Natural Rubber-Based Elastomer Reinforced by Chemically Modified Multiscale Leather Collagen Fibers with Excellent Toughness

Natural rubber (NR) composite elastomers have been increasingly explored recently, because they are renewable and environment-friendly. The excellent toughness of rubber composites is the premise to their wide applications. Unfortunately, an increase in tensile strength for NR is always accompanied by a decrease in extensibility. In this paper, an NR-based composite elastomer reinforced by triethoxyvinylsilane-modified leather collagen fibers (M-LCF) was fabricated for the first time to improve the tensile strength and the extensibility of the rubber composite simultaneously. The synergistic effect of the multiscale structure of M-LCF in toughening and its interfacial interaction with rubber promoted the dispersion of leather collagen fibers in the rubber and facilitated effective interfacial stress transfer, thereby enhancing the mechanical properties of the composite. The tensile strength, elongation, and toughness at the break of the composite elastomer containing 5%-modified collagen fibers reached 18.76 MPa, 740%, and 54.09 MJ·m–3, respectively, which were 31%, 2%, and 64% higher than that of the pure rubber elastomer, respectively

Natural Rubber-Based Elastomer Reinforced by Chemically Modified Multiscale Leather Collagen Fibers with Excellent Toughness

Natural rubber (NR) composite elastomers have been increasingly explored recently, because they are renewable and environment-friendly. The excellent toughness of rubber composites is the premise to their wide applications. Unfortunately, an increase in tensile strength for NR is always accompanied by a decrease in extensibility. In this paper, an NR-based composite elastomer reinforced by triethoxyvinylsilane-modified leather collagen fibers (M-LCF) was fabricated for the first time to improve the tensile strength and the extensibility of the rubber composite simultaneously. The synergistic effect of the multiscale structure of M-LCF in toughening and its interfacial interaction with rubber promoted the dispersion of leather collagen fibers in the rubber and facilitated effective interfacial stress transfer, thereby enhancing the mechanical properties of the composite. The tensile strength, elongation, and toughness at the break of the composite elastomer containing 5%-modified collagen fibers reached 18.76 MPa, 740%, and 54.09 MJ·m–3, respectively, which were 31%, 2%, and 64% higher than that of the pure rubber elastomer, respectively

Natural Rubber-Based Elastomer Reinforced by Chemically Modified Multiscale Leather Collagen Fibers with Excellent Toughness

Natural rubber (NR) composite elastomers have been increasingly explored recently, because they are renewable and environment-friendly. The excellent toughness of rubber composites is the premise to their wide applications. Unfortunately, an increase in tensile strength for NR is always accompanied by a decrease in extensibility. In this paper, an NR-based composite elastomer reinforced by triethoxyvinylsilane-modified leather collagen fibers (M-LCF) was fabricated for the first time to improve the tensile strength and the extensibility of the rubber composite simultaneously. The synergistic effect of the multiscale structure of M-LCF in toughening and its interfacial interaction with rubber promoted the dispersion of leather collagen fibers in the rubber and facilitated effective interfacial stress transfer, thereby enhancing the mechanical properties of the composite. The tensile strength, elongation, and toughness at the break of the composite elastomer containing 5%-modified collagen fibers reached 18.76 MPa, 740%, and 54.09 MJ·m–3, respectively, which were 31%, 2%, and 64% higher than that of the pure rubber elastomer, respectively

Study on the bond properties between basalt fiber-reinforced spontaneous combustion coal gangue concrete and BFRP bars

Microstructural characterization of spontaneous combustion coal gangue (SCCG), the hydration products and mechanism of spontaneous combustion coal gangue concrete (SCCGC) were discerned through microscopic analysis. The bond performance was assessed employing a central pull-out test on samples variably substituted with SCCG (0%, 25%, 50%, 75%, and 100%) and augmented with basalt fiber (BF) (0%, 0.1%, 0.15%, and 0.2%). The failure mode and bonding mechanism were also revealed by this test. The bond-slip curves were fitted by various bond-slip constitutive models and a suitable model was found for each section. As indicated by the results, SCCGC possessed a lower carbon content and higher Al and Si element contents. These elements would undergo secondary hydration reactions with CH, which could enhance the strength of the ITZ and the compactness of the bond interface between BFRP bars and concrete. The failure modes were splitting and pull-out. An inverse correlation was observed between bond strength and the increment in SCCG aggregate substitution, ranging from a decline of 2.6% to 23.1%. As the BF content increased, the bond strength and peak slip increased by 3.9% ∼ 19.7% and 4.0% ∼ 14.6%, respectively. Furthermore, the reinforcing effect of BF on bond strength increased from 3.9% ∼ 10.3% to 8.8% ∼ 19.7% as the SCCG replacement rate increased, which was noticeable. The Malvar model and the Continuous Curve model were the best fitting models for the ascending and descending sections of bond-slip curves, respectively, while the residual stage was well fitted by the Hao Qingduo model.</p

Data_Sheet_1_Repeated inhibition of sigma-1 receptor suppresses GABAA receptor expression and long-term depression in the nucleus accumbens leading to depressive-like behaviors.docx

Sigma-1 receptor (σ1R) downregulation in male mice is known to cause a depressive-like phenotype. The nucleus accumbens (NAc), a region associated with affective regulation, has high levels of σ1R. Here, we investigated the effect of repeated inhibition of σ1R in the NAc on depressive-like behaviors and synaptic plasticity by microinjecting σ1R antagonist NE-100 into NAc nuclei in mice (NE-100 mice); this was followed by behavioral tests and field potentials recordings. We first examined the effect of NE-100 administration on σ1R expression and found that cell surface levels of σ1R were significantly reduced in the NAc of NE-100 mice. Compared to control mice, NE-100 mice exhibited significantly prolonged immobility in forced swim test (FST) and tail suspension test (TST), impaired long-term depression (LTD) as well as multi-spike waveform field excitatory postsynaptic potential (fEPSP) with an extended duration and an increased paired-pulse ratio (PPR). Reduced levels of GABAA receptor (GABAAR)-α1, -α2, -β2, and -β3 subunits, membrane D2R, and PKC phosphorylation in the NAc were observed in NE-100 mice. Activation of GABAAR by muscimol corrected the extended fEPSP duration and increased PPR, restored LTD maintenance as well as alleviated depressive-like behaviors in NE-100 mice. The decline of PKC phosphorylation in the NAc of NE-100 mice was corrected by injecting NAc with quinpirole, a D2R agonist. Injections of quinpirole or PMA (a PKC activator) into NAc of NE-100 mice rescued the expression levels of GABAAR, and alleviated the increase in PPR and impairment in LTD; these effects were sensitive to GF109203X, a PKC inhibitor. Furthermore, injecting NAc with quinpirole or PMA relieved depressive-like behaviors in NE-100 mice. Collectively, these results indicate that repeated inhibition of σ1R in the NAc reduces D2R-mediated PKC phosphorylation and suppresses GABAAR expression, thus impairing LTD maintenance and leading to depressive-like behaviors.</p