This article describes and evaluates the basic properties and the damp heat (85%RH, 85℃) aging behaviour of a 400 µm thick titanium dioxide filled polyoxymethylene film for potential use as backsheet in photovoltaic (PV) modules. The polyoxymethylene monolayer was characterized using analytical methods and technological tests. The stabilizer package contained Tinuvin 234, Tinuvin 770 and Irganox 245. The less than 1 wt% pigmentation resulted in 0.680 solar optical reflectance. The slightly anisotropic mechanical properties elastic modulus and strength were within the requirements for backsheets. Damp heat exposure triggered degradation, stabilizer loss and lead to optical properties degrading (yellowing). However, neither premature embrittlement nor a critical loss of ultimate mechanical properties was found after 5005 h of aging. Hence, polyoxymethylene was classified as a potential candidate for backsheet core layers.
OreskiGWallnerGM. Aging mechanisms of polymeric films for PV encapsulation. Sol Energy2005; 79: 612–617.
2.
RoekensHBeyerA. Big opportunity for the plastics industry. Kunststoffe Int2007; 5: 54–57.
3.
GeretschlägerKJWallnerGMFischerJ. Structure and basic properties of photovoltaic module backsheet films. Sol Energy Mater Sol Cells2016; 144: 451–456.
4.
RichardD. EVA and Tedlar still dominate: Market survey on encapsulation materials. Photon Int2010; 8: 236–259.
5.
RichardD. The right chemistry: Market survey on encapsulation materials sees a new trend, with companies moving toward alternatives to Tedlar, while EVA still holds its ground. Photon Int2011; 8: 280–302.
6.
Mikats G. Solar module and coextrudate element. Patent application CA2782097 A1, AUT, 2010.
7.
GeretschlägerKJWallnerGMHintersteinerIet al.Damp heat aging behavior of a polyamide based backsheet for photovoltaic modules. J Sol Energy Eng2016; 138: 041003 (5 pages)–041003 (5 pages).
8.
Institute of Polymeric Materials and Testing (IPMT)/Johannes Kepler University Linz, SolPol – Solar Energy Technologies based on polymeric materials, www.solpol.at (accessed 25 May 2016).
9.
Poliskie M (ed.) Solar module packaging. Boca Raton: CRC Press, 2011.
10.
HintersteinerISternbauerLBeissmannSet al.Determination of stabilisers in polymeric materials used as encapsulants in photovoltaic modules. Polym Test2014; 33: 172–178.
11.
BirdREHulstromRLLewisLJ. Terrestrial solar spectral data sets. Sol Energy1983; 30: 563–573.
12.
WallnerGMPlatzerWLangRW. Structure–property correlations of polymeric films for transparent insulation wall applications. Part 1: Solar optical properties. Sol Energy2005; 79: 583–592.
13.
D-20 Committee, ASTM D 1925 – 70. Standard test method for yellowness index of plastics.
14.
E-12 Committee, ASTM E 313 – 98. Standard practice for calculating yellowness and whiteness indices from instrumentally measured color coordinates.
15.
KangBMoonOHongCet al.Design of advanced color – temperature control system for HDTV applications. Journal of the Korean Physical Society2002; 41: 865–871.
16.
ShevellSK. The science of color, 2nd ed. Amsterdam: Elsevier, 2003.
17.
MüllerM. Mechanische und thermische Eigenschaften, Prüfnormen, Berlin: Beuth, 2004.
18.
BurgioLClarkR. Library of FT-Raman spectra of pigments, minerals, pigment media and varnishes, and supplement to existing library of Raman spectra of pigments with visible excitation. Spectrochim Acta Part A2001; 57: 1491–1521.
19.
TadokoroHKobayashiAKawaguchiYet al.Normal vibrations and Raman spectrum of polyoxymethylene. J Chem Phys1961; 35: 369–369.
20.
SmithEDentG. Modern Raman spectroscopy: A practical approach, Hoboken: Wiley, 2005.
BeerSTeasdaleIBrueggemannO. Immobilization of antioxidants via ADMET polymerization for enhanced long-term stabilization of polyolefins. Eur Polym J2013; 49: 4257–4264.
28.
GunesISPérez-BolívarCJimenezGAet al.Analysis of energy transfer and ternary non-covalent filler/matrix/UV stabilizer interactions in carbon nanofiber and oxidized carbon nanofiber filled poly(methyl methacrylate) composites. Polymer2011; 52: 5355–5361.
29.
BeißmannSStiftingerMGrabmayerKWallnerGNitscheDBuchbergerW. Monitoring the degradation of stabilization systems in polypropylene during accelerated aging tests by liquid chromatography combined with atmospheric pressure chemical ionization mass spectrometry. Polym Degrad Stabil2013; 98: 1655–1661.
30.
BASF. Technical information plastic additives: Irganox 1098 phenolic primary antioxidant for processing and long-term thermal stabilization. 2014916113622366.pdf, http://www.shanghaiguanan.com/pic/2014916113622366.pdf (accessed 25 May 2016).
31.
EhrensteinGWRiedelGTrawielP. Praxis der thermischen Analyse von Kunststoffen, München: Hanser, 1998.
32.
Hässler R and Kunze W. Thermische Eigenschaften polymerer Werkstoffe: DMA – DSC – TGA – TMA – µTA, Stoffsammlung thermoanalytischer Messungen. TA-Instruments, Germany, 2007.
ArchodoulakiVMLüftlSSeidlerS. Thermal degradation behaviour of poly(oxymethylene): 1. degradation and stabilizer consumption. Polym Degrad Stabil2004; 86: 75–83.
35.
Geretschläger KJ. Polymer physical characterization of pigmented and reinforced polymer components for photovoltaic backsheets and solar thermal absorbers. PhD Thesis, University of Linz, Austria, 2015.
