COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2025
·
IF 8.9
Fengdong Teng,Na Li,Ying Yuan,Junrong Yu,Yan Wang,Zuming Hu
The complex preparation process and high shrinkage of poly(p-phenylene terephthalamide) (PPTA) aerogel limit its wider application. Herein, PPTA and heterocyclic aramid (HPPTA) prepolymer were secondary polymerized to obtain Block-PPTA (BPPTA) with both rigid and flexible segments in the molecular chain. The rigid and flexible segments in molecular chain under non-solvent enable the rapid transformation of BPPTA solutions into well-shaped BPPTA gels. The BPPTA aerogel exhibits the advantages of low shrinkage, high thermal insulation, and high mechanical strength. Then, a small amount of MXene and AgNWs were attached to the surface of BPPTA aerogels by layer-by-layer spraying method, which not only enhanced the flame retardancy capability of the aerogels, but also made organic aerogels possible to be applied in the fields of electromagnetic interference shielding and thermoelectric conversion. This work provides an ideal strategy for the efficient preparation of low shrinkage para aramid aerogels and expands the application areas of aerogels.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Hangzhou Wang,Xiaobin Li,Jun Shi,Xiaoyan Xiong,Chenguang Kong,Cunzhi Li,Youcheng Huang,Shumin Jiang,Kun Wu,Li Yang
The shrinkage of UV-curable polymers is directly related to the structural changes in the monomer behavior of the system. The issue of shrinkage in these systems can be mitigated by leveraging the dynamic behavior of disulfide bonds. However, it remains unclear how light induction affects the contraction of the system through processes such as bond cleavage, migration, and recombination of disulfide bonds. In this study, we modified the polyurethane core of a UV-curable system by incorporating three different topologies of disulfide bonds. We examined the impact of these different arrangements and their dynamic adjustment on reducing shrinkage using scanning electron microscopy, shrinkage rate tests, and theoretical analysis based on the Gauss-type radial distribution probability density function. Our findings show that the modified sample exhibited lower curing shrinkage and a smoother surface compared to unmodified polyurethane. Specifically, while the shrinkage rate before modification (PU) was 5.16%, after modification (DSBT-PU, DSBP-PU, DSBE-PU) it decreased to 1.24% for DSBT-PU, 0.67% for DSBP-PU, and 0.95% for DSBE-PU. We also observed that longer chain lengths in disulfide-containing fragments aided in dynamically adjusting the system structure. However, the increase in the molecular fragment length makes it more difficult to migrate dynamic disulfide bonds. Furthermore, our synthetic sample demonstrated high transmittance levels, exceeding 98%. Additionally, we conducted comprehensive examinations including testing 180° peel strength, differential scanning calorimetry, thermogravimetric analysis, tensile characteristics, and transmittance properties, among others. This work not only sheds light on how dynamic bonds influence system structure but also holds practical implications for applications in liquid optical clear adhesive (LOCA) and unique pressure-sensitive adhesives.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yu Chen,Baolu Shi,Runze Jin,Xinqiao Wang,Donghui Guo,Zhiliang Zhou,Baosheng Xu,Ning Zhou
Polyimide aerogels (PIAs) have garnered considerable attention for thermal protection owing to their outstanding high-temperature resistance, wide operational-temperature range, and flexibility. However, their flexibility improvement, drying-shrinkage reduction, and thermal-insulation and mechanical-property enhancements still remain research hotspots. Herein, flexible copolymer PIAs were synthesized via copolymerization modification–chemical imidization, which exhibited outstanding mechanical properties, ultralow dry shrinkage, and highly efficient thermal insulation. By taking full advantage of the comonomer 3,3′,4,4′-biphenyltetracarboxylic dianhydride has a rotatable single bond and increases a high free volume of the involved chain, the PIAs achieves a notable transition from brittleness to high flexibility. Results demonstrate that the 5 %-weight-loss temperature of the PIAs is up to 512.6 °C in air and that their thermal conductivity is as low as 15.1 mW·m −1 K −1 . Concurrently, the interactions among the involved nanochain segments contribute to the formation of a three-dimensional network structure with high nodal connectivity and robust crosslinking, enhancing the PIA mechanical strength, with the tensile strength and modulus being 17.633 and 468.41 MPa, respectively. Further, the synthesized PIAs exhibit a low density of 0.079 g/cm 3 and low drying shrinkage of 4.323 %. Overall, this research introduces a novel method for developing flexible, low-shrinkage polymer materials with excellent thermal insulation and mechanical properties, exhibiting vast potential for application in aerospace exploration efforts.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
OPTICS EXPRESS
·
2023
·Vol. 31
·期 22
·36037-36047
·
IF 3.8
Dexing Zhu,Jian Zhang,Qiao Xu,Yaguo Li
Three-dimensional printing enables the fabrication of silica glass optics with complex structures. However, shrinkage remains a significant obstacle to high-precision 3D printing of glass optics. Here we 3D-printed Dammann gratings (DGs) with low lateral shrinkage (<4%) using a two-photon polymerization (2PP) technique. The process consists of two steps: patterning two-photon polymerizable glass slurry with a 515 nm femtosecond laser to form desired structures and debinding/sintering the structures into transparent and dense silica glass. The sintered structures exhibited distinct shrinkage rates in the lateral against longitudinal directions. As the aspect ratio of the structures increased, the lateral shrinkage decreased, while the longitudinal shrinkage increased. Specifically, the structure with an aspect ratio of approximately 60 achieved a minimal lateral shrinkage of 1.1%, the corresponding longitudinal shrinkage was 61.7%. The printed DGs with a surface roughness below 20 nm demonstrated good beam-shaping performance. The presented technique opens up possibilities for rapid prototyping of silica diffractive optical elements.
研究领域:
光学
·
材料科学
·
制造技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Additive Manufacturing
·
2022
·
IF 11.632
Weizhe Tang,Tong Zhao,Rui Dou,Li Wang
Vat photopolymerization (VPP) technology has shown great application potential in the manufacture of high-precision complex silicon carbide (SiC) based ceramic components. However, in comparison with the conventional fabrication technologies, the SiC ceramics produced by VPP technology have insufficient strengths or relatively larger shrinkage rates to meet the requirements of practical applications. Herein, we develop a novel bimodal SiC material recipe for VPP technology and prepare Si/SiC composites by the consequent liquid silicon infiltration (LSI) method. The addition of fine SiC particles improves the material’s mechanical properties significantly. The final products possess low shrinkage rates (3.52 ± 0.26% in the x-direction, 3.73 ± 0.39% in the y-direction, and 4.69 ± 0.35% in the z-direction) as well as high flexural strength (363.23 ± 14.21 MPa) and low open porosity of 0.097%. The material compositions and fabrication strategies proposed in this work demonstrate an efficient way for the additive manufacturing of high-precision complex Si/SiC ceramic parts (e.g. lightweight space mirrors and structural ceramic parts).
研究领域:
材料科学
·
先进制造
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2023
·
IF 3
Yujie Yang,Xin Xu,Zhiqiang Li,Xinle Yao,Dongqing Kang,Yaozhong Lu,Yanbin Wang,Yuxiong Guo,Xiaolong Wang
Conventional benzoxazine is difficult for molding and manufacturing parts with complex structures, shaped thin walls, etc. In this work, we presented a new method of synthesizing vat photopolymerization 3D printable benzoxazine inks were proposed to produce high precision constructions with low shrinkage. A creative benzoxazine monomer with excellent printability was synthesized by 2,2′-bis(trif luoromethyl)-4,4′-diaminobiphenyl (TFDB) and Bisphenol AF grafting with isocyanoethyl methacrylate (IEM). Specially, the solvent-free benzoxazine inks have ultra-low shrinkage, line shrinkage up to 1.8%. Minimum printable feature size of 300 µm. This study has solved the problem of benzoxazine being too brittle to be machining. It can be used in aerospace and copper laminate applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Jing Zhang,Hongli Zhang,Tinghui Yan,Ye Fang,Yuzhong Huang,Jijun Tang,Mingyang He
Low shrinkage, open-cell structure, and mechanically-strong polymethylacrylimide (PMI) aerogels were synthesized using a freezing-drying process. Specifically, methacrylonitrile (MAN) and methacrylic acid (MAA) were used as the comonomers to synthesis the copolymer . PMI aerogels after heat treatment presented the lowest shrinkage of 10.5%. The fabricated aerogels exhibited a network-like structure with the minimum measured porosity of 89%. Increasing the copolymer solid contents resulted in a better compression property. The maximum stress of the PMI aerogels at 50% strain can reach 0.256 MPa. The fabricated aerogels presented low thermal conductivity and density, as low as 43 mW/mK and 0.050 g/cm 3 , respectively.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Bioresources and Bioproducts
·
2020
·
IF 0
Yun Hu,Puyou Jia,Qianqian Shang,Meng Zhang,Guodong Feng,Chengguo Liu,Yonghong Zhou
A novel phosphorous-containing acrylated epoxidized soybean oil-based (P-AESO) resin was developed via the ring-opening reaction of epoxidized soybean oil (ESO) with diphenylphosphinic chloride (DPPC), followed by acrylation of the resulting groups. The chemical structure was characterized by Fourier transform infrared spectroscopy (FT-IR), and 1 H nuclear magnetic resonance ( 1 H NMR). Subsequently, the viscosity and volumetric shrinkage of the obtained P-AESO resins were studied. Then the oligomer was formulated into UV-curable coatings, and the mechanical, thermal, and coating properties of the resulting UV-cured bioresins were studied by tensile testing, dynamic mechanical thermal analysis (DMA), thermogravimetric analysis (TGA) coupled with FT-IR spectroscopy (TGA-FT-IR), hardness, adhesion, pencil hardness and chemical resistance. Furthermore, the UV-curing behavior of the P-AESO resin was determined by real-time realtime infrared (RT-IR). Meanwhile, compared with coating from acrylated epoxidized soybean oil (AESO), the P-AESO system coatings showed better volumetric shrinkage, excellent adhesion, and enhanced thermal and glass transition temperature ( T g ) while maintaining reasonably final C = C conversions and cross-link density. For instance, the obtained P-AESO/trimethylolpropanetriacrylate (TMPTA) 20 material possessed a volumetric shrinkage of 4.1%, T g of 115.6°C, char yield of 9.47%, and final C = C conversions of 81.4% respectively, which exhibited superior values than that of the AESO/TMPTA20 material. The improvement of the P-AESO coating performances could contribute to the architectures that combined the structural features of phosphorous-containing rigid benzene. The developed P-AESO resin is promising for applications in the UV-curable coatings.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yanyan Deng,Luke Ma,Xueliang Pei,Qing Huang,Zhengren Huang
Additive manufacturing technology is being developed for manufacturing SiC ceramic parts with designed shape and microstructure. In this study, direct ink writing (DIW) was adopted to print SiC ceramic parts. To avoid incorporating volatile organic solvents or water, a SiC ceramic precursor liquid polycarbosilane (LPCS) was used as the binder of SiC powder and the rheological adjustment additive. The content of LPCS with the content and diameter of SiC powder were optimized to improve the fluidity of slurry, increase its ceramic yield and reduce its shrinkage during pyrolysis. According to the results of rheological analysis and shrinkage during pyrolysis, 78 wt% SiC powders composed of 40 nm SiC powder and 5 μm SiC powder in a ratio of 1:6 was appropriate. For achieving rapid solidification rate of the slurry at low temperature, a free‐radical initiator which can trigger the crosslinking of allyl group on LPCS was incorporated. According to the results of rheology, DSC and FT-IR, the preferred platform temperature for fast curing of DIW slurry was 150 °C. As the slurry accumulated layer by layer on heating platform, the cured green bodies were successfully prepared. After pyrolysis to 1200 °C, SiC ceramic parts were obtained with only 4.43 % linear shrinkage associated with the precursor-to-ceramic conversion. Because the shrinkage was limited, no obvious deformation or crack was found.
研究领域:
材料科学
·
陶瓷制造
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 32
·e55759
·
IF 2.7
Sizhao Zhang,Chun Liu,Zhao Wang,Jing Wang,Guangyu Xu,Hongwei Shi
Polyimide (PI) aerogels possess a rather potential in thermal protection material for aircraft, owing to their low thermal conductivity, high thermal stability, and low bulk density. However, the large shrinkage of pure PI aerogels is still a challenge in the complete preparation process. Herein, a kind of PI hybrid aerogel composite was prepared successfully by introducing polyurethane fiber as the reinforcing agent. The aerogel composite could realize the enhancement for the pure PI aerogels from a micro/macroscopic perspective, ultimately ensuring the ultralow shrinkage rate of 3.52%. Due to the inhibition of the shrinkage characteristic, the aerogel composite obtained achieved excellent thermal insulation, especially retaining a low temperature of 40.7°C despite the hot surface temperature reached up to 150°C. Besides, the lightweight low-density, exceptional flame resistance, and self-extinguishing properties were reflected from PI hybrid aerogel composite constructed, including the outstanding hydrophobic feature (water contact angle of 120°). The PI hybrid aerogel composite as prepared may be used for the thermal management of aircraft in a great measure, illustrating the feasible strategy of fabricating PI-based aerogel composites.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yuejia Li,Fenghua Zhang,Yanju Liu,Jinsong Leng
In recent years, the field of shape memory materials with active deformation capabilities has experienced rapid development. However, bismaleimide, as a widely used structural material in the aerospace industry, has been neglected in the field of shape memory. This work designed a UV-crosslinked network with 1-vinyl-2-pyrrolidone monomer, and prepared 4D printed smart structures based on shape memory bismaleimide resin through UV-assisted DIW printing. 4D printed semi-interpenetrating network polymer materials were obtained through a two-stage UV-thermal curing process, resulted in an increase in the material's glass transition temperature to a maximum of 187.4 °C. The storage modulus was improved to 5229 MPa. More important, we achieved a lowest shrinkage rate (0.21 %) of 4D printed polymer. The composite sandwich structure with electrical-driven shape memory performance was printed by double-sided printing of bismaleimide resin on conductive carbon fabric. 4D printed composite structure realizes in-situ self-blocking secondary curing, deformation process after curing. This significant progress provides a promising prospect for remote controllable and precise driving in the aerospace field.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Xin Xu,Junyi Zhang,Pan Jiang,Desheng Liu,Xin Jia,Xiaolong Wang,Feng Zhou
Three-dimensional (3D) printing of ceramics has attracted increasing attention in various fields. However, the pyrolysis of organic components used for binding or polymerization in 3D printing commonly causes a large shrinkage (up to 30 %–40 %), high porosity, and cracking or deformation, severely limiting practical applications. In this study, 3D printing of Al 2 O 3 ceramic architectures with ultra-low shrinkage is realized by introducing inorganic binder aluminum dihydrogen phosphate (Al(H 2 PO 4 ) 3 , AP) as a ceramic precursor. Compared to organic binders, the inorganic AP binder can undergo crystallization conversion, which reduces mass loss during sintering at high temperatures, resulting in low shrinkage. Moreover, AP can be used as a rheological modifier to regulate the printability of the ceramic ink for direct ink writing of Al 2 O 3 ceramic architectures, such as wood-piled scaffolds, honeycomb structures , and tubes with high fidelity. The resultant Al 2 O 3 structural ceramics sintered at 1250 °C exhibit good mechanical performance and structural integrity. Most importantly, the linear shrinkage of the printed ceramics is less than 5 %, which is several times lower than that of ceramics with organic binders. This study provides a viable strategy for fabricating high-performance ceramic architectures with good dimensional fidelity for practical applications.
研究领域:
材料科学
·
先进制造
✓ 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）