Commercial Prepregs

To consume all epoxide groups in the TGDDM-DDS epoxy system exclusively by P.A.-E and S.A.-E addition reactions would require 37 wt.-% DDS. However, 

In this Section we report systematic FTIR studies of the cure reactions of TGDDM-DDS epoxies. We report our cure and degradation reaction studies of TGDDM-DDS epoxies from 100 to 300 °C as a function of cure time, and DDS and BF3 NH2C2H5 concentration 9-11,26 27). 

---

In this Sect, we discuss 1H, 19F and nB NMR studies of BF3 NH2C2H5 and BF3 NHC5H10 complexes, with principal emphasis on the former. We present the chemical composition of commercial BF3 amine complexes, their thermal stability in the solid state and in solution, the effect of moisture and heat upon their composition, the nature of their interaction with the epoxide and amine components utilized in TGDDM-DDS commercial prepregs, the composition of BF3 amine complexes in commercial prepregs, their thermal stability in the prepregs, and the chemical structure of the predominant catalytic species of the cure reactions of the prepreg. 

In this Sect, we report systematic DSC studies of (i) the constituents of boron tri-fluoride monoethylamine (BF3 NH2C2H5) catalyzed TGDDM-DDS epoxies and their mixtures (ii) the nature of the catalyzed cure reactions and (iii) the environmental sensitivity of the BF3 NH2CzH5 catalyst. DSC studies are also reported on the cure reaction characteristics and environmental sensitivity of commercial prepregs that contain BF3 amine catalysts. 

Toughness is another important property of the matrix and composite. The toughness of the matrix of the neat resin is not very good and an improvement is desirable. In commercial prepregs the toughness was improved by inclusion of a phase-separated rubber. The rubber is a liquid low-mol-... 

Commercial BMI Resins. Since the late 1960s, bismaleimide resins have been commercially available. The first company in the marketplace was Rhc ne Poulenc Chimie, Erance. Several others, Technochemie, Germany CIBA GEIGY, Switzerland DSM, The Netherlands, BASE, West Germany Mitsubishi Gas Chemicals and MitsuiToatsu, both of Japan Reichhold and Polyorganics from the United States and Shell Chemical Company, United States (through the acquisition of Technochemie by Deutsche Shell AG), followed. Some of them lost interest in this speciaUty market sector. Table 13 indicates the BMI resins available at the end of 1992. No reference is made to prepreg systems available from various sources. A complete Hst of available products and information on any particular material should be obtained from the suppHers. 

The catalyst composition in Fiberite 934 and Hercules 3501 prepregs was investigated by 19F NMR. The epoxy resin in these commercial C-fiber/TGDDM-DDS prepregs was dissolved in DMSO. 

Process Monitoring includes papers where, for the most part, commercial resin or prepreg systems are carried through nominal cure cycles. 

Resin Components Epoxy resins used in this study were fabricated from the same components employed to prepare most of the commercially available graphite-epoxy prepreg resins used in military aircraft, namely Narmco 5208,... 

A current version of the low molecular weight concept is the use of bismaleimides made from aromatic diamines and/or mixtures thereof and maleic anhydride in admixture with other vinyl monomers. Several commercial formulations of this type are now available as the neat resins or as FRP prepregs. There is considerable current research in this area because of the favorable processibility. However, to date, FRP products of this type are outperformed by the PMR-type polyimides by about 50 C at elevated temperatures. 

---