Preparation of supramolecular silicone elastomersviahomo- and hetero-assembly

2018 ◽  
Vol 42 (3) ◽  
pp. 1973-1978 ◽  
Author(s):  
Jinfeng Cao ◽  
Linglong Feng ◽  
Shengyu Feng

Supramolecular silicone elastomers were preparedviaself-assembly and they exhibit ultra-low temperature resistance and tunable mechanical properties.

Soft Matter ◽  
2022 ◽  
Author(s):  
Rui Zhao ◽  
Li Jiang ◽  
Ping Zhang ◽  
Dan Li ◽  
Zhenzhong Guo ◽  
...  

In the recent years, a rapid development of the polymeric hydrogel-based sensors has been witnessed. However, conventional hydrogels often exhibit poor mechanical properties. Additionally, the use of these sensors at...


2014 ◽  
Vol 87 (2) ◽  
pp. 360-369 ◽  
Author(s):  
Junping Zheng ◽  
Jin Tan ◽  
Hong Gao ◽  
Chuanzeng Wang ◽  
Zhilei Dong

ABSTRACT To satisfy some special demands of many applications in the fields of aerospace and the electronic industry, low temperature resistant and high electrical insulation chloroprene rubber (CR) was prepared by blending pristine CR with different weight ratios of butadiene rubber (BR). The low temperature resistance, electrical insulation properties, and mechanical properties of CR/BR blends were investigated. With increasing BR content, the low temperature resistance and electrical insulation properties were improved, whereas the tensile strength and elongation at break decreased. For the CR/BR (65/35) blend, filled with SiO2, the brittleness temperature (Tb) was reduced to −61 °C and the high electrical insulation properties were obtained without sacrificing mechanical properties too much. The tan δ plots of CR/BR blends, investigated by dynamic mechanical analysis, also revealed that BR could reduce glass transition temperature (Tg) and improve low temperature resistance of CR. The phase contrast microscope images of CR/BR blends demonstrated that the phase structure of the blends changed with increasing BR content. Furthermore, the fracture surfaces of CR/BR blends, observed by scanning electron microscopy, showed that the compatibility of CR/BR blends was poor although the CR/BR blends were homogeneous in macrostructure.


2011 ◽  
Vol 393-395 ◽  
pp. 1438-1442 ◽  
Author(s):  
Zu Min Qiu ◽  
Chao Yan Qin ◽  
Jun Ming Qiu

This paper discussed the effect of different blending ratio with BNR and ACM on the mechanical properties, heat resistance, low temperature resistance and oil resistance of coat-metal sealing gasket. The result showed that the comprehensive properties of the NBR/ACM blends at the ratio of 85/15 were preferable to the NBR and ACM, the low temperature resistance and oil resistance of NBR are taken into account. The cost of the blends were lower than the ACM. The blends can be used for coat-metal sealing gasket instead of NBR.


2016 ◽  
Vol 703 ◽  
pp. 165-171 ◽  
Author(s):  
Kwan Ho Seo ◽  
Gi Myeong Nam ◽  
Dong Gug Kang ◽  
Gi Hong Kim ◽  
Do Young Kim ◽  
...  

In this study, mechanical properties, oil resistance of Nitrile Butadiene Rubber (NBR) as material of an automotive were investigated at low temperature conditions. In order to find the optimum formulation used various grades of NBR with different contents of Acrylonitrile (ACN) such as NT1846F, DN407, B7150, B6240 and N215SL. The mechanical properties, oil and low temperature resistance of NBR were measured using moving die rheometer, durometer, universal testing machine, differential scanning calorimetry, and Gehman tester. The hardness was increased with an increased ACN contents. The low temperature resistance, and degree of swelling were increased that decreased ACN contents have lower Tg, lower value of Gehaman test.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.


Author(s):  
Jing Lu ◽  
Jianfeng Gu ◽  
Oudong Hu ◽  
Yunhan Fu ◽  
Dezhan Ye ◽  
...  

The conductive hydrogels have found large application prospects in fabricating flexible multifunctional electronic devices for future-generation wearable human-machine interactions. However, the inferior mechanical strength, low temperature resistance, and non-recyclability induced...


2021 ◽  
Author(s):  
Aiju Meng ◽  
Daxing Wen ◽  
Chunqing Zhang

Spring maize is usually subjected to low-temperature stress during seed germination, which retards seedling growth even if under a suitable temperature. However, the mechanism underlying maize seed germination under low-temperature stress modulating seedling growth after being transferred to normal temperature is still ambiguous. In this study, we used two maize inbred lines with different low-temperature resistance (SM and RM) to investigate the mechanism. The results showed that the SM line had higher lipid peroxidation and lower total antioxidant capacity and germination percentage than the RM line under low-temperature stress, which indicated that the SM line was more vulnerable to low-temperature stress. Further transcriptome analysis revealed that seed germination under low-temperature stress caused down-regulation of photosynthesis related gene ontology (GO) terms in two lines. Moreover, the SM line displayed down-regulation of ribosome and superoxide dismutase (SOD) related genes, whereas genes involved in SOD and vitamin B6 were up-regulated in the RM line. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that photosynthesis and antioxidant metabolism related pathways played important roles in seed germination in response to low-temperature stress, and the photosynthetic system displayed a higher damage degree in the SM line. Both qRT-PCR and physiological characteristics experiments showed similar results with transcriptome data. Taken together, we propose a model for maize seed germination in response to low-temperature stress.


Author(s):  
Zhurinov M.Zh., ◽  
◽  
Teltayev B.B., ◽  
Kalybay A.A., ◽  
Rossi C.O., ◽  
...  

A comparative analysis of the low temperature resistance for a nanocarbon bitumen and other 30 neat and modified bitumens has been performed in the work. The stiffness at the temperatures of -24°С, -30°С and -36°С under technical system Superpave has been accepted as an indicator of low temperature resistance of the bitumens. The stiffness of the bitumens has been determined on a bending beam rheometer (standard ASTM D 6648-08). Before testing the bitumens have been subjected to the double artificial aging: short-term aging – under standard AASHTO Т 240-13 and long-term aging – under standard ASTM D 6521-08. The nanocarbon bitumen has been prepared in the laboratory of the Kazakhstan Highway Research Institute (KazdorNII) with the use of a road bitumen of the grade BND 70/100 produced by the Pavlodar petrochemical plant (PNHZ) and a nanocarbon powder (2% by weight) manufactured from a coal rock of the deposit “Saryadyr” “Corporation “ON-Olzha” LLP, Akmola region, Kazakhstan). The nanocarbon powder (150-200 nm) has been manufactured by three-stage size reduction of the coal rock: I – a mechanical dispergator (up to 2-3 mm), II – an aerodynamic mill (up to 20 mcm), III – a reactor with a rotating electromagnetic field. The neat bitumens of the grades BND 50/70, BND 70/100, BND 100/130 have been produced by the plants of Kazakhstan and Russia; they satisfy the requirements of the standard ST RK 1373-2013. The modified bitumens have been prepared in the laboratory of KazdorNII with the use of the neat bitumens, 7 types of the polymers, crumb rubber and polyphosphoric acid and they satisfy the requirements of the standard ST RK 2534-2014. It has been determined that the nanocarbon bitumen is one of the most resistant at the low temperatures: -24°С, -30°С and -36°С.


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