Synthesis of a self-healing siloxane-based elastomer cross-linked via a furan-modified polyhedral oligomeric silsesquioxane: investigation of a thermally reversible silicon-based cross-link

2017 ◽  
Vol 8 (19) ◽  
pp. 2942-2952 ◽  
Author(s):  
Amin Nasresfahani ◽  
Paul M. Zelisko
Keyword(s):  
Polyhedral Oligomeric Silsesquioxane ◽  
Self Healing ◽  
Cross Link ◽  
Elastomeric Material ◽  
Temperature Controlled ◽  
Silicon Based ◽  
Oligomeric Silsesquioxane

We have successfully prepared an elastomeric material exhibiting excellent temperature-controlled self-healing characteristics.

Properties and Improved Space Survivability of POSS (Polyhedral Oligomeric Silsesquioxane) Polyimides

2004 ◽  
Vol 851 ◽  
Author(s):  
Sandra J. Tomczak ◽  
Darrell Marchant ◽  
Steve Svejda ◽  
Timothy K. Minton ◽  
Amy L. Brunsvold ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Polymer Surface ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Silica Layer ◽  
Self Healing ◽  
Application Process ◽  
Cage Structure ◽  
Erosion Rates ◽  
Nanodispersed Silica ◽  
Oligomeric Silsesquioxane

ABSTRACTKapton polyimide (PI) is widely used on the exterior of spacecraft as a thermal insulator. Atomic oxygen (AO) in lower earth orbit (LEO) causes severe degradation in Kapton resulting in reduced spacecraft lifetimes. One solution is to coat the polymer surface with SiO2 since this coating is known to impart remarkable oxidation resistance. Imperfections in the SiO2 application process and micrometeoroid / debris impact in orbit damage the SiO2 coating, leading to erosion of Kapton.A self passivating, self healing silica layer protecting underlying Kapton upon exposure to AO may result from the nanodispersion of silicon and oxygen within the polymer matrix. Polyhedral oligomeric silsesquioxane (POSS) is composed of an inorganic cage structure with a 2:3 Si:O ratio surrounded by tailorable organic groups and is a possible delivery system for nanodispersed silica. A POSS dianiline was copolymerized with pyromellitic dianhydride and 4, 4′-oxydianiline resulting in POSS Kapton Polyimide. The glass transition temperature (Tg) of 5 to 25 weight % POSS Polyimide was determined to be slightly lower, 5 – 10 %, than that of unmodified polyimides (414 °C). Furthermore the room temperature modulus of polyimide is unaffected by POSS, and the modulus at temperatures greater than the Tg of the polyimide is doubled by the incorporation of 20 wt % POSS.To simulate LEO conditions, POSS PI films underwent exposure to a hyperthermal O-atom beam. Surface analysis of exposed and unexposed films conducted with X-ray photoelectron spectroscopy, atomic force microscopy, and surface profilometry support the formation of a SiO2 self healing passivation layer upon AO exposure. This is exemplified by erosion rates of 10 and 20 weight % POSS PI samples which were 3.7 and 0.98 percent, respectively, of the erosion rate for Kapton H at a fluence of 8.5 × 1020 O atoms cm-2. This data corresponds to an erosion yield for 10 wt % POSS PI of 4.8 % of Kapton H. In a separate exposure, at a fluence of 7.33 × 1020 O atoms cm-2, 25 wt % POSS Polyimide showed the erosion yield of about 1.1 % of that of Kapton H. Also, recently at a lower fluence of 2.03 × 1020 O atoms cm-2, in going from 20 to 25 wt % POSS PI the erosion was decreased by a factor of 2 with an erosion yield too minor to be measured for 25 wt % POSS PI.

Polyhedral Oligomeric Silsesquioxanes (Poss): Silicon Based Monomers and their Use in the Preparation of Hybrid Polyurethanes

1998 ◽  
Vol 519 ◽  
Author(s):  
Joseph J. Schwab ◽  
Joseph D Lichtenhan ◽  
Kevin P. Chaffee ◽  
Patrick T Mather ◽  
Angel Romo-Uribe
Keyword(s):  
Polyhedral Oligomeric Silsesquioxane ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Rheological Data ◽  
Chain Extenders ◽  
Step Growth ◽  
Silicon Based ◽  
Oligomeric Silsesquioxane

AbstractA series of Polyhedral Oligomeric Silsesquioxane (POSS) monomers bearing reactive hydroxyl functionalities, suitable for incorporation into step-growth polymers, is described. These monomers are difunctional in nature and are particularly well suited for use as chain extenders in the synthesis of polyurethanes. This work describes the synthesis of these POSS monomers and their incorporation into a series of polyurethanes. Preliminary thermal, mechanical and rheological data for the POSS containing polyurethanes will also be discussed.

Durable Self-Healing Super-Liquid-Repellent Fabrics

2012 ◽  
Vol 80 ◽  
pp. 152-155 ◽  
Author(s):  
Hong Xia Wang ◽  
Hua Zhou ◽  
Tong Lin
Keyword(s):  
Uv Light ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Self Healing ◽  
Coating Solution ◽  
Wet Chemistry ◽  
Coating Technique ◽  
Oligomeric Silsesquioxane

In this study, fabrics having a superhydrophobic and superoleophobic surface were prepared by a wet-chemistry coating technique using a coating solution containing hydrolyzed fluorinated alkyl silane and fluorinated-alkyl polyhedral oligomeric silsesquioxane. The coating shows remarkable self-healing superhydrophobic and superoleophobic properties and excellent durability against UV light, acid, repeated machine washes, and severe abrasion.

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.

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