Synthesis and characterization of copolyimides containing fluorine and silicon surface-modifying agents

2017 ◽  
Vol 30 (3) ◽  
pp. 355-364
Author(s):  
John W Connell ◽  
Christopher J Wohl ◽  
Allison M Crow ◽  
William T Kim ◽  
Michelle H Shanahan ◽  
...  
Keyword(s):  
Laminar Flow ◽  
Surface Area ◽  
Surface Properties ◽  
Silicon Surface ◽  
Fuel Efficiency ◽  
Fine Tuning ◽  
Aromatic Diamine ◽  
Small Scale ◽  
Structure Property ◽  
Structure Property Relationships

Understanding the effects that monomer chemistries have on material properties allows for fine tuning of polymer synthesis for current and future applications. In order to develop polymeric-based coatings that have minimal surface adhesion characteristics when exposed to a variety of contaminants, a more thorough understanding of fundamental structure–property relationships is needed. In the aeronautics field, one concept to improve fuel efficiency of future aircraft is to modify the wing design to enable laminar flow. There is a concern that contaminants such as insect residue and other debris will adhere to airflow surfaces and have sufficient height to disrupt laminar flow thereby increasing drag with concomitant loss of fuel efficiency. One potential solution would be a polymer surface or coating that prevents or minimizes adhesion of such contaminants. As part of a structure–property relationship study involving modification of surface properties, a series of copolyimides containing both fluorine and silicon surface-modifying agents (SMAs) were prepared and characterized. Based on knowledge of structure–property relationships with polyimides containing either type of SMA, it was hypothesized that the combination of two different SMAs may lead to unique surface properties as the two SMAs competed for surface area at the polymer–air interface. Copolyimides for this study were prepared through a multistep synthesis using an aromatic dianhydride with equimolar amounts of diamino functionalities comprised of an aromatic diamine along with two SMAs. Films were cast from copoly(amide acid) solutions that were subsequently thermally imidized under a nitrogen atmosphere. Polyimide films and coatings were characterized using differential scanning calorimetry, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, contact angle goniometry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy to determine chemical, thermal, and surface properties. Select samples were subject to high velocity insect impacts in a small-scale wind tunnel and the resulting residues were characterized for height and surface area and compared to those of a control surface.

Structure–Property Relationships in Addition Polyimides. II. Resins from Three-Ring Aromatic Diamines Containing Carbonyl and Methylene Groups

1997 ◽  
Vol 9 (2) ◽  
pp. 161-176 ◽  
Author(s):  
Peter Delvigs ◽  
David L Klopotek ◽  
Paul J Cavano
Keyword(s):  
Interlaminar Shear Strength ◽  
Aromatic Diamine ◽  
Flexural Properties ◽  
Structure Property ◽  
Aromatic Diamines ◽  
Structure Property Relationships ◽  
Methylene Groups ◽  
Interlaminar Shear ◽  
Bridging Groups

The use of flexibilized three-ring aromatic diamine moieties was investigated in an effort to improve the processing characteristics of addition-type polyimide resins. A series of 10 diamines containing carbonyl and methylene bridging groups was synthesized. The diamines were polymerized with the dimethylester of 3,3′, 4,4′-benzophenonetetracarboxylic acid (BTDE), using the monomethyl ester of nadic acid (NE) as an endcap. The effect of diamine structure on the solubility and rheological properties during cure was determined. The effect of diamine structure and formulated molecular weight on the thermo-oxidative stability and glass transition temperature of the polyimides was also investigated. Unidirectional laminates were fabricated from selected resins, using carbon fibre as the reinforcement. Interlaminar shear strength and flexural properties of the laminates were determined. The results indicate that polyimides from some of the diamines containing methylene bridging groups have potential as matrix resins for long-term applications at temperatures up to 300 °C.

scholarly journals Yellow electrochromic polymer materials with fine tuning electrofluorescences by adjusting steric hindrance of side chains

RSC Advances ◽  
2017 ◽  
Vol 7 (41) ◽  
pp. 25444-25449 ◽  
Author(s):  
Jian Liu ◽  
Yuchen Shi ◽  
Jingchuan Wu ◽  
Mei Li ◽  
Jianming Zheng ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
External Potential ◽  
Polymer Materials ◽  
Fine Tuning ◽  
Side Chains ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Electrochromic Polymer

A series of novel conducting conjugated yellow-to-transmissive electrochromic (EC) polymers were designed to research their structure–property relationships, achieving electrofluorescent (EF) switching with applied external potential.

scholarly journals Structure-Property Relationships of Polyamide 12 Grades Exposed to Rapid Crack Extension

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5899
Author(s):  
Mario Messiha ◽  
Andreas Frank ◽  
Jan Heimink ◽  
Florian Arbeiter ◽  
Gerald Pinter
Keyword(s):  
Water Distribution ◽  
Slow Crack Growth ◽  
Morphological Characteristics ◽  
Crack Arrest ◽  
External Pressure ◽  
Small Scale ◽  
Structure Property ◽  
Polyamide 12 ◽  
Structure Property Relationships ◽  
Axial Crack

Thermoplastic materials have established a reputation for long-term reliability in low-pressure gas and water distribution pipe systems. However, occasional Slow Crack Growth (SCG) and Rapid Crack Propagation (RCP) failures still occur. SCG may initiate only a small leak, but it has the potential to trigger RCP, which is much rarer but more catastrophic and destructive. RCP can create a long, straight or meandering axial crack path at speeds of up to hundreds of meters per second. It is driven by internal (residual) and external (pressure) loads and resisted by molecular and morphological characteristics of the polymer. The safe installation and operation of a pipe throughout its service lifetime therefore requires knowledge of its resistance to RCP, particularly when using new materials. In this context, the RCP resistance of five different polyamide (PA) 12 grades was investigated using the ISO 13477 Small-Scale Steady State (S4) test. Since these grades differed not only in molecular weight but also in their use of additives (impact modifiers and pigments), structure-property relationships could be deduced from S4 test results. A new method is proposed for correlating these results more efficiently to evaluate each grade using the crack arrest lengths from individual S4 test specimens.

Structure-property relationships in addition polyimides. I: Resins from four-ring aromatic diamines containing carbonyl and methylene groups

1994 ◽  
Vol 6 (3) ◽  
pp. 209-223 ◽  
Author(s):  
Peter Delvigs ◽  
David L Klopotek ◽  
Paul J Cavano
Keyword(s):  
Elevated Temperatures ◽  
Dimethyl Ester ◽  
Aromatic Diamine ◽  
Structure Property ◽  
Aromatic Diamines ◽  
Structure Property Relationships ◽  
Methylene Groups ◽  
Bridging Groups ◽  
Monomethyl Ester

In an effort to improve the processing characteristics of addition-type polyimide resins the use of flexibilized four-ring aromatic diamine moieties was investigated. A series of 12 diamines containing carbonyl and methylene, as well as oxo and thio bridging groups, was synthesized. The diamines were polymerized with the dimethyl ester of 3,3',4,4' benzophenonetetracarboxylic acid (BTDE). using the monomethyl ester of nadic acid (NE) as an end-cap. The effect of diamine structure on the solubility and rheological properties during cure was determined. This paper also describes the effect of diamine structure and formulated molecular weight on the glass transition temperature and thermo-oxidative stability at elevated temperatures after various post-cure regimes. The results indicate that polyimides from some of the diamines containing methylene connecting groups have potential as matrix resins for long-term applications at temperatures up to 300 C.

scholarly journals Polypyrrole-Based Metal Nanocomposite Electrode Materials for High-Performance Supercapacitors

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 905
Author(s):  
Ganesh Shimoga ◽  
Ramasubba Palem ◽  
Dong-Soo Choi ◽  
Eun-Jae Shin ◽  
Pattan-Siddappa Ganesh ◽  
...  
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
Electronic Conductivity ◽  
Technical Note ◽  
Fine Tuning ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Metal Organic ◽  
Synthetic Metal ◽  
Supercapacitor Applications

Metallic nanostructures (MNs) and metal-organic frameworks (MOFs) play a pivotal role by articulating their significance in high-performance supercapacitors along with conducting polymers (CPs). The interaction and synergistic pseudocapacitive effect of MNs with CPs have contributed to enhance the specific capacitance and cyclic stability. Among various conjugated heterocyclic CPs, polypyrrole (PPy) (prevalently knows as “synthetic metal”) is exclusively studied because of its excellent physicochemical properties, ease of preparation, flexibility in surface modifications, and unique molecular structure–property relationships. Numerous researchers attempted to improve the low electronic conductivity of MNs and MOFs, by incorporating conducting PPy and/or used decoration strategy. This was succeeded by fine-tuning this objective, which managed to get outstanding supercapacitive performances. This brief technical note epitomizes various PPy-based metallic hybrid materials with different nano-architectures, emphasizing its technical implications in fabricating high-performance electrode material for supercapacitor applications.

Photonic Properties of Dendrons and Dendrimers Incorporating Bis-(Diphenylphosphino)Diphenylpolyenes

1999 ◽  
Vol 598 ◽  
Author(s):  
L. Madrigal ◽  
K. Kuhl ◽  
C. Spangler
Keyword(s):  
Substituent Effects ◽  
Building Blocks ◽  
Optical Nonlinearity ◽  
Fine Tuning ◽  
Structure Property ◽  
Conjugated Molecules ◽  
Structure Property Relationships ◽  
Peak Broadening ◽  
Electro Optic ◽  
Device Applications

ABSTRACTSubstituent effects are quite important in fine tuning the photonic properties of conjugated molecules. In designing new chromophores, electron-donating or withdrawing substituents affect the electron distribution in the conjugation sequence, and previous studies to establish structure- property relationships have noted that when second row elements replace first row elements in the structure (e.g. S for O in donor groups), large enhancements of both the second and third order optical nonlinearity are observed. However, along with the observed enhancement of the nonlinearity, a red-shift in the absorption spectra occurs, often with peak broadening and tailing. This absorptivity-nonlinearity trade-off has been a constant concern in proposing organic materials for electro-optic device applications. In this presentation we will review our recent activity in designing new chromophores wherein P replaces N in donor groups and dendrimer building blocks, and the consequences and opportunities resulting from the observed large blue shifts in the spectra.

Structure-property relationships of PE/PP sandwiched films

1987 ◽  
Vol 45 ◽  
pp. 454-455
Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi
Keyword(s):  
Mechanical Tests ◽  
Polymer Materials ◽  
Ionic Crystals ◽  
Structure Property ◽  
Polymer Systems ◽  
Structure Property Relationships ◽  
Oriented Films ◽  
Materials Used ◽  
Polymer Laminates ◽  
Heated Glass

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.

Approaches for TEM imaging of cavitation in toughened nylon

1989 ◽  
Vol 47 ◽  
pp. 352-353
Author(s):  
Barbara A. Wood
Keyword(s):  
Morphological Characteristics ◽  
Structure Property ◽  
Polymer Systems ◽  
Selective Staining ◽  
Structure Property Relationships ◽  
Rubber Toughened ◽  
Shear Yield ◽  
Controversial Topic ◽  
Selection Of ◽  
Diamond Knife

A controversial topic in the study of structure-property relationships of toughened polymer systems is the internal cavitation of toughener particles resulting from damage on impact or tensile deformation.Detailed observations of the influence of morphological characteristics such as particle size distribution on deformation mechanisms such as shear yield and cavitation could provide valuable guidance for selection of processing conditions, but TEM observation of damaged zones presents some experimental difficulties.Previously published TEM images of impact fractured toughened nylon show holes but contrast between matrix and toughener is lacking; other systems investigated have clearly shown cavitated impact modifier particles. In rubber toughened nylon, the physical characteristics of cavitated material differ from undamaged material to the extent that sectioning of heavily damaged regions by cryoultramicrotomy with a diamond knife results in sections of greater than optimum thickness (Figure 1). The detailed morphology is obscured despite selective staining of the rubber phase using the ruthenium trichloride route to ruthenium tetroxide.

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