JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 30
·e52676
·
IF 3.057
Jie Li,Shufen Zhang,Benzhi Ju
Most of the vitrimers based on transesterification (TE) highly rely on the usage of large amounts of catalysts to promote exchange reactions to obtain re-processability, which brings additional concerns on human health or environmental issues. Herein, we demonstrate that TE vitrimers with soft networks (low T g ), though free of catalysts nor any other special design, can be still dynamic enough to be easily re-processed. In this paper, fully bio-based and catalyst-free thermosets from epoxidized soybean oil (ESO) and bio-dicarboxylic acids (DA) were synthesized and found to possess decent re-processability. By means of compressive remolding (10 MPa, 160°C), the ESO-DA thermosets heal visible defects within 30 min and restore the mechanical strength within 3 h. Upon 3 times of mechanical recycling, the mechanical strengths remain nearly unchanged compared with those of pristine thermosets. Stress relaxation experiments confirm the network rearrangement at high temperatures (≥150°C) as well as vitrimeric flow of the materials. The materials are also capable of being welded without solvents under a small pressure. Lastly, a facile fusion method was employed to tune the mechanical strength of the recycled ESO vitrimers.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Shuren Shao,Xingyuan Lu,Lun Zhang,Jihai Zhang,Aimin Zhang
An ionic conductive elastomer (ICE) is a novel type of ion conductive material that has emerged in recent years. Conventional ionic conductive materials such as hydrogels and solvent gels tend to exhibit poor weathering behavior due to the presence of water or solutions. Ions in ICE are migrated directly into the polymer network without solvents. In this work, a novel ICE based on polyurea (HUBTPU ILx) with a hard segment of hindered urea bonds (HUBs) is prepared. It has a three-dimensional network structure with outstanding mechanical properties. Furthermore, HUBs are introduced in the molecular structure so that the material possesses a certain reprocessing performance. This series of ICEs offer the combination of ideal properties, including the fantastic mechanical properties with the fracture strength of 4.3 MPa, the stretchability up to 1800% and high conductivity, up to 6.61 × 10–3 S/m. The applications of ICEs were demonstrated by creating a sensor that detects the movement of joints and breathing. Furthermore, it was also demonstrated that the reprocessing process had almost no effect on the sensing performance of the prepared sensors.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2022
·
IF 4.966
Xiaowei An,Yi Ding,Ying Xu,Jian Zhu,Chunyang Wei,Xiangqiang Pan
The cross-linked structure of thermosetting carbon fiber composites makes it difficult to degrade and recycle, especially the non-destructive recovery and recycling of high value-added carbon fiber is a major challenge for the sustainable development of carbon fiber composites. The high-efficiency degradation of chemical health and the high performance of materials are mutually restricted and difficult to balance. We report a epoxy resin networks, prepared through ring-opening reaction of epoxy resin with diselenide-labeled diaromatic amine, that can be turned into catalyst-free vitrimer material by exchange of diselenide bonds. When the diselenide bonds are introduced, specific relaxation times and activation energy of the vitrimer have been measured. Based on the dynamic diselenide bonds, this new vitrimer materials can be reprocessed and repaired upon heating via swift metathesis reactions . In addition, the diselenide crosslinks thermoset materials, which have high modulus and high glass transition temperature , exhibit considerable reprocessability, recyclability and reparability. Furthermore, recyclable carbon fiber reinforced composites (CFRC) are prepared using dynamic diselenide covalent network materials as binders.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2021
·
IF 4.089
Shizhen Zhao,Hongkun Yang,Genlai Dong,Dong Wang,Thomas P. Russell
It is of importance, though difficult, to integrate reinforcement, functionalization, and recyclability into elastomeric materials. Here we describe a biomass-derived epoxidized natural rubber (ENR) cross-linked with dynamic covalent bonds and reinforced with functional carboxymethyl chitosan (CMCS). The ENR/CMCS composites show enhanced mechanical properties and thermal stability, due to the uniform dispersion of the CMCS fillers and strong interfacial interaction between the ENR matrix and fillers. These cross-linked rubbers can undergo topological network rearrangements through dynamic exchange reactions, endowing the materials with reprocessability and recyclability. Due to the biologically derived and green features of the both polymeric matrix and filler, the fully biobased ENR/CMCS composites also show excellent biocompatibility, which will expand their application in the field of biomaterials.
研究领域:
材料科学
·
生物技术
·
可持续材料
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 13
·e55172
·
IF 2.7
Guochen Wang,Weiping Xu,Yanxin Zhang,Dong Chen,Yuhong Ma,Changtong Song,Wantai Yang
Dynamic B O bonds are often applied to fabricate reversible-cross-linking and reprocessable polymer networks due to their high thermodynamic stability and kinetic tunability. However, it is still difficult to tailor boronic ester polymers, which have both excellent mechanical and self-healing properties in the absence of external stimuli. To address the above challenge, a range of room-temperature self-healable vitrimers are prepared by the reactions of various poly(vinyl hydroxyalkyl ether- alt -dialkyl maleate) copolymers and 1,4-phenyldiboronic acid. The dynamic cross-linking networks offer the as-prepared vitrimers superior mechanical properties and thermostability. Because of the presence of dynamic boronic ester bonds, the networks also demonstrated self-healing (the tensile strength recovered to 83% after 3 days at room temperature) and reprocessing capabilities (no significant change in tensile strength after thrice process recycles). Moreover, the vitrimers have potential as promising damping materials with wide temperature windows around room temperature. For example, the vitrimer of poly(ethylene glycol monovinyl ether- alt -dibutyl maleate) and 1,4-phenyldiboronic acid demonstrates its tan δ max 1.18, T g = 6.2°C and effective damping temperature range is from −16.4 to 48.5°C.
研究领域:
材料科学
·
高分子化学
·
机械工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）