Co-curing

Ch1orocarhony1trime11itic acid 1,2-anhydride [1204-28-0] (9), is used in the preparation of esters and amide—imide polymers. TriaHyl trimellitate [2694-54-4] (10) is used as a cross-linking or co-curing agent for ethylene-derived mbbers and plastics. 

Interpenetrating networks have been made by co-curing polychloroprene with copolymers of 1-chloro-1,3-butadiene [627-22-5]. The 1-chloro-1,3-butadiene serves as a cure site monomer, providing a cure site similar to that already in polychloroprene. The butadiene copolymer with 1-chloro-1,3-butadiene (44) and an octyl acrylate copolymer (45) improved the low temperature brittieness of polychloroprene. The acrylate also improved oil resistance and heat resistance. 

Simply bonding a stiffener to a panel with adhesive is certainly a very feasible and natural procedure with typical composite structure construction. We have not discussed any procedure for joining parts except co-curing. Alternatively, to use film adhesive for bonding parts together, we simply cut a sheet or film of adhesive to the proper size, place it between the two parts that we wish to bond together, and then go through a cure cycle that causes the adhesive to adhere to both the stiffener and to the panel itself. We can also mechanically fasten any stiffener we like to a panel. 

Aliphatic aldehydes, 13 571 physical properties of, 2 60t syntheses of, 12 187 Aliphatic a-hydroxy acids, 14 130 Aliphatic amine/polysulfide co-curing agent systems, 10 410... 

Although DCPD resins are very brittle due to their ultra-low molecular weights, they are apparently adequate for these not very demanding applications. Furthermore, on many occasions, it is possible to improve the properties by blending a second much stronger resin into the resin solution and then co-cure the formulation. 

The poor performance with 13 and 14 could be substantially Improved by adding a blocked tetraol, pentaerythrltol diacetonide (pentaerythrltol Itself Is Insolublle In toluene), as a co-curing agent. This option Is discussed In more detail below. 

Composites Both UV and EB cures are employed for the production of wood composite materials and in fiber-reinforced composites for aircraft and aerospace applications. The EB technology has been successful in the manufacture of large structures that exceed the size of autoclaves, and in curing adhesive joints in cases where uniform radiation can be provided more easily than uniform heat. In industrial and consumer applications, multiple combinations of different reinforcing fibers can be co-cured in one cycle by EB with considerably lower residual stresses than those introduced by thermal cure.16... 

Electrolyte 0.3% KC1 aq. solution prepared with twice-distilled water, containing 0.02 M benzotriazole. Polarization Cathodic 5 V for 10 min and 10 min without potential (with air bubbling). Joints were tested after 24 h in boiling water. Adhesive 100 parts diglycidyl ether of bisphenol A (Epon 828 from Shell Chemical Co.) cured with four parts dicyandiamide at 175DC for 2 h. 

The adhesive used in this study consisted of Epon 828 (Shell Chemical Co.) cured with 10 phr (parts per hundred resin by weight) of triethylenetetraamine (TETA) (Fisher Scientific Co.). The resin was degassed in a vacuum oven at 50°C, combined with the curing agent, and then mixed for about I min using a magnetic stirrer. 

Co-Cure Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/ CFS) and Fibromyalgia www.co-cure.org... 

In the previous section it was demonstrated that co-agents enhance the crosslinking efficiency via co-curing of elastomer strands with co-agent domains. Because the use of co-agents alters the crosslink structure, the elastic and mechanical properties of the cured... 

FR 2612195 (French) 1988 Thermally stable polymers from bismaleimides, siloxane diamines and optionally maleimide-termi-nated siloxanes Rhone-Poulenc Chimie, Fr. R Barthelemy, Y Camberlin Heat-resistant maleimide-termi-nated siloxane Thermally stable polymers were prepared by co-curing MDA based bismaleimides and male-imide-terminated siloxanes. Michael addition with amino-terminated siloxanes and MDA was also utilized. 

EMI cured epoxy adhesive formulations are claimed to have outstanding adhesion to metals, and for this reason it is added as a co-curing agent in many compositions. It is an excellent anhydride accelerator providing higher thermal resistance than typical tertiary amine accelerators. 

Several features of this route to grafted PEO polymers are attractive. PEO is not very soluble in silicone, a property that can be exploited to direct reaction to interfaces. The ability to control degree of functionality at one or both ends of the PEO polymer permits independent control of crosslink density and total PEO content. Finally, any residual OH or allyl groups can be used for subsequent functionalization. We describe below strategies to graft in (co-cure) and graft to (post-cure) silicone elastomers with PEO. 

Unlike the post-cure modified samples, these co-cure elastomers were not optically transparent, but rather slightly cloudy and translucent, which is attributed... 

Table 2 Results of elastomers prepared via co-cure methodology...

A similar effect is observed with silicone elastomers prepared with the co-cure method the surfaces are hydrophobic and deficient in PEO, because PDMS and PHMS constituents are directed to the air interface. Interestingly, in this case, however, the silicones partition differently at the surface. ATR-FTIR demonstrated a relative increase in SiH functionality over PDMS when compared to the control. These results can only be explained by preferential migration of SiH polymer to the surface when sequestering PEO in the interior, perhaps as a result of the reduced steric bulk of each monomer unit. The resulting inside out elastomers with a hydrophilic interior and a SiH rich exterior may offer a potential route to asymmetrically structured siloxanes by subsequent reactions with other olefinic groups. 

Co-Cure Synthesis of PDMS-PEO Elastomers with 250, 550, and llOOMW Mono- and Di-Allyl PEO... 

A catalyst combination consisting of the barium salt of tri(ethyleneglycol)ethyl ether, Ba(0CH2CH20CH2CH20CH2CH3)2, with tri-n-octyl aluminum and n-butyl lithium has been used to prepare random poly(styrene-co-butadiene) containing a high butadiene transcontent. These polymers were designed to be co-cured with natural rubber and used as components in automotive tires. 

F. 4. TTT cure diagram temperature of cure vs. time to the isoviscous event, gelation and vitrification, including TBA and gel fraction data , isoviscous (TBA) O, gelation (TBA) A, vitrification (TBA) , gelation (gel fraction). The system studied was a difunctional epoxy resin, Epon 828 (DGEBA, Shell Chemical Co.), cured with a tetrafimctional aliphatic amine, PACM-20. (bis(p-aminocyclohexyl)methane, DuPont]... 

Fig. 7. T, vs. temperature of cure for dinerent times of cure. The solid lines are the best straight line fits to experimental data (symbols) the dashed lines are the extrapolations to T, to obtain the temperature of cure to reach full cure for the given time. The T, line is also included. The system studied was a difunctional epoxy resin, DER331 (DGEBA, Dow Chemical Co.), cured with TMAB (see Fig. 3 caption). (Peng, X., GiUham, J. K., Ref. )...

Fig. 9a and b. TBA spectra for a series of isothermal cures showing changes in (a) the relative rigidity and (b) the logarithmic decrement vs. time. Gelation and vitrification are evident in the 80, 125 and 150 °C scans, but only vitrification is observed in the 200 and 250 °C scans. The system studied was a trifunctional epoxy resin, XD7342 [triglycidyl ether of tris(hydroxyphenyl)-methane, Dow Chemical Co.], cured with a tetrafunctional aromatic amine, DDS (diamin iphenyl sulfone, Aldrich Chemical Co.)... 

BOND PARAMETERS AFFECTING FAILURE OF CO-CURED SINGLE AND DOUBLE LAP JOINTS SUBJECTED TO STATIC AND DYNAMIC TENSILE LOADS... 

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