POLYMER
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2021
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IF 4.43
Yongri Liang,Tongtong Cui,Li Liu
High dielectric constant and low modulus of thermoplastic polyurethane elastomers (PUEs) are required for various applications in actuators, sensors and energy harvestings. In this work, we controlled the microphase separated morphology of PUEs by regulation of the content of hydroxyl-terminated four-armed polycaprolactone (4amPCL) chain extender to achieve J-shaped stress-strain curve with low modulus and high electromechanical properties. Our results showed that the hydrogen bonding between hard segments (HSs) and crystallization of soft segment (SS) are significantly impeded by long-chain branched structure when added lower molar fraction (<20% of chain extenders) of 4amPCL as chain extender, whereas the branched long-chains are embedded in microphase separated hard and soft domains (HD and SD) to form strip shaped interconnected hard domain (HD) rich regions when added higher molar fraction (>20% of chain extenders) of 4amPCL as chain extender. The PUE with 29% of 4amPCL (PU-4amPCL-0.29) showed lower modulus (1.5 MPa), higher tensile strength (17.5 MPa) at 1048% of elongation, and 3.9% of actuation strain at 20 kV/mm, and higher contribution (48.1%) of Maxwell stress on actuation strain at 20 kV/mm. We found that the microphase separation of branched long-chains induced semi-interpenetration polymer network like structure of PUEs played an important role in exhibiting J-shaped stress-strain behavior. Our results can provide new insight on fabrication of high electromechanical performance of dielectric polyurethane elastomers.
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
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Yize Han,Ping Fan,Junjiong Jiang,Jiaju Huang,Zhongjie Ye,Jintao Yang,Mingqiang Zhong
Replacing traditional plastics with biodegradable materials, such as poly(butylene adipate-co-terephthalate) (PBAT), is a reliable way to avoid farmland environmental pollution. However, the physical and mechanical properties of PBAT still have much to improve. Adding chain extenders to modify PBAT is one of the primary means. So far, the main chain extenders used are epoxy, anhydride, oxazoline, and isocyanate. In this paper, a blocked isocyanate chain extender with biological cyclodextrin as the skeleton material was designed and prepared(B3H35). When it was added to PBAT for melt blending at high temperature, the active isocyanate groups released by its deblocking reaction wound reacted with the terminal hydroxyl groups or carboxylic acid groups of PBAT to extend the molecular chain of PBAT, and then, a three-dimensional network was constructed based on dynamic hydrogen bonding, molecular entanglement, and physical cross-linking. As a result, the strength and toughness of PBAT improved simultaneously. Compared with pure PBAT, the tensile strength, elongation at break, and toughness of PBAT/B3H35 (2 wt %) increased by 17.7, 8.1, and 31.6%, respectively. In addition, 3,5-dimethylpyrazole, used as a blocking agent in this paper, is also released by deblocking during melt blending and endows PBAT/B3H35 with an excellent nitrification inhibition effect in agricultural soil. The experimental results show that the nitrification inhibition rate of the PBAT/B3H35 (3 wt %) reaches 80.64% after 35 days of landfill, significantly improving the utilization rate of the nitrogen fertilizer, thus reducing greenhouse gas emissions and environmental pollution. Overall, this work provides an idea and direction for designing and preparing functional chain extenders with simultaneous enhancement and toughening effects and nitrification inhibition functions for agricultural materials.
研究领域:
材料科学
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农业科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
·
IF 7.7
Yueling Chen,Wenchao Yang,Zikang Hu,Xiaoyan Gao,Jingbiao Ye,Xiangqian Song,Baoshu Chen,Zhengqiu Li
In order to solve the problem of uneven microporous structure of Poly(L-lactic acid) (PLLA) bulk orientation by using biological safety multi-functional plant oil as chain extenders (CE), multi-armed flexible chains were introduced into PLLA through reactive processing to prepare long chain branched PLLA (LCB-PLLA). When the total content of the CE was 6.15 wt%, PLLA and the CE reacted most fully, while maintaining the tensile strength of PLLA and improving toughness. After introducing the LCB structure, the presence of multi-armed flexible chains increased the mobility of the molecular chains, resulting in a significantly lower degree of crystallinity. When the draw ratio up to 900 %, the crystallinity of LCB-PLLA-F-900 % was only 45.15 %, lower than that of PLLA-F-900 %. Thanks to the mobility of polymer chains can be enhanced, which reduces the degree of crystallinity while promoting the uniform growth of oriented microporous structures. Finally, an oriented micro-porous biomimetic LCB-PLLA material with an average cell diameter of 540 nm was prepared, and the results of in vitro cell culture showed that the oriented micro-porous LCB-PLLA biomimetic material was more conducive to cell proliferation.
研究领域:
材料科学
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生物医学工程
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高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Wei Luo,Yang Yang,Yunxuan Weng,Zhigang Huang,Caili Zhang
Moisture exposure during polyester processing can lead to degradation, resulting in the formation of carboxyl and hydroxyl end-groups. To preserve mechanical properties, thorough drying and the use of chain extenders like epoxy acrylates and isocyanates during extrusion are crucial for maintaining or enhancing molecular weight through in-situ reactions. Our study introduced epoxidized cardanol oleate (ECD-OA), containing epoxy and long-chain alkyl groups, as a potential chain extender, and compared its effectiveness with commercially available epoxidized cardanol glycidyl ether (cardolite NC514). Compared to neat PLA without chain extension, the addition of 1 phr ECD-OA resulted in an increase in the molecular weight ( M w ) of PLA from 15.3 × 10 4 g/mol to 17.1 × 10 4 g/mol, demonstrating a chain extension efficiency of 11.8 %. The melt flow rate of PLA decreased from 9.9 g/10 min to 5.0 g/10 min, and the initial thermal degradation temperature of PLA increased by 5.7 °C. Upon chain extension, there was a substantial increase in both the elongation at break and tear resistance of the PLA film. The results demonstrate that ECD-OA can extend PLA molecular chains through chemical reactions and promote entanglement with the long alkane chain, consequently enhancing the mechanical and thermal properties of PLA. Due to the enzyme's preference for biobased small molecules, the PLA film with the addition of a biobased chain extender is more prone to enzymatic degradation compared to neat PLA. To conclude, ECD-OA acts as a bio-based chain extender that improves the performance of PLA while also enhancing its biodegradability.
研究领域:
聚合物科学
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材料科学
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生物降解材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Polymer Materials
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2023
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IF 5
Hao Wu,Yaxin Chen,Weipu Zhu,Yonggang Shangguan,Qiang Zheng
Preparing polyurethane hot-melt adhesives (HMA) with high bonding strength and toughness is still a huge challenge. As an indispensable component in polyurethane synthesis, the chain extender greatly influences the molecular chain structure, microphase structure, and mechanical properties of resultant polyurethane, so it is crucial to design a chain extender with suitable molecular structures. In this work, a bio-based furandicarboxamide diol chain extender was prepared and used to synthesize thermoplastic furandicarboxamide-based polyurethane (PUFD). The furandicarboxamide group acted as a multiple hydrogen-bonding motif that could endow polyurethane with excellent elongation at break and breaking strength. It was noteworthy that the resultant PUFD-HMA exhibited ultrahigh adhesive strength on a variety of substrates, including metals, composites, and plastics. The strong adhesion was ascribed to the formation of multiple noncovalent bonds between the groups on the polyurethane molecular chain and the surface of the substrate. Meanwhile, rebonding was easily achieved by reheating the separated substrate and PUFD-HMA could retain 75% of its original adhesion strength after 5 repeated uses. It is expected that the molecular design strategy of this work may also be applicable to other polyurethane elastomer or adhesive systems.
研究领域:
材料科学
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聚合物化学
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粘接科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
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2023
·
IF 5.6
Yang Zhao,Jinqing Lai,Ya Huang,Hong Jiang,Yongrong Sun,Yuyin Li,Yuan Li,Fayong Li,Zhengtang Luo,Dong Xie
As an environmentally friendly biodegradable material , poly(butylene adipate-co-terephthalate) (PBAT) has been commercialized as a shopping bag, but its high gas permeability weaken its practicability in mulch, cling film and other fields. Two kinds of barrier materials, poly(propylene carbonate) (PPC) and organically modified montmorillonite (OMt), are used to prepare PBAT/PPC/OMt composites, and the mechanical properties are improved by chain extender (Joncryl® ADR 4468). The dispersion and arrangement of nanomaterials in blends are studied with different molding methods and their effects on the gas barrier and mechanical properties are studied as well. Dissipative particle dynamics are used to simulate the rate at which O 2 molecules pass through the modified PBAT films. The results show that 1 wt% of chain extender can increase the tensile stress and tear strength by about 10% and 15%, respectively. The OMt is preferentially distributed in the PBAT matrix and has a more uniform degree of orientation in the blown film, which is beneficial to the improvement of gas barrier properties . Eventually, the mechanical properties and gas permeability of PBAT films can be regulated through the adjustment of processing methods and the synergistic effect of PPC and OMt, providing a new way for high-performance packaging or agricultural mulching film materials.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
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2024
·
IF 4.4
Shuang Liang,Hengkun Zhao,Xiangyuan Li,Yu Feng,Jingbo Zhao
Dimeric acid (DA) is a biobased derivative of plant oil. Its polyamides are usually weak polymers with a low melting point. In this work, an efficient strategy was developed to enhance the thermal and mechanical properties of DA polyamides (DAPAs). Two H2N-terminated DAPA prepolymers (DAPAhs and DAPAddas) were synthesized through melt polycondensation of dimeric acid with hexanediamine and decanediamine (DDA), respectively. Diethyl oxalate was used as a chain extender to increase the molecular weight, and modified DAPAs (DAPAhs-DEO and DAPAddas-DEO) were obtained. Short and easy crystallizable oxamide hard segments effectively improved the mechanical properties, crystallization, and hydrophobicity of the DAPAs. The biobased modified DAPAs exhibited good tensile strength up to 27 MPa, Tm between 105 and 151 °C, and water contact angles from 84 to 98°. Compared to DAPAhs-DEO, DAPAddas-DEO exhibited better comprehensive mechanical properties because longer DDA segments made the oxamide segments far from bulky DA segments and the oxamide segments in adjacent main chains approached easier. Different from brittle 65DAPAh, 65DAPAh-DEO, 65DAPAdda, and 65DAPAdda-DEO showed good peel strength on the aramid fabric. A simple and efficient method was established to prepare biobased DAPAs with excellent properties.
研究领域:
材料科学
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聚合物化学
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生物基材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2024
·
IF 2.7
Zhen Liu,Heng Xu,Zhijie Fan,Xiandie Zhang,Xuxu Cui,Jie Ji,Haozhe Li,Xiaode Guo
Self-healing materials have not been able to solve the problem of the coexistence of mechanical strength and self-healing function. Despite years of research, high-strength self-healing materials still require external factors to accelerate their self-healing process. For this reason, in this study, two kinds of chain extenders were inserted into the hard segment to design the molecular structure of polyurethane. The introduction of two chain extenders not only provided multiple binding modes for hydrogen bond recombination, but also formed more types of hydrogen bonds. Based on the design, a polyurethane elastomer PUGI-D 3 B 2 with high strength and excellent self-healing properties was synthesized. Data such as FTIR and 1 H NMR spectra clearly demonstrate the successful synthesis of PUGI-D 3 B 2 . The mechanical strength of PUGI-D 3 B 2 is 15.34 MPa, and its surface scratches can completely disappear after self-healing at 60°C for 10 h，and 98.02% of the mechanical strength is restored after 12 h of heal. Therefore, combining the excellent self-healing properties of PUGI-D 3 B 2 , we prepared a multifunctional superhydrophobic material (SHN-SiO 2 /PUGI-D 3 B 2 ). It can be used in a wide range of applications such as waterproof coatings, biomedicine and flexible electronics, which provides a new idea for the future direction of multifunctional materials.
研究领域:
材料科学
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高分子化学
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表面科学
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2020
·
IF 4.469
Zhong Liang,Jiantao Zhu,Fuqiang Li,Zhimin Wu,Yuejin Liu,Di Xiong
In this paper, a series of self-crosslinking waterborne polyurethane (WPU) dispersions with side chain, which is (3-(2-Aminoethyl)aminopropyl)trimethoxysilane (AEAPTMS) as the diamine chain extender, were prepared. The characteristics of WPU with different dosages of AEAPTMS were evaluated, including particle size, crystallinity, surface performance, water resistance and thermal stability. It was demonstrated that AEAPTMS was successfully incorporated into the WPU from Fourier-transform infrared spectroscopy (FT-IR). Once the content of AEAPTMS increased to 5 %, the WPU dispersions became gelatinous. That is, the siloxane groups were hydrolyzed into a cross-linked structure during the emulsification process. The particle size enlarged with the increasing dosage of AEAPTMS in transmission electron microscopy (TEM). The X-ray photoelectron spectroscopy showed that the silane in the cross-linked WPU migrated freely towards the WPU film surface. The addition of AEAPTMS enhanced the tensile strength, hydrophobicity, water resistance and thermal stability of WPU film. Meanwhile, the elongation at break and crystallinity of WPU films were declined. Besides, interestingly, the glass transition temperature of WPU films followed the trend of first rising and then falling. By adding wetting agent, antifoaming agent, adhesion promoter and flatting agent into WPU, the water-based varnish was prepared. The pencil hardness, water resistance, adhesion and anti-adhesion of water-based varnish were best in the application on the stainless steel substrate when the WPU sample was Si-WPU-3.
研究领域:
高分子科学
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材料科学
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表面化学
·
涂料技术
✓ 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）