Polymers in solar energy utilizationA laser photoacoustic technique (LPAT) has been verified for performing accelerated life testing of outdoor photooxidation of polymeric materials used in solar energy applications. Samples of the material under test are placed in a chamber with a sensitive microphone, then exposed to chopped laser radiation. The sample absorbs the light and converts it to heat by a nonradiative deexcitation process, thereby reducing pressure fluctuations within the cell. The acoustic signal detected by the microphone is directly proportional to the amount of light absorbed by the specimen. Tests were performed with samples of ethylene/methylacrylate copolymer (EMA) reprecipitated from hot cyclohexane, compressed, and molded into thin (25-50 microns) films. The films were exposed outdoors and sampled by LPAT weekly. The linearity of the light absorbed with respect to the acoustic signal was verified.Correlations were established between the photoacoustic behavior of the materials aged outdoors and the same kinds of samples cooled and heated in a controlled environment reactor. The reactor tests were validated for predicting outdoor exosures up to 55 days.
Document ID
19830066605
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Liang, R. H. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Coulter, D. R. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Dao, C. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Gupta, A. (California Institute of Technology, Jet Propulsion Laboratory, Pasadena A, United States)