Triassic sedimentation and postaccretionary crustal evolution along the Solonker suture zone in Inner Mongolia, China

Detrital zircon U-Pb dating of the Xingfuzhilu Formation in southern Inner Mongolia yields a maximum depositional age of around 220 Ma. The predominantly Permian and Triassic zircons are characterized by oscillatory zoning and euhedral shapes, with mostly positive zircon εHf(t) values (+2.0 to +16.4), indicating that they were derived from a proximal magmatic source. Early-Middle Paleozoic zircons have variable zircon εHf(t) values from −6.2 to +11.2 and are characterized by weak oscillatory zoning and subhedral-subrounded shapes, suggesting that the sources are a proximal magmatic arc, possibly mixed with components of the Ondor Sum magmatic arc and the magmatic arc at the northern margin of the North China Craton. The remnants of Precambrian blocks in the southeastern Central Asian Orogenic Belt (CAOB), and the North China Craton may also have been a minor source region for the Xingfuzhilu succession. These results, combined with regional data, indicate that a closing remnant ocean basin or narrow seaway possibly existed in the Middle Permian (Guadalupian) immediately prior to final collision of the CAOB and closure of the Paleo-Asian Ocean. Subsequent collision resulted in the crustal uplift and thickening along the Solonker suture zone, accompanied by possible slab break-off and lithospheric delamination during the Latest Permian to Middle Triassic. The resultant orogen in the Late Triassic underwent exhumation and denudation of rocks in response to the postorogenic collapse and regional extension. Vertical crustal growth in the Triassic is documented by detrital zircons from the Xingfuzhilu Formation and appears to have been widespread across entire eastern CAOB

Colorful Luminescence of Conjugated Polyelectrolytes Induced by Molecular Weight

Due to their distinctive intrinsic advantages, the nanoaggregates of conjugated polyelectrolytes (CPEs) are fascinating and attractive for various luminescence applications. Generally, the emission luminescence of CPEs is determined by the conjugated backbone structure, i.e., different conjugated backbones of CPEs produce emission luminescence with different emission wavelength bands. Here, we polymerized the bis(boronic ester) of benzothiadiazole and an alkyl sulfonate sodium-substituted dibromobenzothiatriazole to provide PBTBTz-SO3Na with different molecular weights via controlling the ratio of the monomer and the catalyst. Theoretically, the CPEs with the same molecular structure usually display similar photoelectronic performances. However, the resulting PBTBTz-SO3Na reveal a similar light absorption property, but different luminescence. The higher molecular weight is, the stronger the fluorescence intensity of PBTBTz-SO3Na that occurs. PBTBTz-SO3Na with different molecular weights have different colors of luminescence. It is well known that the molecular aggregates often led to weaker luminescent properties for most of the conjugated polymers. However, PBTBTz-SO3Na exhibits a higher molecular weight with an increasing molecular chain aggregation, i.e., the nanoaggregates of PBTBTz-SO3Na are beneficial to emission luminescence. This work provides a new possible chemical design of CPEs with a controllable, variable luminescence for further optoelectronics and biomedicine applications

Activity and Structural Characteristics of Peach Gum Exudates

Polysaccharide fractions were prepared from peach gum exudates by treatments with alkaline hydrogen peroxide (AHP) and liquid hot water (LHW). The structural characteristics and activities of the polysaccharide fractions were comparatively studied. The results suggested that arabinogalactans substituted with xylose and uronic acids were the main structure of all polysaccharide fractions. AHP and LHW treatments introduced the degradation of the polysaccharides, reducing the molecular weight of polysaccharides from 182500 g/mol to 78450 g/mol and 68420 g/mol, respectively. The decreasement of molecular weights responded to the decrease of thermal stability of polysaccharide fractions. However, AHP and LHW treatments removed most of the nonsugar composition, increasing the DPPH•- and ABTS•+-scavenging activity of polysaccharides. Polysaccharide fractions obtained from LHW treatment showed favorable DPPH•- and ABTS•+-scavenging activity at 22.9% and 34.3%, respectively, at concentration of 1000 μg/mL

Preparation of high molecular weight thermoplastic bio-based phenolic resin and fiber based on lignin liquefaction

In order to improve the application range of lignin phenolic resin, lignin thermoplastic phenolic resin was prepared by controlling the molar ratio (formaldehyde: phenol) with liquefied lignin, phenol and formaldehyde as raw materials, and thermoplastic phenolic fiber was obtained by melt spinning. The effects of different curing bath acid proportion (40%, 50%, 60%) on the mechanical property, thermal property and morphology of the fiber were investigated, and the curing behavior of lignin phenolic fiber was studied. The structure and properties of the resin and fiber were characterized by FT-IR, NMR, GPC, TG, DSC, XRD, SEM and fiber strength testing. The results showed that when the molar ratio was 0.7:1, the resin had the best performance, the O/P value was 1.75, Mw was 8298, and PDI was 2.92. After curing, the fiber continued cross-linking reaction, and the diameter of the cured fiber was thicker than that of the original fiber. The most suitable curing process for the original fiber was that formaldehyde and hydrochloric acid were prepared into curing bath according to the mass ratio of 1:1, the heating rate was 20 ℃ h ^−1 , the curing termination temperature was 170 ℃. The tensile strength of the fibers reached 176.64 MPa and the elongation at break was 1.48%, and finally the carbon yield at 800 ℃ was 37.2%

Effect of alkaline lignin modification on cellulase–lignin interactions and enzymatic saccharification yield

Abstract Background The lignin can compete for binding cellulase enzymes with cellulose fibers and decrease the accessibility of enzymes to carbohydrates. The competitive adsorption of cellulase to lignin mainly depended on the chemical structure of lignin. The post-pretreatment can decrease the lignin content and modify the lignin structure of pretreated substrates, which reduced the lignin inhibition on enzymatic saccharification. Therefore, the post-treatment by modifying the lignin structure would attract considerable attention for weakening the cellulase–lignin interactions. Results Three modified lignins, including sulfonated lignin (SL), oxidized lignin (OL), and carboxylated lignin (CL), were prepared from alkali lignin (AL) and their structures and physicochemical properties were characterized using FTIR, NMR, XPS analysis, zeta potential, and contact angle, respectively. Compared to AL, three modified lignin preparations exhibited the decrease in contact angle by 61–70% and phenolic hydroxyls content by 17–80%, and an obvious increase of negative charges by about 21–45%. This was mainly due to the drop of condensation degree and the incorporation of carboxylic and sulfonic acid groups into modified lignins. Langmuir adsorption isotherms showed that the affinity strength between cellulase and modified lignins significantly reduced by 54–80%. Therefore, the 72 h hydrolysis yield of Avicel with SL, OL, and CL was 48.5, 51.3, and 49.4%, respectively, which was increased 8–15.3% than that of Avicel with AL, 44.5%. In the enzymatic hydrolysis of bamboo biomass, the glucose yield at 5 d was 38.5% for AS-P. amarus, 15.4% for AO-P. amarus and 21.4% for AC-P. amarus, respectively, which were 1.4–3.5 times of alkali pretreated P. amarus. Conclusions The post-treatment can weaken the nonproductive adsorption between lignin and cellulase proteins and improve the enzymatic saccharification efficiency. This study will provide a conceptual combination of pretreatment technologies and post-pretreatment by modifying lignin structure for reducing the cellulase–lignin interaction

Preparation of Anti-Bacterial Cellulose Nanofibrils (CNFs) from Bamboo Pulp in a Reactable Citric Acid–Choline Chloride Deep Eutectic Solvent

In this study, bamboo pulp was simultaneously fibrillated and esterified in one-pot citric acid–choline chloride deep eutectic solvent treatment. The results indicated that increasing the temperature and time promoted esterification, yielding 0.19 to 0.35 mmol/g of the carboxyl group in CNFs. However, increasing the temperature and time resulted in decreases in yields and the diameter of CNFs from 84.5 to 66.6% and 12 to 4 nm, respectively. Analysis of the anti-bacterial activities of CNFs suggested that the high carboxyl group content corresponded to the effective inhibition of Escherichia coli and Staphylococcus aureus Taking yield, size, carboxyl group content, and anti-bacterial activate into consideration, treatment at 120 °C for 24 h was the optimal condition, yielding 76.0% CNF with 0.31 mmol/g carboxyl groups with a diameter of 8 nm and the inhibition fof E. coli (81.7%) and S. aureus (63.1%). In addition, effect of different CNFs on characteristics of polyvinyl alcohol (PVA) films were investigated. The results indicated that CNF obtained from the optimal condition was a favorable additive for the composite film, which enhanced (74%) the tensile strength of composite film compared with the pure PVA film due to its considerable size and carboxyl group content. However, the composite films did not show an anti-bacterial activate as CNF