MATERIALS & DESIGN
·
2014
·
IF 3.171
Ziqing Cai,Xiaoyu Meng,Haimu Ye,Chuanbo Cong,Yufeng Wang,Lishan Cui,Qiong Zhou
In this study, the mechanical properties and structure orientation of pure polyamide 1212 (PA1212) were compared with those of PA1212–carbon nanofibers (CNFs) nanocomposites. The tensile strength of the composite containing 0.3 wt.% modified CNFs was improved from 328 MPa (pure PA1212) to 373 MPa after drawing. The reinforcing effect was investigated in terms of crystallization behavior, crystal morphology, alignment of CNFs, and crystal orientation degree. Spherulites developed into oriented crystals after drawing, and the CNFs aligned along the drawing direction. The heterogeneous nucleation effect of the aligned CNFs improved the crystal orientation degree, which produced the reinforcing effect. The oriented fibril structures with rigid nanofibers acting as nuclei reinforced the entire oriented crystals in the composites.
研究领域:
材料科学
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Jiabao Wang,Qian Gao,Yuda Wang,Xinliang Liu,Shuangxi Nie
Orderly arranged nanocellulose and its composite materials have low density and excellent mechanical properties. A self-twisted microfluidic chip is designed in this work. Its sheath channel and core channel form a staggered layer structure. This structure can make the Cellulose nanocrystals (CNCs) in the core flow undergo twist during the gel forming process, so that it can be better combined and its mechanical properties can be improved. The degree of orientation and mechanical properties of fiber filaments were studied by wide-angle X-ray scattering and universal tensile testing machine. The orientation degree of the fiber is 0.77, the tensile strength is 400 ± 20 MPa, and the Young ' s modulus is 37.3 ± 3.8 GPa. The torsion angle of fiber surface is 5.5°. The mechanical properties of the filaments are 150% higher than those of a previously reported filament made of pure CNCs. This work demonstrates the possibility of preparing high-strength CNCs fiber filaments.
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
·
2022
·
IF 5.532
Zhuo Tian,Jianning Lu,Xiaowei Feng,Bo Feng,Cuicui Yin,Yingfei Lin,Juan Wang
h-BN is a two-dimensional ceramic material with a lamellar structure , known for its typical orientation characteristics on mechanical and thermal properties. By optimizing the size and arrangement of h-BN grains in the matrix, the anisotropic characteristics of h-BN ceramics can be fully utilized to obtain ceramic materials with high thermal conductivity or high strength . In order to study the effect of grain orientation distribution on the mechanical and thermal properties of materials, the index of orientation distribution (IOP) was used to quantitatively characterize the orientation degree of h-BN grains and analyzed the effect of h-BN grain size on material properties . The results show when the initial h-BN size is 13.50 μm, the ceramic has the highest orientation degree/-507, and the mechanical and thermal properties show obvious anisotropy. While the related properties of BN-YAG ceramics varies significantly with the decrease of initial h-BN grain size.
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
CHINESE JOURNAL OF POLYMER SCIENCE
·
2016
·Vol. 34
·期 11
·1373-1385
·
IF 1.811
An Min-fang,Xu Hao-jun,Lv You,Zhang Li,Gu Qun,Tian Feng,Wang Zong-bao
Ultra-high molecular weight polyethylene (UHMWPE)/chitin nanocrystal (CNC) fibers were prepared. Compared with the pure UHMWPE fibers, the ultimate tensile strength and Young’s modulus of UHMWPE/CNC fibers are improved by 15.7% and 49.6%, respectively, with the addition of chitin nanocrystals (CNCs) of 1 wt%. The melting temperature ( T
m ) of UHMWPE/CNC fibers was higher than that of pure UHMWPE fibers. Pure UHMWPE fibers and UHMWPE/CNC fibers were characterized with respect to crystallinity, orientation and kebab structure by wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS) and scanning electron microscopy (SEM). It is found that the CNCs act as the shish structure in UHMWPE/CNC fibers and the kebab crystals are grown around the CNCs. There was almost no difference between pure UHMWPE fibers and UHMWPE/CNC fibers in orientation. But the degree of crystallinity of various stages of UHMWPE/CNC fibers was respectively higher than the corresponding stage of pure UHMWPE fibers. Moreover, the addition of 1 wt% CNCs improved the thickness of kebab crystals and accelerated the transformation of kebab to shish.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 43
·e56125
·
IF 2.7
Yong Liu,Shengtao Dai,Peipei Guo,Honglong Li,Zongwei Guo,Lei Shang,Yuhui Ao
Polyacrylonitrile (PAN)-based precursor fibers with different mechanical properties prepared by wet-spinning and its correlation with microstructure was researched, the primary structural factors that affecting its properties were analyzed. The tensile strength and modulus of precursor fibers increased from 4.63 cN/dtex to 9.16 cN/dtex and 99.09 cN/dtex to 168.92 cN/dtex, respectively, with the increase in crystallinity from 69.29% to 87.84% and orientation degree increased from 83.95% to 93.81%, high performance precursor fibers could be achieved by decrease in the crystallite size and interlayer spacing, these aggregation structure plays a decisive role to the mechanical properties of fibers. The integrality of aggregation structure and properties could reflected by boiling water shrinkage behavior and glass transition temperature from the side. The fracture morphology of fibers with different properties were studied by scanning electron microscope (SEM) and three fracture characteristics were observed, PF1 and PF3 presented the radial extended fracture without microfibril pull out, radial cluster fracture with the pull out of microfibril for PF2, PF4–PF6, together with the axial splitting pattern in PF6, which was revealed by microfibrils/fibrils in longitudinal and transverse combined with solution etching. Precursor fibers with less voids, without serious skin-core, continuous arrangement, tightly stacked, well-developed and complete oriented microfibrils/fibrils, exhibited excellent mechanical properties. Possible fracture process was given from the perspective of aggregation structure and microfibrils/fibrils, which become dominant factors determining properties of precursor fibers. Improve the performance could be achieved by regulating surface structure and cross-sectional shape. As one of the main structural factors that determining properties, by reducing diameter could minimize the numbers and sizes of defects.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Dejun Liang,Xiaojuan Li,Yufeng Pi,Chenchen Xin,Mingyong Ren,Wei Long,Jie Wu,Pinyang Fang,Feifei Guo,Aiguo He,Zengzhe Xi
In this study, anisotropy strategy was employed to effectively enhance the piezoelectric performance and energy harvesting capability of 6 Pb(Sc 1/2 Nb 1/2 )O 3 -61 Pb(Mg 1/3 Nb 2/3 )O 3 -33PbTiO 3 (Abb. 6PSN–61PMN–33PT) ceramics. A high crystallographic orientation (Lotgering factor F 001 exceeding 98.5 %) was obtained in 6PSN–61PMN–33PT textured ceramics using the template grain growth (TGG) method. The piezoelectric response of 6PSN–61PMN–33PT ceramics was significantly improved, while the dielectric constant ( ε r ) was reduced. Compared to random ceramics, the textured ceramics exhibited higher figure of merit ( d 33 × g 33 ), markedly enhanced electromechanical coupling factor ( k p ) and piezoelectric coefficient ( d 33 ). The optimal properties were obtained in 6PSN–61PMN–33PT textured ceramics with 1 wt% BaTiO 3 template: d 33 = 1179 pC/N, k p = 0.87, ε r = 2766， d 33 × g 33 = 5.67 × 10 −11 m 2 /N, dielectric loss tan δ about 0.56 %, mechanical quality factor Q m = 194, and piezoelectric strain constant d 33 ∗ = 1130 pm/V and maximum strain S = 0.23 % at 20 kV/cm. These results demonstrate that 6PSN–61PMN–33PT textured ceramics hold promising application potential in energy harvesters.
研究领域:
材料科学
·
功能陶瓷
·
压电器件
·
能量采集
·
先进制造
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2012
·Vol. 19
·期 12
·1-8
·
IF 1.733
Ma Chi,Wang Bing,Xiong Cheng-Dong,Chen Dong-Liang,Xiong Zuo-Chun
Control of dimensional stability is crucial for using electrospun membranes in biomedical and tissue engineering applications. In this study, the contraction of electrospun membranes of poly( l -lactide-co-glycolide) (PLLGA) after stretch was investigated. Then, by adding PLLGA-b-polyethylene glycol (PLLGA-PEG), the contraction of the membranes was controlled. In addition, the mechanical properties of the membranes were investigated. On the basis of the strain–stress behavior of the membranes, an elongation of 50 % was used to investigate the orientation degrees of the membrane fibers. On the basis of the morphology of the stretched membranes, the contraction was found to depend on the orientation degree of fibers after stretch. A linear relationship between the contraction and degree of orientation after stretch was confirmed. Two-dimensional fast Fourier transform (2D FFT) analysis of the scanning electron microscopy (SEM) images of the membranes was used to quantify the orientation degree. It was surmised that the different orientation degrees were responsible for the different morphologies and thermal behaviors of the membranes.
研究领域:
生物医学工程
·
组织工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2016
·
IF 3.85
Chen Pan,Kaichang Kou,Qian Jia,Yu Zhang,Guanglei Wu,Tiezheng Ji
To achieve polymer-based composites for electronic packaging with low dielectric constant, low dielectric loss tangent and high thermal conductivity , silane coupling agent KH550 modified hexagonal boron nitride (hBN) platelets were introduced into PTFE matrix via a cold pressing and sintering method. The effect of surface treatment on the morphology, thermal conductivity and dielectric properties of the composites was investigated. The results revealed that after surface treatment, the interfacial adhension between hBN platelets and PTFE matrix was improved and the in-plane orientation degree of hBN platelets in PTFE matrix decreased, which effectively improvd the thermal conductivity of the composites. The thermal conductivity of hBN-KH550/PTFE composite with 30 vol% filler content is 0.722 W/mK, which is 2.7 folds of pure PTFE. Moreover, the enhanced interfacial adhension and reduced surface hydrophilicity of hBN platelets significantly decreased the interfacial polarization , resulting in not only lower dielectric constant and dielectric loss tangent but also weaker frequency-dependence.
研究领域:
材料科学
·
复合材料
·
电子封装
·
热管理
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）