scholarly journals Preparation and Characterization of Transparent Polyimide Nanocomposite Films with Potential Applications as Spacecraft Antenna Substrates with Low Dielectric Features and Good Sustainability in Atomic-Oxygen Environments

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1886
Author(s):  
Yan Zhang ◽  
Bo-han Wu ◽  
Han-li Wang ◽  
Hao Wu ◽  
Yuan-cheng An ◽  
...  
Keyword(s):  
Atomic Oxygen ◽  
Composite Films ◽  
Dissipation Factor ◽  
Low Earth Orbit ◽  
Nanocomposite Films ◽  
Dielectric Parameters ◽  
Low Dielectric ◽  
Aerospace Applications ◽  
Optically Transparent ◽  
Order Of Magnitude

Optically transparent polyimide (PI) films with good dielectric properties and long-term sustainability in atomic-oxygen (AO) environments have been highly desired as antenna substrates in low earth orbit (LEO) aerospace applications. However, PI substrates with low dielectric constant (low-Dk), low dielectric dissipation factor (low-Df) and high AO resistance have rarely been reported due to the difficulties in achieving both high AO survivability and good dielectric parameters simultaneously. In the present work, an intrinsically low-Dk and low-Df optically transparent PI film matrix, poly[4,4′-(hexafluoroisopropylidene)diphthalic anhydride-co-2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane] (6FPI) was combined with a nanocage trisilanolphenyl polyhedral oligomeric silsesquioxane (TSP-POSS) additive in order to afford novel organic–inorganic nanocomposite films with enhanced AO-resistant properties and reduced dielectric parameters. The derived 6FPI/POSS films exhibited the Dk and Df values as low as 2.52 and 0.006 at the frequency of 1 MHz, respectively. Meanwhile, the composite films showed good AO resistance with the erosion yield as low as 4.0 × 10−25 cm3/atom at the exposure flux of 4.02 × 1020 atom/cm2, which decreased by nearly one order of magnitude compared with the value of 3.0 × 10−24 cm3/atom of the standard PI-ref Kapton® film.

scholarly journals Self-Healing Anti-Atomic-Oxygen Phosphorus-Containing Polyimide Film via Molecular Level Incorporation of Nanocage Trisilanolphenyl POSS: Preparation and Characterization

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1013 ◽  
Author(s):  
Bohan Wu ◽  
Yan Zhang ◽  
Dayong Yang ◽  
Yanbin Yang ◽  
Qiang Yu ◽  
...  
Keyword(s):  
Atomic Oxygen ◽  
Composite Films ◽  
Polymeric Materials ◽  
Polyimide Film ◽  
Low Earth Orbit ◽  
Nanocomposite Films ◽  
Self Healing ◽  
Passivation Layers ◽  
Pyromellitic Anhydride ◽  
Oligomeric Silsesquioxane

Protection of polymeric materials from the atomic oxygen erosion in low-earth orbit spacecrafts has become one of the most important research topics in aerospace science. In the current research, a series of novel organic/inorganic nanocomposite films with excellent atomic oxygen (AO) resistance are prepared from the phosphorous-containing polyimide (FPI) matrix and trisilanolphenyl polyhedral oligomeric silsesquioxane (TSP–POSS) additive. The PI matrix derived from 2,2’-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,5-bis[(4-amino- phenoxy)phenyl]diphenylphosphine oxide (BADPO) itself possesses the self-healing feature in AO environment. Incorporation of TSP–POSS further enhances the AO resistance of the FPI/TSP composite films via a Si–P synergic effect. Meanwhile, the thermal stability of the pristine film is maintained. The FPI-25 composite film with a 25 wt % loading of TSP–POSS in the FPI matrix exhibits an AO erosion yield of 3.1 × 10−26 cm3/atom after an AO attack of 4.0 × 1020 atoms/cm2, which is only 5.8% and 1.0% that of pristine FPI-0 film (6FDA-BADPO) and PI-ref (PMDA-ODA) film derived from 1,2,4,5-pyromellitic anhydride (PMDA) and 4,4’-oxydianline (ODA), respectively. Inert phosphorous and silicon-containing passivation layers are observed at the surface of films during AO exposure.

Enhancing dielectric and mechanical properties of poly(arylene ether nitrile) based composites by introducing low content “core-shell” like structured MXene&PDA@ BaTiO3

2021 ◽  
pp. 095400832110149
Author(s):  
Weixi Zhang ◽  
Yuan Kai ◽  
Jian Lin ◽  
Yumin Huang ◽  
Xiaobo Liu
Keyword(s):  
Dielectric Properties ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Composite Films ◽  
Dielectric Materials ◽  
Nanocomposite Films ◽  
Core Shell ◽  
Low Dielectric ◽  
The Fourier Transform ◽  
High Dielectric

Polyarylene ether nitrile (PEN) based composites combined MXene, Polydopamine (PDA) and barium titanate (BaTiO3, BT) with “core-shell”-like structure were developed successfully in this work, and then incorporating into the PEN matrix to form the PEN/MXene&PDA@BT nanocomposite films through the solution casting method. The novel MXene&PDA@BT nanoparticles were characterized by the Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Then the structure and properties of the obtained PEN/MXene&PDA@BT nanocomposites are studied in detail. The results show that the modification of PDA improved the dispersibility of MXene nanosheets and BT nanoparticles in the PEN matrix, resulting in the enhancement of mechanical and dielectric properties. The research results reveal that when the content of MXene&PDA@BT is 1%, the tensile strength and modulus reached 114.15 MPa and 3015.74 MPa, respectively. Most important, the PEN based nanocomposites exhibit the outstanding frequency in dependent dielectric properties, including high dielectric constant (5.08 at 1 kHz) and low dielectric loss (0.0178 at 1 kHz). These results indicate that the PEN/MXene&PDA@BT composite films are greatly significant for using as the constructing high performance dielectric materials.

scholarly journals Atomic Oxygen-Resistant Polyimide Composite Films Containing Nanocaged Polyhedral Oligomeric Silsesquioxane Components in Matrix and Fillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 141
Author(s):  
Yan Zhang ◽  
Hao Wu ◽  
Yi-dan Guo ◽  
Yan-bin Yang ◽  
Qiang Yu ◽  
...  
Keyword(s):  
High Temperature ◽  
Atomic Oxygen ◽  
Composite Films ◽  
Linear Thermal Expansion ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Low Earth Orbit ◽  
Aromatic Diamine ◽  
Self Healing ◽  
Passivation Layers ◽  
Oligomeric Silsesquioxane

For the development of spacecraft with long-servicing life in low earth orbit (LEO), high-temperature resistant polymer films with long-term atomic oxygen (AO) resistant features are highly desired. The relatively poor AO resistance of standard polyimide (PI) films greatly limited their applications in LEO spacecraft. In this work, we successfully prepared a series of novel AO resistant PI composite films containing nanocaged polyhedral oligomeric silsesquioxane (POSS) components in both the PI matrix and the fillers. The POSS-containing PI matrix film was prepared from a POSS-substituted aromatic diamine, N-[(heptaisobutyl-POSS)propyl]-3,5-diaminobenzamide (DABA-POSS) and a common aromatic diamine, 4,4′-oxydianline (ODA) and the aromatic dianhydride, pyromellitic dianhydride (PMDA) by a two-step thermal imidization procedure. The POSS-containing filler, trisilanolphenyl POSS (TSP-POSS) was added with the fixed proportion of 20 wt% in the final films. Incorporation of TSP-POSS additive apparently improved the thermal stability, but decreased the high-temperature dimensional stable nature of the PI composite films. The 5% weight loss temperature (T5%) of POSS-PI-20 with 20 wt% of DABA-POSS is 564 °C, and its coefficient of linear thermal expansion (CTE) is 81.0 × 10−6/K. The former is 16 °C lower and the latter was 20.0 × 10−6/K higher than those of the POSS-PI-10 film (T5% = 580 °C, CTE = 61.0 × 10−6/K), respectively. POSS components endowed the PI composite films excellent AO resistance and self-healing characteristics in AO environments. POSS-PI-30 exhibits the lowest AO erosion yield (Es) of 1.64 × 10−26 cm3/atom under AO exposure with a flux of 2.51 × 1021 atoms/cm2, which is more than two orders of magnitude lower than the referenced PI (PMDA-ODA) film. Inert silica or silicate passivation layers were detected on the surface of the PI composite films exposed to AO.

scholarly journals The Effect of Low Earth Orbit Atomic Oxygen Exposure on Phenylphosphine Oxide-Containing Polymers

2000 ◽  
Vol 12 (1) ◽  
pp. 43-52 ◽  
Author(s):  
John W Connell
Keyword(s):  
Thin Film ◽  
Atomic Oxygen ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Earth Orbit ◽  
Cooperative Effort ◽  
Flight Experiment ◽  
Oxygen Exposure ◽  
Atomic Oxygen Exposure ◽  
Phenylphosphine Oxide

Thin films of phenylphosphine oxide-containing polymers were exposed to low Earth orbit aboard a space shuttle flight (STS-85) as part of flight experiment designated Evaluation of Space Environment and Effects on Materials (ESEM). This flight experiment was a cooperative effort between the NASA Langley Research Center (LaRC) and the National Space Development Agency of Japan (NASDA). The thin-film samples described herein were part of an atomic oxygen exposure (AOE) experiment and were exposed to primarily atomic oxygen (∼1×1019 atoms cm−2). The thin-film samples consisted of three phosphine oxide-containing polymers (arylene ether, benzimidazole and imide). Based on post-flight analyses using atomic force microscopy, x-ray photo-electron spectroscopy and weight loss data, it was found that the exposure of these materials to atomic oxygen (AO) produces a phosphorus oxide layer on the surface of the samples. Earlier work has shown that this layer provides a barrier towards further attack by AO. Consequently, these materials do not exhibit linear erosion rates which is in contrast with most organic polymers. Qualitatively, the results obtained from these analyses compare favourably with those obtained from samples exposed to AO and/or an oxygen plasma in ground-based exposure experiments. The results of the low Earth orbit AO exposure on these materials will be compared with those of ground-based exposure to AO.

Atomic Oxygen Resistant Polysiloxane Coatings for Low Earth Orbit Space Structures

2015 ◽  
Vol 830-831 ◽  
pp. 699-702 ◽  
Author(s):  
G.N. Arjun ◽  
T.L. Lincy ◽  
T.S. Sajitha ◽  
S. Bhuvaneshwari ◽  
Thomas Deepthi ◽  
...  
Keyword(s):  
Reaction Time ◽  
Surface Morphology ◽  
Mass Loss ◽  
Atomic Oxygen ◽  
Thermo Gravimetric Analysis ◽  
Orbit Space ◽  
Solid Content ◽  
Low Earth Orbit ◽  
Gravimetric Analysis ◽  
Coating Materials

Polysiloxane resin copolymer was synthesized through acid catalyzed hydrolysis of methyl triethoxysilane (MTEOS) and diethoxytetramethyldisiloxane (DEOTMDS). The effect of reaction time on the properties of the polymer was studied and this copolymer was characterized by GPC, 29Si NMR, IR, TGA, viscosity, refractive index, specific gravity and solid content. 29Si NMR and IR showed characteristic signals of Si-O-Si linkage which confirmed the formation of the polymer. GPC and solid content analysis showed an increasing trend in molecular weight with reaction time. Thermo gravimetric analysis showed that the polymer was thermally stable upto ≈ 260°C and all the polymers gave a ceramic residue in the range of 77-80% at 900°C. Siloxane prepared inhouse and methyl phenyl silsequioxane (control) were used as coating materials and atomic oxygen (AO) resistance was evaluated on Al-Kapton, carbon polyimide composite and glass polyimide composite. The mass loss and surface morphology of the coated samples were measured at different time intervals. It is observed that mass loss of polysiloxane coated samples was very less, compared to coated control samples. The morphology of all the samples were studied using FESEM. Erosion kinetics and surface morphology investigation indicate that the polysiloxane coating possesses excellent AO resistance, and displays better cracking resistance on AO exposure.

Facile preparation of optically transparent and hydrophobic cellulose nanofibril composite films

2015 ◽  
Vol 77 ◽  
pp. 13-20 ◽  
Author(s):  
Yan Qing ◽  
Zhiyong Cai ◽  
Yiqiang Wu ◽  
Chunhua Yao ◽  
Qinglin Wu ◽  
...  
Keyword(s):  
Composite Films ◽  
Cellulose Nanofibril ◽  
Optically Transparent ◽  
Facile Preparation

Study on the Influence Factors of ZnFe2O4 and TiO2 Composite Films Photoelectrocatalytic Properties

2011 ◽  
Vol 287-290 ◽  
pp. 2199-2202
Author(s):  
Gui Qin Hou ◽  
Wen Li Zhang ◽  
Shui Jing Gao ◽  
Xiao Yan Wang
Keyword(s):  
Methyl Orange ◽  
Sol Gel ◽  
Composite Films ◽  
Influence Factors ◽  
Nanocomposite Films ◽  
Gel Method ◽  
Sol Gel Method ◽  
Conductive Glass ◽  
Photocatalytic Activities ◽  
Film Layer

The ZnFe2O4 and TiO2 nanocomposite films was prepared by Sol-Gel method on conductive glass, and the influence factors of it’s photoelectrocatalytic performence such as the film layer, pole and voltage was investigated. The results indicated that: the photocatalytic effects of composite films with ZnFe2O4+ TiO2+ ZnFe2O4 was the best. The decomposing ratio of methyl orange with the photoelectrocatalysis of composite films at voltage 0.2-6V all increased unstably.At the same time, the distance from films to pole plank also had the effects on the photocatalytic activities of the films.

Enhanced functional properties of biodegradable Polyvinyl alcohol /carboxymethyl cellulose (PVA/CMC) composite films reinforced with L-alanine surface modified CuO nanorods

2021 ◽  
Author(s):  
Yamanappagouda Amaregouda ◽  
Kantharaju Kamanna ◽  
Tilak Gasti ◽  
Vijay Kumbar
Keyword(s):  
Polyvinyl Alcohol ◽  
Carboxymethyl Cellulose ◽  
Food Packaging ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Soil Burial ◽  
High Antibacterial Activity ◽  
Active Food Packaging ◽  
Surface Modified ◽  
Cuo Nanorods

Abstract Herein, we described novel biogenic preparation of the CuO nanorods and its surface modification with L-alanine amino acid accelerated by microwave irradiation. The effect of surface functionalized CuO nanorods on the polyvinyl alcohol/carboxymethyl cellulose film physico-mechanical properties were investigated through various characterization techniques. The tensile strength was improved from 28.58 ± 0.73 MPa to 43.40 ± 0.93 MPa, UV shielding ability and barrier to the water vapors were highly enhanced when PVA/CMC matrices filled with 8 wt% of CuO-L-alanine. In addition, the prepared films exhibited acceptable overall migration limit and readily undergoes soil burial degradation. Nevertheless, CuO-L-alanine incorporated films showed potent antioxidant activity against DPPH radicals and had high antibacterial activity against Staphylococcus aureus and Escherichia coli, and antifungal activity against Candida albicans and Candida tropicalis. Furthermore, the nanocomposite films showed negligible cytotoxic effect on HEK293 and Caco-2 cell lines. In these contexts, the developed nanocomposite films can be implementing as an active food packaging material.

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