Coatings
·
2023
·Vol. 13
·期 2
·475
·
IF 3.4
Shuai Guo,Fusheng Zhu,Zhimeng Xiu,Mu Zhang,Xudong Sun
In this study, a type of micro-nano Si3N4matrix ceramic cutting tool material was successfully prepared by controlling the addition amount of TiC0.7N0.3and the hot-pressing sintering temperature. The effects of different volume fractions of TiC0.7N0.3on the microstructure, mechanical properties, particle size distribution, and relative density of Si3N4ceramic tools at the same temperature were investigated. The results show that the addition of TiC0.7N0.3makes the β-Si3N4grains with different diameters and aspect ratios interlaced and tightly bonded, thus achieving the strengthening and toughening effects. In addition, the effects of different hot-press sintering temperatures on the properties of Si3N4ceramic tool materials were studied. It was concluded that the density of the material increased with the increase of the hot-pressing temperature. The relative density, flexural strength, and fracture toughness of the samples with 1 vol% TiC0.7N0.3added at 1750 °C and 30 MPa pressure reached 99.22%, 993 MPa, and 9.81 MPa·m1/2, respectively.Keywords:Si3N4;ceramic cutting tool;hot-pressing sintering;TiC0.7N0.3;self-toughening
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 9
·1403
·
IF 3.164
Lifen Tong,Xiting Lei,Guangyao Yang,Xiaobo Liu
A novel poly(arylene ether nitrile) terminated with hydroxyl groups (PEN–OH) was synthesized successfully. The effects of heat-treatment temperature on the thermal properties, mechanical properties, and dielectric properties of the PEN–OH films were studied in detail. Due to the cross-linking reaction occurring, at high temperature, among the nitrile groups on the side of the PEN–OH main chain to form a structurally stable triazine ring, the structure of materials changes from a linear structure to a bulk structure. Thus, the thermal properties and mechanical properties were improved. In addition, the occurrence of cross-linking reactions can reduce the polar groups in the material, leading to the decrease of dielectric constant. As the heat-treatment temperature increased, the glass-transition temperature increased from 180.6 °C to 203.6 °C, and the dielectric constant decreased from 3.4 to 2.8 at 1 MHz. Proper temperature heat-treatment could improve the tensile strength, as well as the elongation, at the break of the PEN–OH films. Moreover, because of the excellent adhesive property of PEN–OH to copper foil, a double-layer flexible copper clad laminate (FCCL) without any adhesives based on PEN–OH was prepared by a simple hot-press method, which possessed high peel strength with 1.01 N/mm. Therefore, the PEN–OH has potential applications in the electronic field.Keywords:low dielectric constant;poly(arylene ether nitrile);thermal properties;self-toughening;self-enhancement
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2024
·
IF 4.1
Qingchen Lu,Xiaoming Zhang,Yexiong Qi,Haibo Yuan,Guoli Li
Polyvinyl alcohol (PVA) has excellent physical and chemical properties; however, its rigidity easily leads to brittleness and breakage during use. Additionally, due to intramolecular hydrogen bonding, the dense structure of the film limits its application. This research used a self-toughening approach by homogeneously blending PVA 0588 and PVA 0499 with different molecular weights to enhance the toughness of PVA and create a porous structure for broader application in membrane separation. Porous PVA membranes were then produced through mechanical stretching. Rheological testing, differential scanning calorimetry, and dynamic thermomechanical analysis confirmed that the blend system is partially compatible. Mechanical characterization revealed that adding PVA 0499 decreased the tensile modulus, strength, and bending modulus of the blended film but increased the elongation at break, reaching a maximum of 179 %. This result indicates that homogeneous blending effectively achieved PVA self-toughening. After this, the PVA blended membrane underwent mechanical stretching. Results showed that the stretched membrane developed a porous structure with a PVA 0588 content of 60 wt%, yielding a pure water flux of 70.3 L m −2 h −1 MPa −1 and a glucan rejection rate of 91.07 %. The molecular weight cut-off test demonstrated that the resulting porous membrane was suitable for water treatment, effectively filtering substances with a molecular weight of ≥70 kDa. The membrane also exhibited notable antifouling properties. The hydrophilicity and high roughness of the porous membrane facilitated the formation of additional hydrogen bonds between the membrane surface and water molecules, thereby reducing direct contact between pollutants and the membrane surface. This study provides preliminary theoretical and experimental insights into enhancing PVA toughness and expanding its applications in membrane separation. Furthermore, homogeneous blending opens new avenues for improving the mechanical performance of polymers.
研究领域:
材料科学
·
化学工程
·
环境工程
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Materials Interfaces
·
2020
·Vol. 7
·期 15
·2000499
·
IF 4.948
Xidong Suo,Yuxiu Yu,Zhuo Cao,Yaodong Liu
The responsive behaviors of graphene oxide (GO)-based films under external straining make it possible to develop man-made adaptive materials. Some researches have suggested that GO nanosheet alignment plays important roles in dynamic stiffening behaviors; however, the effects of inter-sheet interactions have not been thoroughly investigated. In this study, the GO interlayer interactions are tuned by third components, including hydrophilic nanofumed silica (SiO 2 ) nanoparticles, chemically modified SiO 2 nanoparticles, and waterborne polyurethane particles, and their stiffening behaviors and structural changes during periodic external straining are systematically characterized. During external dynamic straining, the storage modules ( E ′) of GO-based composite films increases up to 55.5% after 12 h. It is observed that the interlayer adhesion is important for the self-stiffening behaviors of GO-based films. The interaction types, including reversible H-bonding and non-reversible chemical bonding, play different roles on the structural-responsive behaviors. During external dynamic straining, the interlayer contact between GO nanosheets is improved, and the higher interlayer adhesion leads to improved mechanical properties, instead of the improvement of GO sheet orientation. These findings are helpful to better understand the responsive behaviors of nanomaterials as well as to develop new types of man-made adaptive materials.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Chun Li,Yue Ma,Jian He,Hongbo Guo
Sandwich structure of cubic (C) phase/monoclinic (M) phase/C phase was formed in 8% mol Y 2 O 3 partially stabilized HfO 2 (Hf 0.92 Y 0.08 O 1.96 , YSH8) samples which were produced by sintering of YSH8 green body cold pressed from nano-powders of C phase at 1500 °C. The geometry of the sandwich structure was approximately tailored by controlling the sintering time. The YSH8 samples with sandwich structure from nano-powders yielded fracture toughness of 2.1–2.4 MPa m 0.5 , which was about 33% higher than that of conventional YSH8 sample sintered from micron powders. Both the experimental results and numerical simulation indicated that the fracture toughness is closely related to the geometry of the sandwich structure.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）