxide (DCP) radical initiation via in situ reactive extrusion. The yield of the grafted (cellulose-g-PHB) copolymer was recorded and grafting efficiency was found to be dependent on the reaction time and DCP concentration. The grafting mechanism was investigated by electron spin resonance (ESR) analysis and showed the presence of radicals produced by DCP radical initiation. The grafted copolymer structure was determined by nuclear magnetic resonance (NMR) spectroscopy. Scanning electronic microscopy (SEM) showed that the cellulose-g-PHB copolymer formed a continuous phase between the surfaces of cellulose and PHB as compared to cellulose-PHB blends. The relative crystallinity of cellulose and PHB were quantified from Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) results, while the absolute degree of crystallinity was evaluated by differential scanning calorimetry (DSC). The reduction of crystallinity indicated the grafting reaction occurred not just in the amorphous region but also slightly in crystalline regions of both cellulose and PHB. The smaller crystal sizes suggested the brittleness of PHB was decreased. Thermogravimetric analysis (TGA) showed that the grafted copolymer was stabilized relative to PHB. By varying the reaction parameters the compositions (%PHB and %cellulose) of resultant cellulose-g-PHB copolymer are expected to be manipulated to obtain tunable properties. [ABSTRACT FROM AUTHOR]

In this study, the target was the generation of fermentable monosaccharides from hardwoods that can be converted into value-added chemicals, such as polyhydroxybutyrates (PHB). Poplar flour was subjected to a hot-water pretreatment. The pretreatment conditions were optimized using a response surface methodology (RSM) on a 2 3 full central composites design by varying temperature, reaction time and solid loading. The optimal pretreatment condition for producing sugars was 200 °C, 22 min and 20% solid loading. After pretreatment the solid residue was treated with a commercial cellulase/xylanase preparation and released sugars quantified. The total sugars yield was applied as response variable to the RSM. A maximum yield of 96% sugars was obtained. Potential fermentation inhibitors were also detected at low concentrations (acetic acid, furfural, hydroxymethylfurfural). A preliminary trial using wood hydrolysates in a fed-batch bioreactor using a mixed microbial consortia afforded PHB (14% on biomass basis) and maximum PHB productivity of 0.18 g/L/h. [ABSTRACT FROM AUTHOR]

Three industrial lignins (Indulin AT Kraft softwood, Protobind 1000, and corn stover) were fractionated in methanol to obtain soluble and insoluble fractions. The original lignin and obtained lignin fractions were characterized chemically by a combination of FTIR spectroscopy, pyrolysis-gas chromatography–mass spectrum (py-GC–MS), and derivatization followed by reductive cleavage (DFRC). The methanol soluble lignin fractions contained fewer condensed structures than the original lignin and methanol insoluble fractions. The thermal (e.g. glass transition temperature ( T g ) and thermal stability) and rheological properties of the lignins were characterized by a combination of DSC, TMA, TGA and parallel plate rheology. TMA and modulated temperature DSC (MTDSC) proved to be sensitive techniques in determining T g . The methanol soluble lignin fractions had the lowest T g values relative to the original lignin and methanol insoluble fractions. The original lignin and methanol insoluble fractions had a higher thermal degradation temperature relative to the methanol soluble lignin. Solvent partitioning offers a practical approach to fractionate lignin into low M w and T g fractions which show promise as starting materials for making lignin-copolymers. [ABSTRACT FROM AUTHOR]

Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g −1 , 0.06 g g −1 , and 0.05 g g −1 . The highest LA concentration of 14.7 g L −1 was obtained from a bioreactor with initial solids loading of 60 g L −1 at 35 °C. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the use of waste natural fibers from milled hop bines and hemp stalks, without chemical treatment, and compare them to a commercial wood fiber for use in wood–plastic composite (WPC) materials. The fibers were characterized (density, fiber size and chemical composition). WPCs were produced by the extrusion of a blend of fibers (50%), high-density polyethylene (HDPE) and coupling agent (2%). The WPCs were characterized for their mechanical, rheological, thermal, viscoelastic and water resistance properties. Pine fiber was about half the size of hemp and hop fibers and thus had a higher surface area. The pine WPC melts had a higher viscosity than the other two WPCs. Additionally, the tensile and flexural strengths of the pine WPC were higher than those of hop and hemp WPCs. The pine WPC was also shown to have the least water absorption followed by hop and hemp WPCs. This study highlights that different lignocellulosic fibers influence their WPC properties. The properties of the hop- and hemp-based WPCs were comparable to commercial WPCs and can be improved by further milling/screening the fibers to a smaller particle size (volumetric mean of ~88 μm) to increase their surface area, fiber–matrix interactions and improve stress-transfer. [ABSTRACT FROM AUTHOR]

Effects of accelerated and natural weathering on the molecular weight distribution (MWD) and crystallinity of polypropylene (PP) in wood plastic composites (WPC) were investigated. The composites were produced from pine fibers (60%) and PP (40%). Prolonged weathering caused an increase in wood degradation and erosion thereby leaving cracks and "pits" on the surface. Pyrolysis gas chromatography-mass spectrometry (Py GC-MS) revealed that PP dominated the weathered surface due to wood degradation. For matrix analysis, PP was extracted using 1,2,4-trichlorobenzene. Crystallinity and molecular weight distribution of PP were monitored by differential scanning calorimetry (DSC) and gel permeation chromatography (GPC), respectively. PP's crystallinity increased upon longer exposure time. The weight and number average molecular weight (Mw and Mn) decreased with an increase in weathering duration. An increased polydispersity (PD = Mw/Mn) implies that a secondary cross-linking process occurred during weathering. [ABSTRACT FROM AUTHOR]

The popularity and demand for wood plastic composites (WPC) has focused research on fiber properties associated with performance. In this study, maple wood fibers (WF) were ball milled and classified into discrete size fractions. Fiber analyses showed only three distinct WF size classes (80-100, 100-200 and <200 mesh). High density polyethylene (HDPE) based WPC were made from classified WF (10 to 50%). The effect of WF size, loading, and maleated polyethylene (MAPE) coupling agent on WPC rheological behavior (torque rheometry and melt flow rate (MFR)) and flexural properties were examined. The WPC MFR decreased with wood loading, increased with a reduction in WF size. The modulus of rupture (MOR) was shown to increase with a reduction in WF size and increase with the addition of MAPE. The increase in MOR is likely due to an increase in the interfacial interaction between the polymer and WF. Modulus of elasticity (MOE) was shown to increase with an increase in wood loading and decrease with a decrease in WF size. The toughness of the WPC was shown to increase with a decrease in WF size and increase upon addition of MAPE. [ABSTRACT FROM AUTHOR]

Abstract: Poplar wood fibers were chemically modified by esterification (acetate, propionate, benzoate) and then compounded with high density polyethylene (HDPE) into wood plastic composites (WPC). The esterified fibers were characterized (spectroscopy, TGA and contact angle) and shown to be more thermally stable and hydrophobic than unmodified fibers. The WPC were characterized for their mechanical and rheological properties, adhesion factor, water resistance, accelerated weathering and biodurability performance. Color change, surface morphology and extent of oxidation on the surface of weathered WPC were monitored using colorimetry, microscopy and FTIR spectroscopy, respectively. Benzoylated fiber based WPC experienced the least surface crazing and color change due to weathering. Esterification of fibers significantly reduced weight losses in the resulting WPC when it was exposed to brown-rot and white-rot fungi as compared to unmodified fiber WPC. Esterification of wood fibers resulted in more biodurable and photostable WPC. [Copyright &y& Elsevier]

The influence of pine fiber treatments on the color and chemical changes of polyvinyl chloride-based wood plastic composites exposed to outside and xenon-arc accelerated weathering was investigated. The wood plastic composites were produced from pine fiber (untreated control, acetone extracted, and holocellulose (delignified)) and polyvinyl chloride. Different analytical tools (colorimetry, microscopy, infrared spectroscopy, and gel permeation chromatography) were employed for weathered wood plastic composites characterization. The study showed that longer exposure time in both outside and accelerated weathering regimes caused an increase in color change and lightness, cracking, higher oxidation but decrease in wood (lignin) content of the weathered wood plastic composites’ surface for all the wood fiber types. The polyvinyl chloride molecular weight decreased with increase in exposure time of the composites. From this study, delignified wood fiber-based wood plastic composites had less color (lightness) change and reduced surface cracking with lowest weathered surface oxidation. Furthermore, relationships between accelerated and outside weathered wood plastic composite surfaces were observed. [ABSTRACT FROM PUBLISHER]

Abstract: The effect of cellulose crystallinity on the formation of a liquid intermediate and on its thermal degradation was studied thermogravimetrically and by Py-GC/MS using a control cellulose (Avicel, crystallinity at 60.5%) and ball-milled Avicel (low cellulose crystallinity at 6.5%). The crystallinity of the materials studied was quantified by XRD and FTIR. Thermogravimetric analyses (TGA) show the samples with lower crystallinity start to degrade at lower temperatures, exhibiting sharper DTG curves and lower thermal degradation activation energies. Scanning electron microscopy (SEM) studies of the solid residues formed in TGA tests showed that, while the conversion of the ball-milled cellulose (mostly amorphous cellulose) occurs through the formation of a liquid intermediate, in the conversion of the control the fibrous structure is conserved. Py-GC/MS studies showed major differences in the thermal behavior of the samples studied. At 300°C, amorphous cellulose yielded more levoglucosan. At temperatures between 350 and 450°C, higher yields of mono-anhydrosugars (levoglucosan and levoglucosenone) were obtained with the samples with higher crystallinity (control). The ball-milled cellulose produced more 5-(hydroxymethyl) furfural, 5-methylfurfural and furfural. The higher yields of these compounds are due to the acceleration of dehydration reactions when a liquid phase intermediate was formed. Fragmentation reactions responsible for the formation of light compounds (glycoaldehyde, acetic acid, methyl-vinyl-ketone and acetol) and the reactions responsible for the formation of cyclopentane do not seem to be affected by cellulose crystallinity and by the formation of a liquid intermediate. [Copyright &y& Elsevier]

Visual appeal of wood is as important as its structural integrity in outdoor applications. Discoloration and checking of wood favor the utilization of alternative materials for outdoor cladding and decking. Lignin depolymerization is one of the critical processes leading to weathering. In the present paper, the potential of different classes of surface protection agents has been assessed on loblolly pine ( Pinus taeda) impregnated with water repellents, organic UV inhibitors, and an organic biocide. The treated samples were exposed to predetermined doses of solar radiation in Eastern Oregon, and the chemical changes occurring on the surfaces were evaluated by FTIR spectroscopy. After 1-year exposure, lignin loss was complete on all surfaces; however, some treatments provided longer term protection than others. Organic UV light inhibitors were most effective in this regard. A petroleum-based water repellent with a melting point of 54-58°C also provided protection against lignin degradation. [ABSTRACT FROM AUTHOR]

Abstract: The preparation of hyperbranched polymers from a unique combination of commercially available A2, B3 and CB1 3-type monomers is presented. Direct melt condensation of aliphatic dicarboxylic acid (A2) to compounds having trihydroxy groups ((B3), triethanolamine) and trihydroxy-monoamino groups ((CB1 3), tris(hydroxymethyl)aminomethane) led to a series of hyperbranched polyesters with amine cores and amide linkages. Because of the monomers availability and simplicity of the synthetic process, hyperbranched poly(ester-amine-amide) (HBPEAA) materials can be readily scaled up. This approach was used to synthesize series of prepolymers with varying degree of branching (DB) and distance between branching points. Taking the advantage of reactivity differences of COOH with the NH2 and OH groups, the hyperbranched polymer with different arrangement of amide linkage along the network was synthesized. The influence of reaction conditions such as monomer compositions, temperature and mode of mixing on the polymerization was examined. The DB of the HBPEAA (0.46–0.63) was dependant on the synthetic route. The HBPEAA exhibited moderate molecular weights as determined by NMR and ESI-MS. Thermogravimetric analysis revealed that the prepolymers exhibit reasonable thermal stability. The synthesized prepolymer was successfully utilized to copolymerize with 40% lignin to form toughened elastomeric materials with tensile strength of 12 MPa, Young''s modulus of 33 MPa and 149% elongation. [Copyright &y& Elsevier]

The effects of thermal compression on the organic-soluble material of a uniform wood substrate, hybrid poplar (clone OP-367), has been studied. Poplar veneers were preconditioned to 0% or 8% moisture content and subsequently hot pressed at 150°C, 200°C, and 250°C. The dichloromethane (DCM) extracts were characterized by various hyphenated analyses [gas chromatography-mass spectrometry (GC-MS), analytical pyrolysis (Py-GC-MS), electrospray ionization-mass spectrometry (ESI-MS), and gel permeation chromatography (GPC)]. The yields and composition of extractable compounds were markedly influenced by treatment at 250°C compared to those obtained at lower temperatures. Most importantly, the organic extracts contained a significant portion of lignin-derived compounds after treatment at 250°C. [ABSTRACT FROM AUTHOR]

Abstract: Combined characteristics of hydrogen bonded/cross-linked polymer networks based on lignin motifs have been developed. This new type of polymeric material was prepared from an industrial lignin and a highly branched poly(ester-amine) (HBPEA) obtained by melt polycondensation of 1,1,1-triethanolamine (TEA) and adipic acid (AA). The lignin-HBPEA polymers were shown to be insoluble in common organic solvents and were characterized by FTIR and NMR spectroscopies. Thermo-mechanical measurements showed that melt mixing HBPEA with 40% lignin results in a flexible and tough material (T g; 7.7 °C and E′ 3.5 GPa). The hydrogen bonding recognition was based on various hydroxyl groups in lignin and aliphatic ester groups from HBPEA. The extent of interactions could be controlled by varying the amount of lignin added. These networks were thermally reversible and have highly tunable mechanical properties that were controlled by the extent of interactions. High level of mechanical properties could be achieved through the addition of lignin-poly(ester-amine) covalent cross-links. This study shows that the poly(ester-amine) structure plays an important role in the thermo-mechanical properties. By varying the spacer length between lignin and tertiary amine unit, materials with various thermo-mechanical properties were also obtained from the same parent polymer backbone. [ABSTRACT FROM AUTHOR]

Corn stover and rice straw lignin samples received from ethanol pilot plants, along with softwood kraft lignin samples, were characterized using pyrolysis GC-MS, 13C CP/MAS NMR spectroscopy, and permanganate oxidation degradation. The lignins were then esterified using 1-methylimidazole as a catalyst in a pyridine-free reaction, and the thermal properties of the products were evaluated. Solid state NMR showed the rice straw lignin contained 18% residual polysaccharides. Pyrolysis GC-MS showed the softwood kraft, corn stover, and rice straw lignins to be G - type, H/G/S - type, and G/S - type, respectively. However, some discrepancy was apparent between the pyrolysis and permanganate oxidation studies as to the ratios of the monomeric makeup of the lignins. The kraft and rice straw lignins were determined to have high degrees of condensation, while the corn stover lignin was uncondensed. Little to no increase in solubility was noticed for corn stover or rice straw lignin esters in organic solvents. Glass transition temperatures (Tg) of the lignin derivatives were determined by a combination of differential scanning calorimetry, dynamic mechanical analysis, and parallel plate rheometry. [ABSTRACT FROM AUTHOR]

Abstract: The effects of outside and accelerated (xenon-arc and UVA) weathering on the visual appearance and chemical changes of wood plastic composite (WPC) formulations based on high density polyethylene (HDPE) and polypropylene (PP) were investigated. Colorimetry, scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) were employed in this study. The study showed that for both outside and accelerated weathering, longer exposure time increased the degree of color change (and lightness), carbonyl concentrations, and wood loss on weathered WPC surfaces. HDPE-based WPC exhibited decreased lightening, carbonyl concentrations, and wood content loss when compared to PP-based WPC. From this study, relationships between chemical and color changes that occurred during exterior weathering of HDPE-based WPC were established. Oxidation and degradation of wood lignin influenced WPC color changes (lightening) during weathering. [Copyright &y& Elsevier]

More than 23 million tonnes of lignin are produced annually in the US from wood pulping and 98% of this lignin is burnt. Therefore, creating products from lignin, such as plastics, offers an approach for obtaining sustainable materials in a circular economy. Lignin-based copolymers were synthesized using a single pot, solvent free, melt condensation reaction. The synthesis occurred in two stages. In the first stage, a biobased prepolymer consisting of butanediol (BD, 0.8–1 molar content) and a diacid (succinic (SA), adipic (AA) and suberic acids (SuA), with varying amounts of diaminobutane (DAB, 0–0.2 molar content) was heated under vacuum and monitored by Fourier transform infra-red (FTIR) spectroscopy and electrospray ionization-mass spectrometry (ESI-MS). In the second stage, prepolymer was mixed with a softwood kraft lignin (0–50 wt.%) and further reacted under vacuum at elevated temperature. Progression of the polymerization reaction was monitored using FTIR spectroscopy. The lignin-copolyester/amide properties were characterized using tensile testing, X-ray diffraction (XRD), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Lignin co-polymer tensile (strength 0.1–2.1 MPa and modulus 2 to 338 MPa) properties were found to be influenced by the diacid chain length, lignin, and DAB contents. The lignin-copolymers were shown to be semi-crystalline polymer and have thermoplastic behavior. The SA based copolyesters/amides were relatively stiff and brittle materials while the AA based copolyesters/amides were flexible and the SuA based copolyesters/amides fell in-between. Additionally, > 30 wt.% lignin the lignin- copolyesters/amides did not exhibit melt behavior. Lignin-co-polyester/amides can be generated using green synthesis methods from biobased building blocks. The lignin- copolyesters/amides properties could be tuned based on the lignin content, DAB content and diacid chain length. This approach shows that undervalued lignin can be used in as a macromonomer in producing thermoplastic materials. [ABSTRACT FROM AUTHOR]

Discusses the separation of lipopolysaccharides from phenol-water extraction of cells of Campylobacter jejuni serotype O:19 into a water-soluble component. Acetic acid hydrolysis of the ketosidic linkages to lipid A; Structural investigations of O-deacetylated lipopolysaccharides.

Examines the liberation of an O antigenic polysaccharide from the lipopolysaccharide extracted from Campylobacter jejuni serotype O:19 by acetic acid hydrolysis of the ketosidic linkage to lipid A. Techniques used to establish the structure of the polysaccharide; Glycan as a derivative of hyaluronic acid; Parallel experiments on O antigens.

Complete structures, including the location of N-acetylneuraminic acid (Neu5Ac) residues, were assigned for the core regions of Campylobacter jejuni serotypes O:1, O:4, and O:23 and O:36 lipopolysaccharides (LPS). In continuation of earlier studies, structure determinations of liberated oligosaccharides and, where necessary, of intact LPS, were by [sup1]H-NMR spectroscopy, Smith degradation, chromium trioxide and enzymic degradations, in conjunction with methylation studies supported by fast-atom-bombardment mass spectrometry and linkage analyses by gas chromatography/mass spectrometry. It was concluded on the basis of the following structures, in which each was linked 1→5 to a terminal 3-deoxy-D-manno-octulosonic acid residue, that the core regions with qualitatively similar sugar compositions showed serotypic differences in one or more of their sequences, linkage types, and anomeric configurations: (formula???).The outer regions of each structure carry Neu5Ac residues linked 2→3 to available β-D-Galp residues and show striking similarities with various glycosphingolipids of the ganglioside family. However, Neu5Ac epitopes are not apparently involved in determining serospecificity. [ABSTRACT FROM AUTHOR]

Stalk lodging contributes to significant crop yield losses. Therefore, understanding the biomechanical strength and structural rigidity of grain stalks can contribute to improving stalk lodging resistance in crops. From the structural constituents of the stalk, the rind provides the principal structure, supporting cells against tension and bending loads. In this work, the biomechanical and viscoelastic behavior of the rind from the internodes of two sweet sorghum varieties (Della and REDforGREEN (RG)), grown in two different growing seasons, were evaluated by three-point micro-bending tests using a dynamic mechanical analyzer (DMA). In addition, the chemical composition of rinds and the microfibril angle (MFA) of the cell wall were determined using XRD. The results revealed that the biomechanical behavior of Della varieties was stiffer and more resistant to loads than that of RG varieties. Two features of the rind biomechanical properties, flexural modulus (FM) and flexural strength (FS), showed a significant reduction for RG. Particularly, a reduction in FS of 16–37% and in FM of 22–41% were detected for RG1. Changes in the stalks' rind biomechanical properties were attributed to cell wall components. Total lignin and glucan/cellulose contents were positively correlated with the FM and FS of the rind. Subsequently, an increase in the two cell wall components drove an increase in stiffness. Furthermore, the MFA of the rind was also found to influence the rind strength. [ABSTRACT FROM AUTHOR]

Peas are an underutilized crop that do not require allergen labeling and are rarely genetically modified. Peas contain less protein than soy and vary in protein composition. Because peas contain more starch than soy and less lipids, an alternative procedure for pea tofu production needs to be developed to prevent excessive starch gelatinization while promoting curd development. To accomplish this, a response surface model design was utilized to determine optimal oil addition, cook time, and salt concentration. Treatment ranges were from 0.0% to 4.2% for oil addition, 60–134 min for cook time, and 5.0%–9.2% for MgCl2 addition. Treatments had varying effects on tofu texture. Cook time was directly proportional to the hardness and could be used to match the soft, firm, and extra firm texture targets of conventional soy tofu. Protein secondary structure was not related to gel strength, indicating a system with synergies between multiple components other than protein. This research will help satisfy the growing demand for alternatives to soy‐based foods. [ABSTRACT FROM AUTHOR]

Tofu, made by coagulating soy milk, is a nutritious food originating in China and is widely consumed globally. Due to allergenicity and consumer perceptions of genetically modified organisms, consumer demand for soy alternatives is increasing. In this study, tofu was made from yellow split peas (Pisum sativum). Effects of pasteurization, fat addition, and curd disruption followed by repressing were studied. Here, disruption was not a chemical disruption, rather a physical disruption of protein curds. Pasteurization alone led to increased uptake of water and nonviable tofus. Disrupted samples became firmer with pasteurization. Texture profile analysis indicated that disruption followed by pasteurization improved hardness from approximately 175 g force from the control, to approximately 325 g force for disrupted + pasteurizated samples without fat addition. A similar trend was observed for samples with fat added, where hardness increased from approximately 50 g force to approximately 75 g force. Fourier‐transform infrared spectroscopy of the amide I region showed that an increase of β‐sheet structures led to increased hardness. The shifts in β‐sheet structures followed the same trends as surface hydrophobicity. Surface hydrophobicity decreased with pasteurization and increased with disruption. Molecular weight analysis showed that shear (from disruption) and heat separately degraded the proteins into smaller polypeptides exposing hydrophobic interiors. Changes to biochemical parameters, such as protein secondary structure and exposure of protein hydrophobic regions, allowed for tofu to be made from yellow field peas. Practical Application: This study provides critical information and a means to produce pea‐based soy‐free tofu. [ABSTRACT FROM AUTHOR]

Biomass and its interactions for heat generation have received little attention. In this study, the woody biomass materials were Prosopis africana (PA), Harungana madascariences (HM), Vitrllaria paradoxa (VP), and Afzelia africana (AA). The composition (extractives, carbohydrate, and lignin) of the biomass was determined. The biomass was converted to charcoal in a traditional kiln. A thermo-kinetic examination of the charcoal samples was carried out. The kinetic parameters and potential reaction mechanisms involved in the decomposition process were both obtained using the integral (Flynn–Wall Ozawa) isoconversional methods in conjunction with the Coats-Redfern approach. The activation energy profiles for the charcoal samples in oxidizing atmospheres were 548 kJ/mol for AA, 274 kJ/mol for VP, 548 kJ/mol for PA, and 274 kJ/mol for HM. All charcoal samples underwent comprehensive, multi-step, complex reaction pathways for thermal degradation. The charcoal samples exhibit not only great potential for biochemical extraction but also for bioenergy applications. The significant amount of combustion characteristics in the raw biomass and charcoal samples indicates that each type of wood charcoal produced has more fixed carbon, less ash, and less volatile matter, all of which are desirable for the thermo-chemical conversion of biomass for the production of heat. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Grown field cultured algae that was fed with diary manure waste water. • Compared field cultured to food grade commercial algae by their chemical and thermal properties. • Bio-oil, biochar and gas products were produced by pyrolysis and yields were temperature dependent. • Pyrolysis bio-oil mainly contained lipid derived compounds. Abstract Chlorella vulgaris algae is comprised of a complex mixture of compounds such as carbohydrates, lipids, and proteins and is a suitable feedstock for biofuels. The aim of this study was to convert commercial and a low cost field cultivated algae, via pyrolysis, to produce bio-oil, synthesis gas, and biochar products. The thermal degradation behaviour of algae was investigated by thermogravimetric analysis. Proximate, ultimate, fatty acid methyl ester and carbohydrates analyses, and pyrolysis–GCMS were further employed to characterize the chemical components of algae. Commercial and field cultured C. vulgaris algae was pyrolyzed (450, 500, and 550 °C) and their pyrolysis products were collected and characterized. The highest biochar yield was 42% at 450 °C and the highest bio-oil yield was 47.7% at 550 °C. The biochar physical and chemical properties were assessed using proximate and ultimate analysis, calorific value, specific surface area, butane absorption activity, Raman spectroscopy, and electron microscopy. Algae biochar was found to be mostly composed of condensed phenolic compounds and majorly disordered amorphous carbon. The bio-oils were characterized by the combination of GC–MS, high-pressure liquid chromatography, and electrospray ionization mass spectrometry. Fatty acids, carbohydrates, nitrogen-containing compounds, and aromatic hydrocarbons were abundantly found in the algae bio-oil. [ABSTRACT FROM AUTHOR]

A strategy of enhancing the reactivity of lignin molecule towards thermally initiated free radical polymerization was examined. Technical lignin samples were reacted with selected esterification agents (butyric and crotonic anhydrides) leading to extensive conversion of the available hydroxyl groups. The esterified lignins were then subjected to thermal processing in the presence or absence of dicumyl peroxide (DCP). The rheological and viscoelasticity behavior during this process were examined by in-situ rheology and dynamic mechanical analysis (DMA). The functionality and glass transition temperature (T g ) of samples before and after modification were assessed for evaluating the validity of modification. After crotonylation, the lignin derivatives were susceptible to thermally initiated free radical polymerization, especially in the presence of DCP. Upon heating, the lignin crotonate showed a significant increase in storage modulus (E′) from around 200 °C to 260 °C. The T g of lignin crotonate increased by about 20 °C after thermal treatment in the presence of DCP. Fourier transform infrared spectroscopy (FTIR) analysis of samples that were collected from rheological test confirmed the reaction of C C took place. Vanillyl alcohol as a lignin model compound was subjected to the same modification procedure with lignin to uncover the mechanism by FTIR and nuclear magnetic resonance (NMR) analysis, indicating there are three potential reaction sites: C C, C O and CH 2 -, among which C C is likely to form a cross-linked network. The conclusions from this study may provide the foundations for a rational design of technical lignin-based polymeric materials, by providing the double bonds to anchor the lignin molecules in the resin or copolymers. [ABSTRACT FROM AUTHOR]

A nanostructured iron (Fe) catalyst for Fischer-Tropsch synthesis (FTS) was prepared and evaluated using a silica nanospring (NS) support. FTS offers an approach of producing biofuels from synthesis gas (syngas) produced via biomass gasification. The Fe/NS catalysts were prepared using three different methods: (i) incipient wetness impregnation, (ii) precipitation and (iii) modified sol-gel, in order to obtain different sizes of deposited Fe nanoparticles on the NS support and investigate the influence of particle size on FTS. The Fe decorated catalysts were calcined and then activated with either H 2 , CO or H 2 + CO mixture. The prepared Fe/NS catalysts were characterized before the FT reaction by BET surface area, X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) in order to find correlations between physico-chemical properties of catalysts and catalytic performance. The decoration of Fe nanoparticles of different sizes onto NS using the various methods ranged from 1.7 to 10 nm. The FTS performance was also evaluated in a quartz fixed-bed microreactor (H 2 /CO of 2:1, 270 °C) and the products trapped and analyzed by GC-TCD and GC–MS to determine CO conversion and reaction selectivity. These results show that the highest CO conversion (76.6%) and a wide distribution of light hydrocarbon (C 6 to C 14 ) were obtained for Fe/NS catalyst prepared by impregnation and activated with CO after 12 h of the FT reaction. [ABSTRACT FROM AUTHOR]

The feasibility of using rattan canes (Laccosperma secundiflorum and Eremospatha macrocarpa) as reinforced fillers for high density polyethylene based plastic composite production was investigated. Extruded composites were tested for water sorption, tensile and thermal properties. The results obtained indicated that the rattan composites were dimensionally (water absorption: 2,2-21,4% thickness swell: 0,9-5,3%) and thermally stable (Tc: 116,8-118,2°C) and possessed adequate tensile properties (7,3-21,7 MPa). Composites made from L. secundiflorum had higher strength and thermal properties but lower sorption values compared to those of E. macrocarpa. Differences in the densities of the composites and the anatomical structures of the rattans seemed to influence properties of the composites. [ABSTRACT FROM AUTHOR]

Brewer’s spent grains, major by-products of the beverage industries, were obtained from a Nigerian brewery and subjected to pyrolysis at 500 °C. Analytical pyrolysis (Py-GC/MS) was conducted on the original BSG, extractive-free BSG and BSG CH 2 Cl 2 extract. There was a marked difference in the concentration of levoglucosan between the extractive-free BSG (40.5%) and the original BSG (11.5%). The Py-GC/MS detected significant amount of palmitic and oleic acids in the three samples. Prior to pyrolysis, the extractives content were isolated through methanolysis, transesterified and subjected to GC/MS analysis. The analysis revealed the presence of linoleic, oleic and palmitic acids in an appreciable quantity. The BSG and its biochar were also characterised according to Fourier transform infrared and Raman spectroscopic, and thermogravimetric analyses alongside some conventional physico-chemical analysis. The total crystallinity and condensation indices were evaluated from specific FTIR spectra peaks so as to monitor structural transformations in the bio-char. Kinetic data were deduced from TGA measurements and it was apparent that thermal decomposition of BSG is better modelled as a multi-step reaction mechanism. The nitrogen content of the bio-char was relatively high making it a suitable feedstock for the production of in situ nitrogenised activated bio-carbon. There was a significant variation between the structural configuration of the original BSG and the bio-char as revealed by the change in the value of the condensation index as well as the cellulose crystallinity content. It may thus be concluded that the BSG biomass would be a viable feedstock for thermal decomposition and other valorisation processes. [ABSTRACT FROM AUTHOR]

Utilisation of lignin in plastic based blends offers a sustainable alternative to non-renewable materials as well as value-added use of technical lignin obtained from pulping operations. To overcome poor compatibility between lignin and plastic, in this study, two industrial lignins (softwood Kraft and agricultural fiber soda) were esterified (with acetic, propionic, butyric, and hexanoic anhydrides) and subsequently blended with poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) or polypropylene (PP) at a weight ratio of 3:7. This paper systematically characterized C 2 –C 6 anhydrides esterified lignins (molar mass, glass transition temperature (T g ), hydrophobicity, and polarity), and provides a comprehensive evaluation of the effect of different lignin esters in the blends on tensile properties, water absorption, thermal transitions, for the first time, spherulite morphology, and dynamic rheological behaviour. Generally, compared to blends with unmodified lignin, a progressive increase of tensile strength (25%) and elongation at break (26%) could be observed with increasing ester carbon chain length in PHBV based systems, while no improvement was seen in PP based systems. Water absorption of PHBV and PP blends decreased by about 50% after lignin esterification. The effect of lignin esterification on the crystallization process was matrix dependent: depression of melting crystallization and occurrence of cold crystallization was observed in PHBV based blends, while the melting crystallization shifted to higher temperature in PP based blends. The lignin acetate and propionate blends were partially miscible showing two-stage glass transitions by thermal mechanical analysis. Esterification led to more uniform dispersion of lignin in the plastic matrix. The frequency of PHBV spherulites increased and their size decreased from 700 μm to less than 100 μm with addition of lignin acetate and propionate. Lignin hexanoate blends showed a T g depression and smaller dynamic elastic and viscous moduli than the other lignin esters, suggesting that it acted as a plasticizer. [ABSTRACT FROM AUTHOR]

Despite its massive potential, Raman imaging represents just a modest fraction of all research and clinical microscopy to date. This is due to the ultralow Raman scattering cross-sections of most biomolecules that impose low-light or photon-sparse conditions. Bioimaging under such conditions is suboptimal, as it either results in ultralow frame rates or requires increased levels of irradiance. Here, we overcome this tradeoff by introducing Raman imaging that operates at both video rates and 1,000-fold lower irradiance than state-of-the-art methods. To accomplish this, we deployed a judicially designed Airy light-sheet microscope to efficiently image large specimen regions. Further, we implemented subphoton per pixel image acquisition and reconstruction to confront issues arising from photon sparsity at just millisecond integrations. We demonstrate the versatility of our approach by imaging a variety of samples, including the three-dimensional (3D) metabolic activity of single microbial cells and the underlying cell-to-cell variability. To image such small-scale targets, we again harnessed photon sparsity to increase magnification without a field-of-view penalty, thus, overcoming another key limitation in modern light-sheet microscopy [ABSTRACT FROM AUTHOR]

Lignosulfonate and lignosulfonate hydrolyzed under alkaline conditions were used as the polyol components in polyurethane foam formulations. Although the treatment increased hydroxyl group abundance, it did not improve the applicability of hydrolyzed lignosulfonate in polyurethane foam. Thus, the use of original lignosulfonate yielded foams of thermal stability and mechanical properties comparable to other types of biobased foams (Young's moduli 0.95 to 4.42 MPa, 50% weight loss, and temperature ca. 500 °C). Lignosulfonates can be a renewable polyol component for the formulation of rigid, semi-rigid, and flexible foams. [ABSTRACT FROM AUTHOR]

Nickel (Ni) and ruthenium (Ru) decorated nanosprings (Ni-NS and Ru-NS) were prepared for use as potential hydrodeoxygenation (HDO) catalysts. The nanocatalysts were characterized by BET surface area measurements, electron microscopy and X-ray diffraction (XRD) and showed the NSs had a helical and mesoporous structure. The Ni and Ru decorated NSs showed good metal dispersity at the NS surface. Catalytic HDO conversion of phenol (model bio-oil compound) using NS were compared to conventional alumina (Al 2 O 3 ) and silica (SiO 2 ) gel catalyst supports. Ni–Al 2 O 3 was easily deactivated in the presence of water while the Ni-NS catalysts performed very well irrespective of water being present. An increase in Ni loading (up to 50%) increased the Ni-NS activity while the high loading resulted in a detrimental effect on the activity of silica gel based catalysts. Ru based catalysts showed better activity and conversion on phenol HDO than Ni based catalysts, even in the presence of water. Ponderosa pine pyrolysis bio-oil was fractionated into water-soluble (WS) and water-insoluble (WI) fractions. The bio-oil WI fraction was first hydrocracked to lower its molar mass and then HDO treated with Ni-NS to successfully form cycloalkanes products. These NS based HDO catalysts show promise for upgrading pyrolysis bio-oils to biofuels. [ABSTRACT FROM AUTHOR]

Stalk lodging (mechanical failure of stalks or stems before harvest) is a major problem in grain production that significantly reduces yield. Efforts to improve stalk lodging are hampered by a limited understanding of the determinants of stalk failure. This study examined the structural bending properties and material bending properties of maize (Zea mays L.) stalks. First, an in-field phenotyping device known as DARLING (Device for Assessing Resistance to Lodging In Grains) was used to determine structural properties of maize stalks. Stalks were then subjected to a rind penetration protocol and morphological measurements were acquired. Finally, small strips of rind tissue were excised from the stalks and micro three-point bending tests were conducted to determine the material properties of the rind tissue. Results showed that the material bending strength of the rind tissue was approximately twice as large as the bending stresses present in the rind tissue when failure occurred during field testing. This indicates that stalks ultimately fail due to some form of buckling (i.e., structural failure) as opposed to material failure. This result is relevant to genetic and breeding studies seeking to address the problem of stalk lodging. In particular, these results suggest that improvements in stalk lodging resistance should focus on the stalk's geometric features, such as the ratio of rind thickness to diameter, rather than solely on enhancing material strength. For the samples in this study, material strength ranged between 64 and 197 MPa whereas material stiffness ranged between 4 and 12 GPa. Rind penetration resistance was found to be a good predictor of material properties but a poor predictor of structural properties. • Structural and material bending properties measured for each maize stalk. • Material strength of the rind was twice as large as the structural stress at failure. • Maize stalks lodged due to local buckling (structural failure) not material failure. • Geometrical properties primarily influenced stalk bending strength. • Rind penetration resistance was a poor predictor of structural bending properties. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with various 3-hydroxyvalerate (3HV) contents biosynthesized by mixed microbial consortia (MMC) fed fermented dairy manure at the large-scale level was assessed over a 3-month period. The thermal, mechanical, and rheological behavior and the chemical structure of the extracted PHBV biopolymers were studied. The recovery of crude PHBV extracted in a large Soxhlet extractor with CHCl3 for 24 h ranged between 20.6% to 31.8% and purified to yield between 8.9% to 26.9% all based on original biomass. 13C-NMR spectroscopy revealed that the extracted PHBVs have a random distribution of 3HV and 3-hydroxybutyrate (3HB) units and with 3HV content between 16% and 24%. The glass transition temperature (Tg) of the extracted PHBVs varied between −0.7 and −7.4 °C. Some of the extracted PHBVs showed two melting temperatures (Tm) which the lower Tm1 ranged between 126.1 °C and 159.7 °C and the higher Tm2 varied between 152.1 °C and 170.1 °C. The weight average molar mass of extracted PHBVs was wide ranging from 6.49 × 105 g·mol−1 to 28.0 × 105 g·mol−1. The flexural and tensile properties were also determined. The extracted polymers showed a reverse relationship between the 3HV content and Young's modulus, tensile strength, flexural modulus, and flexural strength properties. [ABSTRACT FROM AUTHOR]

Plastic waste accumulation has been growing due to the increase in plastic generation and the lack of infrastructure for recycling. One of the approaches is to treat the mixed plastic waste (MPW) through thermal processes to produce feedstocks for other applications. However, the presence of polyvinyl chloride (PVC) in MPW would produce HCl during processing and has negative impacts (emission, catalyst poisoning, etc.). In addition, due to the high heterogeneity of MPW, it is difficult to generate consistent experimental data. In this study, MPW was homogenized through double compounding–extrusion and then formed into a sheet to be treated at 400 °C. The solid products at various mass losses were characterized by heat and chlorine content, Fourier-transform infrared (FTIR) spectroscopy, and elemental composition analysis. It was found that the thermal degradation of MPW started at ~260 °C. The chlorine removal efficiency increased with mass loss and reached an asymptotic value of ~84% at ~28% mass loss, and the remaining chlorine can be attributed to inorganic sources. A PVC de-chlorination model was developed for MPW using TGA data for PVC and MPW to determine organic chlorine removal efficiency. These results show that PVC de-chlorination was not affected by other plastics at this temperature. As the mass loss increases, the heat content first increases and then decreases. It was found that mass loss is a universal parameter for organic chlorine removal efficiency and heat content. The elemental composition analysis and FTIR spectroscopy also shed more light into the chemical changes during MPW thermal degradation. [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB) is a bioplastic biosynthesized by microorganisms as an intracellular granule. In this study, PHB was produced by a mixed microbial culture fed crude glycerol in a sequencing batch bioreactor. Bioreactor operations were monitored by near infrared (NIR) spectroscopy (908–1708 nm) with a direct insertion probe to develop a model for predicting microbial PHB concentration. Multivariate statistical methods, principal component analysis (PCA) and partial least squares (PLS), were applied for modeling of the NIR spectral data. The results showed that NIR spectra can (i) be used to predict PHB content in-situ, with a calibration model and prediction model exhibiting a good fit (R 2 = 0.88 and R 2 = 0.89, respectively) and (ii) also be used to monitor substrate, glycerol, concentration. [ABSTRACT FROM AUTHOR]

In this study, α-cellulose fibers reinforced green biocomposites based on polyhydroxybutyrate (PHB) and the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were prepared and characterized. The α-cellulose fibers were isolated from at-risk intermountain lodgepole pine wood by successive removal of extractives, lignin and hemicellulose. Grafting of PHB or PHBV onto cellulose was conducted using reactive extrusion with dicumyl peroxide free radical initiation at high temperature. It is postulated that the grafted copolymers at the interfaces of cellulose and the polymer matrix performed as an interfacial coupling agent. Grafting tended to interact with both the hydrophilic fibers and the hydrophobic PHB or PHBV matrix. The biocomposites were characterized by scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA) and indicated good interfacial bonding and compatibility between the two phases. The mechanical properties of the biocomposites were improved by grafting due to improved stress transfer between the two interphases of the fiber/polymer matrix as compared to the blend control composite. The crystallinity of PHB, PHBV and cellulose in the biocomposite were reduced as determined by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC) analyses. This in situ reactive extrusion process offers an effective approach to improve the properties of biocomposite materials from sustainable resources. [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB) is one of most biodegradable bioplastic, but its high cost and brittleness limits its applications. In this study, low-value waste byproduct from a fermentation process of potato peel waste, called the potato peel waste fermentation residue (PPW-FR) fibers, were recovered and compounded with PHB to form biocomposites of tunable properties. The mechanical and thermal properties of pure PHB and biocomposites were investigated by thermogravimetric analysis (TGA), tensile and flexural tests, and dynamic mechanical analysis (DMA). Fiber content was shown to have a significant effect on the surface hydrophobicity and water absorption of the biocomposites. All absolute and specific mechanical properties and water absorption (by normalizing the measured parameters against the measured density ( ρ )) were investigated. The biodegradability of PHB and biocomposites were evaluated in soil over 8 months. The surface morphology, chemistry and melting/crystallization behavior were monitored and characterized by microscopy, FTIR spectroscopy and differential scanning calorimetry (DSC), respectively. The biocomposites showed poor mechanical properties but extremely higher biodegradation rate as compared with pure PHB, especially when the fiber content was >15%. The degradation rate increased with increasing fiber content and positively correlated to the water absorption showing more cracks and deeper pits. FTIR spectroscopic analysis showed that the plant polysaccharides and PHB within the biocomposite were degraded with exposure time. At 50% fiber content the biocomposites were completely degraded by 8 months. These PPW-FR based biocomposites offer new opportunities for fast degrading biomaterials in agricultural and horticultural applications. [ABSTRACT FROM AUTHOR]

Copolymers containing as high levels of bio-derived components were obtained mainly from two industrial byproducts, glycerol and lignin. A series of hyper branched prepolymers (HyBP) were prepared from in the first step by melt condensation of glycerol (Gly, B 2 B 3 2 ) and adipic acid (AA, A 2 ) and the prepolymer structure was also modified by the addition of commercially available diisopropanolamine (DIPA, DB 4 2 ) and tris(hydroxymethyl) aminomethane (THAM, CB 3 1 ) units. The HyBP were reacted with lignin to form thermally-stimulated shape memory copolymeric elastomers in the second step in the same pot by melt polycondensation. The prepolymers were characterized chemically by FTIR, NMR, and ESI-MS. Thermal and rheological behaviors were analyzed by DSC, DMA, TGA and dynamic rheometry. The higher branching crosslinkers, DIPA and THAM, were shown to influence the chemical and thermal properties of the prepolymers. The hyperbranched biobased lignin-copolymers demonstrated good shape memory and elastic properties. The shape transition temperature ( T trans ) could be tuned by variations of Gly, DIPA and THAM proportions for applications under different temperature circumstances. This study demonstrates that renewable Gly and AA based prepolymers could be incorporated into lignin based copolymeric systems with high biobased contents acting as soft segment to perform shape memory effect behavior. [ABSTRACT FROM AUTHOR]