Resin cure monitoring

This technique is used principally for the rheological characterisation of polymers (Sections 18.1.3 and 18.1.4) and measurement of dielectric constant (Section 18.2). In the field of thermal and mechanical stability it has also found application in the fields of resin cure kinetics and resin cure monitoring. 

As a representative example of cure monitoring using a common commercially used aerospace resin and a complex cure cycle, Figure 4.6 displays the output of epoxy system. This resin consists of a tetraglycidyl 4,4 -diamino diphenylmethane (TGDDM) and diamino diphenyl sulfone (DDS). This system with catalyst is sold by the Hercules Corporation as 3501-6. 

As an example of cure monitoring in resin film infusion, Figure 4.16 shows the output of oje"(oj) from sensor 1 for the MY720 aromatic TGMDA epoxy system commercially sold as 3501-6 by Hercules. 

Mcllhagger, A., Brown, D., and Hill, B. (2000). The development of a dielectric system for the on-line cure monitoring of the resin transfer moulding process. Composites Part A Appl. Sci. Manuf. 31(12), 1373-1381. 

Zukas, W. X., Schneider, N. S., MacKnight, W. J. Dielectric and dynamic mechanical monitoring of epoxy resin cure, Polym. Prepr., 25 (2), 205 (1984)... 

Allen, J. D. In-process dielectric monitoring of polymeric resin cure, p. 270, Proc. 20th SAMPE Symp., 1975... 

The SkiBlades defect rate was mostly steady, with one exception on day 13. A team of process experts then discovered a correlation between fluctuations in the temperature of the resin curing oven and the defective pulls that broke away from the boots. At the team s recommendation, the temperature controller was replaced with a more modem unit, and the oven temperature was recorded and monitored using a Process Behavior Chart. 

Fluorescence techniques are particularly useful to monitor the change in local viscosity because they are sensitive and can be easily adopted to in-situ, nondestructive monitoring. In a previous paper(1), we described an axcimer-fluorescence technique to monitor the polymerization of methyl methacrylate. We show here an application of the excimer-fluorescence technique to monitor the cure of epoxy resins. In addition, we describe the cure monitoring of epoxy resins with the use of two fluorescent dyes, a dye whose fluorescence intensity increases with local viscosity, and another dye which serves as an internal standard with nearly constant fluorescence intensity. This second technique is similar to the ones used by Loutfy(2,3) and by Levy(4). However, to the best of... 

The effects of cure on the viscosity of thermoset resins are monitored on the catalysed resin and are associated with the late injection, packing and curing cycles of a thermoset process. There are essentially two types of test methods, namely isothermal and non-isothermal tests, which are usually performed in dynamic or steady shear. 

Fabrication of hardware based on the types of resins discussed herein is obviously a chemical process. To control a chemical process the starting raw materials must be precisely defined, and the course of the chemical process must be followed. In the aerospace industry this means the starting resin formulations must be consistent and precisely defined, and the chemical and physical changes that take place as a thermoset resin cures must be monitored and controlled. 

The TMA technique can be used for Tg-value determinations, resin cure studies, penetration experiments or orientation effect determinations. The most important application is thought to be the linear thermal expansion coefficient (l.e.c.) determination of engineering polymers. An example of this application is given in chapter 3.1.2. The results of a polymer shrinkage experiment monitored by TMA are described in chapter 3.1.3. 

In terms of equipment. McDonnell Douglas proposes an automated ultrasonic scanning system (AUSS) with 9 axes of motion, a 7 axes ultrasound system (ADIS-II) and a portable inspection system (MAUS II) for aerospace composite structure inspection [36], The ultrasonic resin analyser (URA 2002A from Quatro Technologies) can be used to measure the resin content in polymer based composites [10]. The UCMS-200 ultrasonic cure monitoring system from Micromet Instruments utilizes measurements of the ultrasonic sound speed to monitor changes in the viscosity, rigidity of composites. 

Applications of FTIR on Epoxy Resins -Identification, Monitoring the Curing Process, Phase Separation and Water Uptake... 

KEENY ET AL. Fluorescent Cure Monitoring of Dental Resins... 

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