Good Mechanical Properties Research Articles

Recent Advances in Polyurethane for Artificial Vascular Application

Artificial blood vessels made from polyurethane (PU) have been researched for many years but are not yet in clinical use. The main reason was that the PU materials are prone to degradation after contact with blood and will also cause inflammation after long-term implantation. At present, PU has made progress in biostability and biocompatibility, respectively. The PU for artificial blood vessels still requires a balance between material stability and biocompatibility to maintain its long-term stability in vivo, which needs to be further optimized. Based on the requirement of PU materials for artificial vascular applications, this paper views the development of biostable PU, bioactive PU, and bioresorbable PU. The improvement of biostable PU from the monomer structure, chemical composition, and additives are discussed to improve the long-term biostability in vivo. The surface grafting and functionalization methods of bioactive PU to reduce thrombosis and promote endothelialization for improving biocompatibility are summarized. In addition, the bioresorbable PU for tissue-engineered artificial blood vessels is discussed to balance between the degradation rate and mechanical properties. The ideal PU materials for artificial blood vessels must have good mechanical properties, stability, and biocompatibility at the same time. Finally, the application potential of PU materials in artificial vascular is prospected.

Three-Dimensional Printing of Hydrogel Blend Tissue Engineering Scaffolds with In Situ Delivery of Anticancer Drug for Treating Melanoma Resection-Induced Tissue Defects

Surgery is considered the gold standard for treating melanoma, but the high recurrence rate after surgery still remains as a major challenge. Therefore, using doxorubicin (DOX) as a model drug, this study investigated the 3D printing of anticancer drug-loaded hydrogel blend scaffolds for inhibiting post-operation melanoma recurrence and for promoting tissue regeneration. Three-dimensional printing could successfully produce methacrylate-modified chitosan (CSMA) and methylcellulose (MC) hydrogel blend scaffolds. Polymer blend inks exhibited satisfactory printability, and the printed porous scaffolds showed good biocompatibility and mechanical properties. Three-dimensionally printed DOX-loaded hydrogel scaffolds displayed controlled drug release, which may effectively prevent/impede tumor recurrence after surgery. Furthermore, combining 3D printing and bioprinting, DOX-loaded and rat bone marrow mesenchymal stem cell (rBMSC)-laden scaffolds were created for assessing local DOX delivery on healthy tissues. Within the 14-day culture period, rBMSCs encapsulated in multilayered scaffolds that were incorporated with DOX displayed rejuvenated cell viability. The 3D printed and bioprinted dual purpose hydrogel scaffolds have the promise of combating tumor recurrence and providing structural support for tissue regeneration.

Lung dECM matrikine-based hydrogel reverses bleomycin-induced pulmonary fibrosis by suppressing M2 macrophage polarization.

Recent studies have shown promising results using decellularized extracellular matrix (dECM) matrikines-based hydrogel as attractive strategies for preventing and alleviating fibrosis.
Methods & Results: Porcine lung decellularization and pepsin digestion were used to prepare the lung dECM hydrogel. Proteomic analysis revealed that the lung dECM hydrogel was enriched in glycoproteins, collagens, laminins, fibrinogen, held receptors, and bound growth factors. With porous structures and good mechanical properties and stability, the lung dECM hydrogel showed low cytotoxicity and good biocompatibility both in vitro and in vivo. The lung dECM hydrogel was further administered to verify the safety and effectiveness of reversing pulmonary fibrosis in a bleomycin induced rat model. The results revealed a relatively complete alveolar structure with less inflammatory infiltration and a reduced amount of collagen fiber deposition. TMT quantification proteomic analyses revealed significant downregulation of proteins, pathways, and interactions involved in the regulation of ECM components, tissue remodeling, inflammation, and the cytoskeleton and indicated that fibrosis-related proteins were obviously downregulated and inflammation-related proteins were significantly changed, particularly in macrophages, after administration of the lung dECM hydrogel. Multiplex immunohistochemical (mIHC) staining of lung tissue revealed that the inflammatory response was regulated by the lung dECM hydrogel, as indicated by a decrease in the number of CD3+ T cells and macrophages and the suppression of M2 macrophage polarization. Gene set enrichment analysis revealed that downregulated ficolin signaling was enriched in macrophages after lung dECM hydrogel administration, and the findings were verified in lung tissue by mIHC. Additionally, the effects of ficolin B proteins on macrophage polarization were proved in vitro.
Conclusion: This study suggested that the lung dECM hydrogel can reverse pulmonary fibrosis by suppressing M2 macrophage polarization through downregulation of the ficolin signaling pathway. Thus, the dECM hydrogel represent a promising class of biological materials for use in regenerative medicine.

An Enhanced Bioactive Glass Composition with Improved Thermal Stability and Sinterability

The development of new bioactive glasses (BGs) with enhanced bioactivity and improved resistance to crystallization is crucial for overcoming the main challenges faced by commercial BGs. Most shaping processes require thermal treatments, which can induce partial crystallization, negatively impacting the biological and mechanical properties of the final product. In this study, we present a novel bioactive glass composition, S53P4_MSK, produced by a melt–quench route. This novel composition includes magnesium and strontium, known for their therapeutic effects, and potassium, recognized for improving the thermal properties of bioactive glasses. The thermal properties were investigated through differential thermal analysis, heating microscopy and sintering tests from 600 °C to 900 °C. These characterizations, combined with X-ray diffraction analysis, demonstrated the high sinterability without crystallization of S53P4_MSK, effectively mitigating related issues. The mechanical properties—elastic modulus, hardness and fracture toughness—were evaluated on the sintered sample by micro-indentation, showing high elastic modulus and hardness. The bioactivity of the novel BG was assessed following Kokubo’s protocol and confirmed by scanning electron microscopy, X-ray energy dispersive spectroscopy, and Raman spectroscopy. The novel bioactive glass composition has shown high sinterability without crystallization at 700 °C, along with good mechanical properties and bioactivity.

Innovative Solid-State Recycling of Aluminum Alloy AA6063 Chips Through Direct Hot Rolling Process

In this paper, the feasibility of an innovative solid-state recycling process for aluminum alloy AA6063 chips through direct rolling is studied, with the aim of offering an environmentally sustainable alternative to conventional recycling processes. Aluminum chips, produced by milling an AA6063 billet without the use of lubricants, were first compacted using a hydraulic press with a 200 kN load and subsequently heat-treated at 570 °C for 6 h. The compacted chips were directly hot-rolled through several successive passes at 490 °C. The bulk material underwent the same rolling schedule to allow comparison of the samples and assess the process, in terms of mechanical properties and microstructure. All the rolled samples were tested by tensile and microhardness tests, whereas the microstructure was observed by an optical microscope and the EBSD-SEM technique. The fracture surface of all tested samples was analyzed by SEM. Recycled samples exhibited good mechanical properties, comparable to those of the bulk material. In particular, the bulk material showed an ultimate tensile strength of 218 MPa, in contrast to 177 MPa for the recycled chips, and comparable elongation at break. This study demonstrates that direct rolling of compacted aluminum chips is both technically feasible and has environmental benefits, offering a promising approach for sustainable aluminum recycling in industrial applications within a circular economy framework.

Ab Initio Investigation of the Mechanics and Thermodynamics of the Cubic EuAlO3 and GdAlO3 Perovskites for Optoelectronic Applications

Perovskites are currently becoming common in the field of optoelectronics, owing to their promising properties such as electrical, optical, thermoelectric, and electronic. Although mechanical and thermal properties also play a crucial part in the functioning of the optoelectronic devices, they have scarcely been explored. The present work performed an ab initio study of the mechanical and thermal properties of the cubic EuAlO3 and GdAlO3 perovskites for the first time using density functional theory. Quantum Espresso and Themo_pw codes were utilized by employing the generalized gradient approximation. Although the results showed that both materials have good mechanical and thermal properties that are ideal for the above–mentioned applications, EuAlO3 possessed better structural and thermal stability, bulk modulus, Poisson ratio, thermal expansion coefficient, and thermal stress; while GdAlO3 possessed better Young’s modulus and shear modulus. Moreover, the mechanical properties of the two materials turned out to be much better than those of the common materials for optoelectronic applications, while their thermal properties were comparable to that of sapphire glass. Since this study was computational, an experimental verification of the computed properties of the two materials needs to be carried out before they can be commercialized.

A Comparative Study on the Wear Resistance of CrNiMo Cast Steels Under Dynamic Load and Ring Block Conditions

Low-alloy CrNiMo cast steels are often used in the caterpillar boards of excavators in mining engineering machinery due to their good mechanical properties and low cost. Three CrNiMo cast steels with different carbon contents (0.20%, 0.29%, and 0.35% by weight) were developed in this work. The mechanical properties of ingots of these cast steels can be optimized by heat-treated quenching and tempering (QT) and surface induction hardening (QTIH). The wear behavior of QT and QTIH specimens was evaluated under dynamic load and ring block conditions. The results show that the QT specimens exhibit a good mechanical performance and wear resistance. Compared to the QT specimens, the wear resistance can be further improved by QTIH treatment. The wear weight loss of QTIH specimens decreased by 42.7% and 73.2% under dynamic load and ring block wear tests, respectively. Additionally, the strength increased while plasticity and toughness decreased with increasing carbon content. Notably, when the carbon content is 0.29%, the CrNiMo cast steel exhibits an excellent combination of strength, ductility, and wear resistance.

Flexible Strain Sensor Based on a Dual Crosslinked Network of PAMgA/GL/PANI Antifreeze Conductive Hydrogel

AbstractConductive hydrogels possess excellent flexibility, conductivity, and sensing properties, making them important carrier materials for flexible strain sensors. They show promising application prospects in fields such as human motion detection and artificial intelligence. This paper introduces polyaniline (PANI) and glycerol (GL) into the magnesium acrylate (AMgA) monomer and prepares the polymagnesium acrylate/glycerol/polyaniline (PAMgA/GL/PANI) hydrogel by free radical polymerization method. When the addition of PANI is 9 wt.%, the PAMgA/GL/PANI hydrogel exhibits good mechanical properties, with a tensile strength of 0.385 MPa, an elongation at break of up to 505%, a compressive strength of 1.04 MPa, and its room temperature conductivity is 1.437 S m−1. Even after freezing at −20 °C, its conductivity can still reach 1.254 S m−1. When the tensile deformation of this conductive hydrogel reaches 500%, the gauge factor (GF) reaches 10.33. In addition, the PAMgA/GL/PANI hydrogel also has good self‐healing, adhesion, and moisture retention. These excellent characteristics make it suitable as a flexible strain sensor that can not only accurately monitor human joint movements and subtle physiological signals but also serve as an encrypted information transmission medium.

Enhancing small diameter tissue engineered vascular grafts with heparin and hepatocyte growth factor: A promising approach.

Currently, there is often a lack of suitable small-caliber graft vessels for treating cardiovascular diseases because of thrombosis and intimal hyperplasia. Tissue engineered vascular grafts (TEVGs) promise a potential solution to this issue. Acellular vascular matrix with good mechanical properties and biocompatibility is commonly used as a tissue engineered scaffold. In this study, acellular rat aortas were preloaded with heparin and hepatocyte growth factor (HGF) to fabricate small diameter TEVGs. In terms of the biomechanical properties, this scaffold was similar to native rat aortas. We implanted this scaffold into a rat abdominal aorta, and the acellular aorta with heparin only was used as control. The patency at 6 months of the two groups was 100%. At 1 month, a complete layer of endothelial cells could be seen on the surface of the vascular lumen of the scaffold with heparin and HGF. The results also showed that the intimal thickness was significantly reduced in the grafts coated with HGF compared to the control grafts. In conclusion, the small-diameter TEVGs constructed by acellular vascular scaffolds coated with heparin and HGF have a promising clinical application prospect.

Study on the physical mechanical properties and freeze-thaw resistance of energy storage concrete with artificial phase change aggregate

As the main material for major infrastructure in cold regions, the mechanical properties and freeze-thaw resistance of concrete have become key scientific issues affecting the safety and normal operation and maintenance of infrastructure in cold regions. Energy storage concrete with phase change materials (PCM) has high thermal storage performance, which is beneficial to improving the frost resistance of concrete. In our preliminary research work, the artificial phase change aggregate (APCA) containing PCM with high latent heat, good mechanical properties and frost resistance were made and tested. The APCA was added to the concrete and replaced with natural coarse aggregate in different proportions, resulting in several energy storage concrete schemes with different APCA contents. The water absorption characteristics, microstructure and pore characteristics of energy storage concrete with different APCA contents were tested and analyzed through negative pressure saturation test, SEM and MIP. The effects of APCA replacement on the composition, mechanical properties, failure morphology characteristics and frost resistance durability of energy storage concrete at various ages were analyzed through XRD test, strength test and freeze-thaw cycle test. The results showed that replacing natural coarse aggregates with APCA changed the pore characteristics of concrete, reduced its saturation water absorption rate, but did not change the composition of hydration products at various ages of concrete. Replacing with an appropriate amount of APCA in concrete is beneficial for reducing the total porosity, the number of more-harmful pores and harmful pores. APCA reduce the compressive strength and splitting tensile strength of energy storage concrete at various ages. The early splitting strength of energy storage concrete increases rapidly, while the later growth is relatively slow. APCA are beneficial for suppressing the expansion of pores and cracks under freeze-thaw action of concrete. APCA is helpful to improve the freeze–thaw resistance of the energy storage concrete. After 100 freeze-thaw cycles, their strength is still 96% of the 28 day strength, and their compressive strength is about 35 MPa. This study provides a reliable experimental and theoretical basis for improving the freezing resistance of concrete in cold area.

Enhancing the oil/water separation efficiency of polylactic acid fiber membrane via polydimethylsiloxane-polycaprolactone copolymer

Membrane technology is one of the important methods of treating oily wastewater due to low energy consumption. How to design the membrane with high efficiency, biodegradable, reusable and good mechanical properties has attracted increasing interest. In this work, a polydimethylsiloxane-polycaprolactone (PDMS- PCL) was synthesized to endow polylactic acid (PLA) fiber membrane with superhydrophobicity and superoleophilicity via electrospinning without secondary processing. When the blend ratio of PDMS-PCL/PLA is 15wt%, the water contact angle of the fiber membrane is 155.1 ± 3°, and the oil contact angle is almost zero. The tensile strength and elongation at break are 2.05 ± 0.16MPa and 37.9 ± 2.3%, respectively. The fiber membrane exhibited high oil/water separation performance and quick adsorption of oil drop underwater. The permeate flux and separation efficiency for n-hexane are 3550 ± 50L·m-2·h-1 and 99.3 ± 0.2%, separately. It also has excellent self-cleaning and durable properties. The fiber membrane maintains high oil flux, separation efficiency, and mechanical properties after more than 10 rounds of separation. The fiber membrane can resist the external environment variation such as to some extent. The water contact angle of the fiber membrane undergoing friction and heating at 100 °C stably remains at about 150°. The weight loss is little in salt solution. Then this simple efficient method is suitable large-scale production and will promote membrane technologies in application of oil/water separation.

3D Printing of Stiff, Tough, and ROS-Scavenging Nanocomposite Hydrogel Scaffold for in Situ Corneal Repair

Despite significant advancements in hydrogels in recent years, their application in corneal repair remains limited by several challenges, including unfitted curvatures, inferior mechanical properties, and insufficient reactive oxygen species (ROS)-scavenging activities. To address these issues, this study introduces a 3D-printed corneal scaffold with nanocomposite hydrogel consisting of gelatin methacrylate (GelMA), poly (ethylene glycol) diacrylate (PEGDA), Laponite, and dopamine. GelMA and PEGDA act as matrix materials with photo-crosslinking abilities. As a two-dimensional nanoclay, Laponite enhances the rheological properties of the hydrogel, making it suitable for 3D printing. Dopamine self-polymerizes into polydopamine (PDA), providing the hydrogel with ROS-scavenging activity. The incorporation of Laponite and the synergistic effect of PDA endow the hydrogel with good mechanical properties. In vitro investigations demonstrated the cytocompatibility of GelMA-PEGDA-Laponite-dopamine (GPLD) hydrogel and its ROS-scavenging activity. Furthermore, in vivo experiments using a rabbit model of lamellar keratoplasty showed accelerated corneal re-epithelialization and complete stromal repair after the implantation of the 3D-printed scaffold. Overall, due to its high bioactivity and simple preparation, the 3D-printed scaffold using GPLD hydrogel offers an alternative for corneal repair with potential for clinical translation. Statement of Significance: The clinical application of hydrogel corneal scaffolds has been constrained by their inadequate mechanical properties and the complex microenvironment created by elevated levels of reactive oxygen species (ROS) post-transplantation. In this study, we developed a kind of nanocomposite hydrogel by integrating Laponite and dopamine into GelMA and PEGDA. This advanced hydrogel was utilized to 3D print a corneal scaffold with high mechanical strength and ROS-scavenging abilities. When applied to a rabbit model of lamellar keratoplasty, the 3D-printed scaffold enabled complete re-epithelialization of the cornea within a week. Three months after surgery, the corneal stroma was fully repaired, and regeneration of corneal nerve fibers was also observed. This 3D-printed scaffold demonstrated exceptional efficacy in repairing corneal defects with potential for clinical translation.

Taxifolin-loaded cellulose/l-arginine-chitosan hydrogel promoting bone defect repair through osteogenesis and angiogenesis.

Bone defects have always been a difficult problem in clinical practice. Taxifolin (TAX) is beneficial to bone regeneration. In order to obtain more attractive biomaterials, we extracted cellulose (LC) from larch sawdust and prepared a TAX-loaded hydrogel (DCT) together with L-arginine chitosan (CA). The hydrogel had a uniform porous structure and good mechanical properties. After drug loading, the adhesion, antibacterial, and antioxidant properties of the hydrogel were improved. In addition, DCT has good biocompatibility. In vitro cell experiment results showed that DCT can promote cell proliferation and migration, and DCT has a certain ability to promote the osteogenic activity and enhance the expression of osteoblastic factors (OCN and Osx) and vascular endothelial growth factor (VEGF) in MC3T3-E1 cells. In addition, in vivo studies showed that the DCT treatment could promote bone regeneration by increasing the levels of osteogenic markers (OPN, OCN, and Osx) and VEGF. Transcriptome analysis showed that DCT intervention affected the hematopoiesis function in bone tissue. Meanwhile, KEGG analysis showed that DCT promoted bone regeneration mainly by activating the PI3K/AKT signaling pathway, which was verified by a western blot. Therefore, DCT is a good material for bone repair.

Three birds with one stone: Preparation of multifunctional Fe-MOF/PAN nanofiber membranes for wastewater treatment

In this research, a new NH2-MIL-88B(Fe)/polyacrylonitrile nanofiber membrane (NPNFM) was synthesized utilizing a straightforward electrospinning technique. The morphological characteristics and performance of nanofiber membranes were finely tuned via adjusting the dosage of NH2-MIL-88B(Fe) (NM88B, the “stone”). The prepared NPNFM exhibits superhydrophilicity/underwater superoleophobicity, coupled with outstanding photo-Fenton self-cleaning ability (the first two “birds”). This membrane efficiently and swiftly facilitated the separation of various surfactant-stabilized emulsions under gravitational force, achieving a separation efficiency and flux of up to 99.5 % and 350.3 L m-2h−1, respectively. The fouling on the membrane surface can be rapidly decomposed, attributing to the superior photo-Fenton activity of NM88B. Furthermore, the organic dye methylene blue (MB) was degraded by 97.4 % within 40 min under the catalytic influence of the membrane. The nanofiber membrane has good mechanical properties and its tensile strength is about 2.3 times that of the original membrane attributing to the good compatibility between NM88B and the membrane matrix (the third “bird”). This study proposed new Fe-MOF-based photo-Fenton multifunctional membranes with the characteristics of environmental stability and high efficiency in wastewater treatment fields.

Hydridoborate‐Based Solid‐State Electrolytes for Sodium Metal Batteries

AbstractHydridoborates have emerged as promising candidates for solid‐state electrolytes in sodium metal batteries owing to their high ionic conductivity, thermal/electrochemical stability, good mechanical properties, and good interface compatible with electrodes. This review provides a comprehensive analysis of the recent advancements in the development and application of Na‐hydridoborate‐based solid‐state electrolytes. We explore the structural properties and electrochemical behaviors of various Na‐hydridoborates, including NaBH4, NaB3H8, closo‐borates, nido‐borates, etc. Additionally, we discuss the approaches for the synthesis of hydridoborate compounds with inexpensive raw chemicals and low toxicity. This review will inspire further efforts to develop fast Na‐ion conducting hydridoborate materials with favorable interfacial compatibility, to promote their applications in high‐performance all‐solid‐state sodium metal batteries.

Facile preparation of soybean protein-based oil-resistant paper for food packaging

The use of plastic packaging is harmful to the environment. Due to the advantages of degradability, renewability, and safety of paper packaging materials, replacing plastic with paper has received much attention. However, the poor oil resistance of traditional paper constrains its application. In this research, oil-resistant agent is prepared using soy protein isolate and montmorillonite through physical blending. This oil-resistant agent has advantages of low cost and food safety. Subsequently, food packaging oil-proof paper is obtained by coating the above-mentioned coating on paper. This oil-proof paper has good heat resistance, oil resistance (kit rating is 8/12) and mechanical properties. In addition, it is found that the optimal storage environment for the oil-proof paper. This study provides a feasible method for producing, biodegradable, and eco-friendly food packaging oil-proof paper.

The osteogenic effect of mesenchymal stem cells regulated by photo‐crosslinked hydrogels with tunable elastic modulus

AbstractBiomimicry is the enduring pursuit in the field of bone implants, wherein bio‐materials with adjustable elastic modulus and porosity, the same as natural bone, offer a novel strategy for developing and applying new bone repair materials. Conventional biomaterials are often used to repair bone defects without complete consideration of structural and functional osseointegration, leading to interface repair failure. In this study, organic‐inorganic interpenetrating network technology was employed using varying amounts of nano‐hydroxyapatite (nHAP) and methacrylated gelatin (GelMA) and osteogenic growth peptide (OGP) to construct biomimetic bones with low, medium, and high nano‐hydroxyapatite content (GelMA‐c‐OGP/nHAP). As the concentration of nano‐hydroxyapatite increases, comprehensive evaluations of the biomimetic materials were conducted using osteogenic ability tests, Micro‐CT scans, nanoindentation tests, and mechanical tests. The developed biomimetic structural material exhibits well‐controlled mechanical properties. Compared to natural bone trabeculae, this biomimetic material not only maintains the organic and inorganic ratio of natural bone but also demonstrates exceptional mechanical load‐bearing capabilities. Additionaly，this scaffold exhibits good porosity and mechanical properties. It enhances cell adhesion, integrates perfectly with bone tissue, and demonstrates excellent osteogenic ability both in vitro and in vivo. This study lays the foundation for constructing biomimetic scaffolds with adjustable mechanical properties, presenting high prospects for applications in the field of tissue engineering.

Recycling B4C grinding waste to fabricate high-performance ceramics by modification treatments and hot pressing

B4C grinding waste, originated from the fine grinding process of sapphire wafers, is discarded without reutilization, which causes environmental pollution and resource waste. This work proposes new methods on recycling B4C grinding waste to fabricate high-performance ceramics by first modification treatments via ball-milling mixing or microwave digestion with sulfuric acid and then hot pressing. The characteristic of B4C grinding waste is studied and Al2O3 is the main impurity. The direct hot pressing of B4C grinding waste is performed and the obtained ceramic is fragile. The large-size and unevenly distributed Al2O3 is verified to cause the fracture according to the structure analysis. Ball-milling mixing can break the Al2O3 agglomerate and make Al2O3 distribute evenly, and microwave digestion with sulfuric acid can remove most Al2O3. The ceramics fabricated via hot pressing with B4C grinding waste treated with ball-milling mixing or microwave digestion show good microstructure and mechanical property. The relative density, hardness, flexural strength and fracture toughness of the ceramics fabricated with grinding waste treated with ball-milling mixing are 98.82%, 32.42 GPa, 439.44 MPa, 4.82 MPam1/2, respectively, higher than those of the ceramics fabricated with grinding waste treated with microwave digestion, which are 98.69%, 29.54 GPa, 368.18 MPa, 4.20 MPam1/2, respectively. This work not only realizes the secondary utilization of waste and avoids pollution, but also provides another way supplying the high-cost B4C powder and ceramic, which has high economic benefits.

Development of a high-strength lightweight geopolymer concrete for structural and thermal insulation applications

Investigating the thermal insulation properties of lightweight geopolymer concrete is essential. This paper aims to develop a lightweight aggregate geopolymer concrete (LWAGC) with good density, compressive mechanical and thermal insulation properties. The dry density of LWAGC was adjusted by incorporating expanded perlite (EP). The variation in physical and mechanical properties of LWAGC with different EP content was discussed, including dry density, P-wave velocity, ultimate compression strength and elastic modulus. Based on infrared thermal imaging technology, a rapid measurement method was proposed to simulate the indoor temperature change of buildings at high ambient temperatures. The thermal insulation performance of the LWAGC with different EP contents was further evaluated. The findings show that as the EP content in LWAGC increases, there is a corresponding decrease in P-wave velocity, dry density, ultimate compressive stress, and elastic modulus. The lowest dry density of LWAGC reaches 1209kg/m3 while the ultimate compressive stress is still larger than 25.0MPa, which can used as LC25 building materials in load-bearing structures. The results also show that the addition of EP can improve the thermal insulation properties of LWAGC. The LWAGC with 50% EP content has the highest reduction rate of temperature and can maintain the indoor temperature lower than 35 °C under high ambient temperature, which have potential application prospects in the load-bearing structures and thermal insulation of tall buildings.

Rubber-assisted and modulated epoxy topological network for developing fatigue-resistant, high-strain-cycle high performance shape memory polymer composites

High performance shape memory polymer (HPSMP) has a wide range of application such as smart device, smart mold. In this study, we designed a rigid-flexible shape memory epoxy with flexible chain segment as the main chain and rigid benzene ring as the side group. Meanwhile, carboxyl-terminated nitrile butadiene rubber (CTBN) was accessed into the epoxy main chain as a fatigue-resistant functional filler. The results showed that the flexible backbone plays a major role in improving the ductility. The superior fatigue-resistant shape memory cycling performance was synergistically achieved by modulating the epoxy topological network through altering the disulfide cross-linker prompted by CTBN, and the materials exhibited good high and low-temperature resistant mechanical properties. Comparatively, it is found that disulfide bonding can significantly improve the tensile property and thermal stability for epoxy. The synergistic effect between the elastic chain segments in CTBN and the flexible backbone achieves excellent shape recovery ratio. Therefore, the rational structural design provides an effective way to develop HPSMP, which can expand the application areas for HPSMP.