Innovative bamboo-plastic composites interfacial compatibility design approach: Self-assembled crosslinked structure of polydopamine with acylated chitin fibers.

Achieving interfacial compatibility through sustainable methods is a key objective in natural fiber-plastic composites research, aimed at optimizing mechanical performance. This study introduced an innovative organic bamboo-plastic composite (BPC) interfacial layer, incorporating O-acylated chitin fibers densely coated with polydopamine (PDA) via a mild and facile self-assembly method. Chitin nanofibers were acylated with dodecenylsuccinic anhydride in a deep eutectic solvent in a one-pot process. The resulting BPCs exhibited significantly enhanced mechanical properties, with tensile strength, flexural strength, modulus, and impact strength increased by 73.64 %, 39.19 %, 15.42 %, and 63.57 %, respectively, compared to untreated BPCs. This improvement highlights the effectiveness of tailoring cross-linked networks across heterogeneous interfaces in providing strength, dissipating strain, and promoting interfacial compatibility. Furthermore, these modified BPCs demonstrated enhanced thermal stability, crystallization behavior, and moderate hydrophobicity. This surface treatment strategy offers a distinctive approach to producing high-performance, eco-friendly BPCs, also facilitating the processing and utilization of marine biological resources on a wide scale.

In-situ construction of chitosan@tannin structure on bamboo fiber for green and convenient reinforcement of poly(3-hydroxybutyrate) biocomposite.

Fiber-reinforced biocomposites were widely considered as the optimal sustainable alternative to traditional petroleum-based polymers due to their renewable, degradable, and environmentally friendly characteristics, along with economic benefits. However, the poor interfacial bonding between the matrix and natural fiber reinforcement remained a key issue limiting their mechanical and thermal properties. Focusing on cost-effective, convenient, and low-pollution chemical methods, this work proposed a strategy for in-situ synthesis of composite structures on bamboo fiber (BF) surfaces. Crude chitosan (CS) and reclaimed tannic acid (TA) were utilized as the raw materials, to construct stereo-netlike chitosan @ tannin structures (CS@TA) via a one-pot method facilitated by hydrogen bonding and complexation. The influence of reactant concentration and pH value on the process was further investigated and optimized. The CS@TA structure improved the interfacial bonding between the BF reinforcement and matrix poly(3-hydroxybutyrate) (PHB), and this non-amino-driven construction provided a potential reaction platform for functionalizing the interfacial layer. The modified biocomposite showed improvements in tensile and impact strengths (51.58 %, 41.18 %), also in tensile and flexural moduli (13.59 %, 26.88 %). Enhancements were also observed in thermal properties and heat capacity. This work presents a simple and promising approach to increase biocomposite interface bonding.

The rigid-flexible balanced molecular crosslinking network transition interface: An effective strategy for improving the performance of bamboo fibers/poly(butadiene succinate-co-butadiene adipate) biocomposites.

The poor interfacial compatibility of natural fiber-reinforced polymer composites has become a major challenge in the development of industry-standard high-performance composites. To solve this problem, this study constructs a novel rigid-flexible balanced molecular crosslinked network transition interface in composites. The interface improves the interfacial compatibility of the composites by balancing the stiffness and strength of the fibers and the matrix， effectively improving the properties of the composites. The flexural strength and flexural modulus of the composites were enhanced by 38 % and 44 %, respectively. Water absorption decreased by 30 %. The initial and maximum thermal degradation temperatures increased by 20 °C and 16 °C, respectively. The maximum storage modulus increased by 316 %. Furthermore, the impact toughness was elevated by 41 %, attributed to the crosslinked network's efficacy in absorbing and dissipating externally applied energy. This innovative approach introduces a new theory of interfacial reinforcement compatibility, advancing the development of high-performance and sustainable biocomposites.

A strong hydrogen bond bridging interface based on tannic acid for improving the performance of high-filled bamboo fibers/poly (butylene succinate-co-butylene adipate) (PBSA)biocomposites.

Natural plant fiber-reinforced bio-based polymer composites are widely attracting attention because of their economical, readily available, low carbon, and biodegradable, and showing promise in gradually replacing petroleum-based composites. Nevertheless, the fragile interfacial bonding between fiber and substrate hinders the progression of low-cost and abundant sustainable high-performance biocomposites. In this paper, a novel high-performance sustainable biocomposite was built by introducing a high density strong hydrogen-bonded bridging interface based on tannic acid (TA) between bamboo fibers (BFs) and PBSA. Through comprehensive analysis, this strategy endowed the biocomposites with better mechanical properties, thermal stability, dynamic thermo-mechanical properties and water resistance. The optimum performance of the composites was achieved when the TA concentration was 2 g/L. Tensile strength as well as modulus, flexural strength as well as modulus, and impact strength improved by 22 %, 10 %, 15 %, 35 %, and 25 % respectively. Additionally, the initial degradation temperature(Tonset) and maximum degradation temperature(Tmax) increased by 12.07 °C and 14.8 °C respectively. The maximum storage modulus(E'), room temperature E', and loss modulus(E")elevated by 199 %, 75 %, and 181 % respectively. Moreover, the water absorption rate decreased by 59 %. The strong hydrogen-bonded bridging interface serves as a novel model and theory for biocomposite interface engineering. At the same time, it offers a promising future for the development of high performance sustainable biocomposites with low cost and abundant biomass resources and contributes to their wide application in aerospace, automotive, biomedical and other field.

Crustacean-inspired chitin-based flexible buffer layer with a helical cross-linked network for bamboo fiber/poly(3-hydroxybutyrate) biocomposites.

Marine biological resources, serving as a renewable and sustainable reservoir, holds significant import for the utilization of composite material. Hence, we produced bamboo fiber/poly(3-hydroxybutyrate) (BF/PHB) biocomposites with exceptional performance and economic viability, drawing inspiration from the resilience of crustacean shells. Polyaminoethyl modified chitin (PAECT) was synthesized using the alkali freeze-thaw method and introduced into the interface between BF and PHB to improve interfacial adhesion. The resulting chitin fibers, characterized by their intertwined helical chains, constructed a flexible mesh structure on the BF surface through an electrostatic self-assembly approach. The interwoven PAECT filaments infiltrated the dual-phase structure, acting as a promoter of interfacial compatibility, while the flexible chitin network provided a greater capacity for deformation accommodation. Consequently, both impact and tensile strength of the BF/PHB composites were notably enhanced. Additionally, this flexible layer ameliorated the thermal stability and crystalline properties of the composites. This investigation aimed to leverage the distinctive helical configuration of chitin to facilitate the advancement of bio-reinforced composites.

Cardiac output measurement after coronary artery bypass grafting using bolus thermodilution, continuous thermodilution, and whole-body impedance cardiography.

OBJECTIVE: To test the feasibility of continuous cardiac output (CO) monitoring with whole-body impedance cardiography after coronary artery bypass grafting and to compare the values obtained with those measured using the bolus and continuous thermodilution methods. DESIGN: A prospective study. SETTING: Intensive care unit in a university hospital. PATIENTS: Twenty patients after coronary artery bypass grafting. INTERVENTIONS: CO was measured intermittently using the bolus thermodilution method, and continuously using the continuous thermodilution method, and whole-body impedance cardiography immediately after transfer to the intensive care unit. MEASUREMENTS AND MAIN RESULTS: Bolus thermodilution CO was measured in triplicate at up to 14 time points overnight. Continuous thermodilution CO and whole-body impedance cardiography CO values were recorded simultaneously. During the study period, the bias in CO values between bolus thermodilution and whole-body impedance cardiography ranged from 0.07 to 1.05 L/min and the precision (standard deviation of differences) ranged from 0.82 to 1.31 L/min. The bias between the bolus and continuous thermodilution methods ranged from 0.06 to 0.58 L/min and the precision from 0.43 to 1.02 L/min. Pulmonary artery temperature and CO level were the major determinants of the bias and precision in both comparisons. CONCLUSIONS: Agreement between whole-body impedance cardiography and bolus thermodilution is slightly inferior to that between the bolus and continuous thermodilution methods but not to the extent that it hampers the use of whole-body impedance cardiography for the continuous monitoring of CO after coronary artery bypass surgery.