Optimization and Modelling of the Physical and Mechanical Properties of Grass Fiber Reinforced with Slag-Based Composites Using Response Surface Methodology.

The construction industry's high energy consumption and carbon emissions negatively impact the ecological environment; large-scale construction projects consume much energy and emit a significant amount of CO2 into the atmosphere. Statistics show that 30% of energy loss and 40% of solid waste in the construction industry are generated during construction. Therefore, reducing emissions during construction has significant research potential and value. Many scholars have recently studied eco-friendly building materials to facilitate the use of high-carbon emission materials like cement. Adding fibers to composite materials has become a research hotspot among these studies. Although adding fibers to composite materials has many advantages, it mainly reduces the compressive strength of the composite material. This research used the response surface methodology (RSM) to optimize the raw material ratios and thus improve the performance of plant fiber composite materials. Single-factor experiments were conducted to analyze the effects of grass size, grass content, and quicklime content on the composite materials' compressive strength, flexural strength, and water absorption. The influencing factors and levels for the response surface experiment were determined based on the results of the single-factor analysis. Using the response surface methodology (RSM), a second-order polynomial regression model was established to analyze the interaction effects of the three factors on the composite materials' compressive strength, flexural strength, and water absorption rate. The optimal ratio was determined: the optimized options for grass size, grass content, and quicklime content are 2.0 mm, 8.2 g, and 38 g, respectively. The actual values of compressive strength, flexural strength, and water absorption rate of the composite materials made according to the predicted ratio are 11.425 MPa, 2.145 MPa, and 21.89%, respectively, with a relative error of 8% between the actual and predicted values. X-ray diffraction and scanning electron microscopy were also used to reveal the factors contributing to the relatively high strength of the optimized samples.

Study on the Effects of Pasture Fiber on Thermal Properties of Slag Bricks.

In the context of ecological sustainability, this study focuses on the effect of variables of pasture fibers on the thermal properties of slag bricks made from a green recyclable material. This experiment uses slag as the binder, sand as the aggregate, and pasture fiber as an additive. The experimental variables include the additive content ratio of the pasture fiber, the size of the pasture fiber, and the type of pasture fiber. Significance analysis of the experimental results of the thermal performance tests is carried out using Minitab 18.1.0 software, and the optimal ratios for the thermal performance of the composite samples are derived from the response optimizer and conformity analysis. The results of the experiment's test analysis using Minitab 18 software indicate that, with an increase in pasture fiber content, the thermal performance of the composite samples initially decreases before increasing. Additionally, the lower the thermal conductivity of the composite sample, the lower the apparent density and the higher the porosity. Incorporating pasture fibers into slag bricks, as revealed in this study, reduces the waste of pasture resources in pastoral areas and promotes the development of sustainable building materials with favorable thermal properties.

Natural rubber bio-nanocomposites reinforced with self-assembled chitin nanofibers from aqueous KOH/urea solution.

Rigid chitin nanofibers (ChNFs) self-assembled from dilute α-chitin/KOH/urea aqueous solution were utilized as 1D filler to reinforce soft natural rubber (NR). The prepared ChNFs suspension has good compatibility with natural rubber latex (NRL) and thus showing favorable dispersibility in NR matrix at nanoscale. The bio-nanocomposites were fabricated by casting and evaporating the pre-mixed NRL/ChNFs suspensions with different ChNFs loadings. Gratifyingly, the NR/ChNFs bio-nanocomposite with only 0.3 wt% ChNFs content presented distinct improvement in both the strength and toughness due to the large aspect ratio of ChNFs and its homogeneous dispersion in NRL matrix. Moreover, the introduction of ChNFs can promote the proliferation of mBMSCs effectively and endow NR/ChNFs bio-nanocomposites with good biocompatibility, enabling expanded applications of NR in biomedical field, such as artificial blood vessel, cosmetology prosthesis and human diaphragm materials.

Effect of surface chemistry on the dispersion and pH-responsiveness of chitin nanofibers/ natural rubber latex nanocomposites.

Chitin nanofibers (ChNFs) have emerged as a rising nanomaterial due to their excellent mechanical properties, biocompatibility and biodegradability etc. Herein, carbonylated ChNFs (C-ChNFs) and zwitterionic ChNFs (NC-ChNFs) decorated with both amino (-NH2) and carboxyl (-COOH) groups were used to prepare ChNFs/natural rubber (NR) nanocomposite films by dip molding method, respectively. The results showed that C-ChNFs had better dispersion than that of NC-ChNFs in NRL matrix. Moreover, C-ChNFs/NR nanocomposite films demonstrated obvious pH-responsiveness owing to the association and disassociation of the hydrogen bonding between C-ChNFs under various pH conditions. In contrast, NC-ChNFs/NR nanocomposite films showed pH-stable mechanical properties because the protonation of -NH2 at pH < 7 and the ionization of -COOH at pH > 7 resulted in electrostatic repulsive force between NC-ChNFs. This study demonstrates that surface chemistry of ChNFs plays an important role on tailoring the performance of ChNFs/NRL nanocomposites.