Xylan cinnamoylation for reinforcing poly (butylene adipate-co-terephthalate): Molecule design and interaction optimization.

PBAT composites with biomass fillers have gained considerable attention as alternatives to non-biodegradable plastics. This work employed xylan derivatives as fillers for PBAT composites. Xylan was modified by introducing cinnamoyl side groups which limit the hydrogen bonding and construct π-π stacking interactions with PBAT chains. The resultant xylan cinnamates (XCi) show degree of substitution (DS) of 0.55-1.89, glass-transition temperatures (Tg) of 146.5-175.0 °C and increased hydrophobicity, which can be simply controlled by varying the molar ratio of reactants. NMR results demonstrate that the C3-OH of xylopyranosyl unit is more accessible to cinnamoylation. XCi fillers (30-50 wt%) were incorporated into PBAT through melt compounding. The filler with a DS of 0.97 exhibited the optimal reinforcing effect, showing superior tensile strength (19.4 MPa) and elongation at break (330.9 %) at a high filling content (40 wt%), which is even beyond the neat PBAT. SEM and molecular dynamics simulation suggest improved compatibility and strengthened molecular interaction between XCi and PBAT, which explains the suppressed melting/crystallization behavior, the substantial increase in Tg (-34.5 â†’ -1.8 °C) and the superior mechanical properties of the composites. This research provides valuable insights into the preparation of high-performance composites by designing the molecular architecture of xylan and optimizing the associated interactions.

Flow synthesis, characterization, anticoagulant activity of xylan sulfate from sugarcane bagasse.

High-value utilization of hemicellulose is critical to improve the append value of integrated biorefineries. In this research, the alkali-soluble sugarcane bagasse hemicellulose was sulfated using chlorosulfonic acid and N,N-dimethylformamide/LiCl under homogeneous conditions. With the aid of flow technique, a rapid, mild, and efficient method for the synthesis of xylan sulfate with high molecular weight and controllable degree of substitution was achieved. The results showed that the reaction time and the degradation of xylan chain were drastically reduced compared to the "in flask" batch conditions. High molecular weight of the product (Mw = 148,217) with a reasonable degree of substitution (DS = 1.49) could be obtained even at room temperature in 10 min under the present flow system. Anticoagulant experiments showed good anticoagulant activity of the resultant xylan sulfate, which could significantly prolong the activated partial thromboplastin time and thrombin time. This work not only provides a novel method for the synthesis of xylan sulfate, but also offers new opportunities for the production of other functional polysaccharide derivatives under the flow reaction conditions.

Organic amine catalytic organosolv pretreatment of corn stover for enzymatic saccharification and high-quality lignin.

A novel and efficient organic amine and organosolv synergetic pretreatment method was developed to overcome the recalcitrance of lignocellulose to produce fermentable sugars and high-quality salt-free lignin. After optimization of the process parameters, a delignification of 81.7% and total sugar yield of 83.2% (87.1% glucose, 75.4% xylose) could be obtained using n-propylamine (10mmol/g, biomass) as a catalyst and aqueous ethanol (60%, v/v) as a solvent. The susceptibility of the substrates to enzymatic digestibility was explained by their physical and chemical characteristics. The physical structure of extracted lignin showed higher ß-aryl ether bonds content and functionalities, offering the potential for further downstream upgrading. The role of organic amine catalyst and a synergistic mechanism is proposed for the present system.