Curing process, characteristics

A description is given of a comparative study of the glycolysis of PETP waste soft drinks bottles by various mixtures of EG and DEG with subsequent polyesterification of the glycolysed products by maleic anhydride in order to obtain unsaturated polyesters suitable for the production of varnishes. The processing characteristics such as viscosity, exotherm temperatures of curing, compatibility of resins with monomers was investigated with respect to the type and amount of reactive monomers. The mechanical properties of varnishes produced were analysed. 13 refs. 

Unlike TMTD, TBzTD is unique since use of small amount of TBzTD (0.1-0.2 phr) with sulfenamide system does not influence the processing characteristics while improving cure rate and dynamic properties. A comparative data are tabulated in Tables 14.6 through 14.10. Details are reported by Datta et al. [24]. 

A substantial effort in our laboratory has been directed toward the synthesis and characterization of acetylene-terminated (AT) matrix resins. The most significant feature and driving force for the effort is that the thermal induced addition reaction provides a moisture Insensitive cured product. This technology offers a wide variety of thermoset resins for various high temperature applications. Backbone structural design for use temperature capabilities, processing characteristics and mechanical performance has demonstrated the versatility of the AT type systems. 

The curing process of epoxies is mainly dependent on the reactivity characteristics, the structure, and the functional group of resin [61,65], The basic chemical reactions, catalyzed by hydroxyl group (OH), between the epoxide group and the curing agent are [194] ... 

Second, by actually monitoring the state of the material, it is possible to control the fabrication process by data rather than a procedure, such as a set time temperature sequence. This means one can have a self-correcting, automated, intelligent cure process that can adapt to variations in material age, fabric permeability, tool heat transfer characteristics, and the like. 

Aziridine. Propellants cured with MAPO have excellent processing characteristics and satisfactory uniaxial tensile properties over a wide range of temperatures. However, the problems associated with the aging behavior of these propellants have led to the use of other types of curing systems which do not contain the P—N bond. These latter materials are di- and trifunctional aziridines, such as those shown in Table IV, and provide satisfactory propellants in which the uniaxial tensile properties can be tailored to a desired modulus. Such mixed aziridine-cured systems give satisfactory initial properties, reduce the postcure behavior, and improve the storage characteristics of CTPB propellants. 

Dynamic mechanical analysis methods are frequently used to investigate polymerization and curing processes in reactive systems. These methods allow us to obtain both relative and absolute rheological characteristics of a material. Measurements can be made in both the fluid and solid states without affecting the inherent structure of the polymerizing system. 

The characteristic aroma of vanilla is obtained after a curing process of green fruits, which contain many different glucosidic compounds. The curing process is required to hydrolyse the glucosides and to release the aroma compounds. /TGlucosidases are believed to play... 

To conclude, it is worth reiterating that the only orchid used as a spice, the vanilla pod, has been recognized for its culinary and medicinal uses since the time of the Aztecs. Vanilla is the world s third most expensive spice, from which is obtained the popular commercial flavouring agent, vanillin. The characteristic aroma of vanilla is obtained only after a time-consuming and labour-intensive curing process. The main aroma compound in vanilla is vanillin over 100 volatile compounds have been detected, including aromatic carbonyls, aromatic... 

The texture of the adhesive around the edges of the joint can be a clue to the effectiveness of the curing process and whether air was entrapped in the adhesive. The adhesion of the adhesive flash to the substrate can also be qualitatively measured by attempting to pry the flash away from the substrate. Table 19.2 lists the characteristics of faulty joints that can be detected visually, their causes, and possible remedies. 

A series of Vap GC analyses on approximately 50 mg of all the aged resin samples was conducted. Ethanal, propanal, isobutyraldehyde, propenal, butenal, methyl ethyl ketone (MEK), and methyl penetenal were positively identified by mass spectrometry. With the exception of MEK, all compounds identified (the major products) were aldehydes. Methyl ethyl ketone, the solvent used in MY720, remains even after cure. The aldehydes, however, are not impurities in either the MY720 or DOS and represent compounds which are characteristic of the resin alone. These compounds are either produced during the curing process or are formed from the thermal decompositon of a labile compound which is formed during cure. 

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