High temperature resins

At a holdup time longer than 10—15 min at a high temperature, resin degradation is avoided by keeping the rear of the cylinder at a lower temperature than the front. At short holdup times (4—5 min), cylinder temperatures are the same in rear and front. If melt fracture occurs, the injection rate is reduced pressures are in the range of 20.6—55.1 MPa (3000—8000 psi). Low backpressure and screw rotation rates should be used. 

Because of this continued emphasis on adhesive bonding technology development over the years, the airframes of modem front-line aircraft such as the B-2 bomber and the F-117 and F-22 fighters are largely structurally bonded advanced composites. They tend to be comprised of materials that are more advanced (expensive) than commercial aircraft such as carbon and boron fiber reinforcements with cyanate esters, bismaleimides, polyimides or other high-temperature resin matrices and adhesives. 

Sulfur cross-links have limited stability at elevated temperatures and can rearrange to form new cross-links. These results in poor permanent set and creep for vulcanizates when exposed for long periods of time at high temperatures. Resin cure systems provide C-C cross-links and heat stability. Alkyl phenol-formaldehyde derivatives are usually employed for tire bladder application. Typical vulcanization system is shown in Table 14.24. The properties are summarized in Tables 14.25 and 14.26. 

The thermal polymerization of reactive polyimide oligomers is a critical part of a number of currently important polymers. Both the system in which we are interested, PMR-15, and others like it (LARC-13, HR-600), are useful high temperature resins. They also share the feature that, while the basic structure and chemistry of their imide portions is well defined, the mode of reaction and ultimately the structures that result from their thermally activated end-groups is not clear. Since an understanding of this thermal cure would be an important step towards the improvement of both the cure process and the properties of such systems, we have approached our study of PMR-15 with a focus only on this higher temperature thermal curing process. To this end, we have used small molecule model compounds with pre-formed imide moieties and have concentrated on the chemistry of the norbornenyl end-cap (1). 

Characterization of Bisbenzocyclobutene High-Temperature Resin and Bisbenzocyclobutene Blended with a Compatible Bismaleunide Resin... 

DENNY ETAL. Bisbenzoeyelobutene High-Temperature Resin... 

Uses. Solvent for high-temperature resins petrochemical processing, in the microelectronics fabrication industry, dyes and pigments, industrial and domestic cleaning compounds agricultural and pharmaceutical formulations... 

The maximum use temperature is of course important in connection with high-temperature resin systems. 

The high-temperature resins described above provide the main elements in the adhesive formulator s recipe. However, there are also additives, fillers, etc., that can further enhance the thermal properties of more conventional epoxy adhesives. These additional components improve thermal resistance by providing oxidation resistance, toughening, and control of bond line stress. 

The only high-temperature resin family that retains a moderate amount of flexibility is the polysiloxanes. A significant amount of research has been devoted to trying to marry the properties of siloxanes with epoxy resins to obtain less brittle, high-temperature adhesives. However, these efforts have yet to result in commercial adhesives systems. 

Use As a construction material in laminate form impregnated and bonded with high-temperature resins. 

NASA-Langley provided a further improvement in processibility by replacing the methylenedianiline with a commercial aromatic diamine mixture that afforded even better handling characteristics (17). This type of product is formed by the reaction of formaldehyde with aniline as a precursor in isocyanate manufacture. Fluorine-containing thermoplastic polyimides and polyimides end capped with acetylene groups for cross-linking are also available as potential commercial high-temperature resins. 

Victrex . [IQ Advanced Materials IQ PLQ PEEK or PEK resins high temperature resins. 

A potential for injection molding of the reaction-induced phase separation system is also used in PPE/triallyl isocyanurate system to obtain high-temperature resin with excellent flexural strength and high chemical resistance [Fujiwara et al., 1996]. 

MAJOR APPLICATIONS Interlayer dielectrics, high-temperature resins. 

Polyamideimide, High-temperature resins, plastics, and man-made fibres belonging to the group of polyimides. 

A high-temperature resin and plastic belonging to the group of... 

Kershaw, D., Still, R. H. and Bashford, V. G. Thermal degradation of polymers. VII. Ablation studies on a series of composite specimens containing asbestos fiber with various high-temperature resin binders. J. Appl. Polym. Sci., 19, 959 (1975)... 

Although polyimides are the largest class of high temperature resin systems, other resins have been developed that are used for specialist applications or, alternatively, were never developed commercially, perhaps due to cost considerations. 

Serafini TT, High temperature resins, G Lubin ed.. Handbook of Composites, Van Nostrand Reinhold Co., New York. 

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