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.

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.

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.

scholarly journals Addition Polyimides from Non-Mutagenic Diamines

2001 ◽  
Vol 13 (4) ◽  
pp. 301-312 ◽  
Author(s):  
Peter Delvigs ◽  
David L Klopotek ◽  
DeNise Hardy-Green
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Carbon Fibre ◽  
Oxidative Stability ◽  
Rheological Properties ◽  
Dimethyl Ester ◽  
Trifluoromethyl Groups ◽  
Monomethyl Ester

Studies were conducted to find an acceptable non-mutagenic diamine to replace 4,4′-methylenedianiline (MDA), a suspect carcinogen, which is currently being used in PMR-15 polyimide applications. Several diamines containing fluorine and trifluoromethyl substituent groups were 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 endcap. The effect of diamine structure on rheological properties, glass transition temperature, and thermo-oxidative stability was investigated. Unidirectional laminates were fabricated from selected resins, using carbon fibre as the reinforcement. The results indicate that some of the diamines containing trifluoromethyl groups are non-mutagenic, and have potential to replace MDA in PMR polyimides for long-term applications at temperatures up to 300 °C.

Processability and mechanical properties of bisbenzoxazine modified by the cardanol-based aromatic diamine benzoxazine

2014 ◽  
Vol 34 (6) ◽  
pp. 561-568 ◽  
Author(s):  
Chengxi Zhang ◽  
Yiyang Zhang ◽  
Qianhao Zhou ◽  
Hong Ling ◽  
Yi Gu
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Glass Transition ◽  
Curing Temperature ◽  
Side Chain ◽  
Aromatic Diamine ◽  
Thermal And Mechanical Properties ◽  
Alkyl Side Chain ◽  
Aromatic Diamines ◽  
Bridging Groups

Abstract To improve the processability and toughness of bisbenzoxazine, a series of cardanol-based aromatic diamine benzoxazine (BZ-Xc) monomers were synthesized from cardanol, formaldehyde aqueous solution and aromatic diamines with different bridging groups such as -CH2-, -O- and -SO2-. The curing behavior, viscosity, thermal and mechanical properties of 4,4′-diaminodiphenylmethane (DDM)-based bisbenzoxazine (BM) and BZ-Xc copolymers were studied systematically. The results demonstrate that the plasticizing effect and flexibility of the alkyl side chain on BZ-Xc significantly reduced the melting viscosity of BM/BZ-Xc blends and improved the toughness of the copolymers. At the same time, the heat-resistant and mechanical properties of the copolymers were retained, because of the bifunctional structure of BZ-Xc. Moreover, the melting viscosity, glass transition temperature and curing temperature of the corresponding copolymers were increased as the result of rigidity and electron-withdrawing effects of the -SO2- bridging group compared to others.

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.

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

2020 ◽  
Author(s):  
Alex Stafford ◽  
Dowon Ahn ◽  
Emily Raulerson ◽  
Kun-You Chung ◽  
Kaihong Sun ◽  
...  
Keyword(s):  
Near Infrared ◽  
Transient Absorption ◽  
Reaction Times ◽  
Infrared Light ◽  
Structure Property ◽  
Light Emitting ◽  
Structure Property Relationships ◽  
Nir Light ◽  
Light Intensities ◽  
Emission Quenching

Driving rapid polymerizations with visible to near-infrared (NIR) light will enable nascent technologies in the emerging fields of bio- and composite-printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. Improving efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of methine- and aza-bridged boron dipyrromethene (BODIPY) derivatives were synthesized and systematically characterized to elucidate key structure-property relationships that facilitate efficient photopolymerization driven by visible to NIR light. For both BODIPY scaffolds, halogenation was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state upon halogenation was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (< 1 mW/cm<sup>2</sup>) and catalyst loadings (< 50 μM), exemplified by reaction completion within 60 seconds of irradiation using green, red, and NIR light-emitting diodes.

A Review on Camptothecin Analogs with Promising Cytotoxic Profile

2019 ◽  
Vol 18 (13) ◽  
pp. 1796-1814 ◽  
Author(s):  
Sk. Abdul Amin ◽  
Nilanjan Adhikari ◽  
Tarun Jha ◽  
Shovanlal Gayen
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Cancer Cell Lines ◽  
Structure Property ◽  
Cytotoxic Potential ◽  
Structure Property Relationships ◽  
Structure Activity ◽  
Camptothecin Analogs ◽  
Pharmacokinetic Properties ◽  
Quantitative Structure Activity Relationships

Camptothecin (CPT), obtained from Camptotheca acuminata (Nyssaceae), is a quinoline type of alkaloid. Apart from various traditional uses, it is mainly used as a potential cytotoxic agent acting against a variety of cancer cell lines. Though searches have been continued for last six decades, still it is a demanding task to design potent and cytotoxic CPTs. Different CPT analogs are synthesized to enhance the cytotoxic potential as well as to increase the pharmacokinetic properties of these analogs. Some of these analogs were proven to be clinically effective in different cancer cell lines. In this article, different CPT analogs have been highlighted extensively to get a detail insight about the structure-property relationships as well as different quantitative structure-activity relationships (QSARs) modeling of these analogs are also discussed. This study may be beneficial for designing newer CPT analogs in future.

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