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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]

Wood extractives are considered the major factor determining the natural durability of wood. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was assessed for rapid determination of western juniper (Juniperus occidentalis Hook. var. occidentalis) durability based on extractives in heartwood, sapwood-heartwood and sapwood regions. Durability was assessed by exposing samples to brown-rot decay fungi [Gloeophyllum trabeum (Pers.) Murrill and Rhodonia placenta (Fr.) Niemelä, K.H. Larss. & Schigel] or eastern subterranean termite (Reticulitermes flavipes Kollar). Durability classifications were compared to their extractive contents, along with ATR-FTIR spectra of extracted and unextracted blocks to establish relationships using hierarchical cluster analysis (HCA) and principal component analysis (PCA). Western juniper durability varied with test organisms, but the majority of samples had high fungal and termite resistance. Moderate to weak connections were observed between durability and extractive content, but HCA and PCA analysis were unable to classify durability with accuracy. The absence of non-resistant samples may have influenced the ability of the chemometric methods to accurately categorize durability. [ABSTRACT FROM AUTHOR]

Four different morphological plant parts of Musa spp. (banana and plantain) residues obtained from the rainforest belt of Nigeria were investigated. The study undertook Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), and physicochemical analysis. The total crystallinity (TCI) and lateral order (LOI) indices showed that the cellulose crystallinity for banana pseudo‐stem (LOI‐5.18; TCI‐0.37) and banana rachis (LOI‐4.25; TCI‐0.44) were relatively higher than for the banana (LOI‐0.11; TCI‐0.20) and plantain (LOI‐0.17; TCI‐0.18) peels. The XRD analysis confirmed the presence of starch in the peels and cellulose I in the structural samples (rachis and the pseudo‐stem). A further demonstration of the marked differences between the morphological parts of Musa spp was highlighted in the analysis of the FAMES extract as banana peels (21 mg g−1 of biomass) and plantain peels (20 mg g−1 of biomass) had the highest quantity of palmitic acids whereas the eicosanoic, behnic, and lignoceric acids were absent in the peels. The relatively high ash content (≤12.30 wt %) in the Musa spp. samples may necessitate a pretreatment process prior to deployment for bioenergy or chemical extraction purposes. Furthermore, kinetic studies, which involved differential Friedman's and integral Flynn–Wall–Ozawa techniques, and analytical pyrolysis of the residues were undertaken. The activation energy varied continuously with conversion; reaching a peak of >290 kJ/mol. The analytical pyrolysis detected acids, sugar derivatives, and phenolic compounds in significant concentrations for all biomass samples. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018 [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]

New approaches for assessing wood durability are needed to help categorize decay resistance as timber utilization shifts towards plantations or native forest regrowth that may be less durable than original native forest resources. This study evaluated attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy combined with principal component analysis (PCA) for distinguishing between groups of Alaska yellow cedar (Cupressus nootkatensis) wood for susceptibility to two decay fungi (Gloeophyllum trabeum and Rhodonia placenta) and the eastern subterranean termite (Reticulitermes flavipes). Alaska yellow cedar durability varied with test organisms, but the majority of samples were highly resistant to fungal and termite attack. Weight losses and extractives yield using sequential extractions (toluene:ethanol > ethanol > hot water) showed moderate to weak relationships. PCA analysis revealed limited ability to distinguish amongst levels of wood durability to all tested organisms. The absence of non-resistant samples may have influenced the ability of the chemometric methods to accurately categorize durability. [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]

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: 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]

This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifications, such as carbonyl and vinyl groups which are formed during weathering. These composites were subjected to three weathering regimes: exterior, accelerated xenon-arc, and accelerated UVA. The change in color was monitored using colorimetry. Fourier transform infrared spectroscopy was used to identify and quantify the chemical modifications (carbonyl formation and vinyl propagation) due to weathering. Additionally, scanning electron microscopy was employed to observe the physical morphological changes that occurred. The results showed that exterior and accelerated xenon-arc and UVA weathering regimes increased the degree of lightness, total color change, carbonyl concentration, and wood loss on the surfaces of the weathered composites. The increased carbonyl concentration during weathering implied that degradation had occurred by oxidation process. Also, oxidation and lignin (from the wood) degradation influenced the color (lightness) of PVC based WPC upon weathering. [ABSTRACT FROM AUTHOR]

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]

Polyhydroxyalkanoate (PHA) production generates a significant amount of residual bacterial biomass (RBB) after PHA extraction. The RBB as a zero-value waste contains proteins, carbohydrates, phenolics, and ash, which can be managed and converted to bio-oil and biochar products by pyrolysis. Thermogravimetric analysis (TGA) was used to investigate the thermodegradation kinetics of RBB and pyrolysis–GCMS studies were employed to determine potential chemical products. Pyrolysis was conducted on a laboratory-scale auger reactor at 500 °C. The bio-oil and biochar yield were 28 and 46%, respectively. The pyrolysis bio-oil was characterized by the combination of GCMS, high-pressure liquid chromatography (HPLC), and electrospray ionization mass spectrometry (ESI–MS). The bio-oil was dominated by nitrogen-containing, hydrocarbons, and aromatic compounds. The biochar was studied for its specific surface area and pore size, chemical functionality by Fourier transform infrared (FTIR) and Raman spectroscopies, and butane absorption activity. Biochar was comprised of a large part of polycondensed phenolic and majorly disordered amorphous carbon. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the effect of sulfuric acid (H2SO4) concentration, as an additive to enhance the production of anhydrosugars via pyrolysis of Douglas-fir, on the yield and composition of the lignin derived oligomers. Pyrolysis tests at 500°C were conducted in auger and fluidized bed reactors. For both reactors the yield of lignin derived oligomers decreased as H2SO4 was added. Several analytical techniques (UV-fluorescence, TGA, ESI-MS, FTIR, solid state 13C NMR and Pyrolysis-GC/MS) were used to characterize the lignin derived oligomers collected. Four peaks were observed in the UV-fluorescence spectra. The addition of H2SO4 reduces the yield of all the peaks. DTG curves also show the presence of several peaks. The addition of H2SO4 decreased the yield of all the peaks but its effect was more pronounced on peaks at 320 and 400°C. Electrospray ionization-mass spectrometry studies did not show any major change on the molecular weight of the lignin oligomers ionized products obtained as a function of H2SO4 concentration. Solid state NMR results indicate that the methoxyl groups decreased and the carbonyl increased gradually as sulfuric acid concentration increases. The Py-GC/MS confirmed the phenolic compounds with methoxyl substitutions were substantially reduced as the acid concentration increased. The experimental results obtained suggest the presence of H2SO4 enhances the polycondensation of methoxyl substituted aromatic rings. [Copyright &y& Elsevier]