Materials Express
·
2020
·Vol. 10
·期 6
·928-933
·
IF 1.65
Tian Liang,Hou Qinglin,Wang Yingxia,Hou Yihui
Si3N4 ceramic has excellent properties such as high temperature resistance, high hardness, and high thermal stability, but it has the disadvantages of high hardness and brittleness and difficulty in later processing. In this paper, ZrO2 was used as toughening
phase, and ZrO2 toughened Si3N4 ceramics was prepared by injection molding. The effects of ZrO2 sintering temperature and content on the mechanical properties and fracture morphology were studied. Experiments show that when the ZrO2 content
is 10 wt.% and the sintering temperature reaches 1650 °C, the bending strength and fracture toughness of Si3N4 ceramics reach the maximum at the same time, which are 767 MPa and 8.7 MPa·m1/2, respectively. The density is high. XRD analysis revealed
that if the sintering temperature is too high, the ZrO2/Si3N4 system will generate a large number of ZrN impurity phases that cannot be phase-transformed, which ultimately affects the ceramic properties. According to fracture morphology, the toughening mechanism
of ZrO2 is stress-induced phase transition.
研究领域:
材料科学
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机械工程
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 47
·51413
·
IF 3.125
Rong Yang,Hongwei Cao,Chong Li,Guoxiang Zou,Xin Zhang,Jinchun Li
Reactive interfacial compatibilization is the most efficient way to prepare super-tough poly (lactic acid) (PLA) materials. Introducing a post-reactive group into a toughening agent that can react with PLA is the key issue. Herein, we reported a series of fully bio-based polyesters (PBSePM) synthesized with sebacic acid, diethyl malate, 1,3-propanediol, and 1,4-butanediol via transesterification in one pot. Super-tough PLA materials can be obtained by reactively blending with PBSePM in the presence of hexamethylene diisocyanate (HDI). In the processing, the side hydroxyl group of the PBSePM reacted with HDI and formed polyurethane elastomer to improve the toughness of PLA. Moreover, the in-situ formed PLA- g -PBSePM grafted copolymer enhanced the interfacial adhesion. With increasing diethyl malate moiety in PBSePM, the PBSePM phase morphology transformed from co-continuous phase structure to semi-continuous and “sea-island” phase structure. When adding 20 wt% PBSePM, all PLA/PBSePM blends have a notched impact strength higher than 53 kJ m −2 , suggested a super toughness effect. Maximum impact strength of 83 kJ m −2 was realized while the PBSePM containing 20% diethyl malate moiety. In addition, super-tough PLA materials can be achieved by only adding 15 wt% PBSePM20, exhibited a highly efficient toughening effect.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 8
·1320
·
IF 3.164
Ailing Sun,Wenjuan Guo,Wenjuan Li,Xin Liu,Hao Zhu,Yuhan Li,Liuhe Wei
Conventional approaches to synthesize thermoplastic polyurethane (TPU) with excellent robustness are limited by a competing relationship between soft and hard segments for tuning mechanical properties in terms of chain flexibility and micro-phase separation. Herein, we present a facile and effective way of simultaneously improving the tensile strength, elongation, and toughness by constructing dynamic cross-linkages from metal-ligand interaction between Zn2+and pyridine moiety in backbone of poly(urethane urea) (PUU) derived from 2,6-diaminopyridine and poly(propylene glycol). It was found that a Zn2+/pyridine ratio of 1:4 is the most effective for improving robustness. Specifically, tensile strength, elongation, and toughness could be remarkably increased to 16.0 MPa, 1286%, and 89.3 MJ/m3with 226%, 29%, and 185% increments compared to uncomplexed PUU, respectively. Results from UV-vis, Fourier transform infrared spectroscopy (FTIR), cyclic tensile tests, and stress relaxation reveal that metal-ligand interaction significantly interferes with the hydrogen bonding of urea groups, thus leading to weakening of stiffness. Furthermore, half of vacant ligands enable dynamic complexation during stretching, which consequently ensures constant noncovalent cross-linkages for constraining mutual chain sliding, contributing to simultaneous improvement of tensile strength, elongation, and toughness. This work provides a promising approach for designing TPU with excellent robustness.Keywords:toughening;strengthening;dynamic cross-linkages;metal-ligand;TPU
研究领域:
材料科学
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高分子化学
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DOI
PubMed
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
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电子工程
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PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2014
·Vol. 132
·期 1
·
IF 1.64
Zhu Xiong,Xinyan Dai,Haining Na,Zhaobin Tang,Ruoyu Zhang,Jin Zhu
In this manuscript, a toughened PLA/nanosilica composite with good storage stability was obtained in the presence of the epoxidized soybean oil (ESO). The composite was fabricated via a twin-screw extruder, and characterized by the FTIR, selective distribution test, and SEM. The surface of nanosilica was modified by the ESO through the chemical bonding, and this rendered the nanosilica to selectively localize in ESO droplets in the composite. As a result, the PLA/nanosilica composite was changed from brittleness to ductility with the addition of ESO. For example, the elongation and notched impact strength of the PLA/silica/ESO nanocomposite with 5 wt % nanosilica and 15 wt % ESO were ∼42% and ∼11 KJ/m 2 , respectively, which were much higher than neat PLA or PLA/nanosilica composite without ESO. Furthermore, the change of the brittle fracture of PLA into ductile fracture was investigated by SEM micrographs in detail. A possible toughening mechanism was also proposed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41220.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
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2016
·Vol. 34
·期 9
·1070-1078
·
IF 1.811
Feng Li-dong,Xiang Sheng,Sun Bin,Liu Yan-long,Sun Zhi-qiang,Bian Xin-chao,Li Gao,Chen Xue-si
Poly(ether urethane)s (PEU), including PEUI15 and PEUH15, were prepared through chain-extension reaction of poly(ethylene glycol) (PEG-1500) using diisocyanate as a chain extender, including isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI). These PEUs were used to toughen polylactide (PLA) by physical and reactive blending. Thermal, morphological, mechanical and aging properties of the blends were investigated in detail. These PEUs were partially compatible with PLA. The elongation at break of the reactive blends in the presence of triphenyl phosphate (TPP) for PLA with PEUH15 or PEUI15 was much higher than that of the physical blends. The aging test was carried out at -20 °C for 50 h in order to accelerate the crystallization of PEUs. The PEUs in the PLA/PEU blends produced crystallization and formed new phase separation with PLA, resulting in the declined toughness of blends. Fortunately, under the aging condition, although PEUH15 in blends could also form crystallization, the reactive blend of PLA/PEUH15/TPP(80/20/2) had higher toughness than the other blends. The elongation at break of PLA/PEUH15/TPP(80/20/2) dropped to 287% for the aging blend from 350% for the original blend. The tensile strength and modulus of PLA/PEUH15/TPP blend did not change obviously because of the crystallization of PEUH15.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 134
·期 18
·
IF 1.86
Binshuang Wu,Xiaoqing Zeng,Linbo Wu,Bo-Geng Li
In order to obtain high performance bioplastics and thermoplastic elastomers, P(LLA-mb-BSA) multi-block copolymers containing 30 wt % and 70 wt % soft segment (PLBSA30 and PLBSA70 for short) were synthesized via chain extension and coupling of poly(L-lactic acid) (PLLA) and poly(butylene succinate -co- adipate) (PBSA) prepolymers in the presence of 1% nucleating agent (NA). They were characterized with proton nuclear magnetic resonance ( 1 H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), polarizing optical microscopy (POM), thermal gravimetric analysis (TGA), transmission electron microscope (TEM), and tensile and impact test. The relatively high molecular weights of ( M n 8200 g/mol and 3100 g/mol for PLLA and PBSA, respectively) the polyester sequences are helpful to improve the PLLA crystallization and the flexibility of the PBSA soft segment. Nucleation effect further accelerates the crystallization of PLLA segment. The synergistic effect of these factors results in good balance between stiffness and toughness. PLBSA30s containing 1% zinc citrate (ZnCC) or talc behave as ultra-tough bioplastics with ultrahigh impact strength over 50 kJ/m 2 and excellent tensile properties. PLBSA70 containing 1% ZnCC possesses elongation at break of 600% and retains high modulus (56 MPa) and strength (16 MPa) and therefore behaves as an excellent thermoplastic elastomer. The excellent and balanced properties would extend the end applications of these PLLA-based materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44777.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Jiongjiong Li,Ruohong Bian,Pu Liu,Zhiqin Wang,Yan Lyu,Xiaona Li,Jing Luo,Jianzhang Li
Phenolic resins are widely utilized in outdoor and structural wood-based panels; however, their high curing temperatures and brittleness have constrained their potential applications. This study developed a fast-curing phenolic resin (HPAQ/PF) with enhanced toughness and strength, achieved by incorporating a quercetin-functionalized hyperbranched polymer (HPAQ) into a phenol-formaldehyde (PF) resin. The HPAQ was synthesized by grafting biomass-derived quercetin onto an amino-terminated hyperbranched polymer. The phloroglucinol structure of quercetin, in conjunction with the amino groups, significantly accelerated the curing process of the HPAQ/PF resin. Consequently, the gel time was reduced from 593 s to 274 s, while the initial and maximum curing temperatures decreased from 155.6 °C and 202.4 °C to 128.7 °C and 171.7 °C, respectively. The moisture uptake value of the HPAQ/PF resin was reduced from 28 % to 7 % compared to the PF resin. The boiling water bonding strength and debonding work of the HPAQ/PF resin were measured at 1.75 MPa and 0.780 J, respectively, which were 51 % and 105 % higher compared to the 1.16 MPa and 0.380 J of the PF resin. These improvements were attributed to the enhanced compatibility and strong interfacial interactions between HPAQ and the PF chains, as well as the unique branched structure and intramolecular cavities of HPAQ. This study presents a simple and effective approach to enhance the curing speed and toughness of phenolic resins.
研究领域:
材料科学
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化学工程
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高影响因子
RSC Advances
·
2020
·Vol. 10
·期 4
·2085-2095
·
IF 3.119
Bingyan Yin,Wenqing Xu,Chengjun Liu,Miqiu Kong,Yadong Lv,Yajiang Huang,Qi Yang,Guangxian Li
Poly(ionic liquid) (PIL), integrating the characteristics of both polymers and ionic liquid, is synthesized and employed to modify diglycidyl-4,5-epoxy-cyclohexane-1,2-dicarboxylate (TDE-85). With the addition of PIL, the fracture toughness, and thermal and dielectric performances of TDE-85 were discovered to be simultaneously improved, meanwhile the tensile modulus and strength is increased. Upon an optimal loading of 3 wt% PIL, the critical stress intensity factor (KIC), tensile modulus and strength are raised by 92.9%, 13.3% and 10.7%, respectively. Multi-toughening mechanisms due to spherical domains of PIL formed in TDE-85 during curing are responsible for the improved toughness. Moreover, the dielectric and thermal properties of TDE-85 are also enhanced by adding PIL. With the optimal addition of 5 wt% PIL, the dielectric constant of the composites is enhanced by 62.5%, the glass transition temperature is increased by 16.58 °C and the residual weight of carbon is increased by 59%.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS CHARACTERIZATION
·
2022
·
IF 4.537
Jianjun Zhang,Ziqiao Wang,Jiajun Luo,Subin Wang,Bingliang Liang,Weihua Chen
MoSi 2 is the most potential high temperature structural materials that can be used in aerospace and aviation industry. But its fracture toughness is low and its low temperature oxidation resistance is poor, which limits its application. To solve these problems, novel MoSi 2 @ZrO 2 core-shell composites were prepared by spark plasma sintering (SPS) at 1300 °C⁓1500 °C. The influences of sintering temperatures on the microstructures, mechanical properties and tribological properties of the composites were studied. It was found that the relative density, Vickers hardness , bending strength and fracture toughness of the composites first ascended and then descended with the sintering temperature rising from 1300 °C to 1500 °C. As the sintering temperature reached 1400 °C, the maximum relative density, the maximum Vickers hardness , the maximum bending strength and the maximum fracture toughness of the composite material achieved 97.5%, 1103 HV, 540 MPa and 7.96 MPa·m 1/2 , respectively. Additionally, the friction coefficient of the composite materials first descended and then ascended with sintering temperature rising. As the sintering temperature reached 1400 °C, the minimum friction coefficient was about 0.355. Moreover, we analyzed the relations between the mechanical properties and microstructure. The toughening mechanisms of the MoSi 2 @ZrO 2 composites were also discussed. In addition, during cyclic isothermal oxidation at below 600 °C, weight gains of the MoSi 2 @ZrO 2 composites evidently decreased, compared with that of pure MoSi 2 , proving better low-temperature oxidation resistance .
研究领域:
材料科学
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机械工程
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产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2024
·
IF 4.8
Zhongyuan Xie,Xinyu Li,Qiyuan Zhang,Hua Jiang
Currently, toughening poly(lactic acid) (PLA) without reducing its strength and modulus is still challenging. Fortunately, this problem could be addressed by incorporating cellulose nanocrystals grafted with epoxidized soybean oil (CNCs-g-ESO) into the PLA matrix. The percolation threshold for uniform dispersion of the CNCs-g-ESO in the PLA matrix was about 0.8 wt%. The loading made the elongation at break and tensile fracture energy of the PLA composite film increase to 26.5 and 11.26 from 3.7% and 0.96 MJ.m −3 , respectively, concerning the neat PLA. Meanwhile, it also resulted in a 4.7% and 12.4% increase in the tensile strength and Young's modulus, respectively. Additionally, the initial decomposition temperature (T 5% ) of the PLA composite increased to 334.9 from 316.1°C after incorporating the CNCs-g-ESO. Therefore, the CNCs-g-ESO, acting as an ESO-like plasticizer and a CNCs-like nucleating agent, is a potential nanofiller for reinforcing and toughening PLA. Highlights Cellulose nanocrystal grafted with epoxidized soybean oil (CNCs-g-ESO) The CNCs-g-ESO acting as both plasticizer and nucleating agent The CNCs-g-ESO decreasing the spherulite size, but increasing the CrI of PLA The CNCs-g-ESO enlarging the window for thermal process of PLA Simultaneous reinforcement and toughness of PLA
研究领域:
材料科学
·
生物材料
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产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2025
·
IF 14.2
Siyu Zhong,Zhongxin Dong,Yanwei Xiao,Yuan Li,LiangLiang Pei,Shengdao Wang,Guibin Wang
In recent years, numerous studies have reported the application of crystalline sizing agents for the interfacial modification of carbon fiber reinforced polyether ether ketone (PEEK/CF) composites. However, the underlying mechanism by which these agents improve the interfacial properties remains unclear. Therefore, the interfacial enhancement mechanism of PEEK/CF composites using crystalline PEEK sizing agents was explored from a microscopic perspective, specifically focusing on interfacial crystallization in this study. Firstly, the crystallization behavior of PEEK on the CF surfaces modified with varying concentrations of crystalline PEEK sizing agents was investigated using polarized optical microscope (POM). It was observed that the sizing agent could induce the formation of PEEK transcrystallinity (TC) on the CF surface, with the 1 wt% concentration of sizing agent resulting in the densest crystal nuclei. The lamellar morphology and molecular orientation of the TC layers were further analyzed. Correspondingly, higher interfacial shear strength (IFSS) was observed in PEEK/CF composites with denser TC structures. Furthermore, the film tensile tests and chemical solvent erosion experiments were conducted to investigate the distribution of weak interfacial phases. It was found that the TC layer did not introduce new “weak interfacial phases” into the composites and exhibited superior resistance to solvent erosion. Finally, the mechanism of action of crystalline PEEK sizing agents was discussed. It was proposed that PEEK molecules from the sizing agent could effectively fill the voids at the interface of the composites which were caused by the low mobility of high-viscosity PEEK resin matrix. This led to an increase in nucleation sites on the CF surface and the formation of a denser TC layer.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）